Methods for binding, delivery, reaction activation, conversion, storage and release of water-soluble gases

Abstract

The present invention relates to a method for selective binding, selective membrane transport and storage of carbon dioxide (CO2) in an aqueous medium. The method of the present invention comprises providing an aqueous receptor solution containing at least one receptor compound having a free guanidinium and / or amidinium group, contacting it with a gas containing carbon dioxide to bind the carbon dioxide in the receptor solution. The receptor solution thus obtained containing bound carbon dioxide can be used for storage of carbon dioxide in an aqueous medium, for release of carbon dioxide again, and for electrochemical processes, such as electrodialysis, for selective transport of bound carbon dioxide through a separation membrane into an aqueous medium. The present invention also relates to the preparation of carbonates starting from a receptor solution containing bound carbon dioxide.

Description

Invention Field

[0001] This invention relates to a method for selectively binding, selectively transporting, and storing carbon dioxide (CO2) in an aqueous medium. The method comprises providing an aqueous acceptor solution containing at least one acceptor compound having a free guanidine group and / or an amidine group, contacting the solution with a carbon dioxide-containing gas to bind carbon dioxide in the acceptor solution. The resulting acceptor solution containing bound carbon dioxide can be used to store carbon dioxide in an aqueous medium, for the re-release of carbon dioxide, and for use in electrochemical methods such as electrodialysis to selectively transport the bound carbon dioxide through a separation membrane into an aqueous medium. This invention also relates to the preparation of carbonates and bicarbonates from acceptor solutions containing bound carbon dioxide. Existing technology

[0002] Gaseous elements, element molecules, or gaseous molecular compounds are often popular raw materials for chemical synthesis. Therefore, attempting to obtain these elements, element molecules, or compounds in their pure form typically requires significant technological costs or energy input. In the prior art, methods for separating and recovering industrial gases using separation membranes are known. In the case of air mixtures, there are usually very low concentrations of the gaseous elements, element molecules, or gaseous molecular compounds to be separated. Especially if the elements, element molecules, or gaseous molecular compounds involved are only slightly different from each other in their physicochemical properties, the separation efficiency is usually not within the desired range.

[0003] Where gaseous elements, element molecules, or gaseous molecular compounds can be absorbed in a liquid, gaseous elements, element molecules, or gaseous molecular compounds that cannot be absorbed / dissolved in the liquid or are only absorbed / dissolved in the liquid to a very small extent can be separated. This is especially true if the gaseous elements, element molecules, or gaseous molecular compounds cause the dissociation of water molecules in an aqueous medium, forming water-soluble compounds of the gaseous elements, element molecules, or gaseous compounds, such as acidic forms. This is the case, for example, with gaseous compounds of carbon and oxygen or sulfur and oxygen, such as carbon dioxide (CO2) or sulfur dioxide (SO2), where, for example, low concentrations of carbonic acid or sulfuric acid are formed in an aqueous medium. These gaseous molecular compounds, such as carbon dioxide (CO2) or sulfur dioxide (SO2), cause the dissociation of water molecules in an aqueous medium and form water-soluble acidic forms, which are also referred to as acidic gases in the prior art. Ions or ionizable compounds, such as salts, can be separated from or separated from the liquid. For separation from aqueous media, methods such as electrodialysis using suitable membranes are known in the prior art. Electrodialysis is a method for separating ions from salt solutions. Desalination, separation, and concentration of salts, acids, and bases are possible applications of electrodialysis. The necessary ion separation is achieved through electric fields applied via the anode and cathode, and via ion-exchange membranes or semi-permeable, ion-selective membranes. Therefore, electrodialysis is an electrochemically driven membrane method in which ion-exchange membranes are used in conjunction with a potential difference to separate ionic compounds from, for example, uncharged solvents or impurities. Such electrodialysis devices are known in the art, for example, and consist of an alternating arrangement of anion and cation exchange membranes arranged between two electrodes, with externally connected electrodes separate from the process taking place on the membranes, and surrounded in a separate chamber by an aqueous solution of electrolytically decomposed conductive electrodes. Hydrogen is produced at the cathode, and oxygen is produced at the anode. The problem is that if the concentration of water-soluble gases or gaseous compounds such as carbonic acid or sulfur dioxide dissolved in the liquid and reacting chemically with water upon contact with water is only very low, the electrophoretic separation performance in the electrochemical method of electrodialysis is limited, and energy loss occurs due to the simultaneous electrolysis of water molecules during the electrodialysis process. Furthermore, a common problem is that the absorbent medium (i.e., the medium in which the compound to be separated or its reaction products with water are concentrated) must also be water-based in order to establish conductivity, and the separated compound or its reaction products with water must first be returned to the gaseous state for use. Therefore, there is no method in the prior art in which a gaseous or gaseous compound is first dissolved in an aqueous medium and then selectively transported to another aqueous medium (the absorbent medium) in order to recover it as a gaseous phase or to be able to release it again as a gaseous or gaseous compound.

[0004] One well-known method for purifying sulfur and carbon dioxide from biogas is so-called pressurized water washing. In pressurized water washing, water and crude biogas are purified under pressure in an absorber using a countercurrent principle, thereby dissolving the gases to be separated and a small portion of the methane they contain in the washing solution. However, subsequent use of materials such as CO2 is not possible with pressurized water washing.

[0005] Another well-known method for separating carbon dioxide, hydrogen sulfide, and other acidic gases from gas mixtures in natural gas processing is the so-called amine washing. In amine washing, weakly alkaline aqueous solutions of amines such as diethanolamine and monoethanolamine, as well as methyldiethanolamine, diisopropylamine, diisopropanolamine, and diethylene glycolamine, are used, which can reversibly chemically absorb the acidic gas components (chemisorption). The gas to be purified is typically introduced into the amine aqueous solution at a pressure of approximately 8 bar and a temperature of approximately 40°C. When CO2 is absorbed in the amine / water mixture, CO2 first dissolves in the water and forms carbonic acid. The formed carbonic acid initially decomposes into H+. + and HCO3 - The ions then react with the amine so that the absorbed CO2 chemically and reversibly binds to form carbamates that are redissolveable in the desorber. In the desorber, the chemical equilibrium is reversed under high temperature and low pressure, thereby removing and releasing the bound acidic gas from the amine solution. However, amine washing has a specific drawback: the amines used in this method are harmful to health and are considered the third leading cause of workplace-related cancers.

[0006] Therefore, there is a great need for a method in which, on one hand, a gaseous element or element molecule or gaseous compound, particularly carbon dioxide, is dissolved or absorbed in an aqueous liquid and becomes ionized or ionizable, and then guided through a separation membrane by a diffusion or electrophoretic process step and transferred to another aqueous medium (absorption medium), whereby the gas and / or the reactive compound of the separated compound is present in the aqueous medium, which reacts with another element or element molecule or compound or is released as a gas from the aqueous medium and separated. Preferably, the solubility and ionizability of the gaseous element or element molecule or gaseous compound should be increased in a manner that enables efficient energy transport of the compound to be separated.

[0007] Therefore, the object of the present invention is to provide a novel method for binding or absorbing and subsequently storing gaseous elements or element molecules or gaseous compounds, especially acidic gases, particularly carbon dioxide (CO2), in an aqueous medium, and for recovering pure gaseous elements or element molecules or gaseous compounds, especially carbon dioxide (CO2). Thus, the object of the present invention relates to providing a method for dissolving / binding / transporting / reactively activating / chemically transforming and selectively releasing water-soluble gaseous compounds, particularly carbon dioxide.

[0008] According to the invention, this task is accomplished through the technical teachings of the independent claims. Other advantageous embodiments of the invention arise from the dependent claims, the description, the drawings, and the examples.

[0009] Invention Description

[0010] Surprisingly, this task was found to be solved by providing an aqueous acceptor medium containing an organic acceptor compound having at least one amidine and / or guanidine group and being hydrophilic. It has been found that this enables the dissolution / binding / transportation / reactive activation / chemical transformation and selective release of water-soluble gaseous compounds. In this context, water solubility refers to the chemical reaction of a gaseous substance / compound with water upon contact, for example, to form an anhydride or acid. It then exists in water as an organic or inorganic acid, or as the corresponding anion after dissociation in water.

[0011] When gaseous compounds come into contact with water, they can form water-soluble reaction products. In the case of carbon dioxide, the reaction with water leads to the formation of bicarbonate (HCO3-). - ) and carbonates (CO3) 2- These are also referred to as carbon dioxide derivatives in the following text.

[0012] It is known in the art that the solubility of gaseous elements, element molecules, or gaseous compounds that react with water to form water-soluble derivatives can be increased by using an alkaline solution. This is particularly applicable to acidic gases such as carbon dioxide or sulfur dioxide.

[0013] In existing technologies, alkaline solutions of alkali metals and alkaline earth metals, such as aqueous solutions of sodium hydroxide or potassium hydroxide, are used to prepare alkaline solutions. Using these compounds to dissolve and absorb gaseous compounds in an aqueous medium leads to the formation of carbonates or bicarbonates (salts of carbonic acid) in the presence of carbon dioxide, and these precipitate as solids, such as calcium carbonate, which is practically insoluble in water. This is undesirable if the gaseous compounds that have entered the aqueous solution are to be recovered in their pure gaseous state.

[0014] It is also known from the prior art that compounds containing tertiary or quaternary nitrogen compounds and suitable for forming an alkaline environment in aqueous media, such as ammonia, also improve the solubility of gaseous and gaseous compounds in aqueous media. A disadvantage is that the tertiary or quaternary nitrogen compounds present in the prior art are electrodynamically transported to the cathode in aqueous solutions under a direct current electric field. Therefore, they are unsuitable for electrophoretic separation, for example, in electrochemical processes such as electrodialysis.

[0015] Surprisingly, it has been found that the reaction of gaseous / gaseous compounds with water can be enhanced by using basic amino acids dissolved in an aqueous acceptor medium, leading to the formation of water-soluble compounds of the gaseous / gaseous compounds. As used herein, a basic amino acid is defined as an amino acid having an amino or nitrogen atom with a free pair of electrons in its amino acid residues (side chains). If these nitrogen atoms accept a proton, a positively charged side chain is formed. The amino acids histidine, lysine, and arginine belong to the basic amino acid family. According to the invention, basic amino acids with at least one guanidine and / or amidine group, such as arginine, are preferred. When using an aqueous solution of amino acids having at least one guanidine and / or amidine group that are readily soluble in an aqueous medium and accept or are capable of accepting protons (these amino acids exist in a dissociated form in the aqueous solution and establish an alkaline pH by dissolving them in water), it has been shown that very rapid absorption of gaseous carbon dioxide occurs in such a solution if the gas or gas mixture comes into contact with it. It has also been found that each guanidine or amidine group is respectively bound with a bicarbonate anion or a carbonate anion. Surprisingly, when the pH of the solution is >8, the dissociation rate of the bound bicarbonate or carbonate anions is very low. This means that, to ensure rapid and complete binding of carbonate / bicarbonate anions formed in alkaline solutions, it is not necessary to pressurize the aqueous acceptor medium with a gas composed of or containing carbon dioxide to guarantee the binding of carbonate / bicarbonate anions. Therefore, on the one hand, good dissolution or absorption of carbon dioxide in aqueous media can be achieved through water-soluble compounds having one or more free guanidine and / or amidine groups, while ensuring very stable binding of carbonate / bicarbonate anions with the free guanidine / midine groups. It can be shown that these properties of the acceptor medium according to the invention can also be used to dissolve and bind other organic and inorganic gaseous / gaseous compounds, such as hydrogen sulfide or chlorine. This can significantly improve the absorption capacity of gas / gas mixtures that are soluble in water and react with it to form water-soluble compounds. In particular, the absorption capacity of carbon dioxide in water can be significantly improved in the presence of water-soluble compounds with one or more free guanidine and / or amidine groups. Therefore, absorption in aqueous media, reaction with water, and binding of carbon dioxide and its derivatives in water are enhanced or accelerated.

[0016] Therefore, compounds containing at least one free guanidine and / or amidine group have been found to promote the reaction and binding of carbon dioxide and its aqueous derivatives (carbonate / bicarbonate anions). The physicochemical interactions formed between carbon dioxide or its aqueous derivatives and compounds containing at least one free guanidine and / or amidine group can endow the compounds with at least one free guanidine and / or amidine group with acceptor properties for dissolution and binding, reaction promotion and chemical transformation, and storage of carbon dioxide or its derivatives in water. Therefore, compounds containing free guanidine and / or amidine groups are hereinafter referred to as acceptor compounds, and media in which at least one compound containing at least one free guanidine and / or amidine group is present are hereinafter referred to as acceptor media.

[0017] Therefore, an aqueous solution containing at least one compound having at least one free guanidine group and / or amido group and present in dissolved form can be used to provide an acceptor solution.

[0018] A preferred method is one in which the solubility of a gaseous compound in an aqueous acceptor medium, i.e., an acceptor solution, is increased. A particularly preferred method is one in which the gaseous compound is carbon dioxide. According to the invention, an aqueous acceptor medium, i.e., an acceptor solution containing at least one acceptor compound having a free guanidine group and / or an amidine group, is provided, which has the technical effect of increasing the solubility of gaseous compounds, particularly carbon dioxide. The term "solubility" in this context refers to the dissolution of a water-soluble gas that reacts chemically with water upon contact, such as an acidic gas that forms an acid or weak acid when dissolved in water.

[0019] A preferred method involves providing an aqueous acceptor solution containing at least one acceptor compound having at least one free guanidine and / or amidine group, and contacting it with a gas or gas mixture. Therefore, the invention more specifically relates to a method in which an aqueous acceptor solution containing at least one acceptor compound having at least one free guanidine and / or amidine group is provided, and the aqueous acceptor solution is contacted with a carbon dioxide-containing gas or gas mixture to bind carbon dioxide from the gas or gas mixture.

[0020] A preferred method involves contacting an aqueous receptor medium, i.e., a receptor solution, with a gas / gas mixture containing at least one gaseous component dissolved in water to form an acid and / or anion, wherein the at least one gaseous compound dissolved in water to form an acid and / or anion is bound by at least one receptor compound present in the receptor medium, i.e., the receptor solution.

[0021] A preferred method is to improve the solubility of acidic / anionic compounds and / or gases existing in anionic form, i.e., acidic gases, in an aqueous acceptor medium and to bind them thereto, wherein the aqueous acceptor medium contains at least one acceptor compound, which is a hydrophilic organic compound having at least one amidine and / or guanidine group. In the preferred method, the gaseous compound in the aqueous acceptor medium binds anionicly with the acceptor compound. An anion is defined as the bound gaseous compound dissociating in the acceptor solution and existing in the aqueous solution in anionic form, with the acceptor compound being protonated to form a counterion. According to the invention, the acceptor compound has a free guanidine and / or amidine group that can be protonated to provide a cation as a counterion to the anion of the gaseous compound in the acceptor solution.

[0022] Therefore, the method of the present invention includes at least the following steps:

[0023] a) Provide an aqueous receptor solution comprising at least one receptor compound having a free guanidine group and / or an amidine group; and

[0024] b) Contact the gas containing carbon dioxide with the acceptor solution from step a).

[0025] A preferred method involves the presence of at least one hydrophilic organic compound having at least one amidine and / or guanidine group in an aqueous acceptor medium to dissolve, neutralize, and bind gaseous compounds that form acids upon contact with water, or gaseous compounds present therein in anionic form, and / or to contact and react the compound with other compounds or selectively release the bound gaseous compounds in gaseous form. In a preferred method, at least one hydrophilic organic compound having at least one amidine and / or guanidine group is present in the aqueous acceptor medium to dissolve, neutralize, and bind acidic gases, particularly carbon dioxide. Furthermore, the aqueous acceptor medium containing the bound acidic gas, particularly carbon dioxide, can be contacted with other compounds to convert the bound acidic gas, particularly carbon dioxide, for example, in the case of carbon dioxide, to a carbonate or bicarbonate that is insoluble or sparingly soluble in water, or to selectively release the bound acidic gas, particularly carbon dioxide, as a gas, particularly gaseous carbon dioxide.

[0026] Therefore, the present invention relates to a method for selectively binding and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0027] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0028] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0029] c) Store the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b).

[0030] The preferred implementation includes step c):

[0031] c) Store the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b) at atmospheric pressure.

[0032] The present invention preferably relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0033] a) Provide an aqueous receptor solution comprising at least one receptor compound having a free guanidine group and / or an amidine group;

[0034] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0035] c) The carbon dioxide / carbon dioxide derivative bound in the acceptor solution of step b) is transported through a separation membrane to an aqueous absorption and release medium.

[0036] Therefore, or, the present invention relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0037] (a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0038] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0039] c) The carbonate / bicarbonate anions in the acceptor solution from step b) are transported through a separation membrane to an aqueous absorption and release medium.

[0040] The present invention preferably relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0041] a) Provide an aqueous receptor solution comprising at least one receptor compound having a free guanidine group and / or an amidine group;

[0042] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0043] c) The carbon dioxide / carbon dioxide derivative bound in the acceptor solution from step b) is transported through a separation membrane to an aqueous absorption and release medium.

[0044] c2) Release carbon dioxide in the gas phase from the absorption and release medium containing bound carbon dioxide / carbon dioxide derivatives from step c).

[0045] Therefore, or, the present invention relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0046] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0047] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0048] c) The carbonate / bicarbonate anions in the acceptor solution from step b) are transported through a separation membrane to an aqueous absorption and release medium.

[0049] c2) Carbon dioxide is released in the gas phase from the absorption and release medium containing carbonate / bicarbonate anions in step c).

[0050] The present invention preferably relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0051] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0052] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0053] c) Contact the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b) with the reaction compound.

[0054] The present invention preferably relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0055] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0056] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0057] c) Transferring the carbon dioxide / carbon dioxide derivative bound in the acceptor solution from step b) to an aqueous absorption and release medium via a separation membrane; and

[0058] d2) The reactant compound is added to the absorption and release medium containing the bound carbon dioxide / carbon dioxide derivative from step c).

[0059] Therefore, or, the present invention relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0060] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0061] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0062] c) The carbonate / bicarbonate anions in the acceptor solution from step b) are transported through a separation membrane to an aqueous absorption and release medium.

[0063] d2) The reactant compound is added to the absorption and release medium containing carbonate / bicarbonate anions from step c).

[0064] The present invention preferably relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0065] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0066] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0067] c) Transfer the carbon dioxide / carbon dioxide derivative bound in the acceptor solution from step b) to an aqueous absorption and release medium via a separation membrane; or

[0068] Store the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b).

[0069] Therefore, or, the present invention relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0070] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0071] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0072] c) Storing the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b); and / or

[0073] The carbon dioxide / carbon dioxide derivative bound in the acceptor solution of step b) is transported through a separation membrane to an aqueous absorption and release medium.

[0074] Therefore, the present invention preferably relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0075] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0076] b) Contact the gas containing carbon dioxide with the acceptor solution from step a);

[0077] c) Transfer the carbon dioxide / carbon dioxide derivative bound in the acceptor solution from step b) to an aqueous absorption and release medium via a separation membrane; or

[0078] Storage of the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b); and

[0079] c2) Releasing carbon dioxide in the gas phase from the absorption and release medium containing bound carbon dioxide / carbon dioxide derivatives in step c); or

[0080] d2) The reactant compound is added to the absorption and release medium containing the bound carbon dioxide / carbon dioxide derivative from step c).

[0081] The present invention preferably relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0082] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0083] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0084] c) Storing the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b); and / or

[0085] The carbon dioxide / carbon dioxide derivative bound in the acceptor solution in step b) is transported through a separation membrane to an aqueous absorption and release medium; and

[0086] c2) Releasing carbon dioxide in the gas phase from the absorption and release medium containing bound carbon dioxide / carbon dioxide derivatives in step c); or

[0087] d2) The reactant compound is added to the absorption and release medium containing the bound carbon dioxide / carbon dioxide derivative from step c).

[0088] A preferred method is to dissolve carbon dioxide in an aqueous medium to form carbonate / bicarbonate anions, wherein the resulting carbonate / bicarbonate anions are stably and physicochemically bonded in an aqueous acceptor medium.

[0089] A preferred method is that the dissolution of carbon dioxide and the binding of the resulting carbonate / bicarbonate anions are achieved via free guanidine and / or amidoyl groups in an aqueous acceptor medium or on free guanidine and / or amidoyl groups in an aqueous acceptor medium.

[0090] A preferred method is that the water-soluble acceptor compound is a compound with a free guanidine group and / or an amidine group, which accepts or is able to accept at least one proton when dissolved in water.

[0091] A preferred method is wherein the water-soluble acceptor compound is an amino acid having at least one guanidine group and / or an amido group and being bound to or capable of binding at least one proton in aqueous solution.

[0092] A preferred method is that the water-soluble acceptor compound used to dissolve carbon dioxide and to bind and transport carbon dioxide, or its derivatives in water, and the resulting carbonate / bicarbonate anions, is arginine and / or an arginine derivative.

[0093] Therefore, a method in which at least one acceptor compound having a free guanidine group and / or amidine group is an arginine derivative or, most preferably, arginine, is particularly preferred. Acceptor solutions containing at least one arginine derivative or, most preferably, arginine, have been found to be particularly advantageous and effective for binding and storing carbon dioxide in aqueous media.

[0094] Surprisingly, it has been discovered that the method of the present invention can completely remove carbon dioxide contained in a gas mixture.

[0095] Complete removal means that after contacting the gas mixture containing carbon dioxide with the acceptor solution, the carbon dioxide content in the treated gas / gas mixture is <1 ppm.

[0096] Contact between a gas or gas mixture and an aqueous acceptor medium can be carried out in various methodologies known in the art. For example, contact between the two phases can be achieved by introducing the gas phase into the liquid phase, or by guiding the gas phase across a surface wetted by the liquid phase. In a preferred embodiment, a method is used to contact the gas and liquid phases, creating a very large interface between the phases. These are devices such as homogenizers / dynamic mixers, but can also be static mixers, as well as filled gas scrubbing devices.

[0097] The preferred method is one in which the gas / gas mixture contacts the receptor medium.

[0098] A preferred method involves contacting the receptor medium with a gas / gas mixture, causing a certain proportion of carbon dioxide present therein to completely dissolve and bind within the receptor medium.

[0099] A preferred method is that the acceptor compound is completely bound to a certain proportion of carbon dioxide and / or the reaction products of carbon dioxide and water present therein by contacting the acceptor medium with a gas / gas mixture.

[0100] A preferred method is to generate a large interface between the aqueous acceptor medium and the carbon dioxide-containing gas phase.

[0101] In particular, the significant advantage of the stable binding between free guanidine and / or amidine groups and carbonate / bicarbonate anions lies in the fact that, despite the high concentration of dissolved carbon dioxide in the acceptor medium, it does not re-dissociate into a gaseous state, thus eliminating the need to pressurize the acceptor medium to maintain a high concentration of dissolved carbon dioxide or its reaction products with water.

[0102] Preferably, the method involves dissolving and combining carbon dioxide and its derivatives without pressurizing the acceptor solution. Preferably, the method involves dissolving and combining carbon dioxide at atmospheric pressure. Preferably, the method involves dissolving and combining carbon dioxide without overpressure. According to standards, the average atmospheric pressure at sea level is 101,325 Pa = 101.325 kPa = 1013.25 hPa ≈ 1 bar. Preferably, the method involves dissolving and combining carbon dioxide at normal pressure. A preferred method involves dissolving and combining carbon dioxide at normal pressure of 101.325 kPa. Preferably, the method involves dissolving and combining carbon dioxide without pressure.

[0103] A preferred embodiment of the method according to the present invention includes step b):

[0104] b) Contact the gas containing carbon dioxide with the acceptor solution from step a), wherein the contact in step b) is carried out at normal or atmospheric pressure.

[0105] A preferred embodiment of the method according to the present invention includes step b):

[0106] b) Contact the gas containing carbon dioxide with the acceptor solution from step a), wherein the contact in step b) is carried out at atmospheric pressure.

[0107] A preferred embodiment of the method according to the present invention includes step b):

[0108] b) Contact the gas containing carbon dioxide with the acceptor solution from step a), wherein the contact in step b) is carried out at atmospheric pressure.

[0109] A preferred embodiment of the method according to the present invention includes step b):

[0110] b) Contact the gas containing carbon dioxide with the acceptor solution from step a), wherein the contact in step b) is carried out without pressure.

[0111] A preferred embodiment of the method according to the present invention includes step b):

[0112] b) Contact the gas containing carbon dioxide with the acceptor solution from step a), wherein the contact in step b) is carried out under no-pressure conditions.

[0113] Here, contact at normal pressure, atmospheric pressure, or without pressure means providing the acceptor solution at normal pressure, atmospheric pressure, or without pressure.

[0114] The present invention preferably relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0115] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0116] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0117] c) Transfer the carbon dioxide / carbon dioxide derivative bound in the acceptor solution from step b) to an aqueous absorption and release medium via a separation membrane; or

[0118] Store the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b).

[0119] The contact in step b) is performed at atmospheric pressure and / or the acceptor solution from step c) is stored at atmospheric pressure. A preferred embodiment is where the contact in step b) is performed at atmospheric pressure; and where the acceptor solution from step c) is stored at atmospheric pressure.

[0120] Preferably, the present invention relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, the method comprising the following steps:

[0121] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0122] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0123] c) Storing the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b); and / or

[0124] The carbon dioxide / carbon dioxide derivative bound in the acceptor solution from step b) is transported through a separation membrane to an aqueous absorption and release medium.

[0125] The contact in step b) is performed at atmospheric pressure and / or the acceptor solution from step c) is stored at atmospheric pressure. A preferred embodiment is where the contact in step b) is performed at atmospheric pressure and the acceptor solution from step c) is stored at atmospheric pressure.

[0126] This aspect of the invention brings further particularly advantageous effects to further method embodiments. For example, carbon dioxide or its reaction products with water absorbed in the acceptor solution can be stored for >6 months without loss under pressure, i.e., without overpressure or at atmospheric or normal pressure. Therefore, a non-corrosive acceptor solution containing bound carbon dioxide or its reaction products with water can be stored and transported in a container without hazard. Here, "transportation" refers to conveying the acceptor solution containing bound carbon dioxide to a transportable container, such as a large tank, container, or barrel. Suitable transport containers for transporting liquids are well known to those skilled in the art. Hazardless storage and transport here does not refer to the transport of bound carbon dioxide / carbon dioxide derivatives in the acceptor solution containing bound carbon dioxide through a separation membrane to an aqueous absorption and release medium. Therefore, the transport of bound carbon dioxide / carbon dioxide derivatives in the acceptor solution containing bound carbon dioxide through a separation membrane to an aqueous absorption and release medium can also be referred to herein as membrane transport.

[0127] Preferably, the method involves dissolving and combining gaseous carbon dioxide and its reaction products with water in a non-pressurized acceptor solution. A preferred method involves dissolving and combining gaseous carbon dioxide and its reaction products with water at atmospheric pressure or normal pressure. A preferred method involves contacting the carbon dioxide-containing gas with the acceptor solution under pressureless conditions. A preferred method involves contacting the carbon dioxide-containing gas with the acceptor solution at atmospheric pressure.

[0128] A preferred method is to store and / or transport (in a transport container) the acceptor solution containing dissolved and bound carbon dioxide or its reaction products with water under pressureless conditions. A more preferred method is to store and / or transport (in a transport container) the acceptor solution containing dissolved and bound carbon dioxide or its reaction products with water under atmospheric pressure.

[0129] The present invention preferably relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, the method comprising the following steps:

[0130] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0131] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0132] c) Store and / or deliver the acceptor solution containing bound carbon dioxide from step b) in a storage container and / or a delivery container.

[0133] Preferably, in this document, the contact in step b) is carried out at atmospheric pressure and / or the acceptor solution from step c) is stored and / or transported at atmospheric pressure in a storage container and / or a delivery container. Furthermore, a preferred embodiment is that the contact in step b) is carried out at atmospheric pressure, and the acceptor solution from step c) is stored or transported at atmospheric pressure in a storage container and / or a delivery container.

[0134] This invention preferably relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0135] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0136] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0137] c) Transfer the carbon dioxide / carbon dioxide derivative bound in the acceptor solution from step b) to an aqueous absorption and release medium via a separation membrane; or

[0138] Storage and / or delivery of the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b).

[0139] Preferably, the contact in step b) is carried out at atmospheric pressure and / or the acceptor solution from step c) is stored and / or transported at atmospheric pressure in a storage container and / or a delivery container. More preferably, an embodiment is provided in which the contact in step b) is carried out at atmospheric pressure and the acceptor solution from step c) is stored or transported at atmospheric pressure in a storage container and / or a delivery container.

[0140] This invention preferably relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0141] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0142] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0143] c) Storing and / or delivering the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b); and / or

[0144] The carbon dioxide / carbon dioxide derivative bound in the acceptor solution in step b) is transported through a separation membrane to an aqueous absorption and release medium.

[0145] Preferably, the contact in step b) is carried out at atmospheric pressure and / or the acceptor solution from step c) is stored or transported at atmospheric pressure in a storage container and / or a delivery container. More preferably, an embodiment is provided in which the contact in step b) is carried out at atmospheric pressure and the acceptor solution from step c) is stored or transported at atmospheric pressure in a storage container and / or a delivery container.

[0146] However, contacting the acceptor medium with a gas / gas mixture containing carbon dioxide while pressurizing the gas / gas mixture can increase the amount of carbon dioxide dissolved and bound per unit time.

[0147] Therefore, in another preferred embodiment, an aqueous acceptor solution containing compounds bearing guanidine and / or amidine groups is enriched or saturated with dissolved carbon dioxide in an enrichment device that allows for pressurization. This facilitates enrichment or reaches the point of saturation. Whether the acceptor medium is saturated with carbon dioxide can be discerned, for example, by an increase in the concentration of carbon dioxide in the gas mixture that has passed through the enrichment device and exited. Surprisingly, it has been found that if there is an excess of free guanidine and / or amidine groups of the acceptor compound in the aqueous acceptor medium relative to carbon dioxide molecules in the gas / gas mixture, the carbon dioxide is completely or almost completely depleted when the gas phase is in contact with the acceptor medium for a sufficiently long time. In this context, "almost completely" refers to the concentration / proportion. < / =100ppm。

[0148] In this respect, the method involves the complete or near-complete extraction of carbon dioxide from a gas / gas mixture.

[0149] This invention preferably relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0150] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group in a pressurized enrichment device;

[0151] b) Contact the acceptor solution containing carbon dioxide in step a), wherein the contact in step b) is carried out under pressure, preferably until the acceptor solution is saturated with carbon dioxide.

[0152] This invention preferably relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0153] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0154] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0155] c) Transfer the carbon dioxide / carbon dioxide derivative bound in the acceptor solution from step b) to an aqueous absorption and release medium via a separation membrane; or

[0156] Store the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b).

[0157] The acceptor solution in step a) is provided in an enrichment device that allows for pressurization; and

[0158] The contact in step b) is carried out under pressure, preferably until the acceptor solution is saturated with carbon dioxide.

[0159] This invention preferably relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0160] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0161] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0162] c) Storing the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b); and / or

[0163] The carbon dioxide / carbon dioxide derivative bound in the acceptor solution in step b) is transported through a separation membrane to an aqueous absorption and release medium.

[0164] The acceptor solution in step a) is provided in an enrichment device that allows for pressurization;

[0165] The contact in step b) is carried out under pressure, preferably until the acceptor solution is saturated with carbon dioxide.

[0166] A preferred method is one in which a gas / gas mixture containing carbon dioxide is contacted with a receptor solution until a carbon dioxide concentration of <100 ppm is achieved.

[0167] A preferred method is one in which a gas / gas mixture containing carbon dioxide is contacted with a acceptor solution until a carbon dioxide concentration of <100 ppm is achieved in the gas, wherein the contact is carried out under pressure.

[0168] A preferred method is one in which a gas containing carbon dioxide is contacted with an acceptor solution until a carbon dioxide concentration of <100 ppm is achieved in the gas, wherein there is an excess of free guanidinyl and / or amidine groups of the acceptor compound relative to the number of carbon dioxide molecules present in the gas / gas mixture.

[0169] However, as shown below, this method can also be used to convert extracted and bound carbon dioxide and its derivatives. For this purpose, it is advantageous if the concentration / content of carbon dioxide and / or carbon dioxide derivatives in the water is as high as possible. Therefore, it is preferable to contact the acceptor medium with a gas / gas mixture containing or composed of carbon dioxide until no further absorption occurs therein, i.e., until the acceptor medium is saturated with carbon dioxide. This can be confirmed, for example, by further increasing the carbon dioxide content in the gas / gas mixture already in contact with the acceptor medium, for example, increasing it to >100 ppm. Thus, the absorbency of the acceptor medium is exhausted and the acceptor medium is saturated with carbon dioxide.

[0170] A preferred method is to saturate the acceptor medium with carbon dioxide and / or carbonate and / or bicarbonate anions, wherein the acceptor medium is contacted with a gas / gas mixture until the concentration of carbon dioxide in the gas / gas mixture that has been contacted with the acceptor medium increases to >100 ppm.

[0171] Preferably, the acceptor medium is saturated with carbon dioxide. In a preferred embodiment, the acceptor solution saturated with carbon dioxide is obtained in step b) of the method according to the invention.

[0172] In a preferred embodiment, after the enrichment phase (where increased pressure relative to atmospheric pressure has been applied to the intake of the gas / gas mixture into the acceptor medium), a depressurization phase is performed, in which the degassing of dissolved gaseous compounds, which are not intended to be separated or may interfere with the ongoing reaction steps, is completed at atmospheric pressure or only slightly increased or decreased pressure, such as nitrogen, oxygen, or methane. Surprisingly, it has been found that carbon dioxide or its reaction products with water do not desorb or degas after the aqueous acceptor medium is saturated with carbon dioxide (even if this is done at increased pressure), even when a negative pressure of 100 mbar is applied. In a preferred embodiment, after the aqueous acceptor medium is contacted with a gas / gas mixture containing carbon dioxide (this is done at atmospheric pressure or overpressure), the removal of gaseous compounds not corresponding to carbon dioxide from the aqueous acceptor medium is achieved by depressurizing to atmospheric pressure and / or applying a negative pressure to the aqueous acceptor medium. In a preferred embodiment, gaseous / gas components not corresponding to carbon dioxide or its reaction products with water are removed from the aqueous acceptor medium by depressurization or the application of a negative pressure.

[0173] In this embodiment, the selective separation of carbon dioxide is preferably performed after a depressurization phase. A preferred method is one in which the contact between the gas / gas mixture and the aqueous acceptor medium is carried out at atmospheric pressure or a raised pressure, and in which gas / gas components not corresponding to carbon dioxide subsequently escape or are extracted during a depressurization phase, which is carried out at atmospheric pressure or a negative pressure.

[0174] This invention preferably relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0175] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group in a pressurized enrichment device;

[0176] b) Contacting the acceptor solution from step a) with a gas containing carbon dioxide, wherein the contact in step b) is carried out under pressure, preferably until the acceptor solution is saturated with carbon dioxide; and

[0177] b') Depressurize the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b) under atmospheric pressure or under reduced pressure.

[0178] Alternatively, the present invention therefore relates to a method for selectively binding and storing carbon dioxide in an aqueous medium, the method comprising the following steps:

[0179] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group in a pressurized enrichment device;

[0180] b) Contact the gas containing carbon dioxide with the acceptor solution from step a) under pressure; and

[0181] b') Expose the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b) to atmospheric pressure or reduced pressure.

[0182] This invention preferably relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0183] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0184] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0185] c) Transfer the carbon dioxide / carbon dioxide derivative bound in the acceptor solution from step b) to an aqueous absorption and release medium via a separation membrane; or

[0186] Store the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b).

[0187] The acceptor solution in step a) is provided in an enrichment device that allows for pressurization; and

[0188] The contact in step b) is carried out under pressure, preferably until the acceptor solution is saturated with carbon dioxide.

[0189] The method further includes step b' after step b).

[0190] b') Depressurize the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b) under atmospheric pressure or under reduced pressure.

[0191] This invention preferably relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0192] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0193] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0194] c) Storing the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b); and / or

[0195] The carbon dioxide / carbon dioxide derivative bound in the acceptor solution in step b) is transported through a separation membrane to an aqueous absorption and release medium.

[0196] The acceptor solution from step a) is provided in an enrichment device that allows for pressurization; and

[0197] The contact in step b) is carried out under pressure, preferably until the acceptor solution is saturated with carbon dioxide.

[0198] The method further includes step b' after step b).

[0199] b') Depressurize the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b) under atmospheric pressure or under reduced pressure.

[0200] In a preferred embodiment, after contacting the gas / gas mixture containing carbon dioxide with the acceptor solution, the carbon dioxide dissolved in the aqueous acceptor medium or its reaction products with water are released as a gas phase.

[0201] Typically, electrolysis involves conducting a direct current through two electrodes in a conductive liquid (electrolyte solution). At the electrodes, reaction products are generated from substances contained in the electrolyte via electrolysis. Surprisingly, it was found that by applying a direct current voltage to an aqueous acceptor medium that has already been infused with carbon dioxide, the carbon dioxide is released as bubbles at both electrodes. It has been discovered that this allows the complete removal / release of (bound) carbon dioxide or its reaction products with water from the aqueous acceptor medium.

[0202] This invention preferably relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0203] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0204] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0205] c1) Release carbon dioxide as a gas phase from the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b).

[0206] This invention preferably relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0207] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0208] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0209] c1) Carbon dioxide as a gas phase is released from the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b) by applying a DC voltage to the acceptor solution from step b).

[0210] Therefore, a preferred embodiment relates to a method for selectively binding and releasing carbon dioxide in an aqueous medium, the method comprising the following steps:

[0211] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0212] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0213] c1) Carbon dioxide as a gas phase is released from the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b) by electrolysis.

[0214] This invention preferably relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0215] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0216] b) Contact the gas containing carbon dioxide with the acceptor solution from step a);

[0217] c) Transfer the carbon dioxide / carbon dioxide derivative bound in the acceptor solution from step b) to an aqueous absorption and release medium via a separation membrane; and

[0218] c2) By applying a DC voltage to the absorption and release medium of step c), carbon dioxide as a gas phase is released from the absorption and release medium containing bound carbon dioxide / carbon dioxide derivatives in step c).

[0219] A preferred method is one in which an aqueous acceptor medium is contacted with and loaded with carbon dioxide, and then the carbon dioxide dissolved / bound in the acceptor medium or its reaction products with water are released as carbon dioxide gas by applying a DC voltage to the acceptor medium.

[0220] As expected, in addition to carbon dioxide, oxygen was released at the anode and hydrogen at the cathode. Surprisingly, it was then discovered that carbon dioxide could be obtained as a high-purity gas phase by means of electrophoresis to separate carbonate / bicarbonate anions present in the acceptor solution in the middle space, and then releasing carbon dioxide by water separation.

[0221] It has been found that the electrophoretic separation of carbon dioxide or carbonate / bicarbonate anions dissolved and bound in aqueous acceptor media can be achieved using electrodialysis devices available in the prior art.

[0222] Further investigation revealed that the open-pore membrane is suitable for enabling the electrophoretic passage of dissolved carbon dioxide or carbonate / bicarbonate anions. In this process, the dissolved carbon dioxide or carbonate / bicarbonate anions are electrophoretically transported to the anode. If a DC voltage is applied to the electrode, the anions migrate to the anode and can pass through the positively charged anion exchange membrane.

[0223] An experimental setup using an electrodialysis unit, consisting of the following arrangement, was found to be particularly suitable for obtaining the purest form of gaseous carbon dioxide: cathode chamber / chamber for receiving the acceptor solution (hereinafter referred to as the acceptor chamber) / chamber in which carbon dioxide is released in gaseous form (hereinafter referred to as the absorption and release chamber) / anode chamber.

[0224] To achieve electrophoretic separation of dissolved carbon dioxide and its derivatives from the acceptor solution, the acceptor chamber is connected to the absorption and release chamber on the anode side via a conductive medium, in which the delivered compounds can preferably be absorbed and / or where the release or reaction of these compounds can take place. The medium present in the absorption and release chamber is preferably an aqueous solution and is referred to below as the absorption and / or release medium.

[0225] Therefore, a preferred embodiment of the present invention relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, the method comprising the following steps:

[0226] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0227] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0228] c) The bound carbon dioxide / carbon dioxide derivative from the acceptor solution in step b) is transported through a separation membrane to an aqueous absorption and release medium.

[0229] The acceptor solution from step b) is in or introduced into the acceptor chamber of the electrodialysis apparatus; and

[0230] The delivery of the carbon dioxide / carbon dioxide derivative in step c) is achieved by means of a lift generated between the acceptor chamber and the absorption and release chamber.

[0231] The receptor chamber and the absorption and release chamber are separated from each other by the separation membrane.

[0232] Therefore, a preferred embodiment of the present invention relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, the method comprising the following steps:

[0233] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0234] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0235] c) The carbonate / bicarbonate anions are transferred from the acceptor solution in step b) through a separation membrane into an aqueous absorption and release medium.

[0236] The acceptor solution from step b) is in or introduced into the acceptor chamber of the electrodialysis apparatus; and

[0237] The carbonate / bicarbonate anions are delivered according to step c) via a lift generated between the acceptor chamber and the absorption and release chamber.

[0238] The receptor chamber and the absorption and release chamber are separated from each other by the separation membrane.

[0239] When tap water is used as the absorption and release medium in this arrangement of the absorption and release chambers, bubbles composed of carbon dioxide form at the membrane separating the chamber from the acceptor chamber. It has been shown that the formation of bubbles covering the membrane plane between the acceptor and absorption / release chambers is highly disadvantageous because the gas layer forms electrical insulation in these areas, significantly reducing the efficiency of the method. Furthermore, using an aqueous medium containing electrolytes is disadvantageous because solids, such as sodium carbonate and / or calcium carbonate, may form. In particular, electrolytes that produce carbonates that are practically insoluble in water, such as calcium carbonate, are disadvantageous. However, for electrophoresis to be performed, the absorption and release medium needs to be highly conductive. Moreover, the compounds that generate conductivity in the absorption and release medium should themselves not be electrophoretically transported in the applied DC electric field. Surprisingly, organic and inorganic acids have been found to be suitable for ensuring the above requirements.

[0240] Surprisingly, water-soluble organic compounds with one or more acid groups have been found to be particularly suitable for converting or separating dissolved carbon dioxide / carbonate / bicarbonate anions into a gaseous state upon entering a chamber containing an absorption and / or release medium via a separation membrane. This is especially advantageous if the organic compound does not transport in an electric field and / or cannot leave the chamber containing the absorption and / or release medium via the separation membrane due to its molecular size.

[0241] Therefore, a preferred embodiment of the present invention relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, the method comprising the following steps:

[0242] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0243] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0244] c) The bound carbon dioxide / carbon dioxide derivative from the acceptor solution in step b) is transported through a separation membrane to an aqueous absorption and release medium.

[0245] The aqueous absorption and release medium contains organic or inorganic acids.

[0246] Therefore, a preferred embodiment of the present invention relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, the method comprising the following steps:

[0247] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0248] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0249] c) The bound carbon dioxide / carbon dioxide derivative from the acceptor solution in step b) is transported through a separation membrane to an aqueous absorption and release medium.

[0250] The aqueous absorption and release medium contains an organic or inorganic acid and has a pH in the range of 1 to 7, more preferably between 2 and 6, and even more preferably between 3 and 5.

[0251] Therefore, another preferred embodiment of the present invention relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, the method comprising the following steps:

[0252] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0253] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0254] c) The bound carbon dioxide / carbon dioxide derivative from the acceptor solution in step b) is transported through a separation membrane to an aqueous absorption and release medium.

[0255] The aqueous absorption and release medium contains an organic acid and preferably has a pH in the range of 1 to 7, more preferably between 2 and 6, and even more preferably between 3 and 5. Preferably, the organic acid is a compound having at least one acidic group and having an isoelectric point in the pH range of 3 to 5, preferably between 3.5 and 4.5. In a preferred embodiment, the organic acid is preferably selected from the group consisting of citric acid, tartaric acid, and ascorbic acid. In a particularly preferred embodiment, the organic acid is citric acid. In a particularly preferred embodiment, the aqueous absorption and release medium contains citric acid.

[0256] In a further preferred embodiment, the aqueous absorption and release medium comprises an organic acid, wherein the organic acid is an acidic amino acid having a carboxylic acid group (-COOH) on its side chain. Embodiments in which the aqueous absorption and release medium comprises an organic acid, wherein the organic acid is an amino acid with an acidic group, are also preferred. Embodiments in which the aqueous absorption and release medium comprises an organic acid, wherein the organic acid is selected from the group consisting of or composed of aspartic acid and glutamic acid. Embodiments in which the aqueous absorption and release medium comprises an organic acid, wherein the organic acid is selected from the group consisting of or composed of citric acid, tartaric acid, and ascorbic acid. Tartaric acid is particularly preferred. Embodiments in which the aqueous absorption and release medium comprises an inorganic acid, wherein the inorganic acid is preferably selected from the group consisting of or composed of sulfuric acid or pyrophosphate.

[0257] Therefore, a preferred embodiment of the present invention relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, the method comprising the following steps:

[0258] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0259] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0260] c) The bound carbon dioxide / carbon dioxide derivative from the acceptor solution in step b) is transported through a separation membrane to an aqueous absorption and release medium containing citric acid.

[0261] In step b), the acceptor solution is in or introduced into the acceptor chamber of the electrodialysis apparatus; and

[0262] The delivery of the carbon dioxide / carbon dioxide derivative in step c) is achieved by means of a lift generated between the acceptor chamber and the absorption and release chamber.

[0263] The receptor chamber is isolated from the absorption and release chamber by the separation membrane.

[0264] Amino acids with acidic groups are found to satisfy this condition particularly well and are therefore especially preferred. Preferably, the pH of the absorption and / or release medium is self-regulated by the dissociation of the dissolved amino acids. Amino acids do not exhibit electrophoretic mobility at their isoelectric points. Therefore, it is particularly advantageous if the aqueously dissolved amino acids are present in the acceptor medium and the absorption and / or release medium, respectively, at their isoelectric points. This results in a particularly advantageous effect that the compounds responsible for dissolving and transporting on one hand and separating / releasing carbon dioxide / bicarbonate anions on the other are not completely mixed or consumed, as they remain in their respective solutions. It can be shown that the electrophoretic separation of carbonate / bicarbonate anions and the diffusion-induced transport of dissolved carbon dioxide through an open-pore mesoporous membrane (e.g., in the form of a ceramic filter plate) are possible. In this case, the pH of the acceptor solution and the absorption and release medium does not change during electrophoresis, and the release of carbon dioxide is completed in the absorption and release chambers, thus there is no voltage drop during electrophoresis due to bubble formation and adhesion to the separation membrane. In this respect, the absorption medium according to the invention satisfies the following conditions: the absorption and binding of carbon dioxide or carbonate / bicarbonate anions are completed in the medium, and the absorbed / bound carbon dioxide or carbonate / bicarbonate anions can be removed and transported away from the separation medium, so that carbon dioxide can be released spatially away from the separation medium or the absorption and release chamber.

[0265] A preferred method is one in which the dissolution, electrophoretic transport, and separation / degassing of carbon dioxide / carbonate / bicarbonate anions are carried out by providing basic amino acids in an aqueous acceptor medium and amino acids with acidic groups at their isoelectric points in an aqueous absorption and / or release medium.

[0266] A preferred method is one in which a gas or gaseous compound and its derivatives are bound in an aqueous acceptor medium, and the gas / gaseous compound or its derivatives in the water are transported through a separation medium (separation membrane) by electrophoresis, thereby entering the absorption and release medium.

[0267] A preferred method is one in which a gas or gaseous compound or its derivative is bound in an aqueous acceptor medium and transported in water through a separation medium by electrophoresis, thereby entering an absorption and release medium, where they are released as a gas phase and / or chemically transformed.

[0268] A preferred method is one in which the release of carbon dioxide / carbon dioxide derivatives transported via a separation medium (separation membrane) occurs in the form of pure carbon dioxide gas in an absorption and release chamber.

[0269] Preferred basic amino acids are arginine and lysine. Preferred amino acids with acidic groups are aspartic acid and glutamic acid.

[0270] It has been found that when acids with pKs > 3 are used as absorption and release media, carbon dioxide or carbonate / bicarbonate anions transported therein by electrophoresis are not released, or only to a very small extent, as gaseous carbon dioxide at the membrane or in the absorption-release chamber. It has been found that in this case, very complete release of carbon dioxide or carbonate / bicarbonate anions dissolved / bound in the absorption and release media can be achieved outside the absorption and release chamber by guiding the absorption and release media through a preferably hydrophobic surface into a collection container. It has been found that, by an arrangement in which the release of carbon dioxide as gaseous occurs virtually only in the release device and not or only to a very small extent in the absorption and release chamber, a high overflow rate is established between the separation medium (separation membrane) and the absorption and release medium in the absorption and release chamber, particularly by using honeycomb spacers that induce turbulence in the absorption and release chamber and transport them to the release device, in which the absorption and release medium contacts the surface on which carbon dioxide separation is achieved, or where carbon dioxide separation is achieved by applying negative pressure. Therefore, in a preferred embodiment of the method, carbon dioxide as a gas is introduced from the absorption and release medium into the release device of the absorption and release medium from the absorption and release chamber (see [link]). Figure 1 Preferably, an interface is provided in the release device to separate carbon dioxide. A hydrophobic interface is preferred.

[0271] Suitable devices for increasing the interfacial area include, for example, fillers.

[0272] A preferred method is to introduce the absorption and release medium into a release device after the carbon dioxide / carbonate / bicarbonate anions have been absorbed in the absorption and release medium in the absorption and release chamber, and there the carbon dioxide is released as a gas.

[0273] Therefore, a preferred embodiment of the present invention relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, the method comprising the following steps:

[0274] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0275] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0276] c) The bound carbon dioxide / carbon dioxide derivative from the acceptor solution in step b) is transported through a separation membrane to an aqueous absorption and release medium.

[0277] In step b), the acceptor solution is in or introduced into the acceptor chamber of the electrodialysis apparatus; and

[0278] The delivery of the carbon dioxide / carbon dioxide derivative in step c) is carried out by means of the elevator generated between the acceptor chamber and the absorption and release chamber.

[0279] The receptor chamber and the absorption and release chamber are separated from each other by the separation membrane;

[0280] The method described above includes step c3) after step c).

[0281] c3) In the release chamber, carbon dioxide as a gas phase is released from the absorption and release medium containing bound carbon dioxide / carbon dioxide derivatives from step c).

[0282] In a preferred embodiment, carbon dioxide as a gas phase is released by applying a DC voltage to the absorption and release medium from step c3).

[0283] Therefore, a preferred embodiment of the present invention relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, the method comprising the following steps:

[0284] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0285] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0286] c) The bound carbon dioxide / carbon dioxide derivative from the acceptor solution in step b) is transported through a separation membrane to an aqueous absorption and release medium.

[0287] In step b), the acceptor solution is in or introduced into the acceptor chamber of the electrodialysis apparatus; and

[0288] The delivery of the carbon dioxide / carbon dioxide derivative in step c) is achieved by means of a lift generated between the acceptor chamber and the absorption and release chamber.

[0289] The receptor chamber and the absorption and release chamber are separated from each other by the separation membrane;

[0290] The method described above includes step c3') after step c).

[0291] c3') Introduce the aqueous absorption and release medium containing bound carbon dioxide / carbon dioxide derivatives from step c) into the release device.

[0292] In a preferred embodiment, the method includes step c3) after step c3').

[0293] c3) In the release chamber, carbon dioxide as a gas phase is released from the absorption and release medium containing bound carbon dioxide / carbon dioxide derivatives from step c3').

[0294] Therefore, a preferred embodiment of the present invention relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, the method comprising the following steps:

[0295] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0296] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0297] c) The bound carbon dioxide / carbon dioxide derivative from the acceptor solution in step b) is transported through a separation membrane to an aqueous absorption and release medium.

[0298] In step b), the acceptor solution is in or introduced into the acceptor chamber of the electrodialysis apparatus; and

[0299] The delivery of the carbon dioxide / carbon dioxide derivative in step c) is achieved by means of the elevator effect generated between the acceptor chamber and the absorption and release chamber.

[0300] The receptor chamber and the absorption and release chamber are separated from each other by the separation membrane;

[0301] The method according to step c) includes steps c3') and c): after step c).

[0302] c3') Introducing the aqueous absorption and release medium containing bound carbon dioxide / carbon dioxide derivatives from step c) into the release device; and

[0303] c3) In the release chamber, carbon dioxide as a gas phase is released from the absorption and release medium containing bound carbon dioxide / carbon dioxide derivatives from step c3').

[0304] It was also found that the gas released in the release chamber / release device or from the absorption and release medium consisted of only or almost only carbon dioxide. It can be demonstrated that, in embodiments of the method according to the invention that include the release of carbon dioxide in gaseous form within the release device, no increase in resistance occurs during the electrophoretic transport of carbon dioxide / carbonate / bicarbonate anions within the electrodialysis apparatus due to gas release at the separation membrane or bubble formation in the absorption and release chamber.

[0305] The preferred method is one that recovers and obtains pure carbon dioxide gas.

[0306] The pure gas contains <0.5% by volume of impurities from other compounds.

[0307] In another preferred embodiment of the method, an ionic liquid is used as the release medium. Ionic liquids are particularly advantageous because they are generally insoluble in water and the anionic and cationic compounds constituting the ionic liquid do not migrate electrophoretically. Therefore, using an ionic liquid as the release medium in conjunction with an open membrane that separates the acceptor chamber from the absorption and release chambers is a particularly preferred embodiment of the method.

[0308] A preferred method is one in which a gas or gaseous compound and its derivatives are bound in an aqueous acceptor medium, and the gas / gaseous compound or its derivatives in the water are transported through a separation medium (separation membrane) by electrophoresis, thereby entering an absorption and release medium, wherein the absorption and release medium is an ionic liquid.

[0309] A preferred method is one in which a gas or gaseous compound and its derivatives are bound in an aqueous acceptor medium, and the gas / gaseous compound or its derivatives are transported in water through a separation medium (separation membrane) by electrophoresis, thereby entering the absorption and release medium of the ionic liquid, where they undergo chemical transformation.

[0310] In a particularly preferred embodiment, the separation of carbon dioxide from the gas / gas mixture is semi-continuous or continuous. For this purpose, an apparatus is preferred in which the dissolution / decomposition of carbon dioxide occurs in one of the aqueous acceptor solutions according to the invention, while simultaneously the separation of dissolved carbon dioxide or carbonate / bicarbonate anions from the acceptor solution. Selective separation of the combined carbon dioxide / carbonate / bicarbonate anions is preferably carried out by conveying them through a separation medium (separation membrane). A membrane is preferably used here as the separation medium to separate the dissolved carbon dioxide or carbonate / bicarbonate anions. Electrophoretic separation is preferred. For this purpose, an electrodialysis unit is particularly preferred. In one embodiment, a gas / gas mixture containing carbon dioxide is introduced into a chamber containing the acceptor solution. The gas / gas mixture, now reduced in carbon dioxide, leaving this chamber is then passed into the next chamber containing the acceptor solution; this arrangement can generally be repeated any number of times. Introduction can occur in the chamber containing the acceptor solution with the corresponding separation cell and in a container outside it, thereby establishing a recirculation between the container and the corresponding chamber of the separation unit. Preferably, the gas / gas mixture is dispersed as finely as possible in the acceptor medium. Existing techniques can be used for this purpose. This arrangement allows for the installation of a gas scrubbing tower, enabling the carbon dioxide-containing gas stream to sequentially contact the acceptor medium several times.

[0311] It has been demonstrated that after separating carbon dioxide / carbonate / bicarbonate anions from a receptor medium saturated with carbon dioxide, the receptor medium can be reused for dissolving, binding, and transporting carbon dioxide. In a particularly advantageous manner, this enables the recycling of the receptor medium, while carbon dioxide can be continuously or semi-continuously absorbed, transported, and separated without loss, and the receptor medium can be used for the method process again any number of times.

[0312] A preferred method is one in which the receptor medium is reused without loss after separating carbon dioxide / carbonate / bicarbonate anions from the receptor medium, in order to dissolve and bind carbon dioxide therein again.

[0313] It has been shown that gaseous carbon dioxide can fully enter and bind in an aqueous solution of a compound with guanidyl / amidino groups, provided that there are non-protonated free guanidyl / amidino groups of the dissolved receptor compound. It is not very important at what ratio carbon dioxide is present relative to other gaseous compounds / elements or whether it is a pure carbon dioxide gas stream. Under these conditions, depending on the contact time and the interface achieved between the aqueous receptor medium and the gas / gas mixture, carbon dioxide can be completely (<1 ppm) or almost completely (< / = 100 ppm) removed from the gas / gas mixture.

[0314] A preferred method is for removing carbon dioxide from a gas or gas mixture.

[0315] Therefore, for the first time, a method is provided by which carbon dioxide can be completely or almost completely removed from a gas or gas mixture by contacting it with an aqueous receptor medium at atmospheric pressure, and in which gaseous carbon dioxide in a very pure or pure form can then be selectively obtained again. Here, very pure means a carbon dioxide content > 99.5 vol%, and pure means a carbon dioxide content > 98.5 vol%.

[0316] In this regard, the method also relates to the selective separation and recovery of pure carbon dioxide and the production of pure carbon dioxide.

[0317] A preferred method is for the selective separation, recovery, and production of pure or very pure carbon dioxide.

[0318] It has been found that if the gas / gas mixture contains multiple gaseous compounds that form acids in water, these gaseous compounds can be absorbed into the acceptor medium, and therefore separation efficiency may be affected when only one of the gaseous compounds needs to be recovered. This is particularly true for gases produced during the fermentation of organic materials, or so-called "acidic natural gas," as well as flue gas or putrefactive gases. Furthermore, flue gas may contain solids that can cause ash formation (Versottung) in the acceptor solution. In a preferred embodiment of the method, all solid particles / liquids soluble in the aqueous medium or forming water-soluble reaction products therein, as well as gaseous compounds, are separated before the gas / gas mixture is contacted with the acceptor medium. This can be achieved using existing techniques.

[0319] Therefore, it is preferable to pre-purify the gas stream in which carbon dioxide is combined or combined and recovered.

[0320] A preferred method is one in which liquid and solid components, as well as gaseous components that do not correspond to carbon dioxide and are dissolved in water or form water-soluble reaction products upon contact with water, are separated / adsorbed before the gas / gas mixture containing carbon dioxide is brought into contact with the acceptor medium.

[0321] Therefore, a method for adsorbing, transporting, and selectively releasing carbon dioxide can be provided, wherein no corrosive or harmful compounds are used, and wherein the aqueous acceptor medium can be completely recycled and used to reabsorb carbon dioxide after the carbon dioxide bound therein is separated.

[0322] A preferred method is one in which an aqueous acceptor medium is provided for the absorption, transport, and selective release of carbon dioxide, wherein no corrosive or harmful compounds are used, and wherein the aqueous acceptor medium can be fully recycled and used for the re-adsorption of carbon dioxide after the carbon dioxide bound therein is separated.

[0323] Preferred is a method for reversibly binding a gaseous compound to a receptor compound dissolved in water in an aqueous receptor medium.

[0324] A preferred method is one in which the reversible binding between a gaseous compound and a water-soluble receptor compound present in an aqueous receptor medium is achieved through the reaction products of the gaseous compound and water.

[0325] A preferred method is one in which the reaction product of the gaseous compound with the aqueous phase of the aqueous acceptor medium is reversibly bound to the dissolved acceptor compound.

[0326] A preferred method is one in which gaseous compounds in an aqueous acceptor medium are bound to acceptor compounds, and wherein the bound gaseous compounds can be released again as gas by changes in the pH of the acceptor solution, by adding anionic compounds to replace the gaseous compounds, or by electrophoretic separation.

[0327] A preferred method is one in which a gaseous compound is bound in an aqueous receptor medium, followed by the release of the gaseous compound, wherein the receptor compound is regenerated and a receptor medium for rebinding the gaseous compound is subsequently provided.

[0328] It has been discovered that other types of method implementation schemes can be achieved through the method of the present invention for absorbing, transporting and selectively releasing carbon dioxide.

[0329] It has been found that hydrogen is released during the dissolution of carbon dioxide in an aqueous acceptor medium. Here, 0.5 to 2 moles of hydrogen can be generated for every mole of carbon dioxide bound in the acceptor medium. Hydrogen enters the gas / gas mixture as a gas and escapes upon contact with the acceptor medium. Hydrogen is a popular feedstock; therefore, in a preferred embodiment of the method, the amount of hydrogen available in the method embodiment according to the invention is recovered. In a preferred method embodiment, hydrogen generated during the process embodiment is adsorbed. Methods and apparatus for adsorbing and separating hydrogen are known in the prior art. For example, the gas / gas mixture collected after contact with the acceptor medium is guided through a medium suitable for binding and / or separating hydrogen therein and recovering and / or reacting directly or in a secondary cycle. In this respect, the method also relates to the production and recovery of hydrogen.

[0330] A preferred method involves producing hydrogen by contacting a gas / gas mixture containing carbon dioxide with a acceptor medium, and then adsorbing and / or separating and recovering the produced hydrogen. A preferred method for producing and recovering hydrogen involves contacting a gas / gas mixture with a acceptor medium. A preferred acceptor medium is used for producing and recovering hydrogen.

[0331] Surprisingly, it has been found that carbonates spontaneously form upon the presence or addition of a cationic compound (in which carbon dioxide has been absorbed or has been bound) to the aqueous acceptor medium of the present invention. It has also been found that solids form upon contact with a gas containing a water-soluble gaseous compound in the presence of sodium or calcium ions in the aqueous acceptor medium. Furthermore, it has been found that sodium carbonate or calcium carbonate forms when the water-soluble gaseous compound is carbon dioxide.

[0332] A preferred method is one in which a gaseous compound is bound in a receptor medium and comes into contact with one or more compounds thereon, wherein a physicochemical or chemical transformation occurs between the gaseous compound bound to the receptor compound or in its anionic form with at least one other compound.

[0333] A preferred method is one in which a gaseous compound in an acceptor medium is bound to an acceptor compound that is capable of and / or catalyzing a reaction between the bound gaseous compound or a gaseous compound in anionic form and one or more other compounds.

[0334] It was subsequently discovered that salts of alkali metals and alkaline earth metals dissolve very readily in the aqueous acceptor medium of this invention. Surprisingly, no reaction or only a very small exothermic reaction occurs compared to the dissolution process in water. This is particularly applicable to the dissolution of calcium, iron, and aluminum salts (e.g., calcium chloride, ferric chloride, or aluminum chloride). Surprisingly, this leads to further particularly advantageous pathways in the preparation of carbonates and bicarbonates.

[0335] When the acceptor solution of the present invention (containing, for example, dissolved aluminum chloride or ferric chloride) is introduced into a acceptor solution saturated with carbon dioxide, very fine white or light brown solid particles are formed, which exist in suspension under stirring and settle after stirring stops. The solids can be identified as aluminum carbonate or ferric carbonate. Surprisingly, when the acceptor solution containing dissolved salts is mixed into the acceptor solution saturated with carbon dioxide, gaseous carbon dioxide is released at or minimally under atmospheric conditions. Therefore, a method can be provided that enables the near-complete or complete chemical transformation of carbon dioxide / carbonate / bicarbonate anions bound in the acceptor medium under ambient pressure and at room temperature.

[0336] Therefore, in a highly advantageous manner, compounds (reactive compounds) that chemically transform with carbon dioxide and / or carbonate and / or bicarbonate anions can be easily, rapidly, and completely dissolved in an acceptor medium containing at least one acceptor compound without causing an exothermic reaction in the aqueous medium, thus contacting them with carbon dioxide / carbonate / bicarbonate anions without releasing carbon dioxide. It has been found that these beneficial effects also occur when the reactive compounds are provided in the same manner in the absorption and release medium or in the reaction medium used for chemical transformation.

[0337] A preferred method is one in which at least one reactive compound is introduced into a solution together with an acceptor compound, and the reactive compound dissolved therein is contacted with carbon dioxide and / or carbonate and / or bicarbonate anions to chemically react with the carbon dioxide and / or carbonate and / or bicarbonate anions.

[0338] It was further discovered that when an acceptor solution containing cation / cationic compounds that are already in dissolved form and can form carbonates and / or bicarbonates is contacted with a gas / gas mixture containing carbon dioxide, carbonates and / or bicarbonates are formed and precipitated during the intake process.

[0339] A preferred method is one in which gaseous compounds can undergo chemical transformation in an aqueous acceptor medium by binding them to dissolved acceptor compounds in the form of reaction products with water and by contacting them with other compounds in this form.

[0340] A preferred method is one in which at least one water-soluble inorganic or organic compound is dissolved in an aqueous acceptor medium, or solubilized such that at least one compound is partially or completely dissolved in the acceptor medium, and the acceptor medium is contacted with at least one gaseous compound simultaneously or after the dissolution of at least one compound, thereby resulting in a physicochemical or chemical transformation between at least one gaseous compound and at least one compound dissolved in the acceptor medium.

[0341] In another preferred embodiment of the method, the introduction of cation / cation compounds that can form carbonates or bicarbonates is carried out by selectively introducing them into the acceptor solution by means of electrophoresis. This is preferably carried out in a method arrangement in which an electrolyte solution in which cation / cation compounds suitable for forming carbonates or bicarbonates are present in dissolved form is introduced into an electrolyte chamber in an electrodialysis apparatus. This electrolyte chamber, instead of an absorption and release chamber, is connected to one of the acceptor chambers containing the acceptor solution, wherein a cation-selective membrane is located between the electrolyte chamber and the acceptor chamber, through which the chambers are electrically coupled to each other. Electrophoretic transport of the cation / cation compounds from the electrolyte chamber to the acceptor chamber is performed by applying a DC voltage between the anode chamber and the cathode chamber. Optionally, the acceptor chamber may contain an acceptor solution that has been saturated with carbon dioxide or continuously charged with carbon dioxide during the separation process. As disclosed in more detail below, chemical transformations of carbon dioxide and / or carbonate and / or bicarbonate with other compounds are also possible. Compounds that can react or transform with carbon dioxide and / or carbonate and / or bicarbonate by being in or transported to the acceptor medium, or compounds whose transformation with carbon dioxide and / or carbonate and / or bicarbonate anions (which are dissolved and transported by means of the acceptor medium) occurs outside the acceptor medium, are referred to below as reactive compounds.

[0342] Therefore, a conversion method can be provided in which a reactive compound is brought into contact with carbonate / bicarbonate anions and chemically reacts with them. As further described below, this conversion method can be designed into various embodiments and implemented with various reactive compounds.

[0343] Further investigation revealed that the improved solubility due to the alkalinity of the acceptor medium allows for the preparation of solutions with significantly higher concentrations than those achievable in pure water, particularly for the salts (and non-salt forms) of the reactant compounds. Experiments involving the introduction of a pure gas consisting of carbon dioxide or a mixture of gases containing carbon dioxide into a acceptor solution containing dissolved sodium, calcium, or aluminum salts showed that emulsion suspensions formed very rapidly. The resulting solids spontaneously precipitated, allowing for complete phase separation via an unstirred settling phase or settling zone. However, phase separation can also be achieved through centrifugation or filtration.

[0344] The carbonates or bicarbonates produced in this way are chemically pure and can exist directly as very small particles of <1 μm, or can be dispersed into very small particles with very little energy input.

[0345] It is undesirable for dissolved salt anions (e.g., chloride ions) to remain in the acceptor solution. Various existing techniques have been found to bind or separate anions of salts dissolved in the acceptor solution. In one embodiment, the separation of salt anions is performed via electrodialysis after the salt or a solution of salt has been introduced into the aqueous acceptor medium or after the aqueous acceptor medium has been contacted with a gas / gas mixture containing carbon dioxide.

[0346] A preferred method is one in which, after binding a gaseous compound or its anionic form, the acceptor medium is purified by means of electrodialysis or contact with an ion-exchange compound or adsorbent to remove anionic compounds other than hydroxide anions, thereby regenerating the acceptor compound present in the acceptor medium.

[0347] Therefore, the method also relates to the production of chemically pure carbonates and bicarbonates that can be obtained in powder form. Preferably, the carbonates and bicarbonates are in amorphous form.

[0348] A preferred method is one in which carbonates and / or bicarbonates can be obtained in chemically pure form by dissolving carbon dioxide or carbonate / bicarbonate anions in an aqueous acceptor medium containing dissolved compounds with guanidine and / or amido groups and binding them therein, and by contacting them with dissolved cationic / cationic compounds that can form carbonate or bicarbonate.

[0349] A preferred method is one in which cationic / cationic compounds capable of forming carbonates or bicarbonates are dissolved in an aqueous acceptor medium containing dissolved compounds with guanidine and / or amidoyl groups, and carbonates and bicarbonates are obtained in chemically pure form by contacting them, respectively, with carbon dioxide or carbonate / bicarbonate anions.

[0350] The preferred method is the preparation of carbonates and bicarbonates.

[0351] It has been discovered that such carbonates and bicarbonates can be produced by absorbing and dissolving carbon dioxide released from a renewable feedstock source according to the present invention, for example, during fermentation into biogas or wood combustion. Regenerated carbonates and bicarbonates can be produced when a regenerated cation / cation compound (which can be obtained, for example, by one of the methods of regenerating organic and inorganic compounds) and renewable energy are used in the implementation of this method.

[0352] The preferred method is for producing recycled carbonates and bicarbonates.

[0353] Regenerated carbonates and bicarbonates are preferred.

[0354] Therefore, in another aspect of the invention, the method also involves providing carbon dioxide or carbonate / bicarbonate anions at a high concentration in an aqueous acceptor medium and causing them to undergo chemical transformation with other compounds therein.

[0355] A preferred method is one in which carbon dioxide or carbonate / bicarbonate anions are provided at a high concentration in an aqueous acceptor medium, and therein they undergo chemical transformation with other compounds.

[0356] Therefore, the method also relates to a conversion method in which reaction products can be obtained by converting organic and / or inorganic compounds with dissolved or dissolved and transported gaseous / gaseous compounds and / or their derivatives.

[0357] A preferred method is a conversion process in which organic and / or inorganic compounds are contacted and converted with dissolved or dissolved and transported gaseous / gaseous compounds and / or their derivatives.

[0358] Preferably, the reaction products can be obtained by the conversion of organic and / or inorganic compounds with dissolved or dissolved and transported gaseous / gaseous compounds and / or their derivatives.

[0359] Preferred methods are those for selectively binding, transporting, activating, converting, and / or releasing carbon dioxide.

[0360] Therefore, this task is solved by a method in which carbon dioxide is dissolved in an aqueous medium containing dissolved compounds with guanidine and / or amidine groups, and stored therein and / or transported therein and / or converted therein and / or released therein.

[0361] As described above, it was surprisingly found that the solubility of carbon dioxide in aqueous media significantly increased compared to pure water through the dissolution of compounds containing free guanidine and / or amidine groups, and the carbon dioxide remained bound in the aqueous solution. Further surprising was the observation that the solubility of compounds containing guanidine and / or amidine groups could increase with increasing amounts of bound carbon dioxide. For example, for arginine, whose solubility limit in water at 20°C is 0.6 mol / L (or, depending on the source, approximately 150 g / L at 20°C, and 150 g–0.86 mol, M(arginine) = 174.20 g / mol), greater than 3 mol / L (522.6 g / L) has been found to dissolve or enter the solution simultaneously with the introduction of carbon dioxide. During this process, the aqueous medium remained clear and the pH was between 10 and 12.5. It has been found that carbon dioxide or its reaction products in water, such as carbonate and bicarbonate anions, dissolve under pressure (at atmospheric or normal pressure) in an aqueous solution containing dissolved compounds with guanidine and / or amidine groups, and bind therein at a molar ratio > / = 1:1. Therefore, by dissolving (at atmospheric or normal pressure) compounds with free guanidine and / or amidine groups in an aqueous medium, carbon dioxide or carbonate / bicarbonate anions can bind under pressure (at atmospheric or normal pressure) at concentrations preferably >0.5 mol / L, more preferably >1.0 mol / L, more preferably >1.5 mol / L, more preferably >2.0 mol / L, more preferably >2.5 mol / L, more preferably >3.0 mol / L, and even more preferably >3.5 mol / L.

[0362] In a preferred embodiment, the aqueous solution for absorbing, transporting, converting, releasing, and / or storing carbon dioxide is provided in the form of an acceptor solution. Preferably, the acceptor solution is provided in an acceptor chamber or acceptor device.

[0363] The acceptor device includes means adapted to generate the maximum possible exchange area between the gas / gas mixture and the acceptor medium and / or adapted to contact the gas / gas mixture with the acceptor medium. For this purpose, prior art methods are known.

[0364] One form is a gas scrubbing device (see also...) Figure 1 Therefore, a method comprising contacting a carbon dioxide-containing gas with the acceptor solution from step a) in a gas scrubbing apparatus or gas scrubbing tower is preferred.

[0365] In the case of gas mixtures containing non-gaseous components, it is preferable to first remove the non-gaseous components from the gas mixture, for example, by filtration or washing the gas with another liquid. Methods for separating non-gaseous components in the prior art are known to those skilled in the art. In a preferred embodiment, the gas containing carbon dioxide is filtered and / or washed to remove non-gaseous components before contact with the acceptor solution according to the invention. To remove unwanted gases such as H2S and NH3 or SO2, as well as acidic gases other than carbon dioxide, these can be washed out from the carbon dioxide-containing gas in an upstream gas scrubbing tower.

[0366] Preferably, the gas mixture is first washed with an acidic solution. Surprisingly, it has been found that when subsequently contacted with a acceptor solution, the carbon dioxide concentration of the gas / gas mixture can decrease significantly faster than in cases where the gas mixture has not been pre-activated by contacting it with an acidic solution.

[0367] This invention preferably relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0368] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0369] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0370] c) Transfer the carbon dioxide / carbon dioxide derivative bound in the acceptor solution from step b) to an aqueous absorption and release medium via a separation membrane; or

[0371] Storage and / or delivery of the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b),

[0372] Before step b), the gas containing carbon dioxide is washed with an acidic solution.

[0373] This invention preferably relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0374] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0375] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0376] c) Storing and / or delivering the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b); and / or

[0377] The bound carbon dioxide / carbon dioxide derivatives in the acceptor solution from step b) are transported through a separation membrane to an aqueous absorption and release medium.

[0378] Before step b), the gas containing carbon dioxide is washed with an acidic solution.

[0379] A preferred method involves activating the gas mixture by contacting it with an acidic solution, thereby improving the solubility of carbon dioxide in the acceptor medium. In a preferred embodiment, the carbon dioxide-containing gas is washed with an acidic solution before contact with the acceptor solution according to the invention. In principle, any acid or acid-forming compound can be used for this purpose. Preferred acids are HCl (hydrochloric acid), sulfuric acid, or phosphoric acid. In a preferred embodiment, the carbon dioxide-containing gas is washed with an acidic solution selected from hydrochloric acid, sulfuric acid, or phosphoric acid before contact with the acceptor solution according to the invention.

[0380] In addition to the methods already mentioned above for direct contact between aqueous acceptor media and gas / gas mixtures, methods for achieving indirect contact between gaseous and liquid media have also been investigated. It has been shown that carbon dioxide or its water-soluble derivatives can be separated from an aqueous acceptor solution containing carbon dioxide using a solid or semi-solid separation medium (gas / liquid separation membrane), thereby efficiently and selectively delivering carbon dioxide or its derivatives into the aqueous acceptor medium. In a preferred embodiment, the indirect contact between the gas and liquid phases is achieved via a membrane contactor.

[0381] Therefore, a preferred method is one that includes the step of contacting a gas containing carbon dioxide with the acceptor solution from step a) via a membrane contactor.

[0382] In a membrane contactor, the phases to be contacted are separated from each other by a membrane. In a preferred embodiment, the contact between the aqueous acceptor medium and the gas / gas mixture is carried out via a membrane contactor. Surprisingly, it has been found that when open-cell membranes are used in such membrane contactors, they allow very high diffusion rates of water-soluble gases or gaseous compounds from the gas phase to the liquid phase. It has been found that the high diffusion / transport rate of gaseous water-soluble compounds is due to the properties of the acceptor medium. For example, the surface tension of an aqueous acceptor solution is no different from that of water compared to prior art aqueous absorbent media (such as alkanolamine solutions). In contrast, the surface tension is reduced in the case of absorbent compounds with surfactant or alcohol properties. Therefore, open-cell membranes are unsuitable when using aqueous solutions of absorbent compounds with prior art properties because liquid leakage occurs. It has been shown that, under atmospheric pressure conditions, neither the gas nor liquid side leaks through or from an open-cell membrane with an average pore size of 200 μm. It has been demonstrated that complete extraction of carbon dioxide can be achieved in a membrane contactor device with a significantly smaller footprint than a gas scrubbing device equipped with packing material, by utilizing the configuration possibilities of membrane contactors. For example, planar membrane modules can be provided, having very flat channels for both the gas and liquid phases on one side, while having relatively short channel lengths. This allows for the design of membrane contactor structures that can be optimally adapted in terms of flow technology to various gas / gas compositions and volumetric flow rates. Various structural forms, such as wound modules, hollow fiber modules, or tubular modules, are known in the prior art.

[0383] The preferred membrane / solid separation medium for the step of contacting a carbon dioxide-containing gas with the acceptor solution according to the invention has a low construction height. (Membrane thickness). This is preferably <300 μm, more preferably <200 μm, more preferably <150 μm, more preferably <100 μm, more preferably <50 μm, and even more preferably <25 μm. Therefore, a method comprising contacting a carbon dioxide-containing gas with the acceptor solution of step a) at atmospheric pressure using a gas-liquid separation membrane having an average pore size of 200 μm is preferred. Therefore, a method comprising contacting a carbon dioxide-containing gas with the acceptor solution of step a) using a membrane having a membrane thickness of <300 μm, more preferably <200 μm, more preferably <150 μm, more preferably <100 μm, more preferably <50 μm, and even more preferably <25 μm is preferred. Therefore, a preferred method is one that includes contacting a carbon dioxide-containing gas with the acceptor solution of step a) at atmospheric pressure using a membrane with an average pore size of 200 μm, wherein the membrane thickness is <300 μm, more preferably <200 μm, further preferably <150 μm, more preferably <100 μm, further preferably <50 μm, and even more preferably <25 μm. Alternatively, a preferred method is one that includes contacting a carbon dioxide-containing gas with the acceptor solution of step a) using a membrane with an average pore size >10 μm, more preferably >50 μm, more preferably >100 μm, more preferably >150 μm, more preferably >200 μm, even more preferably >250 μm, and most preferably >300 μm. Therefore, a preferred method is one that includes contacting a carbon dioxide-containing gas with the acceptor solution of step a) at atmospheric pressure using a membrane with an average pore size >10 μm, more preferably >50 μm, more preferably >100 μm, more preferably >150 μm, more preferably >200 μm, even more preferably >250 μm and most preferably >300 μm, wherein the membrane has a membrane thickness of <300 μm, more preferably <200 μm, even more preferably <150 μm, more preferably <100 μm, even more preferably <50 μm and even more preferably <25 μm. Therefore, a preferred method is one that includes contacting a carbon dioxide-containing gas with the acceptor solution of step a) using a membrane with an average pore size >10 μm, more preferably >50 μm, more preferably >100 μm, more preferably >150 μm, more preferably >200 μm, even more preferably >250 μm and most preferably >300 μm, wherein the membrane has a membrane thickness of <300 μm, more preferably <200 μm, even more preferably <150 μm, more preferably <100 μm, even more preferably <50 μm and even more preferably <25 μm.

[0384] In this context, the membrane / foil can be fixed to or connected to a carrier material. Preferred are open-cell membrane / solid separation media, i.e., exhibiting continuous channels or channel-like structures with openings on both sides of the membrane / solid separation medium. In the prior art, average channel diameter or average pore size has been reported. Preferred membrane / solid separation media have open channels with an average channel diameter or average pore size >10 μm, more preferably >50 μm, more preferably >100 μm, more preferably >150 μm, more preferably >200 μm, even more preferably >250 μm, and most preferably >300 μm. Preferred are membrane / solid separation media with high porosity (number of pores per unit area). Preferred are membrane / solid separation media with a porosity >50%, more preferably >60%, more preferably >70%, more preferably >80%, and even more preferably >90%. In principle, any material that can be used to produce prior art membrane / solid separation media is suitable for the method according to the invention. Selection is preferably made according to the specific application. For example, in applications where a hot gas / gas mixture (e.g., >130°C) is contacted with a membrane, a heat-resistant material is preferred. Suitable materials in this regard include PTFE (polytetrafluoroethylene) or PC (polycarbonate) or ceramic membranes. Therefore, a preferred method includes the following steps: contacting a carbon dioxide-containing gas with a acceptor solution from step a) using a membrane having an average pore size >10 μm, more preferably >50 μm, more preferably >100 μm, more preferably >150 μm, more preferably >200 μm, more preferably >250 μm, more preferably >300 μm, wherein the membrane has a thickness <300 μm, more preferably <200 μm, more preferably <150 μm, more preferably <100 μm, more preferably <50 μm, and even more preferably <25 μm, wherein the membrane is selected from polytetrafluoroethylene (PTFE) membranes, polycarbonate (PC) membranes, or ceramic membranes.

[0385] Particularly suitable materials can be selected for different applications when manufacturing membrane / solid separation media. For example, in a preferred embodiment of a method using air as the gas phase to remove carbon dioxide, a membrane with hydrophobic surface properties, measurable by a water contact angle >90°, is preferably used. Preferably, the membrane also exhibits lipophilic surface properties, measurably measured by a contact angle <10° with oleic acid, for example. In a further preferred embodiment where air is used as the gas phase, a membrane / solid separation media according to the invention is used, which is further endowed with a hydrophilic surface coating. Preferably, the hydrophilic surface coating also exhibits hydrostatic properties.

[0386] It has been shown that membrane contactors can also be used to remove gaseous components other than carbon dioxide from gaseous mixtures, provided that they are water-soluble and absorbed by the receptor medium according to the invention.

[0387] In a preferred embodiment of the method, a very high overflow rate of the liquid and / or gas phase is set at the membrane / solid separation medium of the membrane contactor.

[0388] The acceptor solution contains at least one water-soluble acceptor compound. The acceptor compound may be completely or incompletely dissolved. Preferably, the absorption of carbon dioxide by the acceptor solution / thorough mixing of the acceptor solution with carbon dioxide occurs during the guiding of the gas / gas mixture through / contact with the acceptor solution.

[0389] At least one soluble / soluble compound in the acceptor solution preferably gives the solution an alkaline pH. The pH of the acceptor solution is preferably between 7 and 14, more preferably between 8 and 13, and even more preferably between 9 and 12.5. In other words, a pH between 7 and 14, more preferably between 8 and 13, and even more preferably between 9 and 12.5 is established when the acceptor compound dissolves.

[0390] Preferred water-soluble receptor compounds have at least one guanidine and / or amidine group. Receptor compounds having a guanidine and / or amidine group are preferred, and receptor compounds having a free guanidine and / or amidine group are more preferred. In some embodiments, receptor compounds having an amidine group are preferred, and receptor compounds having a free amidine group are more preferred. In some embodiments, receptor compounds having a guanidine group are preferred, and receptor compounds having a free guanidine group are more preferred. Water-soluble compounds with a free guanidine group are particularly preferred.

[0391] A particularly preferred compound containing a guanidine group is the amino acid arginine. The preferred concentration of the acceptor compound in the acceptor solution is 10 μmol to 10 mol / L, more preferably 10 mmol / L to 5 mol / L, and even more preferably 0.1 mol / L to 3 mol / L. It should be noted that the solubility of the acceptor compound can be increased by the combination with carbon dioxide. Therefore, the acceptor compound can be added while contacting the acceptor solution with a gas containing carbon dioxide.

[0392] The temperature at which the acceptor solution comes into contact with the gas / gas phase can, in principle, be from 0 to 100°C. The preferred temperature for contacting the gas / gas mixture with the acceptor solution is from 1 to 60°C, more preferably from 10 to 35°C, and even more preferably from 15 to 30°C.

[0393] Surprisingly, this acceptor solution is particularly suitable for pressurized (at atmospheric or normal) storage of dissolved carbon dioxide. It has been shown that the acceptor solution containing both dissolved and bound carbon dioxide remains stable over a 12-month period, with no separation of carbon dioxide or microbial colonization of the medium. Remarkably, even at high concentrations of arginine (e.g., 3 mol / L), and even when stored at 3°C, no crystallization or precipitation of arginine occurs.

[0394] The aqueous acceptor solution according to the invention is preferably a solution of one, two, or more amino acids and / or peptides, present at individual and / or total concentrations of 10 mmol / L to 15 mol / L, more preferably 100 mmol / L to 10 mol / L, and even more preferably 0.1 mol / L to 5 mol / L. These can be L- or D-forms of the compounds or racemic mixtures. Preferred amino acids are arginine, and more preferably their derivatives. Particularly preferred are basic amino acids and peptides having cationic groups (positively charged functional groups). Peptides that can be used according to the invention can be di-, tri-, and / or polypeptides. The peptides according to the invention have at least one functional group that binds or can bind protons. Therefore, the preferred molecular weight is less than 500 kDa, more preferably <250 kDa, even more preferably <100 kDa, and particularly preferably <1000 Da. Therefore, preferred functional groups are in particular guanidinyl, amidine, amino, amide, hydrazine, hydrazone, hydroxyimino, or nitro groups. Therefore, amino acids can have a single functional group or contain several functional groups from the same compound class or one or more different compound classes.

[0395] Preferably, the amino acids and peptides according to the invention have at least one positively charged group (cationic group / positively charged functional group), or have a positive total charge. Particularly preferred peptides contain at least one of the amino acids arginine, lysine, and histidine in any number and order.

[0396] Particularly preferred are amino acids and / or their derivatives having at least one guanidine and / or amidine group. However, other acceptor compounds having at least one guanidine and / or amidine group are also preferred. The guanidine group is the chemical residue H₂N–C(NH)–NH₻ and its cyclic form, while the amidine group is the chemical residue H₂N–C(NH)₻ and its cyclic form. These guanidine and amidine compounds preferably have a K₂O group of less than 6.3 kJ / mL between n-octanol and water. OW The allocation coefficient K of <6.3) OW .

[0397] Arginine derivatives are particularly preferred.

[0398] Arginine derivatives are defined as compounds having a guanidinium and a carboxyl group or an amidine and a carboxyl group, wherein the guanidinium and the carboxyl group or the amidine and the carboxyl group are separated by at least one carbon atom, i.e., at least one of the following groups is located between the guanidinium or the amidine and the carboxyl group: -CH2-, -CHR-, -CRR'-, where R and R' independently represent any chemical residue. Naturally, the distance between the guanidinium and the carboxyl group or the amidine and the carboxyl group can exceed one carbon atom, for example, in the case of the following groups: -(CH2)n-, -(CHR)n-, -(CRR')n-, where n = 2, 3, 4, 5, 6, 7, 8, or 9, as in amidine propionic acid, amidine butyric acid, guanidinium propionic acid, or guanidinium butyric acid. Compounds having more than one guanidinium group and more than one carboxyl group include, for example, oligoarginine and polyarginine. Other examples of compounds that fall into this definition include guanidinoacetic acid, creatine, and guanidinoacetic acid (Glycocyamin).

[0399] Preferred compounds share the common characteristic of having general formula (I) or (II).

[0400]

[0401] in

[0402] R,R',R”,R”' and R”” independently represent -H, -CH=CH2, -CH2-CH=CH2, -C(CH3)=CH2, -CH=CH-CH3, -C2H4-CH=CH2, -CH3, -C2H5, -C3H7, -CH(CH3)2, -C4H9, -CH2-CH(CH3)2, -CH(CH3)-C2H5, -C(CH3)3, -C5H 11 , -CH(CH3)-C3H7, -CH2-CH(CH3)-C2H5, -CH(CH3)-CH(CH3)2, -C(CH3)2-C2H5, -CH2-C(CH3)3, -CH(C2H5)2, -C2H4-CH(CH3)2, -C6H 13 -C7H 15 Cyclic -C3H5, Cyclic -C4H7, Cyclic -C5H9, Cyclic -C6H 11 , -C≡CH, -C≡C-CH3, -CH2-C≡CH, -C2H4-C≡CH, -CH2-C≡C-CH3,

[0403] Or R' and R” together form the following groups: -CH2-CH2-, -CO-CH2-, -CH2-CO-, -CH=CH-, -CO-CH=CH-, -CH=CH-CO-, -CO-CH2-CH2-, -CH2-CH2-CO-, -CH2-CO-CH2-, or -CH2-CH2-CH2-.

[0404] X represents -NH-, -NR””-, or -CH2- or a substituted carbon atom; and

[0405] L represents a C1-C8 linear or branched and saturated or unsaturated carbon chain having at least one substituent selected from the following:

[0406] -NH2,-OH,-PO3H2,-PO3H - ,-PO3 2- ,-OPO3H2,-OPO3H-,-OPO3 2- ,-COOH,-COO - ,-CO-NH2,-NH3 + ,-NH-CO-NH2,-N(CH3)3 + ,-N(C2H5)3 + ,-N(C3H7)3 + ,-NH(CH3)2 + ,-NH(C2H5)2 + ,-NH(C3H7)2 + ,-NHCH3,-NHC2H5,-NHC3H7,-NH2CH3 + ,-NH2C2H5 + ,-NH2C3H7 + ,-SO3H,-SO3 - ,-SO2NH2,-C(NH)-NH2,-NH-C(NH)-NH2,-NH-COOH, or

[0407]

[0408] Preferably, the carbon chain L is in the range of C1-C7, more preferably in the range of C1-C6, more preferably in the range of C1-C5, and most preferably in the range of C1-C4.

[0409] Preferably, L represents -CH(NH2)-COOH, -CH2-CH(NH2)-COOH, -CH2-CH2-CH(NH2)-COOH, -CH2-CH2-CH2-CH(NH2)-COOH, -CH2-CH2-CH2-CH2-CH(NH2)-COOH or -CH2-CH2-CH2-CH2-CH2-CH(NH2)-COOH.

[0410] Preferred compounds are those of general formula (III) having a free guanidine group and / or an amidine group, as shown below:

[0411]

[0412] The groups X and L have the meanings shown in this article.

[0413] Preferred compounds having a free guanidine group and / or an amidine group share the general formula (III) as a common characteristic:

[0414]

[0415] in

[0416] X represents -NH-, -NR””-, or -CH2-, or a substituted carbon atom; and

[0417] L represents a linear or branched and saturated or unsaturated carbon chain of C1-C8, having at least one substituent selected from the following: -NH2, -OH, -PO3H2, -PO3H-, -PO3 2- ,-OPO3H2,-OPO3H - ,-OPO3 2- ,-COOH,-COO - ,-CO-NH2,-NH3 + ,-NH-CO-NH2,-N(CH3)3 + ,-N(C2H5)3 + ,-N(C3H7)3 + ,-NH(CH3)2 + ,-NH(C2H5)2 + ,-NH(C3H7)2 + ,-NHCH3,-NHC2H5,-NHC3H7,-NH2CH3 + ,-NH2C2H5 + ,-NH2C3H7 + ,-SO3H,-SO3 - ,-SO2NH2,-C(NH)-NH2,-NH-C(NH)-NH2,-NH-COOH, or

[0418]

[0419] R”' means -H, -CH=CH2, -CH2-CH=CH2, -C(CH3)=CH2, -CH=CH-CH3, -C2H4-CH=CH2, -CH3, -C2H5, -C3H7, -CH(CH3)2, -C4H9, -CH2-CH(CH3)2, -CH(CH3)-C2H5, -C(CH3)3, -C5H 11 , -CH(CH3)-C3H7, -CH2-CH(CH3)-C2H5, -CH(CH3)-CH(CH3)2, -C(CH3)2-C2H5, -CH2-C(CH3)3, -CH(C2H5)2, -C2H4-CH(CH3)2, -C6H 13 -C7H 15 Cyclic -C3H5, Cyclic -C4H7, Cyclic -C5H9, Cyclic -C6H 11 , -C≡CH, -C≡C-CH3, -CH2-C≡CH, -C2H4-C≡CH, -CH2-C≡C-CH3.

[0420] Preferably, the carbon chain L is in the range of C1-C7, more preferably in the range of C1-C6, even more preferably in the range of C1-C5, and most preferably in the range of C1-C4.

[0421] Preferably, L represents -CH(NH2)-COOH, -CH2-CH(NH2)-COOH, -CH2-CH2-CH(NH2)-COOH, -CH2-CH2-CH2-CH(NH2)-COOH, -CH2-CH2-CH2-CH2-CH(NH2)-COOH, or -CH2-CH2-CH2-CH2-CH2-CH(NH2)-COOH.

[0422] Preferred compounds having a free guanidine group and / or an amidine group share the general formula (I) as a common characteristic.

[0423]

[0424] in

[0425] X represents a -NH- or -CH2- or substituted carbon atom, and

[0426] L represents a linear or branched and saturated or unsaturated carbon chain of C1-C8, having at least one substituent selected from the following:

[0427] -NH2,-OH,-PO3H2,-PO3H - ,-PO32- ,-OPO3H2,-OPO3H - ,-OPO3 2- ,-COOH,-COO - ,-CO-NH2,-NH3 + ,-NH-CO-NH2,-N(CH3)3 + ,-N(C2H5)3 + ,-N(C3H7)3 + ,-NH(CH3)2 + ,-NH(C2H5)2 + ,-NH(C3H7)2 + ,-NHCH3,-NHC2H5,-NHC3H7,-NH2CH3 + ,-NH2C2H5 + ,-NH2C3H7 + ,-SO3H,-SO3 - ,-SO2NH2,-C(NH)-NH2,-NH-C(NH)-NH2,-NH-COOH or

[0428]

[0429] Preferably, the carbon chain L is in the range of C1-C7, more preferably in the range of C1-C6, even more preferably in the range of C1-C5, and most preferably in the range of C1-C4.

[0430] Preferably, L represents -CH(NH2)-COOH, -CH2-CH(NH2)-COOH, -CH2-CH2-CH(NH2)-COOH, -CH2-CH2-CH2-CH(NH2)-COOH, -CH2-CH2-CH2-CH2-CH(NH2)-COOH, or -CH2-CH2-CH2-CH2-CH2-CH(NH2)-COOH.

[0431] This invention preferably relates to a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, comprising the following steps:

[0432] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group;

[0433] b) Contact the gas containing carbon dioxide with the acceptor solution from step a); and

[0434] c) Transfer the carbon dioxide / carbon dioxide derivative bound in the acceptor solution from step b) to an aqueous absorption and release medium via a separation membrane; or

[0435] Storage and / or delivery of the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b),

[0436] The receptor compound described thereon has the general formula (I):

[0437]

[0438] in

[0439] X represents -NH-, -NR””-, or -CH2-, or a substituted carbon atom; and

[0440] L represents a linear or branched and saturated or unsaturated carbon chain of C1-C8, having at least one substituent selected from the following:

[0441] NH2,-OH,-PO3H2,-PO3H - ,-PO3 2- ,-OPO3H2,-OPO3H - ,-OPO3 2- ,-COOH,-COO - ,-CO-NH2,-NH3 + ,-NH-CO-NH2,-N(CH3)3 + ,-N(C2H5)3 + ,-N(C3H7)3 + ,-NH(CH3)2 + ,-NH(C2H5)2 + ,-NH(C3H7)2 + ,-NHCH3,-NHC2H5,-NHC3H7,-NH2CH3 + ,-NH2C2H5 + ,-NH2C3H7 + ,-SO3H,-SO3 - ,-SO2NH2,-C(NH)-NH2,-NH-C(NH)-NH2,-NH-COOH, or

[0442]

[0443] R"' means -H,-CH=CH2,-CH2-CH=CH2,-C(CH3)=CH2,-CH=CH-CH3,-C2H4-CH=CH2,-CH3,-C2H5,-C3H7,-CH(CH3)2,-C4H9,-CH2-CH(CH3)2,-CH(CH3)-C2H5,-C(CH3)3,-C5H 11,-CH(CH3)-C3H7,-CH2-CH(CH3)-C2H5,-CH(CH3)-CH(CH3)2,-C(CH3)2-C2H5,-CH2-C(CH3)3,-CH(C2H5)2,-C2H4-CH(CH3)2,-C6H 13 ,-C7H 15 ,C3H5 ring,C4H7 ring,C5H9 ring,C6H 11 ,-C≡CH,-C≡C-CH3,-CH2-C≡CH,-C2H4-C≡CH,-CH2-C≡C-CH3,

[0444] L is in the range of C1-C7, more preferably in the range of C1-C6, even more preferably in the range of C1-C5, and most preferably in the range of C1-C4, wherein L preferably represents -CH(NH2)-COOH, -CH2-CH(NH2)-COOH, -CH2-CH2-CH(NH2)-COOH, -CH2-CH2-CH2-CH(NH2)-COOH, -CH2-CH2-CH2-CH2-CH(NH2)-COOH or -CH2-CH2-CH2-CH2-CH2-CH(NH2)-COOH.

[0445] The acceptor solution according to the invention may contain other compounds that do not have guanidine and / or amidine groups and have an advantageous effect on the implementation of the method. These compounds may be, for example, base-forming compounds such as lysine and histidine. In addition, the acceptor solution may contain, for example, compounds that have antimicrobial activity or alter the surface tension of the medium.

[0446] The preferred method is one in which the receptor compound is an amino acid and the pH of the receptor solution is in the range between 8 and 13.

[0447] In another preferred embodiment, the aqueous acceptor medium contains other compounds or additives. Preferred other compounds are, in particular, potassium hydroxide and sodium hydroxide. Surprisingly, it has been shown that, when a DC voltage is applied, the presence of these compounds enables low-energy-consumption separability of carbon dioxide or carbonate / bicarbonate anions bound in the acceptor medium.

[0448] Alkaline solutions of potassium (KOH) or sodium (NaOH) improve the conductivity (electrolyzability) of water depending on their concentration. The initiation voltage for water electrolysis also decreases, depending on the electrode configuration chosen, ranging from 0.6 to 2 volts. It has been found that water electrolysis does not occur in a mixture of a solution containing arginine as an acceptor compound and a potassium hydroxide or sodium hydroxide solution; this is the case in the absence of arginine, but in aqueous solutions of the same concentration of potassium hydroxide or sodium hydroxide. For example, after 30 minutes in an electrolysis apparatus, when a voltage of 12V is applied to a 3% NaOH solution, 18.2 mL of oxygen is produced at the anode and 6.4 mL of hydrogen is produced at the cathode. Using the same experimental apparatus, no gas formation was observed with a 2-molar arginine solution containing 3 wt% NaOH. Using the same experimental apparatus, with a 2-molar arginine solution already saturated with carbon dioxide, no gas formation was observed within a 30-minute time period when a voltage of 12V was applied. When NaOH is added to the solution to make a 3 wt% solution, 7.8 ml of gas is formed at the cathode under the same conditions (12 V), but no gas is formed at the anode. The gas formed at the cathode is carbon dioxide. Therefore, it can be shown that when a DC voltage is applied, bicarbonate / carbonate anions bound in the acceptor medium can be separated into carbon dioxide at the cathode due to the presence of hydroxide ions. It has been shown that for DC voltages above 40 V, even for a 4 wt% NaOH or KOH solution containing arginine and dissolved carbon dioxide / bicarbonate / carbonate anions, no electrolysis of water leading to oxygen formation occurs. However, at higher DC voltages, a considerable amount of carbon dioxide is released at the cathode. Therefore, it has been surprisingly shown that the presence of caustic soda and / or sodium caustic soda solution in the aqueous acceptor solution according to the invention can lead to bicarbonate-carbonate anion separation and gaseous carbon dioxide release at the cathode during the application of a DC voltage to a carbon dioxide-rich acceptor solution, thereby preventing the electrolysis of water that would lead to the production of oxygen and hydrogen. This allows for the very efficient use of the electricity required to separate and recover carbon dioxide from the acceptor solution.

[0449] It was subsequently discovered that the presence of an alkaline solution in the receptor fluid increased the receptor solution's ability to absorb carbon dioxide, without the formation of potassium carbonate or sodium carbonate precipitates, a situation that would occur when the receptor medium did not contain the receptor compound of the present invention. This implies that carbon dioxide preferentially reacts with arginine.

[0450] This further demonstrates that the presence of alkali has no effect on the storage performance of the acceptor solution. In particular, carbon dioxide is not spontaneously released from the acceptor solution in the presence of alkali.

[0451] Therefore, adding a caustic soda solution or a caustic potassium solution to the aqueous acceptor medium is a particularly preferred embodiment of the method according to the present invention.

[0452] Preferably, NaOH and / or KOH are added to the aqueous acceptor solution to form a concentration of 0.01% to 10% by weight, more preferably 0.5% to 8% by weight, more preferably 1% to 6% by weight, and more preferably 2% to 5% by weight. In another preferred embodiment of the method, an aqueous acceptor solution containing potassium hydroxide or sodium hydroxide with a pH of 12 to 14 is provided.

[0453] A preferred method is one in which the aqueous receptor medium containing the dissolved receptor compound further contains a caustic potassium and / or caustic sodium solution.

[0454] A preferred method is one in which a solution of caustic potassium and / or sodium caustic soda is added to an acceptor solution containing dissolved carbon dioxide / bicarbonate / carbonate anions, resulting in electroless electrophoretic separation of the bicarbonate / carbonate anions and the separation forming gaseous carbon dioxide as the gas phase.

[0455] The corrosivity of the acceptor medium increases with increasing concentration of NaOH or KOH. For example, decomposition of electrode materials made of carbon or aluminum may occur.

[0456] It has been found that sodium and / or potassium salts can also improve the electrophoretic separation of carbon dioxide or its derivatives from the receptor media of the present invention.

[0457] For example, it was shown that when sodium citrate, sodium sulfate, or potassium tartrate was added to a 2-molar arginine solution, resulting in 8-14% by weight of salt solution in each case, the electrophoretic separation of carbon dioxide was improved compared to using NaOH or KOH, while the pH of the solution remained <12.5.

[0458] Studies on the binding capacity of aqueous acceptor solutions containing dissolved sodium and / or potassium salts to carbon dioxide or its water-soluble derivatives have shown that this can increase depending on the concentration. Therefore, by providing aqueous acceptor solutions containing dissolved sodium and / or potassium salts in addition to the acceptor compound according to the invention, the absorption capacity of the acceptor solution for carbon dioxide or its derivatives can be improved. It has been shown that neither the absorption nor desorption of carbon dioxide by electrophoresis leads to the formation of solids. The preferred concentration of the sodium or potassium salt in the acceptor solution according to the invention is 0.1% to 25% by weight, more preferably 1% to 20% by weight, and even more preferably 2% to 15% by weight. The preferred counterion of the salt is sulfate (SO4). 2- phosphate PO4 3-The salts are acetate, citrate, tartrate, and oxalate. They can be added to the acceptor solution alone or in any combination. The pH of the acceptor solution containing dissolved sodium and / or potassium salts is preferably between 8.0 and 13.5, more preferably between 8.5 and 13, and even more preferably between 9 and 12.5. The preferred acceptor solutions containing sodium and / or potassium salts are non-corrosive.

[0459] A preferred method is one in which an aqueous acceptor solution containing at least one dissolved acceptor compound and at least one dissolved sodium and / or potassium salt is provided for the absorption of carbon dioxide, wherein carbon dioxide or its derivatives are dissolved / bound therein.

[0460] It has been found that, under atmospheric pressure, carbon dioxide is not spontaneously released even when the acceptor solution contains sodium and / or potassium salts and has been saturated with carbon dioxide.

[0461] A preferred method is one in which carbon dioxide can bind to an aqueous acceptor solution for more than 12 months under pressureless conditions (atmospheric or normal pressure).

[0462] It has been found that this property also enables the transport of carbon dioxide in aqueous acceptor solutions in a pressureless manner (at atmospheric or normal pressure).

[0463] Preferred is a method in which carbon dioxide can be transported without pressure (at atmospheric or normal pressure) by means of an aqueous acceptor solution.

[0464] A preferred method is one in which an acceptor solution containing bound carbon dioxide / carbon dioxide derivatives is delivered and / or stored.

[0465] Therefore, this task is addressed by a method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium, characterized by the following steps:

[0466] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group,

[0467] b) Contact the gas containing carbon dioxide with the acceptor solution from step a) until the carbon dioxide concentration of the gas is <100 ppm.

[0468] c) Delivery and / or storage of the acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b).

[0469] A preferred method is one in which the receptor compound is an amino acid and the pH of the receptor solution is in the range between 8 and 13.

[0470] Preferably, deionized water (VE-water) is used to prepare the receptor solution. One or more receptor compounds are preferably completely dissolved in water. In this method, the solution may be heated to increase the solubility of one or more compounds.

[0471] Since it has been surprisingly found that contacting the receptor solution with carbon dioxide during or after a portion of the thermally induced dissolution process of the receptor compound can significantly increase the solubility of the receptor compound, in a preferred embodiment, the dissolution process of the receptor compound is carried out simultaneously with the introduction of carbon dioxide. Thus, undissolved receptor compounds can dissolve / enter the solution, or the concentration of the receptor compound can be further increased. For example, with arginine, concentrations of 5 mol / L and higher have been shown to be achievable. Furthermore, these solutions remain stable, i.e., no crystallization of the receptor compound occurs.

[0472] A preferred method is one in which the solubility of the receptor compound is increased by contacting the receptor medium (in which the receptor compound exists in a dissolved and / or undissolved form) with a gas / gas mixture consisting of or containing carbon dioxide.

[0473] A preferred method involves contacting a receptor medium with a gas / gas mixture containing at least one gaseous compound, which forms a water-soluble compound upon contact with water, and wherein the water-soluble compound exists in the receptor medium in an ionic or ionizable form, forming a reversible binding between the dissolved compound and the dissolved receptor compound.

[0474] Preferably, the gas phase is contacted with the acceptor medium until the content of gaseous / gaseous compounds dissolved in the acceptor medium is <100 ppm.

[0475] It has been shown that carbon dioxide extraction according to the invention is possible for a wide variety of gas / gas mixtures and produces very beneficial effects. For example, it has been shown that the carbon dioxide content (between 10% and 25% by weight) in combustion gases from diesel and gasoline engines and from blast furnace coal can be reduced to <0.01% by volume, for example, by contacting the gas with a acceptor solution using a static mixer. Removal of the carbon dioxide component (at a content of 52% by volume) from gas mixtures produced from biogas is also feasible, thereby obtaining biomethane with a purity >98.5% by volume. It has been found that gases or gaseous compounds that do not form acids upon contact with water do not bind to the acceptor compounds according to the invention and are therefore neither emitted from the gas / gas mixture in contact with the acceptor solution nor present in the acceptor solution at a higher concentration than that established at a given partial pressure when the gas phase and acceptor medium are in contact. For example, oxygen, nitrogen, carbon monoxide, rare gases, or hydrocarbons such as methane or butane are not enriched in the acceptor solution.

[0476] The preferred method is for producing pure methane gas.

[0477] The preferred method is for producing pure biomethane gas.

[0478] It has been found that gaseous / gaseous compounds that form acids upon contact with water can be bound in the aqueous acceptor solution according to the invention. If selective extraction and / or acquisition of carbon dioxide is required, it is advantageous to remove other gaseous / gaseous compounds that also form acids in water and thus can compete for carbon dioxide absorption from the gas / gaseous mixture before contacting it with one of the acceptor compounds according to the invention. Preferably, such compounds, such as SO2, H2S, NO, NO2, and other nitrogen oxides or Cl2 or HCl, are removed or reduced from those gas / gaseous mixtures. This can be done using existing methods, such as catalysts, adsorbents, or aqueous gas washing. The temperature of the gas / gaseous mixture to be contacted with the acceptor solution is preferably 0-100°C, more preferably 10-85°C, and even more preferably 15-70°C. In principle, the acceptor solution can also be used to cool the gas / gaseous mixture, allowing the temperature of the gas / gaseous mixture to be even higher. A cooling solution is preferably provided in this case to avoid evaporation of the aqueous acceptor medium. Depending on the temperature, composition, volumetric flow rate, or contact type, the gas / gas mixture obtained after contact with an aqueous acceptor medium may contain water vapor as well as water in droplet form. It is possible that the acceptor solution and therefore the acceptor compound will be lost as a result. Therefore, it is preferable to remove the water component from the treated gas / gas mixture as completely as possible. This can be done using existing methods, such as apparatus for condensate separation. The separated aqueous phase is then returned to the acceptor solution. The acceptor compound according to the invention is not consumed during the implementation of the method according to the invention and does not undergo an autocatalytic process. Therefore, this method relates to an economical implementation process in which the acceptor compound is reused without loss in a recycling process.

[0479] A preferred method is one that is technologically economical, in which the acceptor compound is reused without loss.

[0480] It has been found that when using a membrane contactor, even contact with a hot and dry gas flow does not result in any loss of the aqueous acceptor solution. This can be achieved by selecting a suitable membrane / solid separation medium. For example, gases with temperatures up to 150°C can be processed in a membrane contactor with a polycarbonate membrane as the interface. Gas flows with temperatures >200°C can also be processed if a ceramic membrane is used. Therefore, in a preferred process design, the water-soluble gas / gas components of the gas flow are extracted by contacting the acceptor medium with the gas flow in the membrane contactor. In a particularly preferred embodiment of the method, the contact of a gas flow containing at least one water-soluble gas component at a temperature up to 350°C with the aqueous acceptor medium is carried out in a membrane contactor. Therefore, in a preferred embodiment of the method, a membrane contactor is used to contact the acceptor liquid (acceptor solution) with a gas flow containing at least one water-soluble gas component or consisting of at least one water-soluble gas component, and preferably introduced into the membrane contactor in a temperature range between 10°C and 400°C, more preferably between 50°C and 350°C, and even more preferably between 70°C and 300°C.

[0481] A preferred method is one in which an airflow containing at least one water-soluble gaseous component and at a temperature up to 350°C contacts an aqueous acceptor medium in a membrane contactor.

[0482] Gaseous carbon dioxide is absorbed very rapidly and completely at the interface with the acceptor medium, provided that acceptor compounds that have not participated in the binding of carbon dioxide / carbonate / bicarbonate anions are still present. The carbon dioxide-saturated acceptor solution, in which carbon dioxide is completely dissolved, is clear and there is no spontaneous release of gas.

[0483] In this context, complete dissolution means that in a closed container containing dissolved carbon dioxide / carbonate / bicarbonate anions, no vapor pressure greater than 2 kPa is generated due to carbon dioxide at 20°C.

[0484] It has been found that degassing can be achieved, for example, by lowering the pH of the acceptor medium. This can be done, for example, by adding an acid.

[0485] In the analysis of a gas stream obtained by degassing an aqueous acceptor solution containing compounds with guanidine and / or amidine groups and carbon dioxide dissolved therein in saturated form through an acid (e.g., HCl), no compounds other than carbon dioxide can be detected.

[0486] It has been shown that the release of carbon dioxide dissolved in the acceptor medium of the present invention, or bicarbonate / carbonate anions bound in the acceptor medium, in the form of pure carbon dioxide gas phase, can be achieved by a method that causes protonation of the acceptor liquid (acceptor solution). In one embodiment of this method, an acid from the prior art can be used, for example.

[0487] These can be organic or inorganic acids. Preferred organic acids are formic acid or acetic acid. Preferred inorganic acids are hypochlorous acid. (HCl) or sulfuric acid. The concentration of the acid and the volume ratio at which it is added to the recipient liquid are, in principle, freely selectable. Concentrated acid is preferred. By adding acid, the pH of the recipient liquid is adjusted to a range preferably between 2 and 7, more preferably between 3 and 6, and even more preferably between 3.5 and 5. This achieves the removal of preferably >70 wt%, more preferably >80 wt%, more preferably >90 wt% of carbon dioxide or its water-soluble derivatives dissolved / bound in the recipient liquid, and it can be obtained as pure carbon dioxide gas phase.

[0488] A preferred method is one in which an aqueous receptor medium is saturated with a water-soluble gas, and then the water-soluble gas bound in the receptor liquid (receptor solution) is released by adjusting the pH of the receptor medium to a range of 2 to 7.

[0489] A preferred method involves saturating an aqueous acceptor medium with a water-soluble gas, followed by adjusting the pH of the acceptor medium to a range of 2 to 7 by adding acid to release the water-soluble gas bound in the acceptor liquid (acceptor solution). Adding acid to the acceptor medium results in the introduction of anions, which, when retained in the acceptor liquid, adversely affect the reabsorption capacity of the acceptor compound for the water-soluble gas or its derivatives. Therefore, in a preferred embodiment of the method, after introducing anion that does not correspond to one of the water-soluble forms of the water-soluble gas / gas component already introduced into the acceptor liquid (acceptor solution), the introduced anion is separated before the acceptor liquid (acceptor solution) is introduced again with the water-soluble gas / gas component. Prior art methods are known for this purpose. For example, substances such as Cl- can be removed by electrodialysis. - (chloride ions) or SO4 2- (Sulfate) anions. However, this electrophoretic method can also remove organic acid residues, thereby also achieving regeneration of the acceptor liquid (acceptor solution). In a further and preferred embodiment, an alkaline solution, such as a potassium hydroxide solution or sodium hydroxide solution, is added to the acceptor liquid (acceptor solution) to which the inorganic acid has already been added. Preferably, the alkaline solution is metered so that an equimolar ratio is achieved between the anions added to the acceptor medium and the cations added by adding the caustic alkali solution.

[0490] Preferably, the resulting salt is then separated. This can preferably be done by an electrophoretic method, such as electrodialysis. The acceptor liquid (acceptor solution) regenerated in this way can then be used to reabsorb water-soluble gaseous / gas components or their water-soluble derivatives.

[0491] However, other cationic compounds are also known in the art and can be used as alternatives to alkali solutions to bind or dissolve free anions as well as anions bound to the acceptor compound (which has been added to release water-soluble gases) so that they can then be removed from the aqueous acceptor medium using one of the types of methods described herein, so that the acceptor liquid (acceptor solution) can be used to reabsorb water-soluble gas / gas components.

[0492] A preferred method is one in which the aqueous receptor medium is saturated with a water-soluble gas, followed by the release of the water-soluble gas bound in the receptor liquid (receptor solution) by the addition of an acid, and then the receptor liquid (receptor solution) is regenerated by the addition of an alkaline solution and the salts formed therefrom by electrophoretic separation.

[0493] In another preferred embodiment, the pH of the acceptor liquid (acceptor solution) saturated with a water-soluble gas / gas component or its water-soluble derivative is reduced by an electrochemical method. This can be achieved, for example, by introducing the acceptor liquid (acceptor solution) containing the dissolved water-soluble gas / gas component or its derivative into the electrodialysis apparatus. Preferably, the arrangement of the electrodialysis chambers is chosen such that the electrolyte chamber is connected to the acceptor chamber on the anode side. Preferably, a cation-selective membrane is present between the chambers. The water-soluble derivative of carbonic acid is then released in the acceptor chamber as carbon dioxide.

[0494] A preferred method is one in which the aqueous receptor medium is saturated with a water-soluble gas, and then the water-soluble gas bound in the receptor liquid is released by adjusting the pH of the receptor medium to a range of 2 to 7 via an electrochemical process.

[0495] A preferred method is one in which, after contacting a gas containing carbon dioxide with a receptor solution until the gas reaches a carbon dioxide concentration of <100 ppm, or after transporting and / or storing a receptor solution containing bound carbon dioxide / carbon dioxide derivatives, the following method step is performed: releasing the carbon dioxide bound in the receptor medium as a gas phase.

[0496] In another preferred embodiment of the method, the release of the water-soluble gas / gas component or its derivative dissolved and bound in the aqueous acceptor medium is carried out after spatial separation from the acceptor medium. In a preferred embodiment of the method, dissolved and bound carbon dioxide / carbonate / bicarbonate anions are transported to the absorption and release medium by electrophoresis. It has been shown that, in the absorption and / or release medium according to the invention, where carbonate / bicarbonate anions have been transported, a gas phase is spontaneously formed. In the formed gas phase, only carbon dioxide can be detected. Therefore, without applying any pressure, carbon dioxide can be selectively removed from the gas mixture and released in a separated form into a collection container.

[0497] Surprisingly, it was found that dissolved carbon dioxide / carbonate / bicarbonate anions can be separated very easily from the acceptor solution using membrane methods. This does not require altering the pH of the acceptor solution. Therefore, membranes permeable to gaseous compounds and / or anions were found suitable for the selective transport of carbon dioxide / carbonate / bicarbonate anions. However, it was also found that open-pore membranes / separation media are suitable for allowing the non-selective passage of carbon dioxide / carbonate / bicarbonate anions.

[0498] Surprisingly, open-pore membranes are particularly suitable for separating dissolved carbon dioxide / carbonate / bicarbonate anions from the aqueous medium of this invention. Microporous or mesoporous membranes are preferred. However, macroporous and nanoporous membranes can also be used. The outer and inner surfaces of the membrane can be hydrophilic or hydrophobic. Hydrophobic membrane surfaces are preferred. It has been shown that the mass / volume flow rate of carbon dioxide / carbonate / bicarbonate anions transported by electrophoresis can be significantly greater compared to anion exchange membranes or bipolar membranes composed of closed polymer films.

[0499] The preferred method is to separate dissolved carbon dioxide / carbonate / bicarbonate anions using an open-cell membrane. The open-cell membrane is preferably microporous and / or mesoporous and has hydrophobic surface properties.

[0500] Preferred transport modes for carbon dioxide / carbonate / bicarbonate anions are based on diffusion processes, concentration gradients, or thermal or elevator effects, and combinations thereof. Preferred are open-pore membranes, i.e., solid or semi-solid separation media (separation membranes), suitable for retaining aqueous media under no-pressure conditions and having openings connecting both sides of the membrane, allowing permeation of gases and / or anions. Preferably, the average diameter of the openings is between 10 nm and 1 mm, more preferably between 100 nm and 500 micrometers, and even more preferably between 1 micrometer and 200 micrometers. Preferred membranes have hydrophilic or hydrophobic electrostatic properties on their inner and / or outer surfaces.

[0501] Because of the saturated acceptor medium according to the invention, carbon dioxide is completely bound, resulting in no separation and therefore no pressure buildup in the acceptor chamber. This is particularly advantageous because it allows for the use of open-pore separation membranes for separating dissolved carbon dioxide or its reaction products with water, without requiring pressure equalization between containers containing the acceptor medium or the absorption and / or release medium. Thus, the absorption device for absorbing and / or releasing the medium can be open to atmospheric pressure. In a preferred embodiment, both the acceptor medium and the absorption device (chamber) for absorbing and / or releasing the medium are open to atmospheric pressure.

[0502] Surprisingly, when an aqueous solution containing acid is pre-placed in a chamber unit adjacent to the acceptor chamber, converging (merging) bubbles form very rapidly on both sides of this separation membrane. Therefore, carbonate / bicarbonate anions diffuse through the separation medium (separation membrane) into the adjacent chamber containing the pre-placed acid, thereby releasing carbon dioxide. Hereinafter, this chamber unit is referred to as the absorption and release chamber. Therefore, the medium located in the absorption and release chamber is referred to as the absorption and release medium.

[0503] As will be discussed below, other separation media can also be used to achieve the delivery of carbon dioxide / carbonate / bicarbonate anions from aqueous acceptor media in absorption and release media.

[0504] A preferred method is one in which carbon dioxide / carbonate / bicarbonate anions are separated from an aqueous acceptor medium via a separation medium (separation membrane), thereby absorbing and / or releasing them in an absorption and release medium.

[0505] Preferred methods involve separating carbon dioxide / carbonate / bicarbonate anions from an aqueous acceptor medium via a separation medium (membrane) based on diffusion, permeation, and / or electrophoresis processes.

[0506] A preferred method is one in which the separation medium for separating carbon dioxide / carbonate / bicarbonate anions from an aqueous acceptor medium is a solid or semi-solid separation medium (separation membrane) that is capable of retaining the aqueous medium under no-pressure (atmospheric pressure) conditions and has openings connecting both sides of the membrane that are permeable to gases and / or anions.

[0507] Preferably, the method is a separation membrane in which the solid or semi-solid separation medium (separation membrane) used to separate carbon dioxide / carbonate / bicarbonate anions is a separation membrane.

[0508] Preferably, the separation membrane used to separate carbon dioxide / carbonate / bicarbonate anions is an anion-selective or bipolar polymer membrane.

[0509] Surprisingly, dissolved carbon dioxide or carbonate / bicarbonate anions can be separated very efficiently from the acceptor solution of this invention using electrophoresis.

[0510] Preferably, electrodialysis is performed to separate the dissolved carbon dioxide / bicarbonate anions. In this regard, electrodialysis can be performed using methods and apparatus of the prior art.

[0511] It has been found that carbon dioxide / carbonate / bicarbonate anions transported by electrophoresis are separated in absorption and / or release media containing anionic amino acids and escape as gaseous carbon dioxide.

[0512] In a preferred embodiment, carbon dioxide / carbonate / bicarbonate anions are separated from an aqueous acceptor medium by filling an acceptor chamber containing carbon dioxide / carbonate / bicarbonate anions into the acceptor chamber, which is separated from an adjacent absorption and release chamber by a separation medium (separation membrane). The absorption and / or release medium preferably exists in the absorption and release chamber. This is preferably an aqueous medium. Preferably, its pH is 1 to 7, more preferably 2 to 6, and even more preferably 3 to 5. In a particularly preferred embodiment, a compound having an acidic group is dissolved in the absorption and / or release medium. Compounds having at least one acidic group and an isoelectric point between 3 and 5, or more preferably between 3.5 and 4.5, are particularly preferred. Amino acids having acidic groups, especially aspartic acid and glutamic acid, are particularly preferred. The preferred concentration is in the range of 1 mmol / L to 3 mol / L. Further preferred are organic acids having more than one acidic group and good water solubility, such as citric acid or ascorbic acid. In principle, inorganic acids are also suitable, such as sulfuric acid or pyrophosphate. When inorganic acids are used, the concentration of the aqueous solution of these acids is preferably 1-50 wt%. Furthermore, mixtures of different acids are preferred. The temperature range used in the absorption and release medium can, in principle, be freely chosen between 1-99°C. A preferred temperature range is 30-80°C, more preferably 40-75°C, and even more preferably 50-70°C.

[0513] A preferred method is one in which an absorption and / or release medium is present in the absorption and release chamber, wherein at least one compound having at least one acid group and an isoelectric point in the range of 3 to 5 is present.

[0514] The preferred method is one in which the absorption and / or release medium is an aqueous solution of an organic and / or inorganic acid.

[0515] Surprisingly, it has been found that embodiments of this method are suitable for selectively transporting carbon dioxide or carbonate / bicarbonate anions into an absorption and release chamber or an absorption and / or release medium, wherein carbon dioxide is separated from the absorption and / or release medium and gaseous carbon dioxide is formed from carbonate / bicarbonate anions by the cleavage of water, thereby forming a gas phase containing only carbon dioxide. Therefore, carbon dioxide can be selectively bound and transported and selectively released to any desired location.

[0516] In a preferred embodiment, continuous or discontinuous flow occurs through an absorption and release chamber having absorption and release media, wherein a high overflow velocity is preferably present at the surface of the separation media (separation membrane), thereby completely or almost completely preventing degassing at the surface of the separation media (separation membrane), and bicarbonate / carbonate anions are absorbed into the absorption and release media, thereby preferably being introduced into a separate container where degassing is subsequently carried out. It has been found particularly advantageous that carbon dioxide degassing is as complete as possible in this separate release container, and that the absorption and release media are subsequently returned to the absorption and release chamber, thereby significantly increasing the transport efficiency through the separation media and in the absorption and release media (see...). Figure 1 For example, effective degassing can be achieved by flowing a medium through a surface for absorption and release. Preferably, this involves a hydrophobic surface made of a material such as PTFE or graphite. Furthermore, degassing can be achieved using known techniques such as applying negative pressure, ultrasonic impact, applying shear force to create cavitation, and / or heating to absorb and release the medium.

[0517] In a preferred embodiment, carbon dioxide / carbonate / bicarbonate anions are separated from an aqueous acceptor medium by electrodialysis. In this method, an acceptor solution in which carbon dioxide or its reaction products with water are in dissolved form is fed into the acceptor chamber of an electrodialysis unit. In its simplest form, the electrodialysis unit consists of an acceptor chamber and an absorption and release chamber, which are separated from each other by a separation medium (separation membrane).

[0518] The electrodes can be located directly in the processing medium, i.e., the anode can be located in the absorption and / or release medium, and the cathode can be located in the acceptor solution. More preferably, an electrodialysis apparatus is used in which the electrodes are located in the anode or cathode chamber (electrode chamber), and wherein the acceptor chamber or absorption and release chamber is separated from the electrode chamber by an ion-selective membrane, and the anode and cathode chambers are filled with a medium suitable for electron transport, such as an electrolyte solution (see [link to relevant documentation]). Figure 1 In another preferred embodiment, a multi-chamber unit consisting of a acceptor chamber and an absorber and release chamber is connected together in a repeating arrangement, wherein the stack of chambers terminates at both ends via an anode and a cathode chamber, respectively, and is thereby electrically connected. In a preferred arrangement, a first acceptor chamber is adjacent to a cathode chamber, and a final absorber and release chamber is adjacent to an anode chamber. In another preferred embodiment, each acceptor chamber is separated from the absorber and release chamber by a bipolar membrane.

[0519] Preferably, carbon dioxide or carbonate / bicarbonate anions are transported by applying a DC voltage between the cathode and anode. The voltage and current for implementing electrodialysis according to the invention depend on specific process parameters, such as the distance between electrodes, the number of chamber units, the resistance of the membrane and the process solution, and the cross-sectional area, and therefore must be determined on a case-by-case basis.

[0520] In one preferred embodiment, carbon dioxide delivered via a separation medium (separation membrane) is released as a gas in an absorption and release chamber containing an absorption / release medium. In another preferred embodiment, carbon dioxide or carbon dioxide derivatives delivered via a separation medium (separation membrane) are absorbed in the absorption / release medium and released as a gas in a release device.

[0521] The preferred method is one in which step b) or c) is followed by step c1) or d1): releasing carbon dioxide bound in the acceptor medium as a gas phase.

[0522] A preferred method is one in which the acceptor medium from step b) is located in or introduced into the acceptor chamber of the electrodialysis apparatus, and the delivery of carbon dioxide / carbon dioxide derivatives according to step c) is carried out by means of an elevator generated between the acceptor chamber and the absorption and release chamber, wherein the acceptor chamber and the absorption and release chamber are separated from each other by a separation medium (separation membrane).

[0523] Preferred is a method in which carbon dioxide / carbon dioxide derivatives are transported through a separation medium (separation membrane), wherein the separation medium is a membrane permeable to ions and / or gas molecules.

[0524] A preferred method is one used to electrodialyze the acceptor medium and deliver carbon dioxide / carbon dioxide derivatives according to step c) by means of an elevator generated between the acceptor chamber and the absorption and release chamber, wherein the separation medium is a membrane permeable to ions and / or gas molecules.

[0525] A preferred method is one in which carbon dioxide / carbon dioxide derivatives transported via a separation medium (separation membrane) are released as pure carbon dioxide gas in an absorption and release chamber.

[0526] A preferred method is one in which carbon dioxide / carbonate / bicarbonate anions transported via a separation medium (separation membrane) are released in the absorption and release chamber as pure carbon dioxide gas.

[0527] The preferred method is one in which step b) or c) is followed by step b2) or c2): carbon dioxide / carbonate / bicarbonate anions are separated from the acceptor medium by means of diffusion, permeation or electrophoresis through a separation medium (separation membrane) and transported to an absorber / release medium, wherein carbon dioxide is released as a pure gas phase in the absorber / release medium.

[0528] The preferred method is one in which step b) or c) is followed by step b3) or c3): carbon dioxide / carbonate / bicarbonate anions are separated from the acceptor medium by means of diffusion, permeation or electrophoresis through a separation medium (separation membrane) and transported to an absorber / release medium, wherein carbon dioxide is released as a pure gas phase from the absorber / release medium in a release device.

[0529] The preferred method is one in which step c) is followed by steps c3') and c3):

[0530] c3') Introducing the aqueous absorption and release medium containing bound carbon dioxide / carbon dioxide derivatives from step c) into the release device; and

[0531] c3): Carbon dioxide is released in gaseous form from the absorption and release medium containing bound carbon dioxide / carbon dioxide derivatives from step c3') in the release chamber.

[0532] A preferred method is one in which the acceptor medium from step b) is located in or introduced into the cathode chamber of the electrodialysis apparatus, and the delivery of carbon dioxide / carbon dioxide derivatives according to step c) is carried out by means of an elevator generated between the cathode and anode chambers, wherein the cathode and anode chambers are separated from each other by an ion- or gas-permeable separation medium (separation membrane).

[0533] In a preferred embodiment, the chamber that releases or can release carbon dioxide is provided with a gas collection device, which preferably prevents pressure buildup in the chamber.

[0534] In a preferred embodiment, the carbon dioxide released after binding to the receptor medium is collected in a gas collection device and diverted from there for further application (see [reference]). Figure 1 ).

[0535] A preferred method is one in which carbon dioxide is bound / transported or stored in a receptor medium and then released again as a gas phase for further application.

[0536] In another preferred embodiment of the method according to the invention, in addition to separating water-soluble gas / gas components and selectively releasing them, the method arrangement according to the invention is also used to produce hydrogen and oxygen. In a preferred embodiment where the electrodialysis apparatus is used to deliver carbon dioxide / carbonate / bicarbonate anions, electrolysis of water occurs in the electrode chamber, since a voltage that would normally be applied to the respective selected electrolyte solutions to induce electrolysis must be present. It has been found that a chamber arrangement consisting of an acceptor chamber and absorption and release chambers can be introduced into the method arrangement for electrolysis, thereby significantly improving the energy efficiency of the method according to the invention. Due to the additional availability of hydrogen and oxygen, very high energy efficiency of the method can be achieved, preferably >90%, more preferably >95%, and even more preferably >98%.

[0537] In another preferred embodiment, the water-soluble gas / gas component dissolved in the aqueous acceptor medium is released at the cathode. Surprisingly, the acceptor solution according to the invention is suitable for suppressing the electrolysis of water that leads to the formation of oxygen and hydrogen when a DC voltage is applied, despite the presence of current due to the conductivity of the acceptor solution. This phenomenon is particularly observed when arginine is used as the acceptor compound. Therefore, molecular charge transfer occurs. It has been found that molecular charge transfer preferentially outweighs electrolysis as the distance between the anode and cathode increases. Therefore, no gas formation was observed even when a voltage of 40 V and a low ampere current flow rate (<200 mA) were applied. Furthermore, it was unexpectedly observed that no electrolysis of water leading to the formation of hydrogen or oxygen occurred in the presence of a caustic soda or potassium hydroxide solution in the acceptor solution containing dissolved arginine, whereas water electrolysis occurred when using a pure caustic soda or potassium hydroxide solution of the same concentration at the same voltage and current settings. Therefore, charge transfer preferentially occurs through the dissolved acceptor compound. It was subsequently discovered that when a water-soluble gas was introduced into the acceptor solution, and a water-soluble derivative was formed in the acceptor solution, gas was formed only at the anode when a DC voltage was applied. When carbon dioxide was used as the water-soluble gas introduced into the acceptor liquid (acceptor solution), the gas formed at the cathode consisted of pure carbon dioxide. Therefore, a method was discovered in which a water-soluble gas in its water-soluble form could be selectively released as a gas at the cathode via internal charge transfer within the acceptor solution when a DC voltage was applied.

[0538] A preferred method is one in which the aqueous solution containing dissolved arginine induces inhibition of water electrolysis when a DC voltage is applied to the aqueous solution, which would result in the formation of hydrogen or oxygen.

[0539] A preferred method is one in which a solution containing dissolved arginine undergoes a molecular charge transfer when a DC voltage is applied to an aqueous solution.

[0540] A preferred method is one in which electrolysis can be suppressed by providing an acceptor solution when a DC voltage is applied. A preferred method is one in which a gas dissolved in the aqueous acceptor solution, or a water-soluble derivative thereof, can be released as a gaseous phase at the cathode upon application of a DC voltage without resulting in electrolysis that would form hydrogen or oxygen.

[0541] Therefore, a method can be provided in which the separation of water-soluble derivatives of water-soluble gases can be carried out as a gas phase at the cathode, wherein a DC voltage is applied and there is no electrical loss due to electrolysis that would form oxygen or hydrogen. In principle, this method can be carried out using electrodialysis apparatus from the prior art. It has been shown that, based on the energy density produced at the electrodes when a DC voltage is applied, the distance between the electrodes should be chosen to be sufficiently large such that no oxygen is formed (as can be seen by the absence of gas formation at the anode). Accordingly, for a given configuration of the electrodes and a given distance between them, the voltage can be chosen such that no gas is formed at the electrodes when the voltage is applied to an unloaded acceptor solution. It is advantageous to use electrodes with a large surface area. It is also advantageous if the surface area of ​​the anode is larger than that of the cathode. In an advantageous embodiment, the anode chamber and the cathode chamber are separated by a separation medium (membrane), thereby forming an anode chamber and a cathode chamber electrically connected to each other. It is advantageous if the separation medium (membrane) has the lowest possible resistance. Preferably, the separation medium (membrane) should be perforated but prevent gas passage. In a preferred embodiment, a direct and open connection exists between the chambers, allowing the acceptor fluid to flow freely below the electrode plane, at the height of the electrode plane, or both. In another preferred embodiment, flow through the electrode chambers is achieved by introducing a acceptor liquid loaded with a water-soluble gas into the cathode chamber and continuously passing the solution through the anode chamber. This is guided through the open connection and / or a liquid-permeable separation medium (separation membrane) located between the electrode chambers. It has been found that this significantly increases the separation of the gas phase of the gas dissolved in the aqueous acceptor medium or its water-soluble derivatives.

[0542] In principle, the electrode material can be freely chosen. If, in addition to the acceptor compound according to the invention, caustic potassium or caustic sodium is also present in the acceptor medium, the selection must be adjusted accordingly. Preferred electrode materials are graphite, nickel, stainless steel, platinum, or gold. Combinations of materials for the anode and cathode, as well as mixed alloys, are also preferred. The DC voltage preferably applied between the anode and cathode depends on the electrode configuration and the distance between the electrodes, and therefore must be determined individually. The maximum possible voltage that will not lead to the formation of hydrogen and oxygen can be determined based on tests of oxygen formation at the anode; in this process, the selected voltage should be lower than the voltage required for oxygen to form as a gaseous phase.

[0543] In this respect, the method according to the invention also relates to the cathode separation of carbon dioxide or other water-soluble gases as a pure gas phase from an aqueous acceptor medium.

[0544] The preferred method is the cathode separation of water-soluble gases from an aqueous acceptor medium.

[0545] A preferred method is one in which a gas dissolved therein or its water-soluble derivative is separated from the aqueous acceptor medium in the form of a pure gas phase by cathodic separation in an aqueous acceptor medium.

[0546] In another preferred embodiment, one or more compounds are present in the acceptor and / or release medium, said compounds reacting with and / or binding to carbon dioxide or carbonate / bicarbonate anions transported from the acceptor solution. These compounds (hereinafter referred to as reacting compounds) may be in liquid, solid, or gaseous states. Furthermore, reaction-promoting compounds (e.g., catalysts) may be present in the absorption and release medium. Here, the absorption and release medium may have a different temperature than the acceptor medium. In another preferred embodiment, carbon dioxide / carbonate / bicarbonate anions dissolved in the acceptor medium react with and / or bind to suitable compounds present therein. It is preferred to use reacting compounds to react with and / or bind to carbon dioxide and / or carbonate / bicarbonate anions present in the acceptor solution and / or absorption and release medium.

[0547] Preferred is a method in which one or more reactive compounds for reacting and / or binding carbon dioxide and / or carbonate / bicarbonate anions are present in an acceptor solution and / or an absorption and / or release medium.

[0548] Surprisingly, the reaction conditions in acceptor solutions where carbon dioxide and / or carbonate / bicarbonate anions are present in high concentrations are particularly suitable for the synthesis of carbon compounds. For example, the synthesis of carboxylic acids can be achieved. Examples include reactions with Grignard reagents or telomerization with palladium catalysts. Preferred carbon compounds include, but are not limited to, formic acid, methanol, carbon monoxide (CO), and formaldehyde. It has been shown that this method enables the enrichment of carbon dioxide and its water-soluble derivatives, which allows for the chemical synthesis of organic compounds under ambient pressure. It has also been shown that carboxylic acids synthesized in aqueous acceptor media can be continuously separated by electrodialysis. The electrophoretically separated carboxylic acids are preferably absorbed in and then released from an aqueous medium. Solutions containing dissolved arginine have been shown to be particularly suitable as absorption and / or release media for transporting carboxylic acids in embodiments of this method.

[0549] Preferred is a method in which one or more reactive compounds for reacting and / or binding carbon dioxide and / or carbonate / bicarbonate anions are present in an acceptor solution and / or an absorption and / or release medium.

[0550] The preferred method is one in which, after step b), the carbon dioxide bound in the acceptor solution is converted into a carbon compound by means of a reactant compound.

[0551] In a particularly preferred embodiment of the method, an anion exchange membrane permeable to anions with molecular weights up to 400 Da is used for the selective electrophoretic transport of short-chain carboxylic acids.

[0552] It has been shown that all carbon dioxide components of flue gas can be separated, transported, and chemically converted by one of the methods described herein.

[0553] Conversion method

[0554] A preferred method is one in which, after step b), carbon dioxide bound in the acceptor solution is converted into carbon compounds by means of a reaction compound.

[0555] A preferred method is one in which, after step c), carbon dioxide bound in the receptor and / or release medium, or transported and released carbon dioxide, is converted into carbon compounds by means of a reaction compound.

[0556] Therefore, it can be seen that the content / concentration of carbon dioxide and carbonate / bicarbonate anions in the aqueous acceptor medium can be increased under normal pressure conditions, while establishing optimal reaction conditions, thereby enabling immediate chemical transformation by reaction-promoting compounds immobilized in the acceptor solution. Furthermore, it has been shown that reactants obtained from chemical transformation, such as carboxylic acids, can be simultaneously and continuously removed by using the method arrangement according to the invention, which can be done, for example, using anion exchange membranes. Moreover, it has been shown that in such method embodiments, solutions containing compounds with guanidine or amidine groups dissolved in the absorption and release media are also suitable for absorbing and transporting carboxylic acids produced by previous reactions, which have already been transported by electrodialysis.

[0557] The preferred method is the production of carbon compounds from carbon dioxide.

[0558] In another preferred embodiment, carbon dioxide bound in the aqueous acceptor medium in the form of carbonate / bicarbonate anions is chemically converted into carbonate.

[0559] Surprisingly, it has been found that chemical transformations can be implemented in various ways by absorbing carbon dioxide and its reaction products with water according to the present invention. Three possible types of transformation methods are listed here as examples.

[0560] Conversion Method 1:

[0561] Surprisingly, it was discovered that carbon dioxide dissolved in an aqueous acceptor medium, along with carbonate and bicarbonate anions, can directly form carbonates in or react with the acceptor solution. For this purpose, a solution in which a cationic compound suitable for carbonate preparation exists in dissolved (ionized) form is added to an acceptor solution in which carbon dioxide or its water-soluble derivatives already exist in dissolved / bound form. In this case, a chemical transformation occurs when the solution containing the reactive compound is introduced into a preferably saturated acceptor solution.

[0562] In another preferred embodiment of this conversion method, carbonate production is carried out while the acceptor solution in which the salt of the cation / cationic compound for carbonate / bicarbonate production has been dissolved is contacted with carbon dioxide.

[0563] In another embodiment of the method, an acceptor solution in which carbon dioxide or its water-soluble derivative is already present in a dissolved / bound form is added to a solution in which a cationic / cationic compound suitable for carbonate production is present in a dissolved (ionized) form. A chemical transformation occurs upon introduction of a saturated acceptor solution.

[0564] In all the method variations, an emulsion suspension is rapidly formed, from which solids spontaneously separate by sedimentation. However, phase separation can also be achieved by existing filtration or centrifugation methods.

[0565] Conversion Method 2:

[0566] In another preferred embodiment of the method, a cationic / cationic compound suitable for the preparation of carbonates / bicarbonates is introduced into the acceptor solution during or subsequently by means of electrophoresis during contact with a water-soluble gas / gas component (e.g., carbon dioxide). Preferably, this is carried out by electrodialysis. Preferably, this is carried out in a method arrangement in which the acceptor chamber is adjacent to the electrolyte chamber on the anode side and separated from the latter by a cation-selective membrane. In the electrolyte chamber, the cationic / cationic compounds suitable for the production of carbonates / bicarbonates are present in dissolved (ionized) form. By applying a DC voltage, the electrophoretic transport of the cationic / cationic compounds through the cation-selective membrane into the acceptor solution, where they are then spontaneously converted into the corresponding carbonates. In this method, the acceptor solution may have already been saturated with carbon dioxide, or may have been contacted with carbon dioxide during or subsequently by electrodialysis.

[0567] In another preferred embodiment of the method, the cationic / cationic compound suitable for producing carbonate / bicarbonate is present in ionic form in the absorption and release medium. Carbon dioxide / carbonate / bicarbonate anions are transported from the acceptor chamber to the absorption and release medium via an anion-selective separation medium (separation membrane). The corresponding carbonate is then formed in this medium. It has been found that most of the reaction occurs directly in the separation medium (separation membrane). Surprisingly, when one of the acceptor compounds of the invention is present in dissolved form in the aqueous absorption and release medium, the reaction proceeds more rapidly and uniformly in the aqueous absorption and release medium. Bipolar membranes have also been shown to be suitable for this purpose. In embodiments of the method, it is advantageous if inorganic acids are absent and only low amounts of organic acids are present in the absorption and release medium.

[0568] Conversion Method 3

[0569] In another preferred embodiment of the method, the chemical conversion of carbon dioxide and / or carbonate and / or bicarbonate anions takes place in an absorption and release medium, wherein, on the one hand, carbon dioxide and / or carbonate and / or bicarbonate anions are transported from the acceptor chamber to the absorption and release chamber via a separation medium (separation membrane), and on the other hand, cationic / cationic compounds suitable for producing carbonates / bicarbonates are transported from an electrolyte chamber in which at least one of the cationic / cationic compounds exists in ionic or ionizable form into the absorption and release chamber. The absorption and release chamber is adjacent to the acceptor chamber on the cathode side and to the electrolyte chamber on the anode side. Preferably, mass transfer is performed by electrophoresis, wherein a bipolar or anion-selective membrane is used as the separation medium (separation membrane) between the acceptor chamber and the absorption and release chamber, and a cationic-selective membrane is used between the absorption and release chamber and the electrolyte chamber. In this embodiment of the method, it is advantageous and preferred that at least one acceptor compound is present in dissolved form in the absorption and release medium. Preferably, inorganic acids are absent and only low amounts of organic acids are present in the absorption and release medium.

[0570] In all embodiments of the conversion method, it is advantageous to stir the aqueous solution in which the chemical conversion takes place to prevent localized segregation. In embodiments of the method according to the invention, no or almost no carbon dioxide is released as a gaseous phase during the chemical conversion. Release can be caused by the concentration of counterions of compounds used in carbonate production. Therefore, it is advantageous to remove counterions from the process solution in which the chemical conversion of carbon dioxide and / or carbonate and / or bicarbonate anions takes place.

[0571] Preferably, counterions (anions) of the compound used to provide the cationic / cationic compound for the preparation of carbonates are removed during or after one of the conversion methods. These counterions are, for example, Cl- or SO42-. 2-To this end, in a preferred embodiment of the method, the chamber unit in which counterions accumulate is connected to the anode chamber or flushing chamber on the anode side via an anion-selective membrane. An aqueous conductive medium is present in the flushing chamber, which absorbs and adsorbs the counterions, or the flushing liquid is recycled through the anode chamber. In a preferred embodiment, an acid, such as hydrochloric acid or sulfuric acid, is thus formed in the anode chamber, which may optionally be further concentrated and used to produce a solution containing a cationic / cationic compound suitable for carbonate production. For example, aluminum chloride or ferrous sulfate can be produced from metallic aluminum or iron by this method and can then be used for further carbonate / bicarbonate production.

[0572] The implementation of conversion methods 2 and 3 is particularly advantageous in this respect because no solid aggregates are formed in the acceptor medium, and no additional anions that might compete with the absorption of carbonate / bicarbonate anions are introduced. Therefore, the acceptor solution can be circulated to absorb and release carbon dioxide and / or carbonate and / or bicarbonate anions, which undergo chemical transformation in a secondary recycling process. In conversion method 1, the continuous or discontinuous separation of those anions that do not correspond to carbonate and / or bicarbonate anions can be carried out by adsorption or electrodialysis. Therefore, the recycling of the acceptor solution can also be ensured in conversion method 1.

[0573] It has also been found that if caustic soda or sodium hydroxide is added to the solution, counterions (such as Cl- or SO42-) retained in the acceptor solution after carbonate production can be separated during electrodialysis with lower energy input. 2- Preferably, the feed is metered by titration until a certain pH of the solution is reached at which the counterions are completely dissolved by the acceptor compound. This has been found to be particularly advantageous because it converts the cations retained in the acceptor solution (which are added during the recirculation of the acceptor solution to absorb water-soluble gases) into their hydroxide forms, such as CaOH, thus making them solids and very easy to separate. As a result, no solids (carbonate formation) are formed in the gas scrubbing apparatus during the recirculation of the acceptor solution. After separating the solids formed after titration with caustic potassium or caustic sodium solution, the acceptor solution is purified by electrodialysis to remove any salt components (e.g., Na+). + K + Cl- or SO4 2- Subsequently, the acceptor solution can be used to reabsorb water-soluble gas / gas components, with an absorption capacity corresponding to that of the initially used acceptor solution.

[0574] The conversion method according to the invention is preferably carried out at a temperature range of 5-70°C, more preferably 10-60°C, and even more preferably 15-50°C. The pH of the aqueous solution used for carbonate / bicarbonate production is preferably 5-13, more preferably 6-12.5, and even more preferably 7-12. Carbonate / bicarbonate production is preferably carried out under normal pressure conditions.

[0575] In another preferred embodiment, the chemical conversion according to one of the conversion methods is carried out by conversion under increased pressure and / or increased temperature and / or in the presence of a catalyst.

[0576] However, the conversion method is also applicable to contacting other compounds with carbon dioxide and / or carbonate and / or bicarbonate anions and causing them to react with each other. Therefore, in a preferred embodiment of the method, one or more compounds (hereinafter also referred to as reactants) are added to an aqueous acceptor medium before, during, and / or after the absorption of carbon dioxide from the acceptor solution with one or more reactants to contact and react with carbon dioxide and / or carbonate and / or bicarbonate anions. In another preferred embodiment of the method, the chemical conversion of carbon dioxide and / or carbonate and / or bicarbonate anions is carried out by transporting carbon dioxide and / or carbonate and / or bicarbonate anions into an absorption and release medium containing or transporting one or more reactants, the chemical conversion being carried out in parallel with or after the carbon dioxide and / or carbonate and / or bicarbonate anion absorption process according to the invention.

[0577] A preferred method is one in which at least one reactive compound is present in an aqueous acceptor medium, and the reaction with carbon dioxide and / or carbonate and / or bicarbonate anions is carried out in the acceptor solution during and / or after the absorption of carbon dioxide.

[0578] A preferred method is one in which carbon dioxide in an acceptor solution is absorbed by means of an aqueous acceptor medium, and the aqueous absorbor medium containing carbon dioxide and / or carbonate and / or bicarbonate anions is contacted with at least one reactive compound, and the carbon dioxide and / or carbonate and / or bicarbonate anions react with the at least one reactive compound.

[0579] A preferred method is one in which at least one reactive compound is present in an absorption and release medium for carbon dioxide and / or carbonate and / or bicarbonate anions, and the reaction with the carbon dioxide and / or carbonate and / or bicarbonate anions takes place therein, the carbon dioxide and / or carbonate and / or bicarbonate anions being transported through a separation medium (membrane) between the acceptor chamber and the absorption and release chamber.

[0580] A preferred method is one in which at least one reactive compound and at least one acceptor compound are present in an absorption and release medium, and the chemical transformation of carbon dioxide and / or carbonate and / or bicarbonate anions that have been transported through a separation medium (membrane) between the acceptor chamber and the absorption and release chamber takes place in the absorption and release medium.

[0581] A preferred method is one in which carbon dioxide is absorbed from a receptor solution by means of an aqueous receptor medium, and wherein the absorbed carbon dioxide and / or carbonate and / or bicarbonate anions are transported through a separation medium (membrane) to a reaction chamber containing at least one dissolved reaction compound and react therewith the reaction compound.

[0582] A preferred method is one in which carbon dioxide is absorbed from a receptor solution by means of an aqueous receptor medium, and wherein the absorbed carbon dioxide and / or carbonate and / or bicarbonate anions are transported to a reaction chamber via a separation medium (membrane), and wherein, before and / or during and / or after the transport of carbon dioxide and / or carbonate and / or bicarbonate anions to the reaction chamber, at least one reaction compound is transported from an electrolyte chamber in which at least one reaction compound is in a dissolved form to the reaction chamber, wherein the transport of the compound is carried out by electrophoresis.

[0583] The residual amounts of acceptor compounds and / or anions of the reactants used in the solid obtained by phase separation can be completely removed, for example, by elution.

[0584] It has been found that the obtained solid can be dried very easily. This can be done, for example, on a porous ceramic membrane, where water is very rapidly removed and transported by the membrane. The carbonate or bicarbonate dried in this way then exists immediately as a fine powder, or can be made into this form very easily by a grinding process. In this case, the average diameter of the particles is <1 μm. The carbonate or bicarbonate obtained in this way exists immediately in a chemically pure and amorphous form. In the context, "pure" means that the carbonate or bicarbonate exists with a purity of >95 wt%, more preferably >98 wt%, and even more preferably >99.5 wt%.

[0585] Surprisingly, the method according to the invention can also be used to produce carbonates containing metal ions (e.g., iron, aluminum, and copper ions).

[0586] Surprisingly, aluminum carbonate can be prepared using the described conversion method. This is possible, for example, by dissolving aluminum chloride in a solution containing 0.3 mol / L arginine to obtain a 10% aqueous solution of aluminum chloride. This solution is then slowly added, with stirring, to a 1:4 ratio of a carbon dioxide-saturated acceptor solution (2 mol / L arginine solution), resulting in a whitish turbidity. After the addition and stirring of the suspension are complete, the precipitated white solid is separated by centrifugation and then washed twice with deionized water. The paste is then convectively dried and mechanically pulverized to obtain a white powder. The powder can be completely decomposed by concentrated hydrochloric acid, producing carbon dioxide and an aluminum chloride solution. Surprisingly, no gas is formed or heat is generated during the dissolution of the aluminum chloride salt in the acceptor solution or during solution contact.

[0587] Surprisingly, it has been found that bicarbonate formation preferentially occurs when ammonium ions are simultaneously present in the solution for carbonate production according to the invention. In a preferred embodiment, ammonia is added to the solution in which carbonate / bicarbonate production takes place. This can be done before, during, or after contacting the solution with a water-soluble gas / gas component. Preferably, this method embodiment is carried out in the case of the acceptor solution according to the invention. However, the addition can also be made in conversion methods 2 and 3, in which case the addition is made in the reaction chamber and / or absorption and release chamber. It has been found that even low concentrations of ammonia in one of the solutions in which the conversion to bicarbonate / carbonate is carried out are sufficient to allow bicarbonate to form preferentially over carbonate. In the solution in which bicarbonate / carbonate production is carried out, the preferred concentration of ammonia is 0.001-5.0 wt%, more preferably 0.005-3.0 wt%, and even more preferably 0.01-1.5 wt%. Since the preferential formation of bicarbonate depends on the introduction of anions (e.g., Cl- or SO4-) bound by ammonium ions. 2- The concentration of ammonia is such that the optimal concentration must be determined individually. The resulting bicarbonate is separated and purified using the same separation techniques described herein. In a preferred embodiment, the production of bicarbonate or carbonate is carried out at a process temperature preferably <50°C, more preferably <35°C, further preferably <20°C, and even more preferably <10°C. In a preferred embodiment, the ammonium salt present in the acceptor or reaction solution is separated. Preferably, this can be done by electrodialysis.

[0588] Further findings indicate that, particularly advantageously, anions or anionic compounds can be separated from electrolyte solutions containing cations or cationic compounds suitable for preparing carbonates or bicarbonates, as well as anionic or anionic compounds, by means of a reaction with ammonium. It has been found that, in addition to higher conversion rates and amounts of cations or cationic compounds to carbonates or bicarbonates, impurities that may be present in the electrolyte solution can be removed very easily. This is evident, for example, for recycled aluminum materials (especially aluminum foil) containing organic compounds. Acid hydrolysis is performed using concentrated hydrochloric acid. A gray solid with a pH of 1 is formed, which is completely soluble in water. Flocculation begins at pH 2.5 upon mixing with a 25 wt% ammonia solution, and further addition of ammonia solution enhances flocculation. Centrifugation of the solution at pH 4 reveals that a dark brown solid has been deposited together with the white centrifuged fraction. The supernatant is clear and has no ammonia odor at pH 4. Adding the supernatant to a 2-molar arginine solution saturated with carbon dioxide immediately produces a white solid. Compared to experiments using solutions without added ammonia, more than three times the amount of solids could be separated from the acceptor solution. This is also due to the fact that more than twice the volume of ammonia-pretreated electrolyte solution could be added to the acceptor solution until the pH of the acceptor solution reached a value where carbonates or bicarbonates no longer formed. Pure aluminum bicarbonate was found in the solids analysis. It was also shown that sulfate anions could be removed from the electrolyte solution by this process, and that sulfate-poor electrolyte solutions resulted in higher conversion rates of cations compared to sulfate- or anion-rich electrolyte solutions. In another application, the regeneration liquid (pH 7) of the cation exchanger used for the production of deionized water was investigated. Regeneration was carried out using a NaCl solution. It was found that flocculation caused by the introduction of ammonia could be achieved by centrifugation. The clarified supernatant (pH 9) was added to a acceptor solution saturated with carbon dioxide, in which solids formed. A mixture of calcium bicarbonate and magnesium bicarbonate was recorded in the solids analysis.

[0589] A preferred method for preparing bicarbonate involves incorporating ammonium ions into an electrolyte solution, and then combining and mixing the mixture with an aqueous acceptor solution saturated with carbon dioxide or its water-soluble derivative.

[0590] A preferred method for preparing carbonates and / or bicarbonates is a method in which anions or anionic compounds are separated from an electrolyte solution containing cations or anionic compounds and anions or anionic compounds by ammonium ion complexation, and then the anion-depleted electrolyte liquid is combined and mixed with an aqueous acceptor solution saturated with carbon dioxide or its water-soluble derivative, wherein carbonates and / or bicarbonates are spontaneously formed.

[0591] Therefore, in principle, carbonates and bicarbonates can be prepared from carbon dioxide or its derivatives (which exist in a reactive form in acceptor solution or in a reactive form via acceptor compounds, or in a form combined with such a reactive form) by contacting them with an element or compound that exists as a cation / cation compound (i.e., in ionic form), wherein a chemical transformation occurs. Thus, carbonates (bicarbonates) can be obtained and prepared in pure and amorphous forms, such as sodium carbonate, calcium carbonate, barium carbonate, magnesium carbonate, lithium carbonate, cobalt carbonate, iron carbonate, copper carbonate, aluminum carbonate, silicon carbonate, zinc carbonate, silver carbonate, lead carbonate, and ammonium carbonate, as well as their corresponding bicarbonates.

[0592] Preferred bicarbonates and carbonates produced by the method according to the invention have an average particle diameter preferably <2 μm, more preferably <1.5 μm, even more preferably <1 μm, and still more preferably <0.5 μm.

[0593] It is preferred to prepare bicarbonates and carbonates in amorphous form.

[0594] The preferred method is for the low-energy production of carbonates and / or bicarbonates.

[0595] Preferred methods are those for the low-energy production of carbonates and / or bicarbonates from renewable feedstocks.

[0596] Preferably, the recycled carbonates and bicarbonates are produced by the method according to the invention.

[0597] The preferred method is the production of aluminum carbonate.

[0598] The preferred form is aluminum carbonate produced by the method according to the invention.

[0599] The preferred method is the preparation of aluminum bicarbonate.

[0600] Preferably, it is aluminum bicarbonate produced by the method according to the invention.

[0601] Preferably, the aluminum carbonate is prepared by the method according to the invention, wherein the reacting compound is an aluminum salt, preferably aluminum chloride.

[0602] Preferably, the aluminum bicarbonate is prepared by the method according to the invention, wherein the reacting compound is an aluminum salt, preferably aluminum chloride.

[0603] The reaction compounds used to prepare aluminum carbonate and / or aluminum bicarbonate in the form of aluminum salts are not themselves aluminum carbonate and / or aluminum bicarbonate.

[0604] Preferably, the pH of the acceptor solution used to prepare carbonates or bicarbonates according to one embodiment of the present invention is in the range of 7 to 13.5, more preferably in the range of 8 to 12.5, and even more preferably in the range of 8.5 to 12.

[0605] Preferably, an aqueous solution of the salt of the cationic / cationic compound for the production of carbonates / bicarbonates is prepared and added to an acceptor solution saturated with carbon dioxide. In principle, the concentration of the salt solution can be freely chosen. Preferably, the pH of the acceptor solution should not drop below 4 upon addition of the salt solution, otherwise the bound carbon dioxide will be released. In another preferred embodiment, the solution with dissolved salt is introduced under pressure. To avoid localized pH reduction, the introduction of the salt solution is preferably carried out under stirring. The anion of the salt can be freely chosen in principle. It is preferred to use compounds with the lowest possible molecular weight. Preferred anions are chloride, hydroxyl, sulfate, and citrate ions.

[0606] By introducing salt into the acceptor solution, the anions used aggregate and electrostatically bind to the guanidinium or amidine groups of the acceptor compound. Therefore, it is advantageous to remove anions from the acceptor solution using existing techniques. This can be carried out continuously, for example by means of electrodialysis, or discontinuously, for example using anion exchange compounds or adsorbents / complexing agents.

[0607] Therefore, this method also relates to the production and acquisition of carbonates and bicarbonates. Thus, a method characterized by the following steps is preferred:

[0608] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group,

[0609] b) Contact the gas containing carbon dioxide with the acceptor solution from step a).

[0610] c) The conversion of the carbon dioxide and / or carbon dioxide derivatives contained in and bound to the acceptor solution in step b) is carried out by the following:

[0611] - Add at least one cationic compound to the acceptor solution in step b) and dissolve and mix it therein, or by the following

[0612] d2) - Electrophoretically transporting carbon dioxide and / or carbon dioxide derivatives contained in and bound to the acceptor solution into an absorption and release chamber or reaction chamber, where they are contacted and mixed with at least one cationic compound.

[0613] d) Obtain the reaction product with carbon dioxide and / or carbon dioxide derivatives of step c), which can be obtained in the reaction chamber, and then separate and dry the reaction product by means of a separation method.

[0614] Therefore, this method also relates to the production and acquisition of carbonates and bicarbonates. Thus, a method characterized by the following steps is preferred:

[0615] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group,

[0616] b) Contact the gas containing carbon dioxide with the acceptor solution from step a) until the carbon dioxide concentration in the gas reaches <100 ppm.

[0617] c) Converting carbon dioxide and / or carbon dioxide derivatives contained in and bound to the acceptor solution of step b), which is carried out by:

[0618] - Add at least one cationic compound to the acceptor solution of step b) and dissolve and mix it therein, or by the following methods

[0619] d2) - Electrophoretically transporting carbon dioxide and / or carbon dioxide derivatives contained in and bound to the acceptor solution into an absorption and release chamber or reaction chamber, where they are contacted and mixed with at least one cationic compound.

[0620] d) Obtain the reaction product with carbon dioxide and / or carbon dioxide derivatives from step c), which is obtained in the chamber where the reaction has taken place, and the reaction product is subsequently separated and dried by means of a separation method.

[0621] The implementation scheme of the method described herein is further preferably applicable to other method types, in particular:

[0622] Preferably, the transformation in step c) is a chemical transformation of the reacting compound;

[0623] A preferred method is to prepare a reaction solution by dissolving the reaction compound in an aqueous solution containing an acceptor compound and / or an absorber and release compound;

[0624] The preferred method is one in which the conversion in step c) is carried out in a receptor solution available from step b) and / or in an absorption and release medium and / or in a reaction medium;

[0625] Preferably, the method in which the reaction medium contains at least one receptor compound;

[0626] A preferred method is one in which the conversion in step c) is carried out in an acceptor solution available from step b) or in an absorption and release medium after the delivery of carbon dioxide and / or carbon dioxide derivatives from the acceptor medium according to step b), by combining dissolved or undissolved reaction compounds in the absorption and release medium.

[0627] A preferred method is one in which the conversion in step c) carried out in the absorption and release medium and / or reaction medium occurs during or after the delivery of carbon dioxide and / or carbon dioxide derivatives from the acceptor solution available from step b) to the corresponding medium;

[0628] A preferred method is one in which carbon dioxide and / or carbon dioxide derivatives are transported from an acceptor solution available from step b) to an absorption and release medium and / or a reaction medium via an electrophoretic process.

[0629] The preferred method is one in which the chemical transformation in step c) is carried out using a cationic / cationic compound that allows the formation of carbonates or bicarbonates;

[0630] The preferred method is to obtain chemically pure carbonates and / or bicarbonates in an amorphous form in step d).

[0631] Surprisingly, it has been found that, by combining the method of the present invention for dissolving and transporting carbon dioxide with any of the conversion methods disclosed herein, carbon dioxide and / or its derivatives can be converted into methane and other hydrocarbon compounds.

[0632] In a particularly preferred embodiment, conversion method 3 is used for this purpose. In one embodiment, this is carried out in an electrodialysis apparatus, wherein one or more chamber sequences are stacked in series between a cathode chamber and an anode chamber, arranged as: acceptor chamber / reaction chamber / electrolyte chamber. Preferably, the electrolyte solution circulating through the anode chamber flows through the electrolyte chamber. Preferably, at least one compound facilitating or catalytically electrolyzing is present in the electrolyte solution. Preferably, a medium suitable for absorbing and reversibly binding anions and cations is present in the reaction chamber. In one embodiment, an ionic liquid is used for this purpose. Preferably, an ionic liquid in which the salt compound can bind hydrogen ions (protons) at a molar ratio > / = 1 is used. This can be achieved, for example, by one or more tertiary nitrogen compounds or quaternary nitrogen compounds. In another embodiment, a compound capable of binding hydrogen ions (protons) is dissolved in the ionic liquid. In another embodiment, a compound having catalytic or reaction-promoting properties is included in the ionic liquid. In another preferred embodiment, the electrolyte solution is circulated between the electrolyte chamber and the cathode chamber. Preferably, an open-pore membrane or bipolar membrane exists between the acceptor chamber and the reaction chamber, and a cation-selective membrane exists between the electrolyte chamber and the reaction chamber. It has been shown that in this arrangement, applying a DC voltage between the anode and cathode causes methane to form in the reaction chamber and spontaneously escape from the reaction chamber.

[0633] Advantageously, in the process of the method according to the invention, during or after the implementation of the method according to the invention, the hydrogen generated in the electrodialysis process can be directly used in one of the reactions of the conversion method disclosed herein and converted in the process.

[0634] Therefore, this method also involves the production and acquisition of carbon compounds. Therefore, a method characterized by the following steps is preferred:

[0635] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group,

[0636] b) Contact the gas containing carbon dioxide with the acceptor solution from step a).

[0637] c) The acceptor solution in step b) contains and binds carbon dioxide and / or carbon dioxide derivatives, or

[0638] Delivery of the acceptor solution containing and bound carbon dioxide and / or carbon dioxide derivatives according to step b), and d2) conversion in an absorption and release medium or reaction medium.

[0639] d) Obtain the reaction products with carbon dioxide and / or carbon dioxide derivatives of step c) by phase separation or electrophoretic material separation.

[0640] Therefore, this method also involves the recovery and production of carbon compounds. Thus, a method characterized by the following steps is preferred:

[0641] a) Provide an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group,

[0642] b) Contact the gas containing carbon dioxide with the acceptor solution from step a) until the acceptor medium is saturated with carbon dioxide.

[0643] c) The acceptor solution in step b) contains and binds carbon dioxide and / or carbon dioxide derivatives, or

[0644] The carbon dioxide and / or carbon dioxide derivatives contained and bound in the acceptor solution according to step b) are delivered, and conversion occurs in the absorption and release medium or reaction medium in step d).

[0645] d) Obtain the reaction products with carbon dioxide and / or carbon dioxide derivatives of step c) by phase separation or electrophoretic material separation.

[0646] Therefore, extremely advantageous effects can be obtained by using acceptor solutions containing at least one dissolved acceptor compound having at least one guanidine or amidine group. In particular, carbon dioxide can be efficiently and selectively removed from gas / gas mixtures at atmospheric pressure and room temperature. Carbon dioxide bound in the acceptor medium, along with carbonate and / or bicarbonate anions, is retained therein without pressure (at atmospheric pressure) for at least 6 months and can be transported in this form. Furthermore, acceptor media in which carbon dioxide and carbonate and / or bicarbonate anions are present in dissolved form can provide a reaction solution in which carbon dioxide and carbonate and / or bicarbonate anions can be immediately chemically transformed. Moreover, the acceptor medium is suitable for dissolving and transporting carboxylic acids generated from the transformation of carbon dioxide. Furthermore, acceptor solutions can be saturated with carbon dioxide any number of times, and then they can be removed again without consuming or losing any acceptor compound.

[0647] definition

[0648] receptor mediators

[0649] The term "acceptor medium" refers to a liquid or solvent in which at least one dissolved compound capable of binding carbon dioxide / carbon dioxide derivatives is present. This compound is also referred to herein as an "acceptor compound." The acceptor compound has at least one free guanidine and / or amidine group. The acceptor medium may contain reactive compounds as well as other compounds. If the liquid or solvent in which at least one dissolved compound is present is water, then the "acceptor medium" is also referred to herein as an "aqueous acceptor medium" or "acceptor solution." The terms "aqueous acceptor medium" and "acceptor solution," or even "aqueous acceptor solution," are used interchangeably herein.

[0650] receptor solution

[0651] As used herein, "acceptor solution" should be understood as an aqueous medium in which at least one dissolved compound capable of binding carbon dioxide or carbon dioxide derivatives is present. This compound is also referred to herein as "acceptor compound." The acceptor compound has at least one free guanidine group and / or amidine group. The acceptor solution may contain reactive compounds as well as other compounds.

[0652] receptor compounds

[0653] As used herein, the term "receptor compound" refers to a compound having a free guanidine group and / or an amidine group. Arginine is particularly preferred as the receptor compound.

[0654] cationic groups

[0655] As used herein, the term "cationic group" refers to a chemical functional group that acquires a positive charge upon proton absorption. Therefore, "cationic group" signifies a positively charged functional group. In this document, "cationic group" is also referred to as a positively charged "charged group." Preferred compounds containing "cationic groups" are preferably amino acids and / or derivatives thereof containing at least one guanidine and / or amidine group.

[0656] cationic compounds

[0657] As used herein, the term "cationic compound" refers to a substance having a positive charge. In particular, salts of alkali metals and alkaline earth metals are referred to herein as "cationic compounds." Specifically, alkali metals and alkaline earth metals can form carbonates and bicarbonates, respectively. Preferred "cationic compounds" are inorganic and organic salts of alkali metals and alkaline earth metals that form carbonates or bicarbonates that are practically insoluble or slightly soluble in water. Alkali metal and alkaline earth metal carbonates or bicarbonates can be selectively obtained by adding the "cationic compound" to an aqueous acceptor solution containing bound carbon dioxide. Besides alkali metal and alkaline earth metal salts, other metal cations, as disclosed herein, can also be used to react with carbonate or bicarbonate anions. Examples of preferred "cationic compounds" herein include, but are not limited to, calcium chloride, ferric chloride, and aluminum chloride. Examples of substances that can be used to obtain carbonates or bicarbonates such as sodium carbonate, calcium carbonate, barium carbonate, magnesium carbonate, lithium carbonate, cobalt carbonate, iron carbonate, copper carbonate, aluminum carbonate, silicon carbonate, zinc carbonate, silver carbonate, lead carbonate, and ammonium carbonate, as well as their corresponding bicarbonates and aluminum carbonate or aluminum bicarbonate, include sodium, calcium, barium, magnesium, lithium, cobalt, iron, copper, aluminum, silicon, zinc, silver, and lead. Salts of sodium, calcium, barium, magnesium, lithium, cobalt, iron, copper, aluminum, silicon, zinc, silver, and lead can be used as cationic compounds in this document. Particularly preferred cationic compounds are aluminum salts, such as aluminum chloride.

[0658] carbon dioxide derivatives

[0659] As used herein, the term "carbon dioxide derivatives" refers to all compounds formed or potentially formed through the dissolution of carbon dioxide in water. Specifically, these include H₂CO₃, HCO₃⁻, and other compounds. - CO3 2- Carbon dioxide (CO2) reacts with water to form carbonic acid. Carbonic acid (H2CO3) is an inorganic acid and its anhydride, and is a product of the reaction between carbon dioxide (CO2) and water.

[0660] Reactive compounds

[0661] The term "reactive compound" refers to compounds that react with or cause a reaction with carbon dioxide and / or carbon dioxide derivatives. In this method, carbon dioxide and / or carbon dioxide derivatives undergo chemical transformation and / or combination. The preferred "reactive compound" herein is the "cationic compound" as defined above.

[0662] Absorption and release media

[0663] The term "absorption and release medium" refers to a gas, liquid, or solid in which carbon dioxide and / or carbon dioxide derivatives are adsorbed, absorbed, physically absorbed, or bound, or in which they are transformed and / or released. Preferably, the medium comprises a compound that influences one or more of the above-described properties. In this respect, the absorption and release medium may contain reactive compounds, acceptor compounds, and other compounds. Aqueous absorption and release media are particularly preferred herein. As used herein, the term "absorption and release medium" refers to a medium in which bound carbon dioxide can be released. In this respect, the release of carbon dioxide can occur directly upon the entry of carbon dioxide derivatives (e.g., carbonate / bicarbonate anions) into the absorption and release medium. Preferably, the release of carbon dioxide from the absorption and release medium occurs after it has been introduced into a release device or release chamber.

[0664] Element or element molecule

[0665] As used herein, the term "element" refers to a known chemical element arranged in ascending order of atomic number in the periodic table (PSE). An "element molecule" is a molecule composed of two or more atoms of a single chemical element. In contrast, all other molecules are composed of atoms of at least two different chemical elements (e.g., carbon dioxide (CO2) composed of carbon and oxygen). "Gaseous elements" or "gaseous element molecules" are those elements or element molecules that are gaseous under normal conditions. These are the six noble gases He, Ne, Ar, Kr, Xe, and Rn, and five other elements that are gaseous under normal conditions: hydrogen (H2), nitrogen (N2), oxygen (O2), fluorine (F2), and chlorine (Cl2).

[0666] molecular compounds

[0667] The term "molecular compound" refers to a molecule with at least two atoms of different chemical elements (e.g., carbon dioxide (CO2) derived from carbon and oxygen). The term "gaseous molecular compound," or simply "gaseous compound," refers to a molecular compound that is gaseous under normal conditions. Examples of "gaseous molecular compounds" that are gaseous under normal conditions include, but are not limited to, carbon dioxide (CO2), methane (CH4), ammonia (NH3), carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (also known as laughing gas) (N2O), sulfur dioxide (SO2), hydrogen chloride (HCl), ethane (CH3CH3), propane (CH3CH2CH3), butane (CH3CH2CH2CH3), acetylene (CH≡CH), etc.

[0668] Gas / Gas Phase

[0669] As used herein, the term "gas" or "gas phase" refers to the gaseous phase of an element or compound that exists as a pure substance or as a mixture. Examples of pure gases are gaseous carbon dioxide, methane, or hydrogen. Examples of gas mixtures are air, combustion gas / flue gas, biogas, and wastewater treatment gas. Or acidic natural gas. Besides solids and liquids, the gaseous state is one of the three classic states of matter. For some elements and compounds, standard conditions (temperature 20°C, pressure 101,325 Pa) are sufficient for them to exist as gases. In this context, the term "air" refers to the gaseous mixture of the Earth's atmosphere. Dry air is primarily composed of two gases: nitrogen (approximately 78.08% by volume) and oxygen (approximately 20.95% by volume). In addition, there are components argon (0.93 vol%), carbon dioxide (0.04 vol% or 400 ppm) and trace amounts of other gases at concentrations less than 0.002 vol% or 20 ppm, such as neon (Ne), helium (He), methane (CH4), krypton (Kr), nitrous oxide (N2O), carbon monoxide (CO), xenon (Xe), various chlorofluorocarbons (FCKW) such as dichlorodifluoromethane, trichlorofluoromethane, dichlorofluoromethane, trichlorotrifluoroethane, 1,1-dichloro-1-fluoroethane, 1-chloro,1-1-difluoroethane, as well as carbon tetrachloride, sulfur hexafluoride, bromochlorodifluoromethane, and bromotrifluoromethane.

[0670] Water-soluble gases

[0671] In the dissolution of gases in liquids, the term "solubility" refers to a coefficient representing the amount of gas dissolved in a liquid at a given gas pressure when the gas is in diffusion equilibrium between the gas and liquid phases (i.e., the amount diffusing in and out is exactly equal). Solubility depends on temperature, pressure, and, for some compounds, also on pH. As used herein, the term "water-soluble gas" in the context means a gaseous molecular compound that reacts chemically with water upon contact, for example, to form an anhydride or acid. It then exists in water as an organic or inorganic acid or as an anion. The preferred "water-soluble gas" herein refers particularly to those gases falling under the term "acidic gas," which form an acid or weak acid upon dissolution in water. The gases covered by the term "water-soluble gas" are distinguished from gases that do not react chemically with water upon contact. For example, methane (CH4) has a solubility of 36.7 ml / L water at atmospheric pressure and 20°C. Methane (CH4) does not react with water and is therefore not a "water-soluble gas."

[0672] Water-soluble gas components

[0673] The term "water-soluble gaseous component" includes all gaseous compounds that are present in the gas phase and form water-soluble compounds with water when in contact with and / or mixed with water. Examples include carbon dioxide, sulfur dioxide, hydrogen sulfide, nitric oxide, nitrous oxide, hydrogen chloride, or chlorine dioxide. Therefore, "water-soluble gaseous component" includes "water-soluble gases," particularly "acidic gases."

[0674] acidic gases

[0675] As used herein, the term "acidic gas" refers to a gas or even a mixture of gases that, when dissolved in water, form an acid or weak acid. Acidic gases are generally corrosive and caustic, as well as toxic, and pose a hazard to humans and the environment. Acidic gases can be of natural origin, or they can be produced as desired or undesirable reaction gases in industrial processes. Examples of acidic gases include, but are not limited to, carbon dioxide (CO2) (which forms carbonic acid and bicarbonate in water), sulfur dioxide (SO2) (which forms sulfurous acid in water), hydrogen sulfide (H2S), hydrogen chloride (HCl) (which forms hydrochloric acid in water), nitrogen dioxide (N2O) (which forms nitric acid in water), hydrogen cyanide (HCN) (which forms hydrogen cyanide in water), hydrogen bromide (HBr) (which forms hydrobromic acid in water), and selenium dioxide (SeO2) (which forms selenite in water).

[0676] basic amino acids

[0677] As used herein, the term "basic amino acid" refers to an amino acid having an amino group or a nitrogen atom with a free pair of electrons in its amino acid group (side chain). When these nitrogen atoms accept a proton, a positively charged side chain is formed. The amino acids histidine, lysine, and arginine are basic amino acids. According to the present invention, basic amino acids having at least one guanidine group and / or amidine group are preferred, and arginine is particularly preferred.

[0678] Electrophoretic separation

[0679] As used in this article, “electrophoretic separation” refers to electrochemical separation using a separation membrane in an electrochemical process such as electrodialysis.

[0680] In the electrolysis process, electrolysis is carried out in an electrolytic cell. The electrolytic cell consists of two electrodes made of, for example, carbon or platinum and a conductive liquid. The electrode connected to the positive electrode is called the anode, and the electrode connected to the negative electrode is called the cathode. Cations migrate to the negatively charged cathode, and anions migrate to the positively charged anode. The "electrophoretic separation cell" used in the "electrophoretic separation" of this invention consists of at least two chambers separated by a separation membrane. The "receptor chamber" contains an aqueous acceptor solution according to the invention, which contains at least one acceptor compound having a free guanidine group and / or an amidine group. When a DC voltage is applied to the "electrophoretic separation cell," the bound carbon dioxide / carbon dioxide derivative is transported through the separation membrane into the absorption and release medium in the "absorption and release chamber." The "electrophoretic separation" is based on the principle of electrodialysis.

[0681] Electrodialysis

[0682] Electrodialysis is a method for separating ions from a salt solution. The necessary ion separation is achieved by applying electric fields to the anode and cathode, along with ion-exchange membranes or semi-permeable ion-selective membranes. Electrodialysis is an electrochemically driven membrane method in which ion-exchange membranes are used in conjunction with a potential difference to separate ionic substances from uncharged solvents or impurities. One of the most common membrane materials is polystyrene (PS). To achieve ion selectivity, for anion-selective membranes, surface modification is performed by introducing quaternary ammonium groups, and for cation-selective membranes, by introducing carboxylic acid or sulfonic acid groups. Some membrane types are mechanically reinforced with polyvinyl chloride (PVC), polypropylene (PP), or polyethylene terephthalate (PET).

[0683] Separation medium

[0684] The term "separation medium" as used in this article refers to a medium on which selective substance transport can occur. Therefore, the "separation medium" as used in this article can also be called a separation membrane or a transport membrane.

[0685] Separation membrane

[0686] As used herein, "separation membrane" or simply "membrane" generally refers to a thin layer of material that affects the quality of material transported through it. In separation technologies, membranes serve as separation layers. Membranes can be permeable in different ways: impermeable, selectively permeable, unidirectionally permeable, or omnidirectionally permeable. Most commercial membranes are made of polymers. A wide variety of plastics are used depending on the very different requirements of the application. The two most common forms are wound membranes and hollow fiber membranes. Lipophilic polymer membranes allow some gases or organic substances to pass through, but not water and aqueous solutions. However, ionic groups in the polymer layer can also prevent ions from passing through the membrane. Such membranes are used, for example, in electrodialysis. Other membranes are permeable only to water and certain gases. Commonly used membrane materials include: polysulfone, polyethersulfone (PES), cellulose, cellulose esters (cellulose acetate, cellulose nitrate), regenerated cellulose (RC), silicone, polyamide ("nylon", more precisely: PA 6, PA 6.6, PA 6.10, PA 6.12, PA 11, PA 12), polyamide-imide, polyamide-urea, polycarbonate, ceramic, stainless steel, silver, silicon, zeolite (aluminosilicate), polyacrylonitrile (PAN), polyethylene (PE), polypropylene (PP), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), and piperazineamide. Ceramic membranes are mainly used in applications where high chemical or thermal requirements apply to the filters.

[0687] Separation membrane for electrophoretic separation

[0688] As used herein, the term "separation membrane" refers to a separation medium used for electrophoretic separation or electrolysis. Preferably, the separation membrane is an open-pore membrane, and more preferably an open-pore mesoporous membrane. In some embodiments, the separation membrane is a ceramic filter plate. In some embodiments, the separation membrane is an anion-selective membrane. All suitable separation membranes from the prior art can be used as separation membranes. Ion-selective separation membranes and bipolar separation membranes are known in the prior art.

[0689] A separation membrane used to bring a gas containing carbon dioxide into contact with a receptor medium.

[0690] As used herein, the separation medium for contacting a carbon dioxide-containing gas with a receiver medium refers to a “separation membrane” suitable for mass transfer between the gas and liquid phases. These separation media are also referred to herein as “gas-liquid separation membranes.” Contacting a carbon dioxide-containing gas with a receiver medium is also referred to herein as “indirect contact.” Gas-liquid separation membranes can be provided in the form of membrane contactors. Membrane contactors are preferably used herein for indirect contact between a carbon dioxide-containing gas and a receiver medium. Membranes can also be provided as gas-liquid separation membranes, disposed on a carrier material. These gas-liquid separation membranes are known in the art. Preferred gas-liquid separation membranes have an average pore size >10 μm, more preferably >50 μm, more preferably >100 μm, more preferably >150 μm, and more preferably >200 μm. Gas-liquid separation membranes with an average pore size of 200 μm are particularly preferred. The preferred gas-liquid separation membrane has a membrane thickness of <300 μm, more preferably <200 μm, more preferably <150 μm, more preferably <100 μm, more preferably <50 μm, and even more preferably <25 μm. The preferred gas-liquid separation membrane has an average channel diameter of >10 μm, more preferably >50 μm, further preferably >100 μm, more preferably >150 μm, more preferably >200 μm, even more preferably >250 μm, and most preferably >300 μm of open channels. The preferred gas-liquid separation membrane has a porosity of >50%, more preferably >60%, more preferably >70%, more preferably >80%, and even more preferably >90%. Porosity is defined as the number of pores per unit area. Suitable materials for the gas-liquid separation membrane include, but are not limited to, PTFE (polytetrafluoroethylene), PC (polycarbonate), or ceramics.

[0691] Gas scrubbing

[0692] When a gas or air stream is guided through a washing liquid, it is called gas washing or absorption. In this process, the gaseous components to be absorbed (to be absorbed - unbound, already absorbed - bound) are bound in the washing liquid (absorbed - unloaded, absorbed - loaded).

[0693] Salt

[0694] As used herein, the term "salt" refers to a compound consisting of positively charged ions (cations) and negatively charged ions (anions). Ionic bonds exist between these ions. In "inorganic salts," the cations are typically formed from metals, and the anions are typically formed from nonmetals or their oxides. "Organic salts" are all compounds in which at least one anion or cation is an organic compound; except for carbonates, which by definition are derived from inorganic carbonic acid (H₂CO₃).

[0695] Normal conditions

[0696] The term "normal conditions" or STP (Standard Temperature and Pressure) conditions in this document refer to the "standard pressure" of 101.325 Pa = 1.01325 bar = 1 atm = 760 Torr. The term "standard temperature" refers to the air pressure at any location in the Earth's atmosphere. According to standards, the average air pressure at sea level ("atmospheric pressure") is 101325 Pa = 101.325 kPa = 1013.25 hPa ≈ 1 bar. The terms "atmospheric pressure" and "standard pressure" are used interchangeably herein. The term "no pressure" as used herein also refers to both "atmospheric pressure" and "normal pressure." If a method step is described in this application as being performed "no pressure," this corresponds to a method process performed at "atmospheric pressure" and "normal pressure." The term "no / unpressurized" as used herein also refers to both "atmospheric pressure" and "normal pressure." If a method step is described in this application as being performed "no / unpressurized," this corresponds to a method process performed at "atmospheric pressure" and "normal pressure."

[0697] Gas scrubbing device

[0698] A gas scrubber, wet separator, or absorber is a process device in which a gas stream comes into contact with a liquid stream to absorb gas stream components from the liquid. The components of the transferred gas stream can be solid, liquid, or gaseous substances. Gas scrubbing devices known in the art can be used to separate CO2 from flue gas or biogas. Gas scrubbing devices may include a pre-wash gas scrubbing tower. These are classified as fixed-bed towers, packed towers, plate towers, and spray towers.

[0699] pure gas

[0700] As used in this article, the term "pure gas" is categorized by the following purity levels:

[0701] Raw gas (also known as crude gas) – unpurified quality

[0702] Industrial gas – This gas is used for general industrial purposes, is typically produced on a large scale, and may have an off-odor and color.

[0703] The gas used for synthesis contains a small amount of impurities that generally do not interfere with the synthesis because purification occurs during the production of the synthesized product.

[0704] Pure gas (purum) – unless otherwise specified, refers to chemical purity, with a substance content >98.5% by volume. Color and characteristic data are largely consistent with relevant literature. Suitable for synthetic and laboratory purposes.

[0705] Extremely pure gas (purissimum, puriss.) – of exceptional purity, with a substance content of at least >99.5% by volume. Impurities cannot be detected by conventional analytical methods. Appearance and characteristic data correspond to relevant literature.

[0706] application

[0707] This method is particularly suitable for the selective removal of carbon dioxide components from gases or gas mixtures. Preferred gas / gas mixtures are those with high carbon dioxide content, such as flue / combustion gases. Also included are gas mixtures produced during technical processes / synthesis or through fermentation processes, such as biogas production. This also includes so-called putrefactive gases, which are generated, for example, during the decomposition of wastewater residues. Furthermore, this method is suitable for purifying gases produced by minerals or industries. Therefore, this method is suitable for purifying gas / gas mixtures containing water-soluble gaseous components.

[0708] The extraction of water-soluble components from gas / gas mixtures achievable using this method can be further used to purify anaerobic phases such as putrefactive gases or biogas by removing water-soluble gas components to obtain industrially pure or very pure gases, such as methane or biomethane. In this respect, this method can be used to produce industrial gas / gas mixtures.

[0709] This method is also applicable to the production, recovery, and conversion of hydrogen.

[0710] This method is also applicable to extracting gaseous components from gas / gas mixtures, transporting them, storing them, and making them available. In particular, this method can be used to obtain pure gaseous carbon dioxide, which can be used in a variety of industrial applications. For example, the extracted carbon dioxide can be used as an industrial gas, as a propellant (e.g., for distributors (Zapfanlagen)), for the enrichment of carbonic acid (e.g., in food or concrete), or for dry ice production. Therefore, this method is suitable for producing pure and high-purity carbon dioxide.

[0711] Specifically, this method enables the production of renewable carbon dioxide, which can then be used to produce renewable byproducts. Examples of applications include plant breeding or the production of renewable carbon in a circular economy, thereby producing cyclical components such as synthetic fuel compounds or synthetic carbon compounds. Therefore, this method is suitable for producing renewable carbon dioxide.

[0712] This method is also suitable for long-term storage or transport of bound carbon dioxide.

[0713] Furthermore, this method enables the direct chemical conversion of bound carbon dioxide without further energy input, thus allowing the direct production and simple separation of key raw materials for organic synthesis (the production of carbon compounds). Therefore, this method is suitable for the production of organic compounds.

[0714] Furthermore, carbonates and bicarbonates can be obtained in their pure form with minimal technical cost. Therefore, this method is suitable for preparing carbonates and bicarbonates. Carbonates and bicarbonates are important basic materials, used as fillers in building materials or the paper industry, but also as dietary supplements for humans and animals, and as ingredients in tablets or dental cleaning agents.

[0715] In particular, the methods and processes according to the invention are suitable for producing recycled and sustainable products. Attached Figure Description

[0716] Figure 1 Schematic diagram of a device for adsorbing, transporting and releasing water-soluble gases.

[0717] Wherein: 1) any gas / gas mixture containing water-soluble gas or gaseous components; 1a) represents the inlet device of the gas / gas mixture 1) to be purified; 2) represents a gas washing device in which gas 1) contacts the acceptor solution; and gas 1) exits through outlet 3) after the water-soluble gaseous components have been extracted; 4) represents a collection device for the acceptor solution in contact with gas 1) in the gas washing device 2); 5) represents a circulation loop of the acceptor medium between the gas washing device and the acceptor chamber 7) of the electrodialysis apparatus, wherein acceptor solution saturated with soluble gas is supplied to acceptor chamber 7) through inlet from 4), and acceptor solution from which soluble gas has been extracted exits from acceptor chamber outlet. The gas is introduced into the gas scrubbing device 2) via a conduit; the electrodialysis device consists of the following components: 6) cathode chamber, 7) acceptor chamber, 8) absorption and release chamber, 9) anode chamber and 10) separation medium (membrane) (not shown is an ion-selective separation membrane for the closed electrode chamber); 11) indicates the circulation of the absorption and release medium, wherein after absorbing the electrophoretically transported gas from the acceptor chamber, the absorption and release medium is conveyed through an outlet to the release device 12), wherein degassing of the absorption and release medium and release of the transported gas occur, and wherein the degassed absorption and release medium is then reintroduced into chamber 8) via an inlet; the gas released in 12) is collected in the gas collection device 13) and can be stored therein. Example

[0718] Unless otherwise stated, all studies were conducted at ambient pressure (101.3 kPa) and room temperature (20 °C) using deionized water (VE water).

[0719] Example 1

[0720] A 0.5 mol arginine solution was prepared using deionized water and placed in a gas scrubbing apparatus. A constant gas flow of carbon dioxide was passed through the apparatus for 10 hours, and the pH of the solution was continuously measured. When the pH of the solution fell below 9, powdered arginine was added to the liquid and dissolved using a mixing unit within the apparatus. This process was repeated until the total molar concentration of arginine in the solution reached 3 mol / L. Gas introduction was stopped when the pH reached 8, and a clear liquid without solids was present. A portion of the solution was taken for long-term experiments and stored at 20°C under ambient pressure (101.3 kPa) in a closed gas absorption apparatus. The volume of gas released from the solutions after 3 and 6 months of storage was measured. At the end of the long-term experiment and for samples remaining after the experiment, the gas was filled into a gas collection device, and HCl was added and mixed until the pH reached 1. The molar mass was determined based on the measured volume of released gas and the concentration of carbon dioxide present, and the relationship with the molar concentration of arginine in the solution was calculated. The experiment was repeated three times. The solutions were then purified in an electrodialysis unit to remove chloride and hydrogen ions until the pH reached 12.5. These solutions were used for further repeat experiments, in which carbon dioxide was loaded into the acceptor solution until the pH reached 8. The amount of bound carbon dioxide gas in the solution was then determined on three samples using the aforementioned method steps.

[0721] result:

[0722] At solution pH 8, the molar ratio of carbon dioxide bound to arginine in the solution was 0.96–1.01. Over a period of 3–6 months, 0.1–0.3% by volume of carbon dioxide was released. The solution remained clear during this process. When the experiment was repeated with an arginine solution regenerated by electrodialysis, the proportion of bound carbon dioxide was no different from that in the first experiment.

[0723] Example 2

[0724] Flue gas from cement production and from the wood chip cogeneration (Holzhackschnitzel-BHKW) with carbon dioxide contents of 11.2% and 16.9% by volume, respectively, is passed through a gas scrubbing tower.

[0725] Before entering the scrubbing tower, the flue gas is guided through a soot filter. The first section of the scrubbing tower contains a 50% ammonium nitrate solution acidified to pH 5 with nitric acid as the scrubbing medium. The gas then passes through an aerosol filter. The second section of the gas scrubbing tower has a gas inlet device filled with arginine solution, through which the gas passes a surface area of ​​60 m². 2A nanoporous, textured ceramic membrane (Kerafol, Germany) is discharged into the acceptor liquid. This membrane is located at the bottom of the chamber and through which flue gas is introduced, with the average size of the discharged bubbles ranging from 1 μm to 20 μm. The column section consists of 10 consecutively arranged chambers, each collecting the gas phase above the liquid surface and conveying it via pipes to the inlet of the gas inlet device of the next chamber. The acceptor solution in the scrubbing column flows countercurrently through the chambers. The purified gas mixture is collected, and the carbon dioxide concentration is determined. Experiments were conducted at different arginine concentrations of 0.1–0.5 mol / L and volumetric flow rates of 100–1000 ml / min. Furthermore, the volumetric flow rate of the flue gas to be purified is 200 cm⁻¹. 3 -1m 3 The contact time varies between / minute. The contact time is calculated for concentrations reaching <0.01 vol% (100 ppm) of carbon dioxide. Here, the contact time is calculated for an average bubble size of 10 μm.

[0726] result:

[0727] For the two flue gas mixtures, carbon dioxide removal down to <100 ppm can be achieved. This is possible under all experimental conditions, with the average contact time between the acceptor solution and the gas mixture to be purified depending on the selected arginine concentration and ranging from 1 to 33 seconds.

[0728] Example 3

[0729] Carbon dioxide is continuously separated from a gas mixture using a process arrangement consisting of a carbon dioxide separation unit and a carbon dioxide release unit. For this purpose, flue gas, a gas mixture from biogas production, and industrial gases with carbon dioxide concentrations between 3.5% and 65% by volume are used. These gases are then released at a concentration of 500 ccm. 3 and 1.5m 3A volumetric flow rate between 500 ml and 1.5 L / min is passed through the scrubbing tower described in Example 2. The gas that has passed through is collected and the concentration of carbon dioxide is determined. Arginine is dissolved in the acceptor solution at a concentration of 0.5 mol / L (using deionized water). The carbon dioxide-rich acceptor solution in the scrubbing tower is introduced into an electrodialysis unit consisting of 12 consecutive separation chamber units, each consisting of an acceptor chamber and an absorption and release chamber. The acceptor solution is introduced into the cathode chamber where the cathode is located. The acceptor solution is guided continuously through adjacent acceptor chambers. The acceptor solution discharged from the anode side is returned to the gas scrubbing tower to introduce acceptor solution. Thus, a circulation with a volumetric flow rate between 500 ml and 1.5 L / min is established between the gas scrubbing tower and the electrodialysis unit. The absorption and release chambers of the electrodialysis unit are interconnected to ensure that the chambers are always filled with the absorption and release medium. Above the level of the absorption and release medium, there is a storage chamber for the escaping gas, which is guided to a large-volume external gas storage chamber. Between the cathode and acceptor chambers, and between the absorption and / or release chambers, there exists a mesoporous ceramic separation membrane (water contact angle >120°) coated with a hydrophobic surface. An adjacent separation chamber unit is separated by an electron-conducting membrane (bipolar membrane) in a pressure-stable manner, sandwiched between the acceptor chamber and the absorption and release chambers. Other chamber units are arranged accordingly. In the absorption and release media, a) glutamic acid (10 g / L) or b) citric acid (100 g / L) is present in dissolved form. The pH of the absorption and release media is monitored during electrodialysis. A DC voltage of 20 V is applied between the cathode and anode. The volume of gas released in the absorption and release chambers is measured, and the gaseous compounds contained therein are analyzed. Furthermore, the concentration of carbon dioxide present in the gas mixture that has passed through the gas collection device is determined. The contact time required to reduce the carbon dioxide concentration in the gas mixture guided through the gas scrubbing tower to <100 ppm in each test apparatus is calculated. The tests are conducted at 20 °C and atmospheric pressure.

[0730] result:

[0731] For all the gas mixtures studied, which have been processed using the apparatus setup, the carbon dioxide concentration can be reduced to <100 ppm. The required contact time for this is 0.5 seconds to 2 minutes, and depends primarily on the carbon dioxide concentration of the initial gas mixture and the flow rate of the acceptor fluid through the electrodialysis unit. The gas released in the absorption and release chambers of the electrodialysis unit has a carbon dioxide content of >99% by volume. The calculated mass of carbon dioxide in the separated gas volume corresponds to the calculated mass of carbon dioxide that has been removed from the initial gas mixture.

[0732] Example 4

[0733] The chemical convertibility of carbon dioxide or carbonate / bicarbonate anions present in the acceptor medium in dissolved or bound form was investigated. For this purpose, an aqueous solution containing arginine and lysine or histidine at a concentration of 0.1 mol / L to 0.5 mol / L was used as the acceptor solution, prepared with deionized water. Carbon dioxide was introduced using a gas scrubbing tower according to Example 2, and carbon dioxide was extracted from flue gas with a carbon dioxide content of 22% by volume. Unlike the experimental procedure in Example 2, according to Example 1, if the pH of the acceptor solution decreased by more than 1 compared to the initial (Ausgang) pH due to carbon dioxide absorption, the acceptor compound used was added in solid (powder) form while continuously recording pH. Addition was stopped when a total of 3 mol / L of each acceptor compound was completely dissolved and a clear solution was present. The catalyst (ruthenium complex fixed on MCM-41) was fixed to a PU mesh with an adhesive. These meshes were clamped in the acceptor chamber of the electrodialysis unit according to Example 3, such that they were circulated and rinsed by the acceptor medium flowing through the acceptor chamber. Unlike Example 3, an anion exchange membrane with a rejection cutoff of 400 Da was used as the separation membrane between the receiving chamber and the absorption and release chambers. In this experiment, a 0.3 mol / L arginine solution was used as the absorption and release medium. Furthermore, unlike Example 3, the absorption and release medium was circulated in a secondary cycle, in which the medium was passed through a separation device in which calcium carbonate was added to the solution, and then guided into a settling container where complexes formed from carboxylic acids and calcium complexes transported to the absorption and release medium precipitated. After passing through a column containing cation exchange resin, the solution returned to the anode chamber. The precipitated solids were discontinuously removed from the settling container of the separation device, and the solids were dehydrated by centrifugation. Organic acids (white solids) bound in the centrifuged fraction were prepared by ethanol extraction, followed by methylation, and then analyzed by gas chromatography.

[0734] Electrodialysis is performed by applying a 20V DC voltage between the anode and cathode during the passage of an acceptor solution containing carbon dioxide and carbonate / bicarbonate anions through the acceptor chamber.

[0735] result:

[0736] Flue gas can be purified to a carbon dioxide content of <100 ppm. Absorption and transport are achieved using a acceptor solution in which basic amino acids are dissolved. By absorbing carbon dioxide into the solution, the concentration of these amino acids can be significantly increased beyond their respective solubility limits in neutral water. This allows for the preparation of high concentrations of carbon dioxide and carbonate / bicarbonate anions in an aqueous acceptor solution.

[0737] High concentrations of formic acid were detected by alcohol extraction from the calcium complex separated in the secondary cycle. This indicates that, on the one hand, chemical transformation of carbon dioxide and its derivatives present in the acceptor solution was achieved, and on the other hand, the carboxylic acid formed in this process was transported to the absorption and release media via electrodialysis.

[0738] Example 5

[0739] Research on the conversion of carbon dioxide into carbonates

[0740] 1 L of 2 M arginine solution was prepared separately using deionized water, and 200 g of sodium chloride (A) and calcium chloride (B) were added and dissolved in the solution. Carbon dioxide was introduced into the solution in the gasification apparatus according to Example 2. The pH of the solution was monitored. After 30 minutes, the gasification was stopped, and the solution was allowed to stand for 24 hours. The supernatant was then completely decanted, and the resulting solid was suspended in 100 mL of deionized water. The suspension was then centrifuged. The washing step was repeated twice. The obtained centrifuged fraction was spread on a ceramic filter plate and dried at room temperature. The dried solid was subjected to solid-state NMR analysis. In addition, to detect the presence of carbonate, chemical decomposition was performed using concentrated HCl solution, in which the concentrated HCl solution was added to each powder (3 g) in a nitrogen-filled glass flask. The resulting gas was passed through a CO2 analyzer. The decanted supernatant was treated by electrodialysis using an anion-selective membrane.

[0741] result:

[0742] The solutions were initially clear. After a 2-minute gas inlet duration, the acceptor solutions exhibited a milky turbidity, the intensity of which rapidly increased. During the gas inlet, the pH decreased from 12.4 (A) and 11.8 (B) to 8.6 (A) and 8.3 (B), respectively. After 24 hours, a white solid layer precipitated in both reaction vessels, and the supernatant was clear in each case. The solid obtained after drying was present as a white fine powder. Carbon dioxide was released during acid-catalyzed decomposition. Sodium carbonate (A) and calcium carbonate (B) were detected by NMR analysis, with no other elements or compounds present. Chloride ions in the supernatant were removed by electrodialysis, while chlorine was released at the anode. The pH of the corresponding supernatant thus increased to the level of the corresponding starting solution.

[0743] Example 6

[0744] Research on the conversion of carbon dioxide into carbonates

[0745] In each case, a 1-liter, 2-molar arginine solution was prepared. Each solution was aerated with carbon dioxide for 1 hour according to Example 2. Additionally, in each case, a 1-liter, 1-molar arginine solution was prepared, and (A) aluminum chloride or (B) ferric chloride was dissolved therein until the pH of the solution reached 8. The solutions were then added to one of the carbon dioxide-saturated arginine solutions with stirring. Centrifugation was then performed. The supernatant was then completely decanted, and the resulting solid was suspended in 100 ml of deionized water. The suspension was then centrifuged. The washing step was repeated twice. The resulting centrifuged fraction was spread onto a ceramic filter plate and dried at room temperature. 2 g of each powder was chemically decomposed according to Example 5. The dried solid was decomposed at 900°C, and the residue was subjected to elemental analysis.

[0746] result:

[0747] When a solution containing aluminum or iron ions is mixed into an acceptor solution saturated with carbon dioxide, a white or rust-colored solid is formed. These can be completely separated by centrifugation, and the supernatant becomes clear. After washing out the soluble compounds and drying, a dry solid aggregate is obtained, which can be ground into a fine powder in a mortar. Carbon dioxide is released upon acid-catalyzed decomposition. Combined carbon dioxide is released through thermal decomposition. In elemental analysis, only aluminum oxide (A) or iron oxide (B) can be detected.

[0748] Example 7

[0749] Research on pure gas recovery

[0750] To absorb and extract carbon dioxide, a gas scrubbing device containing a packing material continuously sprayed with a receiver solution is used. Figure 1 :2)). This allows a portion of the biogas flow to be at a volumetric flow rate of 100 m³ / h. 3 / h through the device ( Figure 1 :2)). The packing is impinged with a receiver solution volumetric flow rate of 100 L / min. For this purpose, a receiver solution from storage tank 1 is used ( Figure 1 :4). The acceptor solution used for gas washing is fed from the gas washing unit to the electrodialysis unit to desorb carbon dioxide bound in the acceptor solution. Figure 1 :5)). This is due to the cathode electrolyte chamber ( Figure 1 :6)) and the anolyte chamber ( Figure 1 :9)) and the chamber for receiving the receptor solution ( Figure 1 :7)) and a chamber for receiving and releasing the absorption and release media ( Figure 1 The latter consists of an alternating arrangement of bipolar films (8). Figure 1 :10) They are separated from each other, with the anode chamber connected to the first acceptor chamber by anion-selective membrane, and the cathode chamber connected to the final absorption and release chamber by cation-selective membrane. The total area of ​​the bipolar membrane is 10m².2 A 2 mol / L arginine solution was selected as the acceptor solution.

[0751] The acceptor solution is heated to 34-56°C during absorption. A 10 wt% citric acid solution is used as the absorption and release medium. The volume ratio of the acceptor medium to the absorbor medium flowing through the separation unit is 2:1. A 20 V DC voltage is applied between the anode and cathode.

[0752] The chamber device for receiving the absorption and release medium is provided with a gas outlet, which is connected to an initially evacuated gas collection device. A storage container for the absorption and release medium is also connected to this collection device, allowing the gas formed therein to be collected under depressurized conditions. The CO2 content of the gas flow passing through the gas scrubber and the gas flow collected in the gas collection device is continuously measured.

[0753] result

[0754] The treated biogas has a CO2 content of 48% by volume. The gas passing through the gas scrubber has a CO2 content of 0.002% by volume and a methane content of 99.1% by volume. During continuous gas scrubbing and the passage of the acceptor medium through the electrodialysis unit, CO2 is released in the absorption and release chambers and in the storage container for the absorption and release medium. The CO2 content of the released and collected gas is >98.5% by volume; no methane was detected. Continuous operation can exceed 8 hours without any interference. There is no associated heating of the process medium.

[0755] Example 8

[0756] Research on carbonate production

[0757] Prepare a 5 L 2 M arginine solution using deionized water. Dissolve 500 g of ferric chloride (III) completely in this solution. Pass CO2 gas through the clear, reddish-brown solution according to Example 2. This lowers the pH from 9.2 to 8.5. The solution then becomes clear and free of solids. Add deionized water to the solution at a 1:1 volume ratio and mix. A light brown, flocculated solid immediately forms and slowly settles. Decant the supernatant. The supernatant is clear and has a slightly reddish tint. Centrifuge the precipitate and combine the supernatant with the previously decanted supernatant (WP 1). Resuspend the centrifuged fraction in 3 L each of deionized water and stir for 1 hour. Then, in each case, perform phase separation by centrifugation. Spread the reddish-brown material onto a ceramic filter plate with an average pore size of 200 μm. Place the filter plate on absorbent material until the material is completely dry. Crush the fragile brown material in a mortar. Obtain 480 g of brown powder. Suspend the sample in water and stir. The powder then settles. The supernatant was then clear and colorless, with a pH of 6.8, unchanged from the initial value. A 10% HCl solution was added to another powder sample. Foaming occurred, releasing CO2. The solution then turned reddish-brown, and no solids were present. No nitrogen was detected in the analysis of this decomposition solution. Therefore, the obtained powder corresponds to ferric carbonate. WP1 was guided through the electrodialysis unit. The donor chamber was sealed on the anode side using an anion-selective membrane, and on the cathode side using a cation-selective membrane. A DC voltage of 10V was applied. It has been shown that chlorine gas is released in the anode chamber and hydrogen gas is released in the cathode chamber. After electrodialysis, the solution was purged with CO2. After purging, the CO2 bound in the solution could be released again by changing the pH with the aid of an acid (HCl).

[0758] Example 9

[0759] Carbonate production in a two-cycle process

[0760] A portion of the gas flow (10m) from the bioreactor of an urban wastewater treatment plant 3The water / gas mixture is extracted and brought into contact with the aqueous acceptor medium using a water jet pump. The mixture is then piped into a static mixer and passed through it. The mixture then enters a collection tank from which the gas can freely escape into the atmosphere. The aqueous acceptor medium is present as a 2-molar arginine solution. From the collection tank, the acceptor medium carrying carbon dioxide is continuously pumped into a secondary circulation system. This secondary circulation system consists of an electrodialysis unit comprising an anode chamber, a cathode chamber, and 10 consecutive chamber units arranged as: acceptor chamber / reaction chamber / electrolyte chamber. The acceptor chamber is continuously filled with the acceptor medium and then introduced into the water jet pump. The reaction medium and electrolyte solution are each withdrawn from a storage tank and passed through the reaction chamber or electrolyte chamber, respectively. The acceptor chambers are separated from the reaction chamber on the anode side by an anion-selective membrane. On the cathode side, they are separated from the electrolyte chamber by a bipolar membrane. The reaction chamber and electrolyte chamber are separated by a cation-selective membrane. The chamber unit for the reaction medium is adjacent to the electrolyte chamber on the anode side. Different reaction media are investigated. For this purpose, the following reaction solutions were prepared from 1 mole of arginine solution in each case: a) 30% magnesium chloride solution, b) 20% copper chloride solution, and c) 15% aluminum chloride solution. In each case, the reaction medium was continuously recirculated from the settling tank through the reaction chamber. The reaction chamber was designed such that the reaction medium flowed vertically through the chamber and was discharged into a collection tank through a conical bottom outlet, thereby discharging the solids produced along with the medium. After each 5-hour experimental run, the reaction medium was not further stirred for 12 hours. The aqueous supernatant was then discharged through an outlet placed above the settling phase, followed by solid removal and rinsing twice with deionized water, and then drying on a contact belt dryer.

[0761] The electrolyte solution is fed into another electrodialysis unit in three cycles, where chloride ions are separated.

[0762] The corresponding carbonates obtained as solids were detected according to the method in Example 6.

[0763] result:

[0764] The temperature range of the acceptor medium is 45-75°C. The wastewater treatment gas has a carbon dioxide content of 26% by volume. By contacting the wastewater treatment gas with the acceptor medium, the carbon dioxide content is reduced to <0.01% by volume. After the acceptor medium begins to flow through the electrodialysis unit, the reaction solution rapidly becomes emulsified, and continuous precipitation of solids occurs in each case. Analysis of the rinsed and dried solids shows that they are carbonates of the cations of the electrolytes used in each case. Thus, magnesium carbonate, copper carbonate, and aluminum carbonate were prepared.

[0765] Example 10

[0766] The study utilizes residual materials from both organic and inorganic sources to obtain recycled feed fractions during the recycling process by converting carbon dioxide / carbon dioxide derivatives.

[0767] A pulverized old aluminum can (100g) was completely decomposed in 200ml of concentrated sulfuric acid by adding deionized water in batches in amounts that allowed hydrogen and water vapor to escape. The vapor / gas mixture was collected and the available hydrogen was separated. The resulting solution was grayish-brown and very turbid. The solution was filtered using glass frit and mixed with 600ml of a 1-molar arginine solution. This mixture was then stirred in batches into a 3-molar arginine solution saturated with carbon dioxide from a biogas plant. After the mixing process, the suspension was centrifuged and the centrifuged material was washed twice with deionized water and dried after centrifugation.

[0768] 200 g of purified eggshell sample was decomposed in 500 ml of 60 wt% hydrochloric acid solution. The released carbon dioxide was collected and adsorbed into a 2 molar arginine solution using the apparatus according to Example 2. Organic matter, such as the eggshell membrane, was present in the resulting turbid solution. This was filtered out and the solution was passed through the electrolyte chamber of the electrodialysis apparatus according to Example 9. According to Example 9, the acceptor chamber and reaction chamber were filled with the acceptor and reaction medium, respectively, or washed with the acceptor and reaction medium. In this method, the acceptor solution was saturated with carbon dioxide obtained from the decomposition of the eggshell. The solids formed in the reaction chamber were separated, washed twice with deionized water, and centrifuged before being convectively dried. The electrolyte solution remaining in the anode chamber at the end of the study was concentrated by membrane distillation and used in another experimental process. After this study, the acceptor solution was also used to absorb carbon dioxide during bone decomposition. Solar energy was used to power the study.

[0769] The obtained solid was analyzed according to Example 6.

[0770] result:

[0771] The solid fractions obtained in both implementation schemes are aluminum carbonate and calcium carbonate. They exist as chemically pure powders in the form of amorphous particles. The compound (acid) used to decompose the starting material can be regenerated in a secondary cycle and used in new experimental processes. The acceptor solution can also be regenerated and reused. Thus, inorganic residues can be recovered using regenerated carbon dioxide and renewable energy, while achieving sustainable recycling of the compounds used.

[0772] Example 11

[0773] For experimental procedure 1), 50g of pulverized aluminum foil was hydrolyzed with 300ml of 35% HCl solution. Complete conversion at pH 1 yielded a light gray substance. This substance was completely dissolved in 1 liter of deionized water (IA). 150ml was separated and titrated with ammonia solution to pH 4 with stirring. After 10 minutes, the solution was centrifuged and the supernatant was decanted.

[0774] For experimental procedure 2), 100g of aluminum sulfate was completely dissolved in 300ml of deionized water (2A). 150ml of this solution was separated and titrated with ammonia solution with stirring until the pH reached 3. After 10 minutes, the solution was centrifuged and the supernatant was decanted.

[0775] A 2-molar solution of arginine (prepared with deionized water) was circulated through a static mixer, in which carbon dioxide was introduced as a gas phase into the solution upstream of the static mixer. Gas was introduced under no-pressure conditions until the pH of the acceptor solution reached 8.

[0776] The clear and colorless electrolyte solution 1A is delivered by means of a metering pump. 2A and Each sample was separately mixed into 1000 ml of acceptor solution until pH 7 was reached, thereby carrying out chemical conversion. If the electrolyte solution in the formulation could not be completely consumed / converted, the mixing process was continued with fresh saturated acceptor solution. The reaction mixture was centrifuged 15 minutes after mixing. The supernatant was decanted and combined (V1). The centrifuged fractions obtained from each study series were suspended in 1000 ml of deionized water and stirred for 15 minutes. Phase separation was then performed by centrifugation. This process was repeated twice. The centrifuged fractions were spread onto a mesoporous ceramic membrane and incubated at room temperature for 24 hours. The dried material was then weighed and samples were taken for analysis according to Examples 5 and 6.

[0777] After adding ninhydrin reagent, the concentration of arginine was determined by spectrophotometry.

[0778] result:

[0779] A transparent solution can be prepared from the hydrolysis products of aluminum foil (Experimental Procedure 1). Flocculation is induced by the introduction of ammonia. The resulting solids can be completely separated by centrifugation. Here, centrifuged fraction 2 has a different color: a pure white, slightly glassy substance at the bottom, with a grayish-brown solid substance on top. In Experimental Procedure 2, flocculation also occurs when ammonia is added to the electrolyte solution, but the centrifuged fraction is uniformly white and has a gel-like consistency.

[0780] For all electrolyte solutions, a white solid is produced by mixing with a saturated acceptor solution. Visually, the centrifuged phases are indistinguishable from each other. To mix the electrolyte and acceptor solutions according to the protocol, for electrolyte solutions not pretreated with ammonia, 1.6 times (Experimental Procedure 1) and 1.8 times (Experimental Procedure 2) the volume of acceptor solution must be used compared to those pretreated with ammonia to convert the corresponding total volume of electrolyte solution. On the other hand, for 1A and 2A, only 80% and 75% of the electrolyte solution, respectively, can be obtained from… and The amount of solids obtained. Chemical analysis shows that the obtained solids are aluminum carbonate and aluminum bicarbonate.

[0781] The supernatant after the first centrifugation was purified by electrodialysis to remove any electrolytes. Subsequently, membrane distillation was used to reduce the liquid volume, allowing the initial concentration of the arginine solution to be re-established. Carbon dioxide was then absorbed, and the experimental process was repeated. Aluminum carbonate and aluminum bicarbonate were obtained with the same efficiency.

[0782] Example 12

[0783] Study on the release of gas phase from the cathode in an aqueous acceptor medium

[0784] A 2-mol arginine solution was prepared using deionized water. Two liters were separated from this solution and stored under air-free conditions (A0). The remaining acceptor solution was then introduced into the gas stream according to Example 7. The loading of carbon dioxide or its water-soluble derivatives was monitored by conductivity measurement. The acceptor medium was then introduced into the gas stream until a conductivity of 150 mSi was achieved (A1).

[0785] Prepare 20 wt% KOH (K) and NaOH (N) solutions as backup solutions. From these solutions, prepare 2 liters of solutions a) 1 wt%, b) 2 wt%, c) 3 wt%, and d) 4 wt%.

[0786] Add solid KOH (AlK) and NaOH (AlN) to each 2 liter of Al and dissolve them so that each of them is present in a) 1 wt%, b) 2 wt%, c) 3 wt% and d) 4 wt% solutions.

[0787] A rectangular glass container capable of holding 500 ml of liquid is manufactured, with a separator mounted at its center to separate two chambers within the container. A porous polycarbonate disc with a 2 mm diameter through-hole and a 70% porosity is placed within the separator. Graphite electrodes are placed in retainers within the chambers, allowing axial displacement of the electrodes, which are arranged parallel to the separator. The container is hermetically sealed at the top, and each chamber has an outlet on its lid. These outlets are each connected to a gas collection device capable of unpressurized removal of gas formed in each chamber. Thus, the corresponding gas volume can be quantified. The container has an inlet and an outlet at both ends for filling and for liquid passage, respectively. The electrodes are connected to a rectifier.

[0788] Containers were continuously filled with various experimental solutions to ensure no air remained. In experimental series 0), solutions K and N were filled into the container at concentrations a)–d). First, the DC voltage (Smin) at the onset of current was measured for each solution. Then, the voltage at which bubbles formed at the two electrodes, resulting in a certain volume separation of gas, was measured. In experimental series I), solutions A0 and A1, as well as A1K and A1N, were subsequently studied continuously at concentrations a)–d). A constant voltage, at least 1 volt higher than Smin and a multiple of 2, was applied to each solution for 10 minutes. Every 10 minutes, the voltage was increased by 2 volts until a voltage of up to 32 volts was reached. The formation of bubbles at the electrodes, the current (mA) present at each point, and the amount of gas produced during current delivery were recorded.

[0789] In Experiment Series II), for each solution, the test was repeated using a predetermined voltage (at which no gas is formed at the cathode), in which a container containing the corresponding solution was filled and allowed to flow through a separation medium from the cathode chamber to the anode chamber. The chemical composition of the gases released and collected in the cathode chamber was analyzed.

[0790] Results (see Tables 1A and 1B):

[0791] In Experiment I), electrolysis occurred in solutions K and N in a concentration-dependent manner, resulting in the formation of hydrogen and oxygen from voltages between 2 and 4 V. In solution A0, no current flowed up to 24 V, and no electrolysis leading to gas phase formation occurred up to 32 V. In solution A1, current flow began from 12 V; gas formation at the cathode began from 20 V. Even at 32 V, no gas formation occurred at the anode. For solutions A1K and AlN, Smin decreased with increasing concentration. Furthermore, the voltage required for gas formation at the cathode decreased depending on the concentration. Additionally, no measurable amount of oxygen was formed at the anode for these solutions. The gas formed at the cathode in solutions A1, AlK, and AlN corresponded to carbon dioxide. Here, the amount of gas available under the same voltage equipment was much greater for AlK and AlN than for Al, and increased with the concentration of the added electrolyte.

[0792] In Experiment Series II), the amount of carbon dioxide released at the cathode increased by 20-40% of volume due to filling the container with solutions Al, AlK, and AlN.

[0793] Table 1a

[0794]

[0795]

[0796] V-Nr. = Experiment number; V = Applied DC voltage in volts; AL nativ = Acceptor solution without carbon dioxide loading; AL-CO2 = Acceptor solution loaded with carbon dioxide; NaOH = Concentration of sodium hydroxide in the acceptor solution, in weight %; KOH = Concentration of potassium hydroxide in the acceptor solution, in weight %; K = Volume of gas formed in the cathode chamber during the experimental time period at atmospheric pressure (in mL); A = Volume of gas formed in the anode chamber during the experimental time period at atmospheric pressure (in mL).

[0797] Table 1b

[0798]

[0799]

[0800] V-Nr. = Experiment number; V = Applied DC voltage in volts; AL nativ = Acceptor solution without carbon dioxide loading; AL-CO2 = Acceptor solution loaded with carbon dioxide; NaOH = Concentration of sodium hydroxide in the acceptor solution, in weight %; KOH = Concentration of potassium hydroxide in the acceptor solution, in weight %; K = Volume of gas formed in the cathode chamber during the experimental time period at atmospheric pressure (in mL); A = Volume of gas formed in the anode chamber during the experimental time period at atmospheric pressure (in mL).

Claims

1. A method for selectively binding, transporting, and storing carbon dioxide in an aqueous medium. Its characteristics include the following steps: a) Provides an aqueous receptor solution containing at least one receptor compound having a free guanidine group and / or an amidine group, wherein the receptor compound is an amino acid and the pH of the receptor solution is in the range between 7 and 14; b) Contacting the gas containing carbon dioxide with the acceptor solution from step a), wherein, in the presence of an excess of free guanidinyl and / or amidine groups of the acceptor compound relative to the carbon dioxide molecules present in the gas, the carbon dioxide consumption reaches a gaseous carbon dioxide concentration of <100 ppm. The contact is performed without pressurizing the receptor solution, and The temperature of the acceptor solution during contact is 0 to 100°C; c) The carbon dioxide / carbon dioxide derivative bound in the acceptor solution of step b) is transported through a separation membrane to an aqueous absorption and release medium; or The acceptor solution containing bound carbon dioxide / carbon dioxide derivatives from step b) is stored and / or transported at atmospheric pressure for >6 months in storage and / or transport containers.

2. The method according to claim 1, wherein the pH of the receptor solution is in the range between 8 and 13.

3. The method according to claim 1, wherein in step b), the acceptor solution containing the bound carbon dioxide / carbon dioxide derivative is depressurized under atmospheric pressure or under depressurization.

4. The method according to any one of claims 1 to 3, wherein step b) or c) is followed by step c1) or d1): releasing carbon dioxide bound in the acceptor solution as a gas phase.

5. The method according to any one of claims 1 to 3, wherein the acceptor solution from step b) is located in or introduced into the acceptor chamber of the electrodialysis apparatus, and the delivery of carbon dioxide / carbon dioxide derivative according to step c) is carried out by means of an elevator generated between the acceptor chamber and the absorption and release chamber, wherein the acceptor chamber and the absorption and release chamber are separated from each other by a separation membrane.

6. The method according to claim 5, wherein the separation membrane is a membrane permeable to ions and / or gas molecules.

7. The method of claim 5, wherein the carbon dioxide / carbon dioxide derivative delivered through the separation membrane as pure carbon dioxide gas having >98.5% by volume carbon dioxide is released in the absorption and release chamber.

8. The method according to claim 5, wherein the absorption and release chamber contains an absorption and release medium, and the absorption and release medium contains at least one compound having at least one acid group and an isoelectric point in the range of 3 to 5.

9. The method according to any one of claims 1 to 3, wherein one or more reactive compounds for the reaction and / or binding of carbon dioxide and / or carbonate / bicarbonate anions are present in the acceptor solution and / or the absorption and release medium.

10. The method of claim 9, wherein after step b), carbon dioxide bound in the acceptor solution is converted into a carbon compound by means of a reactive compound.

11. The method of claim 9, wherein after step c), carbon dioxide bound in the absorption and release medium or transported and released carbon dioxide is converted into carbon compounds by means of a reactive compound.

12. The method according to any one of claims 1 to 3, wherein step c) is followed by steps c3') and c3'). c3') Introduce the aqueous absorption and release medium containing bound carbon dioxide / carbon dioxide derivatives from step c) into the release device; and c3) In the release chamber, carbon dioxide as a gas phase is released from the absorption and release medium containing bound carbon dioxide / carbon dioxide derivatives from step c3').

13. The method according to any one of claims 1 to 3, wherein carbon dioxide as a pure gas phase is separated from the aqueous acceptor solution at the cathode.

14. The method according to any one of claims 1 to 3, wherein the gas containing carbon dioxide is washed with an acidic solution prior to step b).

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