Sorption material for CO2 capture, its use and method for making same

Abstract

1. A method for preparing a sorbent material (3) for use as an adsorbent for carbon dioxide separation from a gas mixture (1), the sorbent material (3) comprising primary or secondary amine moieties or a combination thereof immobilized on a solid support, the sorbent material (3) comprising primary or secondary amine moieties or a combination thereof being treated such that after treatment, the sorbent material (3) has a total metal impurity content of less than 1400 ppm.

Description

[Technical field]

[0001] The present invention relates to carbon dioxide capture materials having primary amine carbon dioxide capture moieties and / or secondary amine carbon dioxide capture moieties with optimal carbon dioxide capture capacity properties, as well as methods for preparing such capture materials, uses of such capture materials and carbon dioxide capture methods including such materials and regeneration processes for such capture materials. [Background technology]

[0002] 2017 OECD report [Global Energy & 2 According to the OECD / IEA Status Report 2017, March 2018, CO 2 The annual emissions of carbon dioxide equivalent (CO2) from the United Nations are about 32.5 Gt (gigatons, or 3 × 109 tonnes). As of February 2020, all but two of the 196 countries that negotiated the Paris Agreement within the United Nations Framework Convention on Climate Change (UFCCC) in 2016 have ratified it. This figure means that there is agreement on the threat of climate change and the need for a global response to keep the increase in global temperatures well below 2 degrees Celsius above pre-industrial levels.

[0003] CO to the atmosphere 2 The technical and scientific community, faced with the task of achieving the goal of limiting emissions and providing solutions to remove greenhouse gases from the atmosphere, has conceived many technologies. Flue gas capture, i.e. the capture of specific industrial processes and specific CO 2 CO from emissions and other point sources 2 The capture of CO can occur over a wide range of relatively high concentrations, depending on the process that produces the flue gas. 2 (3-100% by volume). Higher concentrations can be used to reduce CO from sources with lower concentrations such as ambient air, where concentrations are on the order of 400 ppmv. 2 Compared to the separation of CO from other gases 2The separation of CO becomes more thermodynamically and, therefore, economically advantageous. 2 The very concept of capturing CO from point sources has significant limitations: it is particularly suitable for targeting such point sources, but is effectively tied to the specific location where the point source is located, and while it can successfully limit emissions and assist in achieving carbon neutrality, as a technical solution it cannot contribute to negative emissions (i.e., permanent removal of carbon dioxide from the atmosphere) and remove past emissions. Although in early stages of development, the two most notable solutions currently being applied to achieve negative emissions (i.e., permanent removal of carbon dioxide from the atmosphere) are through vegetation (i.e., trees and plants using natural photosynthesis, but not permanent removal), and through DAC technology, which is the only truly permanent removal. 2 The recovery of.

[0004] Afforestation has widespread public support. However, the scope and feasibility of reforestation projects is under debate, and the cost of capturing CO2 is growing. 2 This approach does not seem as simple as it may seem, since it requires a large footprint in terms of the ratio of occupied surface to CO2 emissions. On the other hand, DAC has a smaller land footprint, therefore does not compete with crop production, and has a low CO2 emission. 2 can be permanently removed from the atmosphere and can be deployed anywhere on Earth.

[0005] All of the above strategies for mitigating climate change have potential and are considered as potential parts of an overall solution. The most likely future scenario, after further development, is to deploy a combination of such approaches.

[0006] Several DAC techniques have been described, such as utilizing alkaline earth oxides to form calcium carbonate, as described in US Pat. No. 5,399,633. Various approaches have been proposed, typically in the form of a packed bed of sorbent particles, to remove CO 2is captured at the gas-solid interface, solid CO 2 This involves the use of adsorbents (hereafter referred to as sorbents), which may include various types of amino-functionalized and polymeric sorbents, such as immobilized aminosilane-based sorbents as reported in US Pat. No. 5,399,433 and amine-functionalized cellulose as disclosed in US Pat. No. 5,499,433.

[0007] US Pat. No. 5,399,633 describes the use of ion exchange materials comprising aminoalkylated bead polymers for the removal of carbon dioxide from industrial applications.

[0008] In Patent Document 5, CO 2 Sorbents for reversibly adsorbing from gas mixtures are described, which are composed of polymeric adsorbents with primary amino functional groups. These materials can be regenerated by applying a pressure or humidity swing.

[0009] Several academic publications such as (1) (2) and (3) have also investigated in detail the use of cross-linked polystyrene resins functionalized with primary benzylamines as solid sorbents for DAC applications.

[0010] CO 2 The state of the art for the recovery of benzene from point sources typically uses liquid amines, e.g., in industrial scrubbers, where the flue gas flows into a solution of the amine (Patent Document 6). Other techniques are based on the use of solid sorbents, either in packed bed or flow-through configurations, where the sorbents are made of amines impregnated or covalently bonded onto a support.

[0011] Amines are CO 2 to form a carbamate moiety, which can be reacted in a subsequent step, for example, by increasing the temperature of the sorbent bed to about 100° C., thereby converting the CO 2 An economically viable process for carbon capture would require hundreds or thousands of cycles of CO2 release on the same sorbent. 2The term refers to the ability of a sorbent to perform repeated sorption / desorption of CO. 2 It should not undergo significant chemical transformations which would hinder its reactivity towards

[0012] In Non-Patent Document 4, it is reported that copper is widely used in semiconductor circuits as a multilayer metal. In addition to copper, waste streams often contain chelating agents such as EDTA, which are widely used in processes to increase the solubility of copper, which tends to form copper-chelated complexes. PEI-agarose adsorbents in packed-bed columns can remove these anionic complexes, but the competitive binding between this chelating agent and PEI for copper is not fully understood. This study focuses on investigating copper sorption by PEI-agarose adsorbents in the presence of EDTA. The pH of the column is fixed at 5.5 using 0.1 M acetate buffer. The ratio of chelating agent to copper ions is varied. The copper binding capacity and copper breakthrough curves are compared and contrasted with the results in the absence of additional chelating agent. The presence of an excess of EDTA increases the fraction of free dissociated (anionic) ligands competing for electrostatic attraction to the protonated amine groups, thus reducing the sorption capacity in the column. However, this waste treatment technique is still viable in the semiconductor industry, as it can concentrate large volumes of copper-contaminated solutions from actual waste by a factor of 12. When equimolar (copper to EDTA) or greater concentrations of EDTA are present, acetate can be utilized to recover the metal; when the copper to EDTA ratio is low, metal recovery is accomplished using hydrochloric acid.

[0013] In Patent Document 7, CO 2 A structure is disclosed that contains a sorbent having amine groups capable of reversible adsorption and desorption cycles for recovering from a gas mixture, the structure being composed of fiber filaments, the fiber material being carbon and / or polyacrylonitrile.

[0014] Patent Document 8 discloses an acid gas sorbent containing an amine complex. The complex may include a first component containing an amine compound at a concentration of about 1% to about 75% by weight, a second component containing a hydrophilic polymer and / or prepolymer compound at a concentration of about 1% to about 30% by weight, and a third component containing a crosslinker and / or coupling agent at a concentration of about 0.01% to about 30% by weight.

[0015] Patent Document 9 discloses a core-shell amine-based carbon dioxide adsorbent containing a chelating agent resistant to oxygen and sulfur dioxide, which is an adsorbent having a core of a porous support on which an amine compound is immobilized and a shell of an amine layer resistant to inactivation by sulfur dioxide, and a method for preparing the same. The amine-based carbon dioxide adsorbent containing a chelating agent exhibits a fairly high oxidation resistance because the added chelating compound functions to directly remove various transition metal impurities that catalyze the oxidation of amines. Furthermore, the shell's sulfur dioxide-resistant amine layer selectively adsorbs sulfur dioxide to protect the core's amine compound, and at the same time, the core's amine compound selectively adsorbs only carbon dioxide. Furthermore, the sulfur dioxide adsorbed on the shell is easily desorbed from the shell at about 110° C., and thus a significantly improved regeneration stability is obtained during a temperature swing adsorption (TSA) process involving sulfur dioxide. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] US Patent Publication No. 2010034724 [Patent Document 2] U.S. Patent No. 8,834,822 [Patent Document 3] International Publication No. 2012 / 168346 [Patent Document 4] International Publication No. 2011 / 049759 [Patent Document 5] International Publication No. 2016 / 037668 [Patent Document 6] U.S. Pat. No. 9,186,617 [Patent Document 7] US Patent Publication No. 2012076711 [Patent Document 8] US Patent Publication No. 2013213229 [Patent Document 9] US Patent Publication No. 2019143299 [Non-patent literature]

[0017] [Non-Patent Document 1] Alesi et al. in Industrial & Engineering Chemistry Research 2012, 51, 6907-6915 [Non-Patent Document 2] Veneman et al. in Energy Procedia 2014, 63, 2336 [Non-Patent Document 3] Yu et al. in Industrial & Engineering Chemistry Research 2017, 56, 3259-3269 [Non-Patent Document 4] Maketon et al. in “Removal Efficiency and Binding Mechanisms of Copper and Copper-EDTA Complexes Using Polyethyleneimine”, ENVIRONMENTAL SCIENCE & TECHNOLOGY, vol. 42, no. 6, 8 February 2008, pp. 2124-2129 Summary of the Invention

[0018] Amino-based sorbents for repeated continuous carbon dioxide capture from air, in particular amino-based sorbents containing primary and / or secondary amino units, preferably benzylamine units or combinations thereof, e.g. connected to styrene divinylbenzene moieties, are known sorbents for carbon capture from air and flue gases.

[0019] In the present invention, the inventors have surprisingly found that the CO 2 By performing an inductively coupled plasma optical emission spectroscopy (hereinafter referred to as ICP-OES) analysis, the inventors have surprisingly found that the total metal content can be varied by the CO 2 We identified that this correlates with recovery performance (see Figure 1).

[0020] Without being bound by theoretical explanation, it appears that, to be particularly suitable for carbon capture, amino-based sorbents need to be as free as possible of impurities that may bind to amino groups and / or block pores, thereby reducing the availability of amino sites and thus affecting the carbon dioxide capture performance. Therefore, competitive binding to amino groups that competes with carbon dioxide capture should be avoided. It has been found that the amino moieties provided for carbon dioxide capture can and do bind to a wide range of metals, and such binding reduces the carbon dioxide capture capacity of the material. Reducing the metal content of the sorbent unexpectedly provides a very efficient and simple way to enhance the carbon dioxide capture properties of the material. In fact, amino-based sorbents are typically produced using catalysts and with washing steps, in which apparently a significant number of surface-exposed amino groups are covered by metal ions from catalysis and / or washing, from the starting materials, or from other synthesis steps.

[0021] Accordingly, the present invention provides a method for efficiently converting all amino groups into CO 2The present invention relates to the purity level required for amino-based sorbents functionalized with primary or secondary amines or combinations thereof to be able to capture carbon dioxide. The present invention also relates to a method for removing impurities and reaching a purity level acceptable for carbon capture. The presented method can be used to prepare sorbents for carbon dioxide capture processes, but it can also be used to refresh sorbents after they have been used as carbon dioxide capture materials. In particular, the latter is important when water, steam and / or water vapor are used in the desorption process to desorb carbon dioxide from the sorbent, and in this water, steam and / or water vapor, metal impurities continuously accumulate in the sorbent, impairing its carbon dioxide capture capacity.

[0022] As further demonstrated below, the metal or impurity content of a material not only affects the initial carbon dioxide capture capacity of the material, but also affects the stability of the carbon dioxide capacity after aging, which means use over an extended period of time. Surprisingly, it has been found that materials that are purified and have a low metal content also exhibit a higher stability of the carbon dioxide capture capacity, i.e., they appear to be less susceptible to degradation and oxidation during use.

[0023] In one embodiment, the amount of metals in the carbon dioxide capture portion of the sorbent comprising a first benzylamine moiety and / or a second benzylamine moiety or a combination thereof, preferably a sorbent consisting of a first benzylamine moiety, is in the range of 5 to 1600 ppm, most preferably less than 1500 ppm. The ppm values ​​given here for the metal content are in each case given in ppm by weight. The solid support of the sorbent is preferably an organic and / or inorganic material, preferably a porous or non-porous material based on (organic) polymeric materials. The (organic) polymeric support material is preferably selected from the group of linear or branched, crosslinked or non-crosslinked polystyrene, polyethylene, polypropylene, polyamide, polyurethane, acrylate-based polymers including PMMA, polyacrylonitrile or combinations thereof, preferably the polymeric material is based on poly(styrene) or poly(styrene-co-divinylbenzene), cellulose, or inorganic materials including silica, alumina, activated carbon, metal-organic frameworks, covalent organic frameworks and combinations thereof.

[0024] In another embodiment, a sorbent comprising polyethyleneimine either physically impregnated or chemically bonded to the surface of a support (the support can be, but is not limited to, silica, alumina, zeolite, activated carbon, metal organic framework, covalent organic framework) exhibits impurity levels in the range of 5-2000 ppm, most preferably less than 1500 ppm, such that most or all amino sites are available for capturing carbon dioxide.

[0025] In another embodiment, the metal (or more precisely, the metal ion) is removed, and thus the CO 2 To restore recovery performance, the sorbent is added with HCl, HNO at a concentration of 0.01-10 mol / L or 0.25-10 mol / L. 3 , H 2 SO 4 , C.H. 3The sorbent is then treated with an acid, which may be COOH. The sorbent may be allowed to continue to react with the acid solution under stirring for 1 to up to 24 hours. The sorbent is then subsequently treated with an acid, preferably NaOH, Na 2 CO 3 The sorbent is treated with a base, which may be 0.1% ethanol, KOH or a combination thereof. Hereafter, this treatment is referred to as acid-base washing, keeping in mind that the base treatment can be replaced with an extended washing treatment with substantially neutral and / or demineralized water. After treatment, the capacity of the purified sorbent can be measured with a breakthrough analyzer, and the results for a run-on system are shown in Figure 2. Surprisingly, the carbon dioxide capture capacity was increased by up to 2.8 times.

[0026] In another embodiment, the sorbent is purified and the CO 2 Another treatment to increase the capacity has been described. This treatment involves washing in an eluotropic row sequence, which includes or consists of treating the sorbent with solvents ranging from high to low polarity by performing at least two or at least three successive washing steps with two or three solvents of different polarity. The first solvent can be methanol, ethanol, isopropanol or a combination thereof, the second solvent can be acetone or another ketone with up to 10 carbon atoms, and the third solvent can be hexane, heptane, octane, dodecane. Unexpectedly, the CO2 retention of benzylamine-based sorbents was significantly improved by eluting the sorbent with 10% CO2. 2 The recovery volume increases 2.54-fold after elution column treatment (Figure 2).

[0027] In another embodiment, a styrene-divinylbenzene resin functionalized with benzylamine is treated with a chelating agent, in particular ethylenediaminetetraacetic acid (EDTA), and used to remove metal impurities. 2 The recovery volume was increased by 2.8-fold (Figure 2).

[0028] In another embodiment, the acid and base washes, elution power train, and EDTA wash are performed in various combinations, such as performing multiple (2-5) acid-base washes in succession, performing a first acid and base wash followed by an elution power train or vice versa, performing a first acid and base wash followed by an EDTA wash step or vice versa, and performing an elution power train followed by an EDTA wash or vice versa. Figure 2 shows the effect of three successive acid-base washes on CO 2 This results in a 3.2-fold increase in recovery capacity.

[0029] More generally, according to a first aspect of the present invention, it relates to a method for preparing a sorbent for use as an adsorbent for carbon dioxide separation from a gas mixture, the sorbent comprising a primary or secondary amine moiety or a combination thereof immobilized on a solid support. According to this first aspect, the sorbent comprising a primary or secondary amine moiety or a combination thereof is treated so that after treatment it has a total metal impurity content of less than 1400 ppm. As pointed out above, the original amine-based recovery material resulting from the manufacturing process essentially comprises a large number of surface-exposed amino moieties covered with metal ions, and according to the inventors' analysis, the metal impurity content in the system is always above or around 1600 ppm. Only one additional treatment leads to the claimed lower metal impurity content and accordingly leads to a significant improvement in carbon dioxide capture capacity.

[0030] When discussing a method for preparing a sorbent for use as an adsorbent for carbon dioxide separation from a gas mixture, this means treating the sorbent to prepare it and / or to rehydrate / refresh it and / or to clean and optimize it for use as an adsorbent for carbon dioxide separation from a gas mixture. The term preparation is therefore understood to mean physically and / or chemically transforming the sorbent to convert it into a sorbent with a lower metal impurity content, in particular a total metal impurity content of less than 1400 ppm. The presented method comprises at least one step of transforming the sorbent into such a purified sorbent to make it (more) suitable as an adsorbent for carbon dioxide separation from a gas mixture, which step can be constructed and carried out as described in further detail below.

[0031] In other words, the presented method is therefore a method in which a starting sorbent is treated with a purification step in order to obtain, after treatment, a lower metal impurity content as claimed, making the starting sorbent in particular (more) suitable as a sorbent for use as an adsorbent for carbon dioxide separation from gas mixtures.

[0032] One possible construction of a process for carbon dioxide separation from a gas mixture is the CO 2 The method includes inducing an increase in the temperature of the sorbent to initiate the desorption of CO, for example to a temperature of 60-110° C., by injecting a flow of saturated or superheated steam by flow-through through the unit, thereby 2 It should be noted that this is done by inducing an increase in the temperature of the sorbent to temperatures between 60 and 110 °C, which initiates the desorption of CO. As further experimentally shown below, such steaming does not result in any reduction in the metal impurity content, and in fact, simple water washing or steaming treatments have no effect on the metal impurity content and only a small reduction in the CO 2 Recovery capacity is not beneficially affected either.

[0033] According to a first preferred embodiment of this first aspect, the sorbent material has a total metal impurity content after treatment of less than 1200 ppm, preferably less than 1100 ppm, and most preferably in the range of 200-1000 ppm. Purifying the sorbent material to these low metal impurity levels can increase carbon dioxide capture capacity by up to three times, which is totally unexpected and a very significant increase in the efficiency of the overall process.

[0034] Total metal impurity content, as defined herein, is considered as the sum by weight of all metals in the sorbent relative to the total sorbent weight, where metals are defined as elements in Groups 1-16 of the Periodic Table, excluding hydrogen in Group 1, excluding beryllium in Group 13, excluding elements in Periods 2-4 in Group 14, and excluding elements in Periods 2-5 in Groups 15 and 16.

[0035] Metal impurities are determined using the following analytical methods:

[0036] For the quantitative determination of metal impurities in the sorbent (especially Al, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Sn, Ti and Zn, which can and often are present in the original material in amounts greater than 1 ppm by weight), inductively coupled plasma optical emission spectrometry (ICP-OES) is used. The measurements were carried out using a Spectro Arcos FHM22 ICP-OES instrument (SPECTRO Analytical Instruments GmbH). The sample solution is introduced through a pneumatic atomizer system. At temperatures of 5000-7000 K in the plasma, the elements contained in the solution are atomized and excited to emit light. The atoms / ions emit electromagnetic radiation characteristic of the chemical element after excitation, so the intensity of the emitted light at a specific wavelength is measured and used to determine the concentration of the element of interest. The concentration in the sample is calculated using the measured intensities of the individual elements and using a function of the recorded calibration of the individual elements.

[0037] The calibration of the instrument is carried out as follows: To prepare the working standards, Merck multi-element standard solutions for ICP (MISA-04-1, MISA-05-1, MISA-06-1) were used. 3 Deionized water acidified with (Merck) was used as the calibration blank.

[0038] The samples are prepared as follows: Dissolution of the sorbent is achieved by microwave digestion. The sorbent is dried under a stream of N2 at 94 °C for 1 h and then cooled to room temperature. 0.5 g of sample is weighed and placed in a 100 mL sample holder. The sample is diluted with 10 mL of 65% HNO3. 3 is added and the mixture is allowed to react for 10 minutes before closing the sample holder. The sample holder is then placed in a microwave oven (StarT, MWS GmbH) until the sample is completely dissolved. The following temperature profile is used: heat to 240°C at 3°C / min, hold for 1 hour, then cool to 50°C, and then the sample is removed from the oven. The sample is then filtered through a Whatman 42 (2.5 μm particle retention) filter paper. 2 mL of deionized water is used to wash the inner walls of the beaker to prevent sample loss. Deionized water is then added to bring the final volume up to 50 mL.

[0039] The concentration of metal impurities in the sorbent is determined as follows: the concentration in the sample is calculated using the measured intensity of the individual elements and using a function of the recorded calibration of the individual elements. The metal impurity concentration is expressed as the average of three measurements. The concentration of the metal is expressed in mg metal per kg sorbent, i.e., ppm by weight.

[0040] The metals forming said metal impurities are typically selected from the group consisting of Al, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Sn, Ti, Zn or combinations thereof. In most cases, the metal impurities concerned are selected from the group consisting of Al, Ca, Fe, Mg, Mn, among others, because these metals are abundant and / or form part of the catalyst and / or starting material and / or process during the synthesis and / or are present in the water used for the treatment of the sorbent.

[0041] According to yet another preferred embodiment, said treatment is selected from the group of acid-base washing, elution column washing or treatment with metal chelating agents, or a combination thereof.

[0042] Preferably, in the case of acid-base cleaning, the treatment is preferably HCl, HNO 3 , H 2 SO 4 and / or CH 3 It involves at least one step of treatment with an aqueous solution of pH less than 5, preferably less than 3, most preferably less than 1, in the form of a COOH solution, also preferably followed by treatment with NaOH, Na 2 CO 3 At least one step of treatment with an aqueous solution in the form of a solution of 1,2-dichlorophenyl ether, KOH or a combination thereof, having a pH greater than 9, preferably greater than 11, most preferably greater than 13.5, is carried out. This base treatment step can be replaced by and / or followed by a water wash, for example to establish a pH in the range of 6-8 with water, preferably deionized water.

[0043] Preferably, in the case of elution column washing, the sorbent is subjected to a treatment with an alcoholic solvent at room temperature, preferably selected from the group consisting of methanol, ethanol or (iso)propanol or combinations thereof, and / or preferably subsequently to a treatment with another polar organic solvent, preferably selected from acetone (or another ketone or acetate, typically having less than 10 carbon atoms), methyl acetate or ethyl acetate or combinations thereof, preferably further followed by washing with a non-polar organic solvent, preferably an alkane selected from the group consisting of propane, pentane, hexane, heptane, octane, decane, dodecane, in branched or linear form, or combinations thereof.

[0044] Preferably, in the case of treatment with a metal chelating agent, said chelating agent is selected from the group of bidentate or polydentate chelating agents, preferably water-soluble chelating agents, preferably water-soluble chelating agents having primary and / or secondary amino groups, alcohol groups and / or ether groups for complexing with metal ions to form metal impurities. The chelating agent is preferably selected from the group consisting of ethylenediamine and its polymers, oxalates, diethylenetriamine, triphosphates, ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA) or combinations thereof.

[0045] These treatment methods can be combined and / or repeated, for example, an acid-base wash can be performed as a sequence of three alternating acid and base treatment steps followed by a neutral wash.

[0046] The sorbent material typically takes the form of sorbent particles, sorbent powder, a porous monolith structure, or a substantially contiguous layer of adsorbent on a solid support carrier structure, or combinations thereof.

[0047] The amine moiety at the α-carbon is preferably substituted by two hydrogen substituents, or by one hydrogen and one alkyl group (preferably having up to 10 carbon atoms, preferably selected as methyl or ethyl) which may be linear or branched and may include further amino moieties in the branches, or by two alkyl groups (preferably having up to 10 carbon atoms, preferably selected as methyl or ethyl) which may be linear or branched and may include further amino moieties in the branches, or by one hydrogen and one amino group, or by one hydrogen and an alkylamino moiety (up to 10 carbon atoms, preferably methyl or ethyl) which may be linear or branched and may include further amino moieties in the branches, preferably the sorbent comprises a primary benzylamine moiety and / or a secondary benzylamine moiety. Most preferably, the carbon dioxide capture portion of the sorbent consists of a primary benzylamine moiety.

[0048] The solid support of the sorbent may be an organic and / or inorganic material, preferably a porous or non-porous material based on a polymeric material, preferably selected from the group of linear or branched, crosslinked or non-crosslinked polystyrene, polyethylene, polypropylene, polyamide, polyurethane, acrylate-based polymers including PMMA, polyacrylonitrile or combinations thereof, preferably the polymeric material is based on poly(styrene) or poly(styrene-co-divinylbenzene), cellulose or an inorganic material including silica, alumina, activated carbon, metal organic frameworks, covalent organic frameworks and combinations thereof.

[0049] Preferably, the sorbent material is a polystyrene material, preferably a cross-linked polystyrene material, most preferably based on poly(styrene-co-divinylbenzene), which is preferably at least partially functionalized with (primary or secondary) amino moieties or contains benzylamine moieties, either throughout the material or at least or only on its surface. The material or functionalization can be obtained, for example, by amidomethylation or phthalimide or chloromethylation reaction routes or combinations thereof.

[0050] The primary amine moieties and / or secondary amine moieties may be part of a polyethyleneimine structure, preferably obtained using an aziridine, which is preferably chemically and / or physically bound to a solid support.

[0051] Preferably, it is in a porous form, and has a thickness of 0.5 to 4000 m 2 / g or 1 to 2000, preferably 1 to 1000m 2 The sorbent material having a specific BET surface area in the range of 0.1 μm / g is preferably in the form of a monolith, a layer or layers, hollow or solid fibers including woven or non-woven (layered) structures, or hollow or solid particles.

[0052] The sorbent material according to yet another preferred embodiment is in the form of preferably substantially spherical beads having a particle size (D50) in the range of 0.002-4 mm, 0.005-2 mm, 0.002-1.5 mm, 0.005-1.6 mm, or 0.01-1.5 mm, preferably in the range of 0.30-1.25 mm.

[0053] According to a second aspect of the invention, it relates to a method for separating gaseous carbon dioxide from a gas mixture, preferably from at least one of the ambient air, flue gas and biogas containing said gaseous carbon dioxide, and from further gases different from gaseous carbon dioxide, by repeated adsorption / desorption in a unit using a sorbent material which adsorbs said gaseous carbon dioxide.

[0054] The method includes at least the following steps (a) through (e) repeated in this order: (a) contacting said gas mixture with a sorbent to adsorb at least said gaseous carbon dioxide onto the sorbent by flowing through said unit under ambient atmospheric pressure and temperature conditions in an adsorption step (if ambient atmosphere is forced through the unit using a ventilator or the like, this is still considered to be ambient atmospheric conditions in accordance with this application even though the air forced through the reactor by the ventilator has a pressure slightly higher than the surrounding ambient atmospheric pressure and the pressure is within the ranges as detailed above in the definition of "ambient atmospheric pressure"); (b) separating the sorbent material with adsorbed carbon dioxide in the unit from the flow-through, preferably while maintaining the temperature at the sorbent; (c)CO 2 Inducing an increase in the temperature of the sorbent, preferably to a temperature of 60-110° C., which initiates the desorption of CO (this can be done, for example, by injecting a stream of saturated or superheated steam by a heat exchanger or by flow-through through the unit, thereby 2 (This is possible by inducing an increase in the temperature of the sorbent to a temperature of 60-110 °C, which initiates the desorption of (d) extracting at least the desorbed gaseous carbon dioxide from the unit and separating the gaseous carbon dioxide from the water vapor, preferably by condensation, preferably within the unit or downstream thereof; (e) bringing the sorbent to ambient temperature conditions (if the sorbent is not cooled to just the ambient temperature conditions in this step, it is considered to be due to this step, preferably the ambient temperature established in this step (e) is within +25°C, preferably +10°C or +5°C of the ambient temperature). Includes.

[0055] In accordance with the present invention, the sorbent material to be regenerated for use or used in such repeated cycles comprises primary and / or secondary amine moieties immobilized on a solid support.

[0056] In the context of the present disclosure, the expressions "ambient atmospheric pressure" and "ambient atmospheric temperature" refer to the pressure and temperature conditions to which a plant operated outdoors is exposed, i.e. typically ambient atmospheric pressure denotes a pressure in the range of 0.8 to 1.1 bar (absolute) and typically ambient atmospheric temperature refers to a temperature in the range of -40 to 60°C, more typically -30 to 45°C. The gas mixture used as input for the process is preferably ambient atmosphere, i.e. air at ambient atmospheric pressure and ambient atmospheric temperature, which usually contains CO in the range of 0.03 to 0.06% by volume. 2 However, lower or higher CO 2 Air having a concentration of, for example, 0.1-0.5% by volume can also be used as input for the process, generally speaking, it is preferred to use the input CO 2 The concentration is in the range of 0.01-0.5% by volume. However, flue gas may also be a source, in which case the input CO 2 The concentration is typically in the range of up to 20% by volume or up to 12% by volume, preferably in the range of 1-20% by volume or 1-12% by volume.

[0057] In the sequence of steps (a) to (e) of the carbon dioxide capture method above, in steps (a) and (e) reference is made to ambient atmospheric pressure and temperature conditions. This applies only if the gas mixture fed is provided under these conditions, e.g. in the case of direct air capture where the source of the gas mixture is atmospheric air. However, if the source of the gas mixture is a different source, the feed conditions may not be ambient atmospheric pressure and / or ambient atmospheric temperature conditions. In particular in the case of flue gas, the gas mixture may be at high temperature, typically at high temperatures, e.g. above room temperature, which may even be above 50°C. The temperature may even go up to 70°C, in which case the setup is typically adjusted so that the temperature for desorbing carbon dioxide in step (c) is at least 10°C, preferably at least 20°C, higher than the temperature of the feed gas. Thus, under these non-ambient temperature and pressure conditions in steps (a) and (e), the pressure and temperature conditions will typically be different, in particular the contacting in step (a) is carried out under the temperature and pressure conditions of the fed gas mixture, and in step (e) the sorbent is subjected to the temperature and pressure conditions of the fed gas mixture.

[0058] According to a second aspect of the present invention, in such a process, either the material prepared as above is used as a sorbent or, after repeating a series of steps (a)-(e) above for a number of times which has resulted in degradation of the sorbent in the form of reduced carbon dioxide capture capacity due to capping of surface exposed amino groups with metal, the sorbent is treated, preferably using a method as above, to have, after treatment, a total metal impurity content of less than 1400 ppm, preferably less than 1200 ppm, more preferably less than 1100 ppm and most preferably in the range of 200-1000 ppm.

[0059] The unit is preferably capable of being degassed to a vacuum pressure of 400 mbar (absolute) or less, step (b) may comprise separating the sorbent with adsorbed carbon dioxide in the unit from the flow-through while maintaining the temperature at the sorbent and then degassing the unit to a pressure in the range of 20 to 400 mbar (absolute), in step (c) the injection of a saturated or superheated steam stream also induces an increase in the internal pressure of the reactor unit, and step (e) comprises bringing the sorbent to ambient atmospheric pressure and temperature conditions.

[0060] Preferably, after step (d) and before step (e), the following step is carried out: (d1) stopping the injection and circulation (if used) of water vapor and venting the unit to a pressure value in the range between 20 and 500 mbar (absolute), preferably 50 to 250 mbar (absolute), thereby resulting in both evaporation of water from the sorbent and drying and cooling of the sorbent.

[0061] Step (e) is preferably carried out solely by contacting said ambient air with the sorbent material under ambient atmospheric pressure and temperature conditions to evaporate and remove water within the unit and bring the sorbent material to ambient atmospheric temperature conditions.

[0062] After step (b) and before step (c), the following step may be carried out: (b1) flushing the unit of non-condensable gases with a flow of non-condensable water vapour whilst substantially maintaining the pressure of step (b), preferably maintaining the pressure of step (b) within a window of ±50 mbar, preferably within a window of ±20 mbar, and / or maintaining the temperature below 75°C or below 70°C or below 60°C, preferably below 50°C.

[0063] In a further embodiment of step b1, the temperature of the adsorbent structure is increased from the conditions of step (a) to a range of from 80 to 110°C, preferably from 95 to 105°C.

[0064] In step (b1), the unit can be flushed with saturated steam or superheated steam at up to 20° C., preferably at a rate of 1 kg / h to 10 kg / h of steam per liter of volume of the adsorbent structure, while maintaining the pressure of step (b1), to purge the residual gas mixture / ambient air from the reactor. The purpose of removing this portion of the ambient air is to remove the recovered CO 2 The aim of the present invention is to improve the purity of the

[0065] In step (c), water vapor can be injected in the form of steam introduced by a corresponding inlet of said unit, and water vapor can be recycled (partially or completely) from an outlet of said unit to said inlet, preferably with reheating of recycled water vapor or by recycling water vapor from a different reactor.

[0066] It should be noted that the heating for desorption by this process in step (c) is preferably only affected by this steam injection, and there is no additional external or internal heating, such as by piping with a thermal fluid.

[0067] In step (c), more preferably the sorbent may be heated to a temperature in the range of 80-110°C or 80-100°C, preferably to a temperature in the range of 85-98°C.

[0068] According to yet another preferred embodiment, in step (c) the pressure in the unit is in the range of 700 to 950 mbar (absolute), preferably in the range of 750 to 900 mbar (absolute).

[0069] According to a first preferred embodiment of the second aspect of the present invention, the treatment to reduce the total metal impurity content is carried out in situ in the apparatus for separating gaseous carbon dioxide from a gas mixture, preferably by acid-base washing, elution column washing or treatment with a metal chelating agent, or a combination thereof. In practice, this can be carried out in situ using any of the schemes as described in the context of the previous method for preparing a sorbent material for use as an adsorbent for carbon dioxide separation from a gas mixture.

[0070] Alternatively, the second aspect of the invention may be practiced by removing the sorbent from the apparatus for separating gaseous carbon dioxide from a gas mixture, treating the sorbent to reduce its total metal impurity content, and then reintroducing it into the apparatus for separating gaseous carbon dioxide to continue the separation process.

[0071] Treatment of the sorbent is typically performed when the carbon dioxide capture capacity has decreased by more than 30%, preferably more than 20%, more preferably more than 15% compared to the carbon dioxide capture capacity of the original sorbent.

[0072] Treatment of the sorbent material may also be carried out after repeating the sequence of steps at least 500 times, preferably at least 1000 times, more preferably at least 10,000 times, but preferably before repeating the sequence of steps 50,000 times, preferably before repeating the sequence of steps 25,000 times.

[0073] The time to refresh the material may be dynamically selected as a function of the observed carbon dioxide capture capacity as detected by a corresponding sensor, may be calculated and / or dynamically adjusted as a function of the metal impurity content measured in the sorbent, and may be calculated and / or dynamically adjusted as a function of the metal content in the water and / or steam and / or water vapor used in the carbon dioxide capture process.

[0074] According to a third aspect of the invention, this relates to the use of a material produced as described above for separating gaseous carbon dioxide from a gas mixture, preferably from at least one of the ambient air, flue gas and biogas containing said gaseous carbon dioxide, as well as from further gases different from gaseous carbon dioxide, by repeated adsorption / desorption in a unit using a sorbent material that adsorbs said gaseous carbon dioxide.

[0075] According to a fourth aspect of the present invention, this relates to a sorbent material, preferably prepared using a method as described above, for use as an adsorbent for the separation of carbon dioxide from a gas mixture, having a total metal impurity content of less than 1400 ppm, preferably less than 1200 ppm, more preferably less than 1100 ppm, most preferably in the range of 200-1000 ppm. The sorbent preferably, but not necessarily, comprises primary or secondary amine moieties or a combination thereof immobilized on a solid support.

[0076] Further embodiments of the invention are defined in the dependent claims. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described with reference to the drawings, which are for the purpose of illustrating the preferred embodiments of the present invention and are not intended to limit the present invention. [Brief description of the drawings]

[0077] [Figure 1] FIG. 1 shows the correlation between CO2 capture capacity and metal content, i.e., the effect of metal impurity (Al, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Ti, Zn) content on the CO2 capture capacity of the sorbent under DAC conditions. [Diagram 2] FIG. 1 shows the effect of various treatments (acid-base wash, elution column wash, EDTA wash, three successive acid-base washes) on the CO2 capacity of the sorbent under DAC conditions. [Diagram 3] FIG. 1 shows the behavior of CO2 capture capacity as a function of aging for sorbents with high and low impurities. [Figure 4] FIG. 1 shows an apparatus for measuring CO2 capture capacity. [Diagram 5] FIG. 1 shows the effect of deionized or desalted liquid water and steam treatment on the CO2 capacity of sorbents under DAC conditions. [Figure 6] FIG. 6 shows the correlation between CO2 capture capacity and metal content, i.e., the effect of metal impurity (Al, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Ti, Zn) content on the CO2 capture capacity of sorbents under DAC conditions including samples subjected to deionized / desalinated liquid water and steam treatment as also shown in FIG. 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0078] In the following examples, cross-linked polystyrene beads functionalized with benzylamine units (substantially spherical beads with particle size (D50) in the range of 0.30-1.2 mm) were used. The untreated material used (designated "as received") has a metal content of 1715 ppm (by weight), determined using ICP-OES, considering the contents of Al, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Sn, Ti and Zn as the sum of the metal impurity contents. Using a carbon dioxide capacity measurement set-up as further described below, this material had a carbon dioxide capacity of 0.65 mmol / g (see also Figures 1 and 2).

[0079] The elemental analysis of the untreated material is as follows (element content / wt%): C=78.6; H=8.3; N=11.0.

[0080] Procedure for the synthesis of styrene-divinylbenzene resins functionalized with benzylamine units In a 1 L reactor, 1% (by weight) gelatin and 2% (by weight) sodium chloride are dissolved in 340 mL of water at 45 °C for 1 h. In a separate flask, 1 g of benzoyl peroxide is dissolved in 57.8 g of styrene, 5.86 g of divinylbenzene (content 80%), and 63.84 g of C 11~C 13 The isoparaffin is dissolved in the mixture. The resulting mixture is then added to the reactor. The reaction mixture is then stirred and heated up to 70°C, the temperature is maintained for 2 hours, then the temperature is increased to 80°C, which is held for 3 hours, then increased to 90°C for 6 hours. The reaction mixture is cooled to room temperature and the beads are filtered using a funnel glass filter and vacuum suction. The beads are washed with toluene and dried on a rotary evaporator.

[0081] Polystyrene-divinylbenzene beads are functionalized using a chloromethylation reaction. 5 g of the beads so obtained are added to a three-necked flask containing 50 mL of chloromethyl methyl ether. The mixture is stirred for 1 hour, 2 g of zinc chloride is added, heated to 40° C., and maintained for 24 hours. The beads are then filtered and washed with 25% HCl and water to obtain the chloromethylated beads. To obtain the benzylamine units, the chloromethylated beads are aminated using the following procedure: The chloromethylated beads are added to a three-necked flask with 27 g of methylal, and the mixture is stirred for 1 hour. To this mixture, 16 g of hexamethylenetetramine and 13 g of water are added and maintained under gentle reflux for 24 hours. The beads are filtered and washed with water. To obtain the primary amine, a hydrolysis step is required, followed by treatment with a base. The beads are placed in a three-neck flask containing 140 mL of a solution of hydrochloric acid (30%) - ethanol (95%) (1:3 by volume) and the reaction mixture is heated to 80°C and kept at this temperature for 20 hours. The beads are then filtered and washed with water. At this stage, the amines are protonated and, in order to liberate the base, the beads are treated with 50 mL of a 2M NaOH solution and stirred at 80°C for 1 hour. The aminated beads are filtered and washed with demineralized water until a neutral pH is reached.

[0082] Procedure Acid-base cleaning 6 g of styrene-divinylbenzene resin functionalized with benzylamine units (as-received material) is placed in a 250 mL beaker. 60 mL of 0.5 M HCl solution is added to the sorbent and left under stirring at 35 °C for 24 h. The suspension is filtered and washed with deionized water until pH 7. Then 60 mL of 0.5 M NaOH solution is added to the sorbent in a 250 mL beaker. The sorbent is allowed to react under stirring at 35 °C for 15 min. The sorbent is filtered and washed with deionized water until pH 7.

[0083] The resulting acid-base washed material had a metal content of 637 ppm (by weight) as determined using ICP-OES.

[0084] Using a carbon dioxide capacity measurement setup as further described below, this material had a carbon dioxide capacity of 1.78 mmol / g (see Figure 2).

[0085] Procedure Elution force column 6 g of styrene-divinylbenzene resin functionalized with benzylamine units (as-received material) are placed in a chromatography column with a frit at the bottom. 60 mL of methanol are placed in the column and allowed to pass through the resin by gravity. When no more methanol is present, 60 mL of acetone are added. When no more acetone is present in the bed, 60 mL of n-heptane are added. The sorbent is then spread in a Petri dish. The Petri dish is placed in a vacuum oven at 40 °C and a pressure between 300 and 400 mbar is maintained for 24 h.

[0086] The resulting elution column washed material had a metal content of 772 ppm (by weight) as determined using ICP-OES.

[0087] Using a carbon dioxide capacity measurement setup as further described below, this material had a carbon dioxide capacity of 1.65 mmol / g (see Figure 2).

[0088] EDTA Procedure 6 g of styrene-divinylbenzene resin functionalized with benzylamine units (as-received material) is placed in a 250 mL beaker. 60 mL of 1.0 M EDTA in 0.44 M NaOH solution is added to the sorbent and left under stirring at 35° C. for 24 h. The suspension is filtered and washed with deionized water until pH 7. Then 60 mL of 0.5 M NaOH solution is added to the sorbent in a 250 mL beaker. The sorbent is allowed to react under stirring at 35° C. for 15 min. The sorbent is filtered and washed with deionized water until pH 7.

[0089] The resulting acid-base washed material had a metal content of 762 ppm (by weight) as determined using ICP-OES.

[0090] Using a carbon dioxide capacity measurement setup as further described below, this material had a carbon dioxide capacity of 1.80 mmol / g (see FIG. 2).

[0091] Procedure: Triple acid-base cleaning 6 g of styrene-divinylbenzene resin functionalized with benzylamine units (as-received material) is placed in a 250 mL beaker. 60 mL of 0.5 M HCl solution is added to the sorbent and left under stirring at 35° C. for 24 h. The suspension is filtered and washed with deionized water until pH 7. This acid washing step is repeated two more times, so that the material is washed three times in total. Then 60 mL of 0.5 M NaOH solution is added to the sorbent in a 250 mL beaker. The sorbent is allowed to react under stirring at 35° C. for 15 min. The sorbent is filtered and washed with deionized water until pH 7.

[0092] The resulting acid-base washed material had a metal content of 914 ppm (by weight) as determined using ICP-OES.

[0093] Using a carbon dioxide capacity measurement setup as further described below, this material had a carbon dioxide capacity of 2.10 mmol / g (see FIG. 2).

[0094] Comparison test of water washing and steam treatment Water Wash: 15 g of untreated styrene-divinylbenzene resin functionalized with benzylamine units (as-received material) was added to a 150 mL beaker containing a stir bar. Deionized water (150 mL) was added to the beaker and stirring was started and maintained at 250 rpm. After 3 hours, the stirring was stopped and the sorbent was filtered using a vacuum pump and air-dried in a Petri dish at 25° C. for 24 hours to a solids content of approximately 80 w / w%.

[0095] The resulting liquid water washed material had a metal content of 1560 ppm (by weight) as determined using ICP-OES (see FIG. 6).

[0096] Using a carbon dioxide capacity measurement setup as further described below, this material had a carbon dioxide capacity of 0.46 mmol / g (see FIG. 5).

[0097] Steam treatment: 15 g of untreated styrene-divinylbenzene resin functionalized with benzylamine units (as-received material) was added to a closed reactor. Air (450 ppm CO 2 , 60% RH) was passed through the reactor for 1 h. The vacuum was pulled to 200 mbar and the sample was heated up to 95° C. (900 mbar) with a water vapor flow of 10 mL / min and held at this temperature for 10 min. The sample was cooled again by pulling the vacuum and removing the water vapor system to reach a temperature of 18° C. This cycle was repeated three times.

[0098] The resulting steam treated material had a metal content of 1620 ppm (by weight) as determined using ICP-OES (see FIG. 6).

[0099] Using a carbon dioxide capacity measurement setup as further described below, this material had a carbon dioxide capacity of 0.50 mmol / g (see FIG. 5).

[0100] As can be seen, neither the deionized / demineralized liquid water treatment nor the steam treatment equivalent to the steam treatment in the DAC adsorption / desorption process affects either the metal impurity content or the recovery capacity in the context of the treatment according to the invention, which never results in the metal impurity content as claimed.

[0101] Deterioration Test To assess the degradation rate of the sorbent, the sorbent is oxidized under a stream of air at approximately 90°C. This test provides an indication of the extent to which the sorbent oxidizes over time. Two samples were used in the experiment, one with a high metal content (2872 ppm) and one with a low metal content (514 ppm). The test is carried out using the following procedure: 60 g of sorbent is charged to the reactor and 100 mL / min of synthetic air is pumped through the sorbent bed at 90°C. After 4 days of exposure, the sample is removed from the reactor and CO 2 The adsorption / desorption experiment was carried out by filling a cylinder with an inner diameter of 40 mm and a height of 40 mm with 6 g of dried sample and then soaking it in CO 2 The adsorption / desorption apparatus was placed in a 450 ppmv CO2 solution with 60% relative humidity, corresponding to a temperature of 30°C. 2 The adsorption was carried out by exposing the sorbent bed to a 2.0 NL / min air flow containing 1,2-dichloro-1,2,3-tetrahydrofuran (1,2,4-tetrafluoroethylene) at 30° C. for a period of 600 minutes. Prior to adsorption, the sorbent bed was desorbed by heating the sorbent to 94° C. under a 2.0 NL / min air and / or nitrogen flow.

[0102] The adsorption capacity of the oxidized sample is compared to the capacity of the sample before exposure to high temperature synthetic air. As can be seen from Figure 3, the percentage of retention capacity compared to the untreated sorbent is much higher for the sample with low metal content than for the sample with high impurity level (2872 ppm), 57% vs. 40%, respectively. This is rationalized based on the fact that transition metals are known to catalyze oxidation reactions via multiple mechanisms. It is therefore crucial to keep impurity levels as low as possible, as this has a tremendous impact on sorbent degradation and, consequently, the economics of carbon capture, as shown in Figure 3.

[0103] Carbon dioxide capture capacity characteristics: The beads according to the previous examples were tested in a laboratory setup in which the beads are contained in a packed bed reactor or in an air permeable layer. The setup is diagrammatically illustrated in FIG. 4. There is an ambient air inlet structure 1 and the actual reactor unit 8 comprises a vessel or wall 7 in which a layer of sorbent material 3 is placed. If, for example, water vapor is used for desorption, there is an inlet structure 4 for desorption and a reactor outlet 5 for extraction. Furthermore, there is a vacuum unit 6 for degassing the reactor.

[0104] For adsorption measurements, 6 g of dry sample was packed into a cylinder with an inner diameter of 40 mm and a height of 40 mm, and CO 2 The adsorption / desorption apparatus was placed in a 450 ppmv CO2 solution with 60% relative humidity, corresponding to a temperature of 30°C. 2 The sorbent bed was exposed to a 2.0 NL / min airflow at 30° C. containing CO for a period of 600 minutes. Prior to adsorption, the sorbent bed was desorbed by heating the sorbent to 94° C. under an airflow of 2.0 NL / min. The CO adsorbed on the sorbent was 2 The amount of CO in the airflow leaving the cylinder 2 The content was determined by integrating the signal of an infrared sensor that measures the content.

[0105] Alternatively, the adsorbent structure can be operated using a temperature / vacuum swing direct air recovery process with temperatures up to and vacuum pressures ranging from 50 to 250 mbar (absolute) and by heating the sorbent to temperatures between 60 and 110 °C. Additionally, experiments with water vapor, with and without vacuum, have been carried out.

[0106] Results and Interpretation: As can be seen from the graphical representation shown in Figure 2, each of these metal refining methods results in significantly increased carbon dioxide capacity values ​​compared to the as-received material, in each case more than double that of the untreated material, and it can also be seen that repeated treatment with one method, or successive use of different methods, results in even higher carbon dioxide capacity.

[0107] Furthermore, when correlating the metal impurity content in ppm (by weight) in the sorbent material with carbon dioxide capacity, there is unexpectedly a nearly linear correlation between metal impurity content and carbon dioxide capacity, as can be seen in Figure 1. Untreated materials typically have metal impurity contents in the range of at least 1600 ppm, and reducing the metal impurity content to less than 1400 ppm, preferably less than 1200 ppm, and most preferably less than 1000 ppm significantly increases carbon dioxide capacity.

[0108] As can be seen from FIG. 6, which further contains data for two samples subjected to deionized / desalinated liquid water treatment and steam treatment, this type of exposure of the sorbent material does not result in a decrease in metal content. [Explanation of symbols]

[0109] 1. Surrounding air, surrounding air inflow structure 2 Ambient air outflow downstream of the adsorption unit in adsorption flow-through mode 3. Sorption materials 4. Water vapor inlet structure for water vapor and desorption 5. Reactor outlet for extraction 6 Vacuum unit / separator 7. Wall 8. Reactor Unit

Claims

1. 1. A method for preparing a sorbent material (3) for use as an adsorbent for carbon dioxide separation from a gas mixture (1), comprising the steps of: the sorbent material (3) comprises primary amine moieties or secondary amine moieties or a combination thereof immobilized on a solid support; The method wherein the sorbent material (3) comprising primary amine moieties or secondary amine moieties or a combination thereof is treated to have a total metal impurity content of less than 1400 ppm after treatment.

2. 2. The method of claim 1, wherein the sorbent material (3) has, after treatment, a total metal impurity content of less than 1200 ppm, or less than 1100 ppm, or in the range of 200 to 1000 ppm.

3. 3. The method of claim 1, wherein the metals forming the metal impurities are selected from the group consisting of Al, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Sn, Ti, Zn, or a combination thereof, or are selected from the group consisting of Al, Ca, Fe, Mg, Mn, or a combination thereof.

4. the treatment is selected from the group consisting of acid-base washing, elution column washing, or treatment with a metal chelating agent, or a combination thereof; 3. The method according to claim 1 or 2.

5. 3. The method of claim 1 or 2, wherein the sorbent material (3) takes the form of sorbent particles, sorbent powder, a porous monolith structure, or a substantially contiguous adsorbent layer on a solid support carrier structure, or a combination thereof.

6. 3. The method of claim 1 or 2, wherein the amine moiety at the α-carbon position is substituted with hydrogen and / or alkyl, including one methyl and one hydrogen substituent, or two hydrogen substituents.

7. The solid support of the sorbent material (3) is a porous or non-porous material of an organic and / or inorganic material; 3. The method according to claim 1 or 2.

8. 3. The method of claim 1 or 2, wherein the primary amine moiety and / or the secondary amine moiety is part of a polyethyleneimine structure, including one obtained using an aziridine, which can be chemically and / or physically bound to a solid support.

9. Porous, 0.5 to 4000 m ２ / g, or 1 to 2000 m 2 / g, or 1 to 1000 m ２ 3. The method according to claim 1 or 2, wherein the sorbent material (3) having a specific BET surface area in the range of 1 / 2000 / g is in the form of a monolith, one or more layers, hollow or solid fibers including woven or nonwoven (layer) structures, or hollow or solid particles.

10. 3. The method of claim 1 or 2, wherein the sorbent material is in the form of substantially spherical beads having a particle size (D50) in the range of 0.002 to 4 mm, 0.005 to 2 mm, 0.002 to 1.5 mm, 0.005 to 1.6 mm, 0.01 to 1.5 mm, or 0.30 to 1.25 mm.

11. 1. A method for separating gaseous carbon dioxide from a gas mixture comprising at least one of the ambient atmosphere (1), flue gas and biogas containing said gaseous carbon dioxide, and from further gases different from gaseous carbon dioxide, by repeated adsorption / desorption in a unit (8) using a sorbent material (3) that adsorbs said gaseous carbon dioxide, comprising: The method comprises steps (a) to (e) repeated in at least the following order: (a) contacting the gas mixture (1) with the sorbent material (3) to adsorb at least the gaseous carbon dioxide onto the sorbent material (3) by flowing it through the unit (8) in an adsorption step under ambient atmospheric pressure and temperature conditions in the case of ambient air as the gas mixture, or under temperature and pressure conditions of the gas mixture supplied in other cases; (b) separating the sorbent material (3) with adsorbed carbon dioxide in the unit (8) from the flow-through; (c) CO ２ Inducing an increase in the temperature of the sorbent material (3) to a temperature that initiates desorption of CO by injecting a stream of saturated or superheated steam by means of a heat exchanger or by flow-through through the unit (8), thereby ２ inducing an increase in temperature of the sorbent material to a temperature of 60-110°C to initiate desorption of (d) extracting at least the desorbed gaseous carbon dioxide from said unit (8) and separating the gaseous carbon dioxide from the water vapor within said unit (8) or downstream thereof; (e) subjecting the sorbent material (3) to ambient temperature conditions in the case of ambient air as the gas mixture, or to the temperature and pressure conditions of the supplied gas mixture in other cases; Including, the sorbent (3) comprises primary amine moieties and / or secondary amine moieties or a combination thereof immobilized on a solid support; and, The material prepared by the method according to claim 1 or 2 is used as the sorbent material (3), or treating the sorbent material (3) using the method of claim 1 or 2 so as to have, after treatment, a total metal impurity content of less than 1400 ppm, or less than 1200 ppm, or less than 1100 ppm, or in the range of 200 to 1000 ppm, after repeating the sequence of steps a number of times that results in degradation of the sorbent material in the form of reduced carbon dioxide capture capacity. method.

12. 12. The method of claim 11, wherein the treatment to reduce the total metal impurity content is carried out in situ in an apparatus for separating gaseous carbon dioxide from a gas mixture, or by removing the sorbent / support material from the apparatus for separating gaseous carbon dioxide from a gas mixture, treating it to reduce the total metal impurity content, and then reintroducing it into the apparatus for separating gaseous carbon dioxide to continue the separation process.

13. treating the sorbent material when the carbon dioxide capture capacity has decreased by more than 30%, or more than 20%, or more than 15% compared to the carbon dioxide capture capacity of the original sorbent material; Alternatively, treating the sorbent material after repeating the series of steps at least 500 times, or at least 1000 times, or at least 10,000 times, or before repeating the series of steps 50,000 times, or before repeating the series of steps 25,000 times. The method of claim 11.

14. 3. Use of a material produced or treated according to claim 1 or 2 for separating gaseous carbon dioxide from a gas mixture comprising at least one of the ambient atmosphere (1), flue gas and biogas containing said gaseous carbon dioxide, and from further gases different from gaseous carbon dioxide, by repeated adsorption / desorption in a unit (8) using a sorbent material (3) that adsorbs said gaseous carbon dioxide.

15. A sorbent material (3) for use as an adsorbent for separating carbon dioxide from a gas mixture (1), prepared or treated using the method of claim 1 or 2, having a total metal impurity content of less than 1400 ppm, or less than 1200 ppm, or less than 1100 ppm, or in the range of 200 to 1000 ppm.

16. When the treatment is an acid-base wash, the treatment involves at least one step of treatment with an aqueous solution of pH less than 5, or less than 3, or less than 2, or less than 1, or less than 0.5, and at least one step of treatment with an aqueous solution of pH greater than 9, or greater than 10, or greater than 11, or greater than 13, or greater than 13.5, followed by washing with water to establish a pH in the range of 6 to 8; If the treatment is an elution column wash, the sorbent is subjected to a treatment with an alcohol comprising one selected from the group consisting of methanol, ethanol or (iso)propanol, or a combination thereof, and / or another polar organic solvent comprising one selected from the group consisting of acetone, methyl acetate, ethyl acetate, or a combination thereof, followed by washing with a non-polar organic solvent comprising an alkane selected from the group consisting of propane, pentane, hexane, heptane, octane, decane, dodecane, in branched or linear form, or a combination thereof; When the treatment is a treatment with a metal chelating agent, the chelating agent is selected from the group consisting of bidentate chelating agents and multidentate chelating agents. The method of claim 4.

17. When the treatment is an acid-base wash, the treatment involves at least one step of treatment with an aqueous solution in the form of a solution of HCl, HNO3, H2SO4, CH3COOH, or a combination thereof, having a pH of less than 5, or less than 3, or less than 2, or less than 1, or less than 0.5, and at least one step of treatment with an aqueous solution in the form of a solution of NaOH, Na2CO3, KOH, or a combination thereof, having a pH of more than 9, or more than 10, or more than 11, or more than 13, or more than 13.5, followed by washing with water and with deionized water to establish a pH in the range of 6 to 8; If the treatment is an elution column wash, the sorbent is subjected to a treatment with an alcohol selected from the group consisting of methanol, ethanol or (iso)propanol, or a combination thereof, and / or a treatment with another polar organic solvent selected from acetone, methyl acetate, ethyl acetate, or a combination thereof, followed by washing with a non-polar organic solvent comprising an alkane selected from the group consisting of propane, pentane, hexane, heptane, octane, decane, dodecane, in branched or linear form, or a combination thereof; When the treatment is a treatment with a metal chelating agent, the chelating agent is selected from the group of water-soluble bidentate or multidentate chelating agents having a primary amino group and / or a secondary amino group, an alcohol group and / or an ether group for complex formation with metal ions that form metal impurities, and is selected from the group consisting of ethylenediamine and its polymers, oxalate, diethylenetriamine, triphosphate, ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), or a combination thereof. The method of claim 4.

18. The method of claim 1 or 2, wherein the sorbent (3) comprises a primary benzylamine moiety and / or a secondary benzylamine moiety, or the carbon dioxide capture portion of the sorbent material consists of a primary benzylamine moiety.

19. The solid support of the sorbent (3) is a porous or non-porous polymeric material selected from the group consisting of linear or branched, cross-linked or non-cross-linked polystyrene, polyethylene, polypropylene, polyamide, polyurethane, acrylate-based polymers including PMMA, polyacrylonitrile, or combinations thereof, wherein the polymeric material is poly(styrene) or poly(styrene-co-divinylbenzene)-based, or cellulose; or the solid support of the sorbent (3) is a porous or non-porous inorganic material, including silica, alumina, activated carbon, metal organic frameworks, covalent organic frameworks, and combinations thereof; or, the sorbent material (3) is a polystyrene material, including cross-linked polystyrene materials and poly(styrene-co-divinylbenzene) systems, which is at least partially functionalized with amino moieties throughout the material or at least on or only on its surface, or contains benzylamine moieties, and the material or the functionalization is obtained by amidomethylation, phthalimide, chloromethylation reaction pathways, or combinations thereof; The method of claim 7.

20. The method of claim 12, wherein the treatment to reduce the total metal impurity content is carried out in situ in an apparatus for separating gaseous carbon dioxide from a gas mixture by acid-base washing, elution column washing, or treatment with a metal chelating agent, or a combination thereof.

Images