Moulded bodies with salts melting below sintering temperature for the reversible chemisorption of co 2

Abstract

The invention relates to a sorbent for CO2, comprising a moulded body (i) sintered at a sintering temperature TS and composed of at least one metal oxide and at least one salt (S) which has a melting point TM lower than Ts, wherein the amount of the at least one salt (S), in relation to the total mass of the sorbent, is less than 0.7 wt.%, and at least one sorption agent (ii) for CO2, with which the moulded body is functionalized. The invention also relates to the preparation of said sorbent and to the use of said sorbent as a fixed-bed sorbent in the chemisorption of CO2.

Description

[0001] WA12414S / Wi

[0002] Molded bodies with salts that melt below sintering temperature for the reversible chemisorption of CO2

[0003] The present invention relates to a sorbent for CO2, comprising a shaped body (i) sintered at a sintering temperature Ts, made of at least one metal oxide and at least one salt (S), which has a melting point TM lower than T s is , wherein the amount of at least one salt ( S ) is less than 0.7 wt.% based on the total mass of the molded body and at least one sorbent ( ii ) for CO2 with which the molded body is functionalized, the production of this sorbent and the use of this sorbent as a fixed bed sorbent in the chemisorption of CO2 .

[0004] Climate change and global warming are considered the most serious environmental problems of our time. It is now widely accepted that the main cause of global warming is the release of so-called greenhouse gases into the atmosphere. One important greenhouse gas is carbon dioxide (CO2), which is released primarily during the combustion of fossil fuels such as coal, oil, and natural gas. Together, these fossil fuels cover about 80% of global energy needs. Because fossil fuels remain relatively inexpensive and easy to use, and no satisfactory alternatives are yet available to replace them to the necessary extent, they are expected to remain our primary energy source for the foreseeable future.It is therefore all the more important to channel CCt emissions into innovative technologies capable of storing CO2 as a valuable resource and / or using it as a feedstock for further processes. WA12414S / Wi.

[0005] 2

[0006] “Carbon Capture and Storage” (CCS) is a representative of such technologies, in which CO2 is captured either from the environment or directly at the sources of fossil CO2 emissions of an industrial or energy-related nature, processed, compressed and transported to a storage site.

[0007] In contrast to the pure storage purpose of CCS, “Carbon Capture and Utilization” (CCU) concerns the capture of CO2, especially from combustion exhaust gases, and its subsequent use in further chemical processes, such as the conversion to methanol.

[0008] Another method for obtaining CO2 is "Direct air capture" (DAC), in which CO2 is extracted from the ambient air.

[0009] All these technologies require that CO2 can be (reversibly) sorbed onto a solid sorbent. This sorbent is typically used as a fixed-bed sorbent in sorption columns, through which the gas from which CO2 is to be removed flows.

[0010] Solid sorbent materials are currently used in the form of finely divided powders, which, however, have disadvantages for sorption columns. The use of finely divided powders in the columns leads to an undesirably high pressure drop, accompanied by turbulence and the discharge of the sorbent from the column.

[0011] Instead of using finely divided powders, EP2102131A1 teaches larger metal oxide particles, which, however, are not functionalized and therefore unsuitable for selectively adsorbing CO2 from gas mixtures. WA12414S / Wi

[0012] Processes for producing stable shaped bodies from metal oxides are also described in WO 2008 / 071611 Al and WO 2008 / 071612 Al. In these processes, an aqueous dispersion of the metal oxide is prepared, which is then made more solid by the addition of a coagulant. The coagulant is a basic salt that decomposes below the sintering temperature and does not melt. Coagulation is initiated by increasing the pH value. This solidified mass is then shaped, for example, by extrusion. The resulting green bodies are dried and subsequently sintered to strengthen the supports. For the reliable use of these shaped bodies in sorption columns with low pressure drop and minimal turbulence, the following should be considered:

[0013] However, strength can be further increased.

[0014] It would therefore be desirable to provide a CO2 sorbent that overcomes the disadvantages associated with powdered sorbent materials, i.e., when used as a fixed-bed sorbent in a sorption column, exhibits high strength, results in low pressure drop, and minimizes turbulence or even carry-out of the sorbent from the column. Simultaneously, CO2 should be reversibly bound with high sorption efficiency and capacity.

[0015] The problem according to the invention is solved by the first aspect of the present invention, namely a sorbent for CO2, in particular a solid sorbent, comprising

[0016] (i) a shaped body sintered at a sintering temperature Ts (i) made of at least one metal oxide and at least one salt (S) which has a melting point TM which is lower than T sis, wherein the amount WA12414S / Wi of the at least one salt (S) is less than 0.7 wt.% based on the total mass of the sorbent; and

[0017] (ii) at least one sorbent (ii) for CO2 with which the molded body (i) is functionalized.

[0018] “Functionalised” within the meaning of the invention means, for example, that the shaped body (i) is impregnated and / or coated with the sorbent (ii).

[0019] The strength of metal oxide components is typically improved by sintering at high temperatures. However, this process also reduces porosity and specific surface area, thus significantly decreasing the CO2 sorption capacity of these materials.

[0020] Surprisingly, it has been shown that the addition of at least one salt (S) to the molded body according to the invention ensures that the molded body has excellent mechanical properties (expressed via the compressive strength and / or breaking load of the molded body) without significantly reducing the porosity and the associated specific surface area.

[0021] The porosity is crucial for the sorption efficiency of the molded bodies for CO2. Sufficiently high sorption efficiencies within the meaning of the present invention are achieved, for example, when the pore volume of the sintered molded bodies with the addition of the at least one salt (S) is at least 20%, preferably at least 40%, and particularly at least 50% of the pore volume of the molded bodies sintered in the same way without WA12414S / Wi

[0022] 5. The addition of at least one salt (S) according to the invention is acceptable. Due to the drastically improved mechanical properties of the molded bodies containing the salt (S) according to the invention, such reductions in pore volume are acceptable. Acceptable pore volumes within the meaning of the present invention are, in a particularly preferred embodiment, also at least 0.2 mL / g, and optimally at least 0.5 mL / g.

[0023] High compressive strengths combined with acceptable pore volumes offer the advantage of efficient CO2 sorption and optimal flow-mechanical properties in the sorption column, such as low pressure drop, no discharge of the sorbent from the column, etc.

[0024] Additionally, it is possible to sinter the carriers at a lower temperature, thereby reducing production costs.

[0025] In the context of the present invention, sintering refers to a treatment of a green body (easily machinable blank) formed, for example, by extrusion, in order to transform it into a solid finished body. The green body can sometimes be dried at lower temperatures before sintering.

[0026] Ts is preferably in a range of 800-1200 °C, more preferably in a range of 900-1100 °C.

[0027] The at least one salt (S) which has a melting point TM is characterized in particular by the fact that it melts during the sintering of the molded body and does not decompose.

[0028] TM is preferably in the range of 600 to 900 °C, particularly in the range of 800 to 900 °C. WA12414S / Wi

[0029] 6

[0030] In a preferred embodiment, the at least one salt (S) is selected from salts, preferably chlorides or carbonates, of the alkali and alkaline earth metals, preferably of the alkali metals.

[0031] It is particularly preferred that the at least one salt (S) is selected from the group consisting of LiCl, NaCl, KCl, Na2COa and K2CO3, preferably consisting of NaCl, NaCOs and K2CO3, in particular consisting of NaCl and K2CO3.

[0032] The amount of the at least one salt (S) based on the total mass of the molded body is preferably a maximum of 0.6 wt.%, more preferably a maximum of 0.5 wt.%, more preferably a maximum of 0.4 wt.%, more preferably 0.04-0.4 wt.%, and in particular 0.05-0.2 wt.% based on the total mass of the

[0033] Sorbs .

[0034] In a preferred embodiment, the at least one metal oxide is selected from aluminium oxide, silicon dioxide, titanium dioxide or zirconium dioxide, preferably from silicon dioxide, in particular from amorphous silicon dioxide.

[0035] The amorphous silicon dioxide is particularly preferably selected from pyrogenic or precipitated silicon dioxide, especially from pyrogenic silicon dioxide.

[0036] To produce pyrogenic silicon dioxide, a volatile silicon halide (e.g., silicon tetrachloride) is usually injected into an oxyhydrogen flame of hydrogen and air. Under the influence of the water produced during the oxyhydrogen reaction, this substance hydrolyzes to form silicon dioxide. After leaving the flame, the silicon dioxide enters a so-called coagulation zone, where the primary particles and primary aggregates agglomerate. WA12414S / Wi

[0037] 7

[0038] To produce precipitated silica, for example, commercially available sodium silicate is reacted with acid (e.g., sulfuric acid) at a pH between 7.5 and 10.5. The pH is then adjusted to 3.0 to 5.0, and the precipitated silica is filtered, washed, and dried.

[0039] A preferred sorbent comprises shaped bodies having dimensions in one, two or three dimensions, more preferably in two or three dimensions, particularly in all three dimensions in the range of 0.5 mm to 30 mm, preferably 1.0 mm to 15 mm.

[0040] Preferably, the sorbent according to the invention has the same dimensions as the corresponding molded body.

[0041] When a gas mixture flows through powder beds known in the prior art, a high pressure drop occurs between the sides facing the gas source and those facing away from it. A coarser shaped body having the dimensions according to the invention is advantageous because the pressure loss (= pressure drop) when flowing through such a bed is reduced.

[0042] The sorbent according to the invention is therefore particularly well suited as an efficient fixed-bed sorbent for CCU, CCS or DAC, since – in contrast to finely divided powders – it results in a lower pressure drop and little turbulence or even carry-out of the sorbent from the sorption column. Efficient CO2 adsorption is only possible using the shaped bodies according to the invention.

[0043] The molded bodies according to the invention also exhibit improved mechanical stability and improved long-term stability. In contrast to powdered sorbents, the molded bodies according to the invention, WA12414S / Wi, tend to deteriorate during impregnation (=

[0044] Functionalizing with sorbents does not cause agglomeration or clumping and does not require extensive grinding.

[0045] Surprisingly, it has been shown that particularly good adsorption efficiencies can be achieved in the sorption column only if the mechanical properties (compressive strength and / or breaking load) of the sorbent according to the invention are observed.

[0046] It is preferred that the sorbent has a compressive strength of at least 2 N / mm². 2 , preferably at least 8 N / mm 2 , exhibits .

[0047] The compressive strength according to the invention can be determined using all methods known in the field, for example with the aid of a material testing machine, such as the Texture Analyser XT plus from Winopal.

[0048] It is preferred that the sorbent in the form of cylindrical shaped bodies has a breaking load of at least 30 N, preferably at least 50 N, more preferably at least 80 N, and particularly preferably at least 100 N.

[0049] The breaking load is determined as is customary in the field, for example using Texture Analyser XT plus from Winopal, as described in the examples.

[0050] Molded bodies whose mechanical properties do not conform to the invention cannot withstand the CCt pressure in the adsorption column sufficiently and are destroyed, exhibiting, for example, spalling. Destroyed molded bodies again lead to the same disadvantages that also occur when using WA12414S / Wi

[0051] 9

[0052] Problems occur with sorption powders in the sorption column (e.g. higher pressure drop, turbulence, discharges).

[0053] The molded body according to the invention can be highly pure. Highly pure within the meaning of the invention means that it is essentially free of inorganic and organic impurities. Preferably, the sum of impurities (all metals as well as carbon, phosphorus and sulfur) is less than 400 ppm, more preferably less than 250 ppm, particularly preferably less than 100 ppm, even more preferably less than 50 ppm, and even more preferably less than 20 ppm, even more preferably less than 10 ppm, and most preferably less than 1 ppm based on the total mass of the molded body.

[0054] Impurities can be quantified using all standard analytical methods, such as XRF, AAS, ICP-OES, or ICP-MS. If necessary, the molded part must be dissolved in a suitable solvent, e.g., hydrofluoric acid, before analysis.

[0055] In a particular embodiment, the shaped bodies are essentially spheres, ellipsoids, cylinders, hollow cylinders (e.g., tubes), or cuboids, preferably cylinders or hollow cylinders. It is also clear to those skilled in the art that the geometry described is not perfect, so deviations from the ideal geometry are possible.

[0056] The shaped bodies preferably have an aspect ratio of at most 15, more preferably of at most 10, most preferably of at most 6.

[0057] Furthermore, it has been shown that the aforementioned aspect ratio has a particularly positive effect on the suitability of the molded body in a sorption column, since the already WA12414S / Wi

[0058] 10. The low pressure drop when using the molded parts according to the invention can be further reduced due to the aforementioned aspect ratio. Molded parts whose aspect ratio exceeds that of the invention are no longer practical to pack in reaction / sorption columns and tend to break. Fractures are disadvantageous because they result in very small fragments of the molded parts, which cause a high pressure drop and turbulence in the column, as well as discharge from the column.

[0059] The molded body is preferably composed of agglomerates of amorphous silicon dioxide / silica. The agglomerates are preferably composed of aggregates of a plurality of primary silica particles.

[0060] In a preferred design, the BET surface area of ​​the sorbent lies in the range of 30 to 500 m². 2 / g, especially in the range of 50 to 400 m 2 / g .

[0061] The BET surface area can be determined using measurement methods known in the field. The BET surface area is preferably determined using nitrogen according to DIN 66131.

[0062] Preferably, the molded bodies are characterized by a high pore volume, which is between 0.2 ml / g and 1.8 ml / g, preferably between 0.5 ml / g and 1.7 ml / g and particularly preferably between 0.8 ml / g and 1.6 ml / g.

[0063] These high pore volumes give the sorbent according to the invention the advantage that it can be functionalized with a particularly large amount of sorbent, thereby significantly increasing its sorption capacity for CO2. WA12414S / Wi

[0064] 11

[0065] If the pore volume exceeds the ranges mentioned above, the molded bodies are too fragile and tend to break when used in a sorption column. This results in the formation of very small molded body fragments and thus a high pressure drop. Fragments with a smaller pore volume than specified have too small an internal surface area and therefore lead to low sorption efficiencies and capacities.

[0066] The determination of the pore volume and pore size is carried out using methods known in the field, for example by means of Hg porosimetry, for example as described in ISO 15901 - 1.

[0067] In a preferred embodiment, the metal oxide of the molded body, in particular the silicon dioxide of the molded body, has a mesoporous structure, in particular a mesoporous structure with an irregular pore structure.

[0068] The irregular pore structure of the silica, according to the preferred embodiment described above, is retained in the molded body. This pore structure creates channels within the molded body, defining its inner surface.

[0069] The functionalization with the sorbent is preferably located on the inner surfaces of the molded bodies according to the invention.

[0070] Mesoporous solids are, according to the IUPAC definition, porous materials with a pore diameter between 2 nm and 50 nm.

[0071] It is known to those skilled in the art that mesoporous silica is usually produced by a complex template-based synthesis. Silica produced in this way is characterized by a defined, WA12414S / Wi

[0072] 12 channel-like pore structure made of . In contrast, the molded bodies according to the invention are based on silica, which is characterized by an irregular pore structure. In this context, “irregular pore structure” means that the pores within the silica extend asymmetrically and / or randomly without any recognizable repeating sections, either with or without at least one branch and / or division.

[0073] Silica with such an irregular pore structure offers economic advantages, for example, as it is far cheaper and easier to produce than silica with a predefined and regular channel structure. Surprisingly, it has also been shown that the CO2 adsorption efficiency of the silica molded bodies according to the invention with an irregular pore structure can significantly exceed the adsorption efficiency of silica molded bodies with a defined, uniform pore structure, since silica with an irregular pore structure is less prone to clogging and blockage of the channels by sorbents. Thus, the inner surfaces of the molded bodies according to the invention can be more homogeneous and completely functionalized, thereby increasing the adsorption capacity of the molded bodies according to the invention for CO2.Sufficient capacities for efficient CO2 sorption are preferably at least 20 mg CO2 per gram of sorbent (corresponding to approximately 0.45 mmol CO2), more preferably at least 40 mg CO2 per gram of sorbent.

[0074] In a preferred embodiment, the at least one sorbent (ii) is able to undergo a reversible reaction with CO2, in particular a reversible sorption reaction.

[0075] The sorption reaction is specifically a chemisorption. In this case, the CO2 is chemically bound to the WA12414S / Wi.

[0076] 13

[0077] The sorbent is bound to the inner surface of the molded body. By increasing the temperature and / or decreasing the pressure, the chemisorbed CO2 can be released from the molded body and thus driven off. This has the advantage that the CO2 can not only be removed from the gas phase (e.g., DAC, CCS), but can also be released again at any later time and, for example, fed into a process that uses CO2 as a feedstock (e.g., CCU), such as the conversion to methanol.

[0078] The at least one sorbent ( ii ) can be an inorganic or an organic sorbent .

[0079] In one embodiment, the shaped body (i) is functionalized with a mixture of an inorganic and an organic sorbent, in particular with a mixture of a carbonate and an organic amine.

[0080] The inorganic sorbent (ii) is preferably a carbonate, in particular selected from the group consisting of metal carbonate, metal hydrogen carbonate and mixtures thereof.

[0081] Preferably, the metal is selected from alkali metals and alkaline earth metals, in particular from Na and K.

[0082] The organic sorbent can be an organic monoamine or polyamine, wherein the polyamine comprises at least two nitrogen atoms per molecule separated by at least one carbon atom, in particular selected from the group consisting of ethyleneamine, aminosilane, polyethyleneimine (PEI), polypropyleneamine, polyvinylpyridine, polydimethylaminoethyl methacrylate, polyamidoamine, polyvinylamine, and polyallylamine. WA12414S / Wi

[0083] 14

[0084] The ethyleneamine is preferably selected from the group consisting of ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetraamine (TETA), tetraethylenepentamine (TEPA), aminoethylethanolamine (AEEA), aminoethylpiperazine (AEP), piperazine (PIP), hydroxyethylpiperazine (HEP), pentaethylenehexamine (PEHA) and polyethylenepolyamine (PEPA).

[0085] The aminosilane is preferably selected from the group consisting of aminopropylsilane, [3-(2-Aminoethylamino)-propyl]-trimalkoxysilane, 3-[2-(2-Aminoethylamino)-ethylamino]-propyltrialkoxysilane, mixtures thereof and condensation products of 3-aminopropyltrialkoxysilane.

[0086] The polyamine can be silylated, for example obtained by reacting one or more amino groups of the polyamine with suitably functionalized alkoxysilanes, for example selected from the group consisting of 3-chloropropyl trialkoxysilane, 3-chloropropyl trialkoxysilane, glycidoxypropyl trialkoxysilane and 1-socyanatopropyl trialkoxysilane.

[0087] For the purposes of this application, ‘alkoxy group’ preferably means a Gl- to C4-alkoxy group, and in particular preferably an ethoxy or methoxy group.

[0088] The silylated polyamine can be obtained by silylation, which can be carried out in isolation or in situ.

[0089] In a preferred embodiment, the invention comprises

[0090] Sorbs further

[0091] (iii) at least one excipient (iii) selected from the group consisting of polymeric binders, silicon WA12414S / Wi

[0092] 15 containing binders such as silicates and silica sol, spreading agents and wetting agents.

[0093] The polyamine can be present in combination with at least one amino-functional alkoxysilane.

[0094] The at least one amino-functional alkoxysilane is preferably selected from the group consisting of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane and 3-aminopropyltriisoproxysilane.

[0095] The amount of polyamine is preferably at least 50% by weight based on the total amount of polyamine and amino-functional alkoxysilane.

[0096] In a preferred sorbent, the amount of the at least one sorbent (ii) is 10 to 90 wt.%, preferably 25 to 80 wt.%, based on the total weight of the sorbent.

[0097] In a special version, the molded body of the sorbent is free of inorganic and organic chemical binders, such as glycerin, kaolin, sugar, starch, urea, wax, methylcellulose, magnesium stearate, graphite, aluminum stearate, polyethylene glycol or polyethylene oxide.

[0098] Another aspect of the present invention relates to a method for producing the sorbent according to the invention for CO2, comprising the following steps in the specified order:

[0099] (A) Providing a shaped body (i) sintered at a sintering temperature Ts from at least one metal oxide (M) and at least one salt (S) , which WA12414S / Wi

[0100] 16 has a melting point TM which is lower than Ts, wherein the amount of the at least one salt (S) is less than 0.7 wt.% in relation to the total mass of the sorbent;

[0101] (B) Impregnating the provided molded body with at least one sorbent (ii) for CO2 in order to functionalize the molded body.

[0102] In a preferred embodiment, the provision of the molded body in step (A) is carried out by the following steps in the specified order:

[0103] (Al) Providing a metal oxide dispersion by dispersing at least one metal oxide (M) in a dispersing agent;

[0104] (A2) Coagulation of the dispersion by raising the pH value;

[0105] (A3) Mixing the at least one salt (S) into the coagulated dispersion;

[0106] (A4) Shaping the coagulated dispersion to produce a green body; and

[0107] (A5) Drying and subsequent sintering of the green body at a sintering temperature T s , in order to produce the sintered molded body.

[0108] In the process according to the invention, a metal oxide dispersion is therefore first produced in the first step (Al).

[0109] This dispersion is coagulated in a subsequent step (A2).

[0110] In the next step (A3), the at least one salt (S) according to the invention is mixed into the coagulated dispersion, for example by means of a speed mixer. WA12414S / Wi

[0111] 17

[0112] In the next step (A4), the coagulated dispersion can be transferred into a mold, resulting in a green body, i.e., a shaped blank made from the coagulated dispersion.

[0113] This green compact is transformed into a sintered body by drying and sintering according to step (A5). Only then is the body given the mechanical stability required for use in sorption columns.

[0114] Surprisingly, it has been shown that adding small amounts of the salt (S) according to the invention to the molded body gives it excellent mechanical properties (such as compressive strength or breaking load) without limiting the porosity required for sorption efficiency.

[0115] The proportion of the at least one metal oxide in the metal oxide dispersion of step (Al ) can be 10-50 wt. -%, preferably 20-40 wt. -%, based on the total mass of the dispersion .

[0116] In a preferred method, the provision of the metal oxide dispersion in step (Al ) is carried out by stirring in the at least one metal oxide using a dissolver disk and a butterfly insert simultaneously.

[0117] The mixer used is therefore preferably equipped with a dissolver disc and a butterfly insert.

[0118] A dissolver disc is a stirring disc mounted in a mixer, rotatable around an axis, and immersed in the product to be dispersed. When the disc rotates, shear forces are generated that break down the product to be dispersed (in this case, the at least one metal oxide). WA12414S / Wi

[0119] 18

[0120] A butterfly insert is a mixing organ with an open profile, which usually has at least three wings that have a high dispersing effect.

[0121] In a preferred method, the provision of the metal oxide dispersion in step (Al) is carried out by stirring the total amount of the at least one metal oxide (M) into water in at least two portions, wherein the portion stirred in first is stirred in at a higher stirring speed of the dissolver disk and a lower stirring speed of the butterfly insert compared to the portion stirred in after.

[0122] The stirring according to step (Al) according to the invention has the particular advantage that the metal oxide dispersion produced thereby has particularly good rheological properties, which is accompanied by easy handling.

[0123] It is preferred that the dispersing agent in step (Al) is water or an aqueous solution, preferably an aqueous solution with a pH value in the range of 1.0 to 7.0, preferably from 1.5 to 6.0, particularly preferably from 2.0 to 4.0.

[0124] The pH of the dispersant in step (Al) can be adjusted by adding acid, preferably by adding phosphoric acid.

[0125] The at least one metal oxide in step (Al) is preferably selected from a pyrogenic silicon dioxide or a precipitated silicon dioxide, in particular from a pyrogenic silicon dioxide. WA12414S / Wi

[0126] 19

[0127] The silicon dioxide provided in step (Al) is preferably in powder form. The powdered silicon dioxide preferably has aggregate sizes of 100 nm to 500 nm, measured by dynamic light scattering.

[0128] Mixing the metal oxide provided in step (Al) with the aqueous solution preferably produces a dispersion.

[0129] At the end of the dispersion process, the dispersions can also be freed from non-dispersible, unwetted and other coarse particles by sieving.

[0130] In a preferred method, the pH value is increased in step (A2) by 0.5-5.5 units, wherein the target pH value after the change of the pH value in step (A2) is preferably in the range of 4.0 to 8.0, particularly preferably in the range of 5.5 to 7.0.

[0131] The pH increase in step (A2) is preferably achieved by adding suitable bases, in particular by adding a basic coagulant to the metal oxide dispersion from step (Al) . Examples of the basic coagulant are alkali and alkaline earth metal hydroxides, carbonates and mixtures thereof, such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, magnesium carbonate, magnesium hydroxide carbonate, NHa or mixtures thereof, in particular magnesium hydroxide carbonate.

[0132] In a preferred embodiment, during step (A2), the dispersion is first acidified to achieve a pH value < 4.0, and subsequently the reaction mixture is raised to a value > 4.0 with a base. WA12414S / Wi

[0133] 20

[0134] In the event that the pH value is only raised during step (A2), an aqueous solution with pH < 4.0 can already be used in step (Al) before the pH value is then raised to a value > 4.0 in step (A2).

[0135] The pH increase in step (A2) is preferably carried out by stirring and / or kneading. Planetary mixers or centrifugal mixers, for example, can be used for this purpose.

[0136] The increase in pH in step (A2) is accompanied by an increase in viscosity, so that typically a highly viscous mass is obtained.

[0137] The production of shaped bodies by forming in step (A4) is preferably carried out by extrusion, tableting, or pressing, particularly by extrusion. All equipment known to those skilled in the art, such as extruders, tablet presses, or piston extrusion presses, is conceivable. The geometry of the shaped body results from the respective forming tool selected. Geometries such as rings, pellets, cylinders, wagon wheels, spheres, etc., can be produced. The length of rings and pellets is preferably defined directly after forming using a cutting device.

[0138] After shaping, the shaped part is dried in process step (A5). This is preferably carried out using methods known to those skilled in the art (e.g., climate chamber, drying oven, IR heating, microwave). Preferably, the drying takes place in a climate chamber under controlled humidity. Drying can be carried out at temperatures preferably between 25°C and 200°C, more preferably between 30°C and 100°C, and most preferably between 40°C and 80°C. The drying time depends on the ratio of metal oxide to water, WA12414S / Wi

[0139] 21, however, preferably lies between 2 and 48 hours. Process step (A5) can be carried out at normal pressure at 1013 mbar or under reduced pressure. If the drying of the molded part in step (A5) takes place under reduced pressure, the pressure can be 10 -3 mbar to normal pressure, in particular 10 -1 mbar to 800 mbar.

[0140] After drying, sintering takes place using methods known to experts.

[0141] The sintering step (A5) is also called calcining and can take place at a temperature Ts in the range of 800°C to 1200°C, especially at 900°C to 1100°C.

[0142] Sintering is carried out particularly under gentle heating rates, for example 180 °C / h, and gentle cooling rates, for example 80 °C / h. These gentle heating and cooling rates ensure that the mechanical stability of the sorbents is not compromised, for example, due to the occurrence of mechanical stresses at excessively rapid heating and / or cooling rates.

[0143] Calcination in a furnace under an atmospheric atmosphere is preferred. An additional gas can be added to the air. Various protective gases are suitable for this purpose. All protective gases known to experts are suitable, with nitrogen, argon, or helium being particularly preferred. Alternatively, the air can be completely replaced by the protective gas.

[0144] Sintering in step (A5) typically takes place over a period of 1-10 hours, preferably 4-8 hours. WA12414S / Wi

[0145] 22

[0146] Fine-pored molded bodies can be formed from finely divided silica by calcination. The proportion of pores with a diameter between 10 nm and 20 nm is typically more than 50%, preferably more than 70%, and particularly preferably more than 80%.

[0147] The at least one sorbent in the process according to the invention can be an inorganic or an organic sorbent.

[0148] The inorganic sorbent in the process according to the invention can be a carbonate, in particular selected from the group consisting of metal carbonate, metal hydrogen carbonate and mixtures thereof.

[0149] The organic sorbent in the process according to the invention can be an organic monoamine or polyamine, wherein the polyamine comprises at least two N atoms per molecule, which are separated by at least one C atom, in particular selected from the group consisting of ethyleneamine, aminosilane, polyethyleneimine (PEI), polypropyleneamine, polyvinylpyridine, polydimethylaminoethyl methacrylate, polyamidoamine, polyvinylamine and polyallylamine.

[0150] The ethyleneamine in the process according to the invention can be selected from the group consisting of ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), aminoethylethanolamine (AEEA), aminoethylpiperazine (AEP), piperazine (PIP), hydroxyethylpiperazine (HEP), pentaethylenehexamine (PEHA), and polyethylenepolyamine (PEPA). WA12414S / Wi

[0151] 23

[0152] The aminosilane in the process according to the invention can be selected from the group consisting of aminopropylsilane, [3- (2- Aminoethylamino )-propyl ]-trialkoxysilane, 3- [2- (2- Aminoethylamino )-ethylamino ]-propyltrialkoxysilane, mixtures thereof and condensation products of 3-aminopropyltrialkoxysilane .

[0153] The polyamine in the process according to the invention can be silylated, for example obtainable by reacting one or more amino groups of the polyamine with suitablely functionalized alkoxysilanes, for example selected from the group consisting of 3-chloropropyl-trialkoxysilane, 3-chloropropyl-trialkoxysilane, glycidoxypropyl-trialkoxysilane and 1-socyanatopropyl-trialkoxysilane.

[0154] The polyamine is obtainable in particular by silylation, which can be carried out in isolation or in situ.

[0155] Preferably, the at least one sorbent is present in liquid form during impregnation in step (B), for example as a solution, emulsion, or dispersion in a solvent or liquid medium, or in pure form. Within the scope of this invention, the sorbent is also referred to as the impregnating agent. The solvent or liquid medium is preferably removed after impregnation. In the process according to the invention, the at least one sorbent can be a solution of a metal carbonate, in particular potassium carbonate and / or sodium carbonate, in water, or a solution of a metal hydrogen carbonate, in particular potassium hydrogen carbonate and / or sodium hydrogen carbonate, in water.

[0156] Water . WA12414S / Wi

[0157] 24

[0158] In a preferred process, the at least one sorbent is a saturated aqueous solution of potassium carbonate, sodium carbonate, potassium hydrogen carbonate and / or sodium hydrogen carbonate, preferably of potassium carbonate and / or potassium hydrogen carbonate, more preferably of potassium carbonate.

[0159] In a preferred method, the amount of metal carbonate or metal hydrogen carbonate is 15-40 wt.%, preferably 15-33 wt.% of the total weight of the aqueous solution.

[0160] In a preferred method, the sorbent is in the form of a solution of an organic sorbent, for example an organic amine, in a suitable solvent, wherein the amount of dissolved organic sorbent is preferably at least 30 vol.%, more preferably at least 60 vol.%.

[0161] The organic solvent preferably has a boiling point of no more than 200 °C, more preferably no more than 150 °C, in each case at 1013 mbar.

[0162] Examples of suitable solvents include water; alcohols, such as methanol, ethanol, n-propanol, isopropanol, n-amyl alcohol, i-amyl alcohol; ethers, such as dioxane, tetrahydrofuran, diethyl ether, diisopropyl ether, diethylene glycol dimethyl ether; chlorinated hydrocarbons, such as dichloromethane, trichloromethane, tetrachloromethane, 1,2-dichloroethane, trichloroethylene; hydrocarbons, such as pentane, n-hexane, hexane isomer mixtures, heptane, octane, white spirit, petroleum ether, benzene, toluene, xylenes; ketones, such as acetone, methyl ethyl ketone, diisopropyl ketone, methyl isobutyl ketone (MIBK); esters, such as ethyl acetate, butyl acetate, propyl propionate, ethyl butyrate, ethyl isobutyrate; WA12414S / Wi

[0163] 25

[0164] Carbon disulfide and nitrobenzene, or mixtures of these solvents.

[0165] The impregnation in step (B) is preferably carried out by bringing the molded body into contact with the at least one sorbent for CO2.

[0166] For impregnating the silica molded body, any prior art method suitable for the surface treatment of fillers or particles is generally appropriate. This is an advantage of the silica molded bodies according to the invention, as they are mechanically stable enough and, due to their size and shape, do not tend to agglomerate or stick together during drying.

[0167] In a preferred method, impregnation is carried out by mixing, spraying or soaking the molded body or the incipient wetness method with the at least one sorbent in liquid form, in particular by means of the incipient wetness method.

[0168] “Impregnation” within the meaning of this invention means the penetrating treatment with liquid, dissolved, emulsified or dispersed impregnating agents. The impregnating agent can be physically deposited on the inner and outer surface of the porous molded body or bond to it chemically, either wholly or partially.

[0169] The "incipient wetness method" is known in the literature in connection with the coating of support materials with a catalyst, and the principles are described in Marceau, E.; Carrier, X.; Chet, M., Impregnation and Drying. In Synthesis of Solid Catalysts, 2009; pp. 59-82. It has been WA12414S / Wi

[0170] 26 Surprisingly, it was shown that the incipient wetness method is also suitable for coating the molded bodies according to the invention with the CO2 sorbent in such a way that CO2 binding sites are homogeneously distributed over the entire surface of the molded body. This allows particularly high sorption efficiencies to be achieved in the sorbent. In the incipient wetness method, the sorbent is usually dissolved or dispersed in a solution (e.g., aqueous or organic). This mixture can then be applied to the support material, which preferably has the same pore volume as the volume of the added mixture. Capillary action draws the mixture into the pores, leading to functionalization there.

[0171] Unlike the wet method (“Wet Impregnation”), the incipient wetness method does not cause the particles to stick together and the impregnating agent is deposited very homogeneously on the inner and outer surface of the mold body.

[0172] The impregnation in step (B) preferably takes place in a temperature range of 0-150 °C, preferably in a temperature range of 15-120 °C.

[0173] The impregnation in step (B) preferably takes place at normal pressure, under increased pressure or under reduced pressure.

[0174] Normal atmospheric pressure is usually 1013 mbar.

[0175] If impregnation in step (B) is carried out under increased pressure, the maximum pressure can be 2 bar. WA12414S / Wi

[0176] 27

[0177] In the event that impregnation in step (B) takes place under reduced pressure, the pressure can be IO -3mbar to normal pressure, especially IO -1 mbar to 500 mbar .

[0178] A preferred method is characterized in that the molded body has a mesoporous structure and the volume of the at least one sorbent for CO2 used is 80 to 120%, preferably 90 to 110%, more preferably 95-105% based on the total pore volume of the molded body.

[0179] Using such quantities of sorbent ensures that the inner surface of the molded body is homogeneously and completely functionalized with the sorbent. This results in high sorption efficiencies.

[0180] In a preferred method, the molded body is pre-impregnated at a pressure of 10 -3 up to 10 2 treated with mbar; and / or dried.

[0181] The impregnation in step (B) of the provided molded body with at least one sorbent for CO2, in order to functionalize the molded body, is preferably carried out together with at least one impregnating agent, selected from wetting agent, emulsifier, colorant, binder, adhesion promoter, higher-grade alcohols and higher-grade polyols.

[0182] In a preferred embodiment, the molded body retains its shape, defined by the molding tool / mold, at the moment of manufacture. Deformations during and immediately after molding cause density differences and stresses that lead to defects (flaking, fine dust) on the molded body during the drying and sintering process. According to the invention, the manufactured carriers exhibit a proportion of flaking WA12414S / Wi.

[0183] 28 preferably less than 5 wt.%, preferably less than 1 wt.% and most preferably less than 0.5 wt.%. Spalling is disadvantageous because it leads to a high pressure drop in a column or reactor in the application.

[0184] The present invention is therefore directed in particular to a sorbent for CO2 obtainable by the inventive process for producing a sorbent for CO2, wherein the impregnation is preferably carried out using the incipient wetness method. This has the advantages already described in detail above of a particularly homogeneous distribution of the CO2 sorption sites and an associated outstanding sorption efficiency for CO2.

[0185] Another aspect of the present invention is directed towards the use of the sorbent according to the invention for CO2 for the reversible binding of CO2 from a gas mixture, in particular in the form of a fixed bed sorbent, for example for CCU, CCS and / or DAC.

[0186] Reversible binding is achieved primarily through chemisorption. In this case, the CO2 is chemically bound to the inner surface of the molded body by the sorbent with which the metal oxide is functionalized. By increasing the temperature and / or decreasing the pressure, the chemisorbed CO2 can be released from the molded body and thus driven off. This has the advantage that the CO2 can not only be removed from the gas phase (e.g., DAC, CCS), but can also be released again at any later time and, for example, fed into a process that uses CO2 as a feedstock (e.g., CCU). WA12414S / Wi

[0187] 29

[0188] Examples of implementation

[0189] The following examples were carried out at atmospheric pressure, i.e., at about 1013 mbar, and at room temperature, i.e., about 23°C or a temperature that occurs when the reactants come together at room temperature without additional heating or cooling, and describe the basic feasibility of the present invention, without, however, limiting it to the contents disclosed therein.

[0190] Determination of the breaking load

[0191] The breaking load of the molded parts was verified using a material testing machine. The Texture Analyser XT plus from Winopal was used for this purpose. The following parameters were used to measure the breaking load:

[0192] Test speed: 2.00 mm / sec; probe travel: 14.5 mm.

[0193] The target parameter is the displacement; that is, the sample is subjected to pressure until the set displacement of 14.5 mm is reached. A 6 mm diameter stainless steel punch is used as the tool. A 150 kg load cell was used for all measurements with the texture analyzer.

[0194] The cylindrical shape was placed in the apparatus in such a way that the punch pressed on the lateral surface (not the cut surface), the result is the breaking load in Newtons (N).

[0195] Determination of CO2 adsorption capacity

[0196] The BELCAT II gas adsorption analyzer from Microtrac is used to determine the CO2 adsorption capacity. The method described in WA12414S / Wi is typically employed.

[0197] 30 temperature-programmed desorption (TDD) methods are used, which work as follows.

[0198] For sample preparation, the substrate to be examined is heated to 200 °C under a continuous helium flow at a rate of 10 K / min and held at this temperature for 35 min.

[0199] For analysis, the sample is first rinsed with helium at 40 °C. Then, CO2 is passed over the sample for 90 minutes at 40 °C. If necessary, the CO2 can be humidified using a commercially available steam injection device ("Bubbier").

[0200] The sample is treated for 30 minutes at 40 °C in a helium stream.

[0201] Helium is used as the desorption gas. The temperature of the support is increased to 200 °C at a rate of 10 K / min (linear temperature gradient) and the temperature is held for 20 minutes.

[0202] The gas mixture is passed through a dry molecular sieve (3 Å) to remove water and analyzed using a thermal conductivity detector (TCD) and mass spectrometry (MS). This allows the desorbed amount of CO2 to be determined.

[0203] Metal oxide shaped bodies of variant 1

[0204] The metal oxide molded body was made from hydrophilic pyrogenic silica HDK® S13 (BET surface area: 110-140 m²). 2 / g, tapped density: 50 g / ml; available from WACKER Chemie AG) manufactured as follows: WA12414S / Wi

[0205] 31

[0206] Example 1:

[0207] General procedure for the preparation of slurry A (silica dispersion)

[0208] Three kilograms of demineralized water are added and adjusted to a pH of 3 by adding 6 g of hydrogen peroxide (H3PO4). A total of one kilogram of pyrogenic silica (WACKER HDK® S13) is stirred into a mixer equipped with a dissolver disc and butterfly attachment. This is done in six portions of approximately 180 g of silica each. For portion 1, the stirrer speeds are started at 200 rpm (dissolver) and 960 rpm (butterfly). Portion 2: 260 rpm (dissolver) and 800 rpm (butterfly). Portion 3: 400 rpm.

[0209] (Dissolver) and 600 rpm (Butterfly). Portion 4: 400 rpm

[0210] (Dissolver) and 750 rpm (Butterfly). Portion 5: 300 rpm

[0211] Portion 1: (Dissolver) and 900 rpm (Butterfly) or 400 rpm (Dissolver) and 900 rpm (Butterfly). Portion 6: 500 rpm (Dissolver) and 950 rpm (Butterfly) or 1060 rpm (Dissolver) and 1500 rpm (Butterfly) or 1070 rpm (Dissolver) and 1550 rpm (Butterfly). Portions 1-4 were each stirred for 5 minutes, portion 5 was stirred twice for 5 minutes, and portion 6 was first stirred for 10 minutes, then 5 minutes, and then another 10 minutes. This dispersion (slurry A) has a solids content of approximately 26%.

[0212] Example 2 (not according to the invention):

[0213] Production of the molded body without the addition of under

[0214] Sintering temperature of melting salt

[0215] 280 g of slip A, which has gelled after a certain time, are stirred and liquefied twice at 2350 rpm for 20 seconds each time using a speed mixer. 2.3 g of magnesium hydroxycarbonate paste (25% in water) is added to the liquid dispersion. This mixture is blended at 2350 rpm for 20 seconds using a speed mixer, causing the mass to solidify. For WA12414S / Wi

[0216] 32

[0217] During extrusion, the mass is filled into an empty cartridge and strands with a diameter of about 3.8 mm are extruded using an electric cartridge press, which are then cut to a length of about 8 mm.

[0218] The extruded bodies are dried in a climate-controlled chamber using a drying program. The temperature is maintained at 60 °C and the relative humidity is reduced from 60% to 10% over a total of 38 hours. The green bodies are then sintered. This process involves heating them at a rate of 180 °C / h to 930 °C, which is then held for 6 hours. The resulting carrier bodies have a breaking load of 23 N per edge and a pore volume of 1.5 ml / g.

[0219] The low breaking load is unacceptable for use in sorption columns.

[0220] Example 3:

[0221] Production of the molded body with the addition of 0.04 wt% K2CO3

[0222] 280 g of slip A, which has gelled after a certain time, are stirred and liquefied twice at 2350 rpm for 20 seconds each time using a speed mixer. 2.3 g of magnesium hydroxycarbonate paste (25% in water) are added to the liquid dispersion. This mixture is blended at 2350 rpm for 20 seconds using a speed mixer, causing the mass to solidify. Subsequently, 30 mg of potassium carbonate (0.04 wt%) dissolved in 10 g of deionized water are added and blended again at 2350 rpm using a speed mixer for 20 seconds. For extrusion, the mixture is filled into an empty cartridge, and strands with a diameter of approximately 3.8 mm are extruded using an electric cartridge extruder. These strands are then cut to a length of approximately 8 mm. WA12414S / Wi

[0223] The extruded bodies are dried in a climate-controlled chamber using a drying program. The temperature is maintained at 60 °C and the relative humidity is reduced from 60% to 10% over a total of 38 hours. The green bodies are then sintered. This process involves heating them at a rate of 180 °C / h to 930 °C, which is then held for 6 hours. The resulting carrier bodies have a breaking load of 32 N per edge and a pore volume of 1.35 ml / g (90% of the initial pore volume, 10% reduction).

[0224] Example 4:

[0225] Production of the molded body with the addition of 0.1 wt% K2CO3

[0226] 280 g of slip A, which has gelled after a certain time, are stirred and liquefied twice at 2350 rpm for 20 seconds each time using a speed mixer. 2.3 g of magnesium hydroxycarbonate paste (25% in water) are added to the liquid dispersion. This mixture is blended at 2350 rpm for 20 seconds using a speed mixer, causing the mass to solidify. Subsequently, 81.1 mg of potassium carbonate (0.1 wt%) dissolved in 10 g of deionized water are added and blended again at 2350 rpm using a speed mixer. For extrusion, the mixture is filled into an empty cartridge, and strands with a diameter of approximately 3.8 mm are extruded using an electric cartridge extruder. These strands are then cut to a length of approximately 8 mm.

[0227] The extruded bodies are dried in a climate-controlled chamber using a drying program. The temperature is maintained at 60 °C and the relative humidity is reduced from 60% to 10% over a total of 38 hours. The green bodies are then sintered. This process involves heating them at a rate of 180 °C / h to 930 °C. WA12414S / Wi

[0228] The material was heated to 34°C and held for 6 hours. This yields a carrier body with a breaking load at the edge of 39 N and a pore volume of 1.28 ml / g (85% of the initial pore volume, 15% reduction).

[0229] Example 5:

[0230] Production of the molded body with the addition of 0.2 wt% K2CO3

[0231] 280 g of slip A, which has gelled after a certain time, are stirred and liquefied twice at 2350 rpm for 20 seconds each time using a speed mixer. 2.3 g of magnesium hydroxycarbonate paste (25% in water) are added to the liquid dispersion. This mixture is blended at 2350 rpm for 20 seconds, causing the mass to solidify. Subsequently, 143 mg of potassium carbonate (0.2 wt%) dissolved in 16 g of deionized water are added and blended again at 2350 rpm for 20 seconds using the speed mixer. For extrusion, the mixture is filled into an empty cartridge, and strands with a diameter of approximately 3.8 mm are extruded using an electric cartridge extruder. These strands are then cut to a length of approximately 8 mm.

[0232] The extruded bodies are dried in a climate-controlled chamber using a drying program. The temperature is maintained at 60 °C and the relative humidity is reduced from 60% to 10% over a total of 38 hours. The green bodies are then sintered. They are heated at a rate of 180 °C / h to 930 °C and held at this temperature for 6 hours. This process yields carrier bodies with a breaking load of 51 N (based on the edge) and a pore volume of 1.21 ml / g (81% of the initial pore volume, 19% reduction). WA12414S / Wi

[0233] 35

[0234] Example 6:

[0235] Production of the molded body with the addition of 0.4 wt% K2CO3

[0236] 280 g of slip A, which has gelled after a certain time, are stirred and liquefied twice at 2350 rpm for 20 seconds each time using a speed mixer. 2.3 g of magnesium hydroxycarbonate paste (25% in water) are added to the liquid dispersion. This mixture is blended at 2350 rpm for 20 seconds, causing the mass to solidify. Subsequently, 282 mg of potassium carbonate (0.4 wt%) dissolved in 15 g of deionized water are added and blended again at 2350 rpm for 20 seconds using the speed mixer.

[0237] For extrusion, the mass is filled into an empty cartridge and strands with a diameter of about 3.8 mm are extruded using an electric cartridge press, which are then cut to a length of about 8 mm.

[0238] The extruded bodies are dried in a climate-controlled chamber using a drying program. The temperature is maintained at 60 °C and the relative humidity is reduced from 60% to 10% over a total of 38 hours. The green bodies are then sintered. This process involves heating them at a rate of 180 °C / h to 930 °C, which is then held for 6 hours. The resulting carrier bodies have a breaking load of 120 N per edge and a pore volume of 0.60 ml / g (40% of the

[0239] (initial pore volume, 60% reduction) .

[0240] Example 7 (not according to the invention):

[0241] Production of the molded body with the addition of 0.7 wt% K2CO3

[0242] 280 g of the slip A, which is present after a certain time, are mixed twice at 2350 rpm on the speed mixer for 20 WA12414S / Wi

[0243] 36

[0244] The mixture is stirred for a few seconds and liquefied. 2.3 g of magnesium hydroxycarbonate paste (25% in water) is added to the liquid dispersion. This mixture is blended in a speed mixer at 2350 rpm for 20 seconds, causing the mass to solidify. Then, 493 mg of potassium carbonate (0.34 wt%) dissolved in 19 g of deionized water is added and blended again in the speed mixer at 2350 rpm for 20 seconds. For extrusion, the mixture is filled into an empty cartridge, and strands with a diameter of approximately 3.8 mm are extruded using an electric cartridge gun. These strands are then cut to a length of approximately 8 mm.

[0245] The extruded bodies are dried in a climate-controlled chamber using a drying program. The temperature is maintained at 60 °C and the relative humidity is reduced from 60% to 10% over a total of 38 hours. The green bodies are then sintered. This process involves heating them at a rate of 180 °C / h to 930 °C, which is then held for 6 hours. The resulting carrier bodies have a breaking load of 440 N (based on the edge) and a pore volume of 0.29 ml / g (19% of the initial pore volume, an 81% reduction).

[0246] A reduction in pore volume of more than 80% is no longer acceptable for the use of the solid as a sorbent.

[0247] Metal oxide shaped bodies of variant B

[0248] The metal oxide molded body was made from hydrophilic pyrogenic silica HDK® T30 (BET surface area: 270-330 m²). 2 / g, tapped density: 40 g / ml; available from WACKER Chemie AG) manufactured as follows: WA12414S / Wi

[0249] 37

[0250] Example 8:

[0251] General procedure for the preparation of slurry B (silica dispersion)

[0252] Three kilograms of demineralized water are added and adjusted to a pH of 3 by adding 6 g of hydrogen peroxide (H3PO4). A total of one kilogram of pyrogenic silica (WACKER HDK® T30) is stirred into a mixer equipped with a dissolver disc and butterfly attachment. This is done in six portions of approximately 180 g of silica each. For portion 1, the stirrer speeds start at 200 rpm (dissolver) and 960 rpm (butterfly). Portion 2: 260 rpm (dissolver) and 800 rpm (butterfly). Portion 3: 400 rpm.

[0253] (Dissolver) and 600 rpm (Butterfly). Portion 4: 400 rpm

[0254] (Dissolver) and 750 rpm (Butterfly). Portion 5: 300 rpm

[0255] Portion 1: (Dissolver) and 900 rpm (Butterfly) or 400 rpm (Dissolver) and 900 rpm (Butterfly). Portion 6: 500 rpm (Dissolver) and 950 rpm (Butterfly) or 1060 rpm (Dissolver) and 1500 rpm (Butterfly) or 1070 rpm (Dissolver) and 1550 rpm (Butterfly). Portions 1-4 were each stirred for 5 minutes, portion 5 was stirred twice for 5 minutes, and portion 6 was first stirred for 10 minutes, then 5 minutes, and then another 10 minutes. This dispersion (slurry B) has a solids content of approximately 26%.

[0256] Example 9 (not according to the invention):

[0257] Production of the molded body without the addition of under

[0258] Sintering temperature of melting salt

[0259] 280 g of slip B, which has gelled after a certain time, are stirred and liquefied twice at 2350 rpm for 20 seconds each time using a speed mixer. 2.3 g of magnesium hydroxycarbonate paste (25% in water) are added to the liquid dispersion. This mixture is blended at 2350 rpm for 20 seconds using a speed mixer, causing the mass to solidify. WA12414S / Wi

[0260] 38

[0261] Next, 33 g of deionized water are added and mixed again for 20 seconds at 2350 rpm using a speed mixer. For extrusion, the mixture is filled into an empty cartridge, and strands with a diameter of approximately 3.8 mm are extruded using an electric cartridge gun. These strands are then cut to a length of approximately 8 mm.

[0262] The extruded bodies are dried in a climate-controlled chamber using a drying program. The temperature is maintained at 60 °C and the relative humidity is reduced from 60% to 10% over a total of 38 hours. The green bodies are then sintered. This process involves heating them at a rate of 180 °C / h to 930 °C, which is then held for 6 hours. The resulting carrier bodies have a breaking load of 69 N at the edge and a pore volume of 1.16 ml / g.

[0263] Example 10:

[0264] Production of the molded body with the addition of 0.05 wt% K2CO3

[0265] 327 g of slip B, which gels after a certain time, are stirred and liquefied twice at 2350 rpm for 20 seconds each time using a speed mixer. 2.7 g of magnesium hydroxycarbonate paste (25% in water) is added to the liquid dispersion. This mixture is blended at 2350 rpm for 20 seconds using a speed mixer, causing the mass to solidify. Subsequently, 41.4 mg of potassium carbonate (0.05 wt%) dissolved in 21 g of deionized water is added and blended again at 2350 rpm using a speed mixer for 20 seconds. For extrusion, the mixture is filled into an empty cartridge, and strands with a diameter of approximately 3.8 mm are extruded using an electric cartridge extruder. These strands are then cut to a length of approximately 8 mm. WA12414S / Wi

[0266] 39

[0267] The extruded bodies are dried in a climate-controlled chamber using a drying program. The temperature is maintained at 60 °C and the relative humidity is reduced from 60% to 10% over a total of 38 hours. The green bodies are then sintered. This process involves heating them at a rate of 180 °C / h to 930 °C, which is then held for 6 hours. The resulting carrier bodies have a breaking load of 132 N at the edge and a pore volume of 0.97 ml / g (84% of the initial pore volume, a 16% reduction).

[0268] Example 11:

[0269] Production of the molded body with the addition of 0.1 wt% K2CO3

[0270] 280 g of slip B, which has gelled after a certain time, are stirred and liquefied twice at 2350 rpm for 20 seconds each time using a speed mixer. 2.3 g of magnesium hydroxycarbonate paste (25% in water) are added to the liquid dispersion. This mixture is blended at 2350 rpm for 20 seconds using a speed mixer, causing the mass to solidify. Subsequently, 90 mg of potassium carbonate (0.1 wt%) dissolved in 27 g of deionized water are added and blended again at 2350 rpm using a speed mixer for 20 seconds. For extrusion, the mixture is filled into an empty cartridge, and strands with a diameter of approximately 3.8 mm are extruded using an electric cartridge extruder. These strands are then cut to a length of approximately 8 mm.

[0271] The extruded bodies are dried in a climate-controlled chamber using a drying program. The temperature is maintained at 60 °C and the relative humidity is reduced from 60% to 10% over a total of 38 hours. The green bodies are then sintered. This process involves heating at a rate of 180 °C / h to 930 °C, which is held for 6 hours. The resulting product is WA12414S / Wi.

[0272] Carrier body with a breaking load perpendicular to the edge of 141 N and a pore volume of 0.82 ml / g (71% of the initial pore volume, 29% reduction).

[0273] Example 12:

[0274] Production of the molded body with the addition of 0.2 wt% K2CO3

[0275] 280 g of slip B, which has gelled after a certain time, are stirred and liquefied twice at 2350 rpm for 20 seconds each time using a speed mixer. 2.3 g of magnesium hydroxycarbonate paste (25% in water) are added to the liquid dispersion. This mixture is blended at 2350 rpm for 20 seconds using a speed mixer, causing the mass to solidify. Subsequently, 140 mg of potassium carbonate (0.2 wt%) dissolved in 27 g of deionized water are added and blended again at 2350 rpm using a speed mixer for 20 seconds. For extrusion, the mixture is filled into an empty cartridge, and strands with a diameter of approximately 3.8 mm are extruded using an electric cartridge extruder. These strands are then cut to a length of approximately 8 mm.

[0276] The extruded bodies are dried in a climate-controlled chamber using a drying program. The temperature is maintained at 60 °C and the relative humidity is reduced from 60% to 10% over a total of 38 hours. The green bodies are then sintered. They are heated at a rate of 180 °C / h to 930 °C and held at that temperature for 6 hours. This process yields carrier bodies with a breaking load of 207 N (based on the edge) and a pore volume of 0.59 ml / g (51% of the initial pore volume, 49% reduction). WA12414S / Wi

[0277] 41

[0278] Example 13:

[0279] Production of the molded body with the addition of 0.4 wt% K2CO3

[0280] 280 g of slip B, which has gelled after a certain time, are stirred and liquefied twice at 2350 rpm for 20 seconds each time using a speed mixer. 2.3 g of magnesium hydroxycarbonate paste (25% in water) are added to the liquid dispersion. This mixture is blended at 2350 rpm for 20 seconds, causing the mass to solidify. Then, 290 mg of potassium carbonate (0.4 wt%) dissolved in 27 g of deionized water are added and blended in again at 2350 rpm for 20 seconds.

[0281] For extrusion, the mass is filled into an empty cartridge and strands with a diameter of about 3.8 mm are extruded using an electric cartridge press, which are then cut to a length of about 8 mm.

[0282] The extruded bodies are dried in a climate-controlled chamber using a drying program. The temperature is maintained at 60 °C and the relative humidity is reduced from 60% to 10% over a total of 38 hours. The green bodies are then sintered. This process involves heating them at a rate of 180 °C / h to 930 °C, which is held for 6 hours. The resulting carrier bodies have a breaking load of 572 N per edge and a pore volume of 0.23 ml / g (20% of the

[0283] (Baseline pore volume, 80% reduction) . WA12414S / Wi

[0284] 42

[0285] Example 14 (not according to the invention):

[0286] Production of the molded body with the addition of 0.7 wt% K2CO3

[0287] 280 g of slip B, which has gelled after a certain time, are stirred and liquefied twice at 2350 rpm for 20 seconds each time using a speed mixer. 2.3 g of magnesium hydroxycarbonate paste (25% in water) are added to the liquid dispersion. This mixture is blended at 2350 rpm for 20 seconds using a speed mixer, causing the mass to solidify. Then, 500 mg of potassium carbonate (0.34 wt%) dissolved in 27 g of deionized water are added and blended again at 2350 rpm using a speed mixer for 20 seconds. For extrusion, the mixture is filled into an empty cartridge, and strands with a diameter of approximately 3.8 mm are extruded using an electric cartridge extruder. These strands are then cut to a length of approximately 8 mm.

[0288] The extruded bodies are dried in a climate-controlled chamber using a drying program. The temperature is maintained at 60 °C and the relative humidity is reduced from 60% to 10% over a total of 38 hours. The green bodies are then sintered. This process involves heating them at a rate of 180 °C / h to 930 °C, which is then held for 6 hours. The resulting carrier bodies have a breaking load of 1091 N (based on the edge) and a pore volume of 0.04 ml / g (3% of the initial pore volume, 97% reduction).

[0289] Example 15:

[0290] Production of the molded body with the addition of 0.04 wt% NaCl

[0291] 280 g of slip B, which has solidified after a certain time, are stirred and liquefied twice at 2350 rpm for 20 seconds each time using a speed mixer. This results in the liquid dispersion WA12414S / Wi

[0292] 43. 2.3 g of magnesium hydroxycarbonate paste (25% in water) are added. This mixture is blended in a speed mixer at 2350 rpm for 20 seconds, causing the mass to solidify. Then, 28 mg of sodium chloride (0.04 wt%) dissolved in 27 g of deionized water are added and blended again in the speed mixer at 2350 rpm for 20 seconds. For extrusion, the mixture is filled into an empty cartridge, and strands with a diameter of approximately 3.8 mm are extruded using an electric cartridge gun. These strands are then cut to a length of approximately 8 mm.

[0293] The extruded bodies are dried in a climate-controlled chamber using a drying program. The temperature is maintained at 60 °C and the relative humidity is reduced from 60% to 10% over a total of 38 hours. The green bodies are then sintered. This process involves heating them at a rate of 180 °C / h to 930 °C, which is then held for 6 hours. The resulting carrier bodies have a breaking load of 108 N per edge and a pore volume of 1.00 ml / g (86% of the initial pore volume, a 14% reduction).

[0294] The following table summarizes the development of the fracture load and the pore volume with increasing proportion of the at least one salt (S) according to the examples above (non-inventive examples marked with (*)).

[0295] WA12414S / Wi

[0296] 44

[0297] WA12414S / Wi

[0298] 45

[0299] Example 16:

[0300] General procedure for functionalizing the silica carrier

[0301] The functionalization of the support is achieved by spraying the functionalizing agent using a commercially available rotary evaporator. The silica mold is located in the rotating evaporator flask and is dried for 6 hours at an oil bath temperature of 140 °C and a pressure of 25 mbar before the functionalizing agent is added. For functionalization, a Teflon tube is connected to the vent valve of the rotary evaporator. The functionalizing agent is drawn in from the outside through this tube by applying a vacuum and then conveyed via another Teflon tube located inside the rotary evaporator, extending into the evaporator flask.

[0302] Immediately after spraying the functionalizing agent, the sprayed silica molded body is post-treated by rotation in the evaporator flask for one hour under normal pressure at room temperature and subsequently dried at an oil bath temperature of 80 °C and 25 mbar.

[0303] Example 17:

[0304] Determination of the adsorption capacity of the carrier according to Example 10, functionalized with potassium carbonate

[0305] 10 g of the silica molded body with a pore volume of 0.97 mL / g from Example 2 are functionalized according to Example 6 by introducing 12.7 g of 30 wt% potassium carbonate into water. After functionalization, 16.3 g of the functionalized molded body are obtained. The adsorption capacity, determined by chemisorption, is 1.5 mmol CO₂ per gram of molded body. WA12414S / Wi

[0306] 46

[0307] Example 18:

[0308] Determination of the adsorption capacity of the support according to Example 10, functionalized with pentethylenehexamine, 10.0 g of silica molded bodies with a pore volume of 0.97 mL / g.

[0309] Example 2 is impregnated according to Example 6 by introducing 9.7 mL of pentethylenehexamine (available from Merck KGaA, Darmstadt, Germany). The adsorption capacity, determined by chemisorption, is 2.0 mmol CO2 per gram of molded body.

[0310] WA12414S / Wi

[0311] The present invention is further characterized by the following points:

[0312] 1. Comprehensive CO2 sorbent

[0313] (i) a shaped body sintered at a sintering temperature Ts (i) made of at least one metal oxide and at least one salt (S) which has a melting point TM which is lower than T s is, wherein the amount of the at least one salt (S) is less than 0.7 wt.% in relation to the total mass of the sorbent; and

[0314] (ii) at least one sorbent (ii) for CO2 with which the molded body (i) is functionalized.

[0315] 2. Sorbens according to point 1, wherein TM is in the range of 600 to 900 °C, in particular in the range of 800 to 900 °C.

[0316] 3. Sorbens according to any of the preceding points, wherein the at least one salt (S) is selected from salts, preferably chlorides or carbonates, of the alkali and alkaline earth metals, preferably of the alkali metals.

[0317] 4. Sorbens according to any of the preceding points, wherein the at least one salt (S) is selected from the group consisting of LiCl, NaCl, KCl, Na2COs and K2CO3, preferably consisting of NaCl, NaCOs and K2CO3, in particular consisting of NaCl and K2CO3.

[0318] 5. Sorbs according to one of the preceding points, wherein the

[0319] The amount of the at least one salt (S) based on the total mass of the sorbent is a maximum of 0.6 wt.%, more preferably a maximum of 0.5 wt.%, more preferably a maximum of 0.4 wt.%, more preferably 0.04-0.4 wt.%, in particular 0.05-0.2 wt.%.

[0320] 6. Sorbens according to any of the preceding points, wherein the at least one metal oxide is selected from aluminium oxide, silicon dioxide, titanium dioxide or zirconium dioxide, preferably from silicon dioxide, in particular from amorphous silicon dioxide.

[0321] 7. Sorbens according to any of the preceding points, wherein the metal oxide of the molded body has a mesoporous structure, in particular a mesoporous structure with an irregular pore structure.

[0322] 8. Sorbens according to any of the preceding points, wherein the shaped body is built up from agglomerates of amorphous silicon dioxide.

[0323] 9. Sorbens according to any of the preceding points, wherein the at least one metal oxide is selected from pyrogenic or precipitated silicon dioxide, in particular from pyrogenic silicon dioxide.

[0324] 10. Sorbens according to any of the preceding points, wherein the molded body has dimensions in at least one dimension in the range of 0.5 mm to 30 mm, preferably 1.0 mm to 15 mm .

[0325] 11. Sorbens according to one of the preceding points, wherein Ts is in a range of 800-1200 °C, particularly in a range of 900-1100 °C. WA12414S / Wi

[0326] 49

[0327] 12. Sorbens according to one of the preceding points, which has a compressive strength of at least 2 N / mm² 2 , preferably at least 8 N / mm 2, and / or wherein the sorbent in the form of cylindrical shaped bodies has a breaking load of at least 30 N, preferably at least 50 N, more preferably at least 80 N, particularly preferably at least 100 N.

[0328] 13. Sorbens according to one of the preceding points, wherein the BET surface of the sorbs is in the range of 30 to 500 m 2 / g lies, especially in the range of 50 to 400 m 2 / G.

[0329] 14. Sorbent according to any of the preceding points, wherein the at least one sorbent (ii) is able to undergo a reversible reaction with CO2, in particular a reversible sorption reaction.

[0330] 15. Sorbens according to any of the preceding points, wherein the at least one sorbent (ii) is an inorganic or an organic sorbent.

[0331] 16. Sorben according to any of the preceding points, wherein the shaped body (i) is functionalized with a mixture of an inorganic and an organic sorbent, in particular with a mixture of a carbonate and an organic amine.

[0332] 17. Sorbs according to point 16, whereby the inorganic

[0333] (ii) sorbent is a carbonate, in particular selected from the group consisting of metal carbonate, metal hydrogen carbonate and mixtures thereof.

[0334] 18. Sorbent according to point 16, wherein the organic sorbent is an organic monoamine or polyamine, wherein WA12414S / Wi

[0335] 50

[0336] Polyamine comprising at least two N atoms per molecule, which are separated by at least one C atom, in particular selected from the group consisting of ethyleneamine, aminosilane, polyethyleneimine (PEI), polypropyleneamine, polyvinylpyridine, polydime thylaminoethyl methacrylate, polyamidoamine, polyvinylamine and polyallylamine.

[0337] 19. Sorbens according to point 18, wherein the ethyleneamine is selected from the group consisting of ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetraamine (TETA), tetraethylenepentamine (TEPA), aminoethylethanolamine (AEEA), aminoethylpiperazine (AEP), piperazine (PIP),

[0338] Hydroxyethylpiperazine (HEP) , Pentaethylenehexamine (PEHA) and Polyethylenepolyamine (PEPA) .

[0339] 20. Sorbens according to point 18, wherein the aminosilane is selected from the group consisting of aminopropylsilane, [3- (2- Aminoethylamino ) -propyl] -trimalkoxysilane, 3- [2- (2-

[0340] Aminoethylamino ) -ethylamino] -propyltrialkoxysilane, mixtures thereof and condensation products of 3-Aminopropyltrialkoxysilane .

[0341] 21. Sorbens according to any of points 18-20, wherein the polyamine is silylated, for example obtainable by reacting one or more amino groups of the polyamine with suitably functionalized alkoxysilanes, for example selected from the group consisting of 3-chloropropyl-trialkoxysilane, 3-chloropropyl-trialkoxysilane, glycidoxypropyl-trialkoxysilane and isocyanatopropyl-trialkoxysilane.

[0342] 22. Sorbens according to point 21, wherein the silylated polyamine is obtainable by silylation carried out either in isolation or in situ. WA12414S / Wi

[0343] 51

[0344] 23. Sorbs according to one of the preceding points, furthermore comprehensively

[0345] (iii) at least one auxiliary substance (iii) selected from the group consisting of polymeric binders, silicon-containing binders such as silicates and silica sol, spreading agents and wetting agents.

[0346] 25. Sorbs according to one of points 18-23, where the polyamine in

[0347] A combination with at least one amino-functional alkoxysilane is present.

[0348] 26. Sorbens according to point 25, wherein the at least one amino-functional alkoxysilane is selected from the group consisting of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane and 3-

[0349] Aminopropyltriisoproxysilane .

[0350] 27. Sorben according to point 25 or 26, wherein the amount of polyamine is at least 50% by weight based on the total amount of polyamine and amino-functional alkoxysilane.

[0351] 28. Sorbs according to one of the preceding points, wherein the

[0352] Quantity of at least one sorbent (ii) 10 to 90

[0353] wt.%, preferably 25 to 80 wt.%, based on the total weight of the sorbent.

[0354] 29. Sorben according to any of the preceding items, which has a spalling content of less than 5 wt.%, preferably less than 1 wt.%, and most preferably less than 0.5 wt.%, based on the total weight of the sorbent. WA12414S / Wi

[0355] 52

[0356] 30. Method for producing a sorbent for CO2 according to any of points 1-29, comprising the following steps in the specified order:

[0357] (A) Providing a shaped body (i) sintered at a sintering temperature Ts from at least one metal oxide (M) and at least one salt (S) having a melting point TM lower than Ts, wherein the amount of the at least one salt (S) is less than 0.7 wt.% in relation to the total mass of the sorbent;

[0358] (B) Impregnating the provided molded body with at least one sorbent (ii) for CO2 in order to functionalize the molded body.

[0359] 31. Procedure according to point 30, wherein the provision of the molded body (i) in step (A) is carried out by the following steps in the specified order:

[0360] (Al) Providing a metal oxide dispersion by dispersing at least one metal oxide (M) in a dispersing agent;

[0361] (A2) Coagulation of the dispersion by raising the pH value;

[0362] (A3) Mixing the at least one salt (S) into the coagulated dispersion;

[0363] (A4) Shaping the coagulated dispersion to produce a green body; and

[0364] (A5) Drying and subsequent sintering of the

[0365] green body at a sintering temperature T s , to produce the sintered molded body. WA12414S / Wi

[0366] 32. Method according to point 31, wherein the proportion of the at least one metal oxide in the metal oxide dispersion of step (Al) is 10-50 wt.%, based on the total mass of the

[0367] Metal oxide dispersion.

[0368] 33. Method according to one of points 31-32, wherein the provision of the metal oxide dispersion in step (Al) is carried out by stirring in the at least one metal oxide using a dissolver disc and a butterfly insert at the same time.

[0369] 34. Method according to point 33, wherein the provision of the metal oxide dispersion in step (Al) is carried out by stirring the total amount of the at least one metal oxide (M) into water in at least two portions, the portion stirred first being stirred at a higher stirring speed of the dissolver disc and a lower stirring speed of the butterfly insert compared to the portion stirred subsequently.

[0370] 35. Method according to any one of points 31-34, wherein the dispersing agent in step (Al) is water or an aqueous solution, preferably an aqueous solution with a pH value in the range of 1.0 to 7.0, preferably from 1.5 to 6.0, particularly preferably from 2.0 to 4.0

[0371] 36. Method according to one of points 31-35, wherein the pH of the dispersant is adjusted in step (Al) by adding acid. WA12414S / Wi

[0372] 54

[0373] 37. Method according to one of points 31-36, wherein the pH value of the

[0374] The dispersant in step (Al) is adjusted by adding phosphoric acid.

[0375] 38. Method according to any of points 31-37, wherein the at least one metal oxide in step (Al) is selected from a pyrogenic silicon dioxide or a precipitated silicon dioxide, in particular from a pyrogenic silicon dioxide.

[0376] 39. Method according to one of points 31-38, wherein the pH is increased by 0.5-5.5 units in step (A2), wherein the target pH after the increase in step (A2) is preferably in the range of 4.0 to 8.0, particularly preferably in the range of 5.0 to 7.0.

[0377] 40. Method according to one of points 31-39, wherein the increase of the pH value in step (A2) is carried out by adding a basic coagulant to the metal oxide dispersion, preferably by adding magnesium hydroxycarbonate.

[0378] 41. Method according to one of points 31-40, wherein the shaping in step (A4) is carried out by extrusion.

[0379] 42. Method according to one of points 31-41, wherein the drying in step (A5) takes place at a temperature in the range of 25°C and 200°C, preferably between 30°C and 100°C, most preferably between 40°C and 80°C.

[0380] 43. Method according to one of points 31-42, wherein the sintering in step (A5) takes place at a temperature T s in the range of 800-1200 °C, preferably 900-1100 °C. WA12414S / Wi

[0381] 44. Method according to one of points 31-43, wherein the sintering in

[0382] Step (A5) is carried out at a heating rate of 100-250 °C / h, preferably 150-200 °C / h.

[0383] 45. Method according to one of points 31-44, wherein the sintering in

[0384] Step (A5) is carried out for a period of 1-10 hours, preferably 4-8 hours.

[0385] 46. ​​Method according to one of points 30-45, wherein the at least one sorbent is an inorganic or an organic sorbent.

[0386] 47. Method according to point 46, wherein the inorganic sorbent is a carbonate, in particular selected from the group consisting of metal carbonate, metal hydrogen carbonate and mixtures thereof.

[0387] 48. Method according to point 46, wherein the organic sorbent is an organic monoamine or polyamine, wherein the polyamine comprises at least two N atoms per molecule separated by at least one C atom, in particular selected from the group consisting of ethyleneamine, aminosilane, polyethyleneimine (PEI) ,

[0388] polypropyleneamine, polyvinylpyridine,

[0389] Polydimethylaminoethyl methacrylate, polyamidoamine, polyvinylamine and polyallylamine.

[0390] 49. Method according to point 48, wherein the ethyleneamine is selected from the group consisting of ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), aminoethylethanolamine (AEEA), aminoethylpiperazine (AEP), piperazine (PIP), WA12414S / Wi

[0391] 56

[0392] Hydroxyethylpiperazine (HEP) , Pentaethylenehexamine (PEHA) and Polyethylenepolyamine (PEPA) .

[0393] 50. Method according to point 48, wherein the aminosilane is selected from the group consisting of aminopropylsilane, [3- (2- aminoethylamino ) -propyl] -trimalkoxysilane, 3- [2- (2-

[0394] Aminoethylamino ) -ethylamino] -propyltrialkoxysilane, mixtures thereof and condensation products of 3-Aminopropyltrialkoxysilane .

[0395] 51. Method according to any of points 48-50, wherein the polyamine is silylated, for example obtained by reacting one or more amino groups of the polyamine with suitably functionalized alkoxysilanes, for example selected from the group consisting of 3-chloropropyl-trialkoxysilane, 3-chloropropyl-trialkoxysilane, glycidoxypropyl-trialkoxysilane and isocyanatopropyl-trialkoxysilane.

[0396] 52. Method according to point 51, wherein the polyamine is obtainable by silylation, which can be carried out in isolation or in situ.

[0397] 53. Method according to any of points 30-52, wherein the at least one sorbent is in liquid form during the impregnation in step (B), for example as a solution, emulsion or dispersion in a solvent or liquid medium or in pure form.

[0398] 54. Method according to point 53, wherein the at least one sorbent is a solution of a metal carbonate, in particular potassium carbonate and / or sodium carbonate, in

[0399] Water or a solution of a metal bicarbonate, WA12414S / Wi

[0400] 57 in particular potassium bicarbonate and / or

[0401] Sodium bicarbonate in water.

[0402] 55. Method according to point 53 or 54, wherein the at least one sorbent is a saturated aqueous solution of potassium carbonate, sodium carbonate, potassium hydrogen carbonate and / or sodium hydrogen carbonate, preferably of potassium carbonate and / or potassium hydrogen carbonate, more preferably of potassium carbonate.

[0403] 56. Method according to point 54 or 55, wherein the amount of metal carbonate or metal hydrogen carbonate is 15-40 wt.%, preferably 15-33 wt.% of the total weight of the aqueous solution.

[0404] 57. Method according to any of points 30-56, wherein the sorbent is in the form of a solution of an organic sorbent, for example an organic amine, in a suitable solvent, wherein the amount of dissolved organic sorbent is preferably at least 30 vol%, more preferably at least 60 vol%.

[0405] 58. Method according to one of points 30-57, wherein the impregnation in step (B) is carried out by bringing the molded body into contact with the at least one sorbent for CO2.

[0406] 59. Method according to one of points 30-58, wherein the impregnation in step (B) takes place in a temperature range of 0-150 °C, preferably in a temperature range of

[0407] 15-120 °C. WA12414S / Wi

[0408] 58

[0409] 60. Method according to one of points 30-59, wherein the impregnation in step (B) takes place at normal pressure, under increased pressure or under reduced pressure.

[0410] 61. Method according to any of points 30-60, wherein the impregnation is carried out by mixing, spraying or soaking the molded body or the incipient wetness method with the at least one sorbent in liquid form, in particular by means of the incipient wetness method.

[0411] 62. Method according to any one of points 30-61, wherein the molded body has a mesoporous structure and the volume of the at least one sorbent for CO2 is 80 to 120%, preferably 90 to 110%, more preferably 95-105%, based on the total pore volume of the molded body.

[0412] 63. Method according to one of points 30-62, wherein the molded body is pre-impregnated

[0413] - at a suppression of 10 -3 up to 10 2 is treated in mbar; and / or

[0414] - is dried.

[0415] 64. Method according to any of points 30-63, wherein in step (B) the provided molded body is impregnated with at least one sorbent for CO2 to functionalize the molded body, together with at least one impregnation aid selected from wetting agent, emulsifier, dye, binder, adhesion promoter, higher alcohols and higher polyols.

[0416] 65. Use of the sorbent for CO2 according to one of points 1-29 for the reversible binding of CO2 from a gas mixture, WA12414S / Wi

[0417] 59 especially in the form of a fixed-bed sorbent, for example for CCU, CCS and / or DAC .

Claims

WA12414S / Wi 60 Claims 1. Comprehensive CO2 sorbent (i) a shaped body sintered at a sintering temperature Ts (i) made of at least one metal oxide and at least one salt (S) , wherein the salt (S) has a melting point TM which is lower than T s is, wherein the amount of the at least one salt (S) is less than 0.7 wt.% in relation to the total mass of the sorbent; and (ii) at least one sorbent (ii) for CO2 with which the molded body (i) is functionalized.

2. Sorben according to claim 1, wherein the at least one salt (S) is selected from salts of the alkali and alkaline earth metals.

3. Sorbens according to any of the preceding claims, wherein the at least one metal oxide is selected from aluminium oxide, silicon dioxide, titanium dioxide or zirconium dioxide.

4. Sorben according to claim 3, wherein the at least one metal oxide is selected from pyrogenic or precipitated silicon dioxide.

5. Sorbens according to any of the preceding claims, wherein the metal oxide of the molded body has a mesoporous structure.

6. Sorbens according to any of the preceding claims, wherein Ts is in a range of 800-1200 °C, in particular in a range of 900-1100 °C WA12414S / Wi 61 7. Sorben according to any of the preceding claims, wherein the at least one sorbent (ii) is an inorganic or an organic sorbent.

8. Sorbens according to claim 7, wherein the inorganic (ii) sorbent is a carbonate, in particular selected from the group consisting of metal carbonate, metal hydrogen carbonate and mixtures thereof.

9. Sorbent according to claim 7, wherein the organic sorbent is an organic monoamine or polyamine, wherein the polyamine comprises at least two N atoms per molecule separated by at least one C atom, in particular selected from the group consisting of ethyleneamine, aminosilane, polyethyleneimine (PEI) , polypropyleneamine, polyvinylpyridine, Polydimethylaminoethyl methacrylate, polyamidoamine, polyvinylamine and polyallylamine.

10. Sorbens according to any of the preceding claims, further comprising (iii) at least one excipient selected from the Group consisting of polymeric binders, silicon-containing binders such as silicates and silica sol, Spreading agents and wetting agents. WA12414S / Wi 11. A method for producing a sorbent for CO2 according to any one of claims 1-10, comprising the following steps in the specified order: (A) Providing a shaped body (i) sintered at a sintering temperature Ts from at least one metal oxide (M) and at least one salt (S) wherein the salt (S) has a melting point TM which is lower than Ts, wherein the amount of the at least one salt (S) is less than 0.7 wt.% in relation to the total mass of the sorbent; (B) Impregnating the provided molded body with at least one sorbent (ii) for CO2 in order to functionalize the molded body.

12. The method of claim 11, wherein the provision of the molded body (i) in step (A) is carried out by the following steps in the specified order: (Al) Provision of a metal oxide dispersion by dispersing at least one metal oxide (M) in a dispersing agent; (A2) Coagulation of the dispersion by raising the pH value; (A3) Mixing the at least one salt (S) into the coagulated dispersion; (A4) Shaping the coagulated dispersion to produce a green body; and (A5) Drying and subsequent sintering of the green body at a sintering temperature T s , in order to produce the sintered molded body. WA12414S / Wi 63 13. Method according to claim 11 or 12, wherein the pH value of the dispersion obtained after step (Al) is in the range of 1.0 to 7.0 and the pH value is raised in step (A2) to a value in the range of 4.0 to 8.

0.

14. Method according to one of claims 11-13, wherein the sintering takes place at a sintering temperature T s in the range of 800°C to 1200°C, especially in the range of 850°C to 1150°C .

15. Use of the sorbent for CO2 according to any one of claims 1-10 for the reversible binding of CO2 from a gas mixture.

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