Amine-functionalized cellulose material, method for producing same, and use thereof as co2 adsorber

Abstract

The invention relates to an amine-functionalized cellulose material that has a cellulose carrier which is based on cellulose fibers and is provided in the form of a flat textile structure and on which a coating is formed made of a cross-linked polyalkylene amine. The amine-functionalized cellulose material is characterized by high CO2- and water-adsorption capacity values. The amine-functionalized cellulose material is produced in particular according to a method in which the cellulose carrier is mixed into an alcohol solution of a compound which cross-links the polyalkylene amine and forms an alcohol polyalkylene amine solution together with the alcohol solution. In order to start a cross-linking reaction, water is added to the mixture. The amine-functionalized cellulose material thus obtained is particularly suitable for directly adsorbing CO2 from air. A desorption of the CO2 can then be carried out in order to supply the CO2 to a useful application, in particular in order to produce chemicals and promote the growth of plants in greenhouses.

Description

[0001] Amine-functionalized cellulose material, process for its preparation and use as a CO2 adsorber

[0002] The invention relates to an amine-functionalized cellulose material containing a cellulose carrier coated with a cross-linked polyalkylene amine, a process for its preparation and its use for the direct adsorption of CO2 from air (direct air capture).

[0003] According to the current state of the art, cellulose materials in the form of powder, staple fibers, and textiles are already being functionalized with amine-containing compounds, using both monomers and polymers. The process according to EP 3 878 550 A1 is based on the oxidation of cellulose, resulting in an oxidized cellulose polymer. The cellulose can be in powder or textile form. Laccase and 2,2,6,6-tetramethylpiperidine-l(oxyl) (TEMPO) or NaClO are particularly used as oxidizing agents. The oxidized cellulose material is then functionalized with polyalkyleneamines, such as polyethyleneimine (correctly polyethyleneamine), tetraethylenepentamine, diethylenetriamine, and pentaethylenehexamine. The amine-functionalized cellulose polymer can optionally be brought into contact with a dialdehyde. When the oxidized cellulose polymer is reacted with polyalkylene amine, a coupling agent is present.For use as DAC (cf / - rect air capture) materials, they are used in the form of textiles or as bulk material (powder). Amine functionalization of the oxidized cellulose materials is only possible in batch operation, which is time-consuming.

[0004] In powder form, the known amine-functionalized cellulose material has a high bulk density, which is characterized by poor air permeability, thus increasing energy consumption during adsorption and desorption. The known process also involves various steps of combining the amine-functionalized polymer, for example with a binder. This produces a surface finishing solution. A textile is treated with this solution. If necessary, the surface of the treated textile is crosslinked. The known powdered and textile CO2 adsorbers have only a low adsorption capacity of up to 0.46 mmol / g of material. The amount of CO2 recovered is too small for use of this adsorber in large-scale DAC processes or for downstream processing of the desorbed CO2 into fuels or for final storage.

[0005] Based on the above-mentioned prior art, the object of the invention is to propose an amine-functionalized cellulose material that contains cellulose as a carrier, but exhibits a significantly improved CO2 adsorption capacity and also an improvement in the desorption of the CO2 in order to make it suitable for useful uses. Furthermore, a good water adsorption capacity is to be achieved. In particular, an advantageous process for producing an improved amine-functionalized cellulose material is to be proposed, which can be carried out economically and technically advantageously and, in particular, does not require the surface of the cellulose materials used as carriers to be subjected to complex chemical pretreatment, for example with an oxidizing agent.

[0006] This task is solved by an amine-functionalized cellulose material containing cellulose as a carrier coated with a cross-linked polyalkylene amine, which is characterized in that the cellulose carrier is based on cellulose fibers that are in the form of textile fabrics.

[0007] According to the invention, it is preferred if the cellulose fiber of the textile fabric is in the form of a microfiber, in particular a continuous fiber. Thus, the fiber is preferably a round fiber whose diameter is in particular between about 4 and about 20 μm and particularly preferably between about 6 and 12 μm, or a trilobal fiber whose dtex value is in particular between about 2 and 5 dtex and particularly preferably between about 2.5 and 3.5 dtex.

[0008] The fiber is present in the textile fabrics according to the invention in particular as a nonwoven, wherein the basis weight of the nonwoven is in particular between about 150 and 600 g / m 2and more preferably between about 250 and 440 g / m 2 and / or the thickness of the nonwoven fabric is in particular between approximately 0.5 and 15 mm, particularly preferably between approximately 0.7 and 13 mm. With regard to the origin of the cellulose fibers used according to the invention as a carrier material, the invention is not subject to any significant restrictions. These can be natural cellulose fibers, such as hemp fibers, jute fibers, linen fibers, cotton, but also regenerated cellulose fibers, such as lyocell and viscose fibers. The fibers are preferably present in the textile fabrics in the form of wovens, knitted fabrics, scrims, crocheted fabrics and nonwoven material, in particular as a nonwoven fabric. Viscose fiber is preferred. In principle, natural fibers such as cotton can be considered.

[0009] The degree of polymerization of the cellulose material is not particularly important. As a general rule, the molecular weight could preferably be approximately 200 to 3500, particularly approximately 250 to 3000.

[0010] Within the scope of the invention, the cellulose fiber as a carrier is treated with a combination of a polyalkyleneamine and a suitable crosslinker according to the process described below. The polyalkyleneamine is preferably linear, branched, cyclic, or dendritic. The polyalkyleneamine used is preferably a polyethyleneimine (PEI), polypropyleneamine, polybutyleneamine, polypentyleneamine, tetraethylenepentamine (TEPA), diethylenetriamine (DETA), and / or pentaethylenehexamine (PEHA).

[0011] It should be noted that the cellulose fibers referred to above should not be treated in any relevant way, but rather left in their pure form if possible, so as not to jeopardize the technical success sought by the invention. In particular, no chemical modification of the cellobiose unit (glucose dimer) within the cellulose structure should be carried out. This would also entail considerable additional technical effort and result in the coating of the cellulose carrier required by the invention not producing the desired effects. This applies to the prior art according to EP 3 878 850 A, which proposes a disadvantageous modification whereby the cellulose (cellobiose unit) is first subjected to oxidation, resulting in an oxidized cellulose polymer, which is converted into an amine-functionalized cellulose polymer via a special reaction.This procedure only achieves adsorption capacities of up to 0.46 mmol. CO2 / G Adsorbens Attention should be paid to the molecular weight of the polyalkyleneamine used according to the invention: It has been found that the polyalkyleneamine preferably has a molecular weight of 600 to 100,000, in particular of about 1,000 to 50,000, and most preferably of about 1,500 to 30,000.

[0012] In a particular embodiment of the invention, it is expedient to use certain advantageous crosslinkers for the polyalkyleneamines in order to utilize them in the crosslinking according to the invention, which will be described in more detail later. These are preferably a dialdehyde, a diketone, a dicarboxylic acid, a dicarboxylic acid salt, and / or a dicarboxylic acid halide, in particular dicarboxylic acid chloride. It is particularly preferred that the crosslinked polyalkyleneamine, in particular polyethyleneamine, is based on a crosslinking of polyalkyleneamine with a dialdehyde of the formula CHO(CH2) n CH2CHO, where n is preferably an integer between 2 and 9, in particular between 2 and 6, in particular in the form of oxaldialdehyde, glutardialdehyde, adipine dialdehyde, succinic dialdehyde, malondialdehyde and / or 1,9-nonanedialdehyde. Glutardialdehyde is particularly preferred.

[0013] In a further advantageous embodiment of the invention, the coating of the cellulose carrier with crosslinked polyalkyleneamine has a thickness of about 1.0 to 10 pm, in particular about 1.0 to 10.5 pm.

[0014] The particular advantages that can be achieved with the present invention are reflected in the surprisingly increased CO2 adsorption capacity of preferably about 0.6 to 2.0 mmol compared to the prior art. CO2 / G Adsorbens , in particular from about 0.8 to 1.9 mmol CO2 / G Adsorbens , as well as a very favorable H2O adsorption capacity of preferably about 15 to 35 wt.%, in particular 20 to 30 wt.%. In principle, the amine-functionalized cellulose material according to the invention is also advantageous if it has a CO2 adsorption capacity of at least about 0.50 mmol CO2 / G Adsorbens , preferably at least about 0.6 mmol CO2 / G Adsorbens , in particular of at least about 0.7 mmolCO2 / G Adsorbens and most preferably at least about 0.8 mmol CO2 / G Adsorbens , The same applies if the amine-functionalized cellulose material (adsorbent) has a CO2 adsorption capacity of at most about 3.0 mmol CO2 / G Adsorbens , preferably not more than about 2.4 mmol CO2 / G Adsorbens , in particular of at most about 2.0 m molcoz / g adsorbent and particularly preferably of at most about 1.9 m molcoz / g adsorbent.

[0015] The key to the success sought according to the invention described above also lies in the improved processes A and B for producing the amine-functionalized cellulose material according to the invention, which are described in more detail below:

[0016] The process A according to the invention for producing the described amine-functionalized cellulose material is characterized in that 1) the cellulose carrier is added to an alcoholic solution, in particular ethanolic solution, of a compound that crosslinks the polyalkyleneamine, wherein the crosslinking compound is at least bifunctional with respect to the crosslinking reaction, 2) the polyalkyleneamine is added to an alcoholic, in particular ethanolic solution, and 3) the alcoholic solutions from step 1) and step 2) are mixed, 4) water is added to the resulting mixture, in particular in an amount of about 10 to 40% by weight, based on the total reaction system, to start a crosslinking reaction, whereby a layer of a crosslinked polyalkyleneamine is formed on the cellulose carrier and 5) after completion of the crosslinking reaction, the amine-functionalized cellulose material is obtained.

[0017] The present invention is not subject to any critical restrictions regarding the choice of suitable alcohol. In principle, alcohols with 1 to 6 carbon atoms can be used, in particular methanol, ethanol, propanol, butanol, pentanol, and / or hexanol. Ethanol is particularly preferred for a variety of reasons. It allows the inventive objective to be achieved in an optimal manner.

[0018] In principle, it is also possible to combine the two above steps 1) and 2) into a single step, after which the three components mentioned above are simultaneously introduced into an alcoholic solution, especially an ethanolic solution. However, this carries the risk that step 4), which is intended to trigger the crosslinking reaction, is at least partially anticipated. This could result in the product of the process, in the form of the amine-functionalized cellulose material, not achieving the desired properties to the desired extent.

[0019] Where specific chemical compounds are mentioned in the following description of process A according to the invention, which is a batch process, but also of the continuously conducted padding process B, which will be discussed later, these are the same ones already discussed above in connection with the amine-functionalized cellulose material according to the invention. When an alcohol is mentioned, the invention is not subject to any relevant restrictions. In particular, it can be methanol, ethanol, butanol, propanol, and the like, with ethanol being preferred.

[0020] The amount of respective alcohol which is advantageous in the stated steps 1), 2) and 3) is about 10 to 95, preferably about 30 to 75, in particular about 45 to 65 wt.% alcohol in the respective solution.

[0021] In step 4), the water is preferably added in such an amount that approximately 1 to 5 parts by weight of alcohol, in particular approximately 3 to 4 parts by weight of alcohol, in particular ethanol, are added to 1 part by weight of water. The above statements regarding the choice of alcohol also apply here.

[0022] The temperature can be considered during crosslinking to optimize the process according to the invention. The crosslinking reaction is advantageously carried out at a temperature of approximately 15°C to 50°C, in particular approximately 20 to 30°C.

[0023] The process according to the invention is advantageously further developed as follows: The process product is dried under vacuum. Here, the amine-functionalized cellulose material is preferably dried at an elevated temperature of approximately 20°C to 100°C, in particular of approximately 50°C to 70°C, preferably under a vacuum of approximately 20 mbar to 300 mbar, in particular of approximately 50 mbar to 150 mbar. To carry out these drying measures, a vacuum drying cabinet is preferably used according to the invention. The temperature plays an optimizing role in the further treatment of the process product according to the invention in the form of the amine-functionalized cellulose material: It is advantageous if the amine-functionalized cellulose material is washed at approximately 40°C to 80°C, in particular approximately 50°C to 70°C, in particular with water and / or ethanol. Preferably, drying is then carried out again.The procedure is as follows: Drying is preferably carried out at an elevated temperature of approximately 40°C to 80°C, in particular approximately 50°C to 70°C, preferably under a vacuum of approximately 50 mbar to 250 mbar, in particular approximately 100 mbar to 200 mbar. This is preferably carried out using the vacuum drying cabinet described above.

[0024] Surprisingly, it is advantageous if the washing is carried out in two steps, with the first step being water and the second step being alcohol, especially ethanol, to remove unreacted polyalkyleneamine. Drying is then carried out, preferably at elevated temperature, especially at about 50°C to 70°C. The range from about 55°C to 65°C is particularly preferred.

[0025] Further embodiments of the invention, which can be easily integrated into the method according to the invention, are described as follows:

[0026] It is therefore highly beneficial to use approximately 5 to 50, particularly approximately 10 to 25, parts by weight of polyalkyleneamine per part by weight of crosslinking compound (crosslinker). Furthermore, the liquor ratio should be optimized. This is achieved when the liquor ratio of cellulose carrier to the remaining cellulose coating mixture (polyalkyleneamine, crosslinker, alcohol) is approximately 1:20 to 1:100, particularly approximately 1:60 to 1:80.

[0027] The amine-functionalized cellulose material according to the invention can be produced particularly advantageously using the continuously conducted padding process B, in which the coating composition is continuously applied to the cellulose carrier in the form of a textile fabric, in particular a nonwoven. Before the relevant process teaching according to the invention is comprehensively presented, the special features of the padding process with regard to the present invention will be described: Padding, padding, or full-bath impregnation is understood to be a process for the wet treatment of textile fabrics (wovens, knits, nonwovens, and the like) on a padding machine. Here, the textile fabric is continuously impregnated and generally passed through a pair of rollers to partially press out the liquor.

[0028] The liquor is located in an upstream trough or padding tank, or above a pair of rollers assigned to the padding machine. The finished and impregnated textile fabric is squeezed out to a precisely defined level of excess liquor using the pair of rollers of the padding machine. The amount of liquor absorbed is specified as a percentage of the raw weight of the respective textile fabric, especially the nonwoven. A liquor absorption or remaining liquor (after pressing with the pair of rollers) of 20% means that 20 g of liquor are absorbed per 100 g of raw textile fabric. In this case, padding is followed by a drying process, particularly in a vacuum drying cabinet, and a subsequent washing process. Therefore, the following can be generally described for the inventive continuous process theory according to the padding process:

[0029] 1. The textile fabric, in particular the nonwoven fabric, is first impregnated with an alcoholic crosslinking agent solution, in particular glutaraldehyde solution, and then (while still wet) impregnated with an alcoholic, in particular ethanolic, polyalkyleneamine solution, or the two steps shown are reversed (a total of 2 impregnation steps). After each impregnation, the liquor is partially pressed or squeezed out using the roller pair of the padding machine. 2. The textile fabric is impregnated with a single alcoholic, in particular ethanolic, solution, which solution contains both the crosslinking agent and the polyalkyleneamine. Consequently, the liquor or impregnation solution contains both reactants. In this case, impregnation takes place at least once. However, double impregnation can offer advantages. The pressing or squeezing mentioned above always takes place.Squeezing the impregnated textile fabric with the pair of rollers. The subsequent drying and / or washing steps are largely identical. Taking into account the above explanations regarding the preferred padding process according to the invention, this can be represented in the embodiment of a further advantageous process B according to the invention as follows:

[0030] The invention accordingly further relates to a process B for producing the above-described amine-functionalized cellulose material, which has a textile fabric as cellulose carrier, in particular in the form of a nonwoven, and which is characterized in that 1 the textile fabric is impregnated in the dip tank of a padding machine with an alcoholic, in particular ethanolic, solution of a polyalkyleneamine-crosslinking compound (crosslinker), in particular in the form of glutaraldehyde, and the thus impregnated textile fabric is pressed in a subsequent pair of rollers of the padding machine and 2 the wet impregnated textile fabric of step 1 is subsequently impregnated in the dip tank of a further padding machine with an alcoholic, in particular ethanolic, polyalkyleneamine solution, in particular a polyethyleneimine solution,is impregnated and 3 this impregnated textile fabric obtained after steps 1 and 2 is pressed over another pair of rollers of the padding machine to a liquor pick-up of about 20 to 50 wt.%, in particular about 35 to 45 wt.%, and 4 then, optionally with heating, the crosslinking reaction between the crosslinker and the polyalkyleneamine is effected to form a layer of crosslinked polyalkyleneamine on the surface of the textile fabric.

[0031] In step 4, the crosslinking reaction begins as soon as sufficient alcohol, especially ethanol, has evaporated. At the end of the crosslinking reaction, the designated layer of crosslinked polyalkyleneamine is present on the surface of the textile fabric. To promote step 4, it is carried out at an elevated temperature of approximately 40 to 80°C, in particular approximately 50 to 70°C, and most preferably at approximately 60°C. A further advantageous development of step 4 is that a vacuum is applied to carry it out, in particular of approximately 50 to 250 mbar, more preferably of approximately 100 to 200 mbar.

[0032] It is particularly advantageous if the roller pairs of the padding machine are operated at a speed of approximately 0.2 to 5 m / min, in particular approximately 0.5 to 2 m / min, and most preferably approximately 1 m / min, and / or the contact pressure of the rollers is set between approximately 0.2 to 5 bar, in particular between approximately 0.5 and 2.5 bar, most preferably at approximately 1 bar. Also important is the mass fraction of crosslinker in the polyalkyleneamine in the respective liquor. It is preferred that the mass fraction of crosslinker, in particular glutaraldehyde, in the liquor of step 1 is about 0.3 to 6 wt.%, in particular about 1 to 3 wt.%, and particularly preferably about 2 wt.%, and / or the mass fraction of polyalkyleneamine in the liquor of step 2 is about 3 to 18 wt.%, in particular about 7 to 14 wt.%, and particularly preferably about 10 wt.%.

[0033] In individual cases, it is advantageous to modify steps 1 and 2. The technical teaching would therefore be characterized in that 1 the textile fabric is impregnated in the dip tank of a padding machine with an alcoholic, in particular ethanolic, polyalkyleneamine solution, and the thus impregnated textile fabric is pressed in a subsequent pair of rollers of the padding machine, and 2 the wet, impregnated textile fabric from step 1 is subsequently impregnated in another dip tank of a padding machine with an alcoholic, in particular ethanolic, solution of a polyalkyleneamine-crosslinking compound (crosslinker), in particular in the form of glutaraldehyde. This would be followed by the further measures of the above-described process teaching of the invention.

[0034] In individual cases, it may also be advantageous to combine steps 1 and 2 described above and treat the textile fabric with an impregnation solution containing the required reactants, and then subject the impregnated textile fabric to steps 3 and 4 to form the amine-functionalized cellulose material. The liquor ratio of textile fabric to the remaining coating mixture also plays an optimizing role: Therefore, it is expedient for the liquor ratio of textile fabric to the remaining coating mixture (alcohol, crosslinker, polyalkyleneamine) to be approximately 1:20 to 1:100, in particular approximately 1:60 to 1:80.

[0035] It offers advantages if the weight ratio of crosslinking compound (crosslinker) to polyalkyleneamine is taken into account. Therefore, process B according to the invention is preferably further developed in that approximately 5 to 50, in particular approximately 10 to 25 parts by weight of polyalkyleneamine are used for 1 part by weight of crosslinking compound (crosslinker).

[0036] The particular advantage of the invention is demonstrated when the amine-functionalized cellulose material according to the invention, as described above, is used for the direct adsorption of CO2 from air (direct air capture). It is particularly advantageous if the amine-functionalized cellulose material is used in the form of textile tapes or textile fabrics, in particular nonwovens, for the continuous adsorption of CO2, especially at room temperature of approximately 20°C.

[0037] The inventive use teaching is not only directed toward adsorbing CO2 to a high degree. The particular advantage of the invention lies in the adsorption / desorption combination. The adsorbed CO2 bound to the amine-functionalized cellulose material can be desorbed favorably and put to useful use. It is advantageous here if the amine-functionalized cellulose material is subjected to CO2 desorption while heating, preferably at a temperature of up to about 100°C, in particular from about 60°C to 85°C, particularly preferably from about 75°C to 85°C, in order to then put the desorbed CO2 to a useful use that can be determined by a person skilled in the art. Desorption can be promoted by applying a reduced pressure of 100 mbar to 900 mbar, in particular of 200 mbar to 800 mbar and particularly preferably of 400 mbar to 600 mbar with or without increasing the temperature.When useful uses of the amine-functionalized cellulose material according to the invention are discussed, these are in particular the further processing of the desorbed CO2 into chemicals, in particular fuels and plastics, or the promotion of plant growth in greenhouses.

[0038] As a result, the present invention relates to an advantageous amine-functionalized cellulose material that exhibits unusually high CO2 and H2O adsorption capacities. These values ​​are significantly higher than those achieved with the prior art described above. While the latter only exhibits a CO2 adsorption capacity of 0.46 mmol CO2 / G Adsorbens achieved, the corresponding values ​​according to the invention easily reach up to about 3 mmol CO2 / G Adsorber , conveniently up to about 2 mmol CO2 / G AdsorberIn this context, reference is made to the above statements. The CO2 adsorption capacity achievable according to the invention advantageously reaches up to 35 wt.%.

[0039] It is advantageous to use untreated cellulose fibers, especially in the form of continuous fibers with various cross-sections (round, trilobal), in the form of textile fabrics such as wovens, knitted fabrics, scrims, and especially nonwovens, as starting materials for implementing the present invention. Their modification to the amine-functionalized cellulose material is carried out using various polyalkyleneamines, with polyethyleneimine (PEI) being preferred.

[0040] The preferred PEI can be used as either a branched or a linear polymer with various molecular weights (Mw) between 2,000 and 25,000. The PEI is fixed to the fiber material through a chemical reaction. For this purpose, advantageous chemical crosslinkers are used, in particular the difunctional aldehydes described above. Glutaraldehyde is particularly preferred. Due to the open structure and the good volume-to-surface ratio of the advantageously used nonwoven materials, the energy required to flow CO2-contaminated air through these materials can be significantly reduced. The cellulose carrier material used according to the invention improves the properties of the adsorber and further protects against mechanical abrasion. The shape of the materials can be adapted as desired to different modules, i.e., in terms of length, width, thickness, and shape, round or square.The CO2 adsorption capacity is particularly > 1.1 mmol. CO2 / G Adsorber , but can also be beneficial up to 3.0 mmol CO2 / G Adsorber and is therefore highly suitable for DAC (direct air capture) and downstream processes. The ability of the adsorber according to the invention to bind additional water significantly improves its application possibilities, since the water can be used for further process steps, e.g., for the subsequent production of fuels or, if appropriate, for subsequent final storage.

[0041] Further particular advantages that distinguish the present invention include the following: Continuous cellulose fibers can be produced in large quantities and through various industrial processes, and can be adapted to their specific applications. Compared to the treatment of powders, staple fibers, or textiles using the TEMPO process described above, in which the cellulose material must first be oxidized in batch mode and then functionalized in an additional step, the functionalization of nonwovens, for example, can be carried out according to the invention in a continuous process, particularly using a padding process. This significantly facilitates upscaling and is easily transferable to existing processes.

[0042] In the following examples, several fiber types are used, which are chemical fibers made from regenerated cellulose. The fiber types differ in their fiber cross-section, which can be either round or trilobal, as well as in their fiber diameter, which is preferably between 6 and 12, especially between 8 and 10 pm. The trilobal fibers are characterized by a particularly high water retention capacity, which can be advantageously used in various applications.

[0043] The cellulose fibers or regenerated cellulose fibers can be processed by mechanical processes into nonwovens (VS), which are advantageous in this case. The thickness of the nonwovens (VS) advantageously varies between approximately 0.5 and 15 mm, in particular between approximately 0.7 and 13 mm, and in individual cases, particularly advantageously between approximately 0.7 and 1.2 mm, while the basis weight preferably lies between approximately 250 and 440 g / m 2, in particular between about 250 and 400 g / m 2 , lies. In its particular embodiment, the process according to the invention relates to the use of nonwovens (VS), which are converted into the amine-functionalized cellulose material according to the invention. After their functionalization, a weight increase of 30 to 150% is observed. The water absorption of the VS material is between 20 and 35%.

[0044] The following examples address the process of adsorption and desorption: Adsorption and desorption processes are investigated using thermogravimetry. Thermogravimetry is an analytical method with which physical and chemical phenomena can be investigated and measured. For measurement, the samples are placed in a crucible and continuously measured using an integrated balance. This is continuously flushed from below with nitrogen to prevent the condensation of water from moist gases. To determine the adsorption capacity, 40 mg of the material is heated to 80°C at a heating rate of 10°C / min and held constant for 30 minutes, with a nitrogen flow rate of 200 ml / min. The first heating step serves to prepare the sample, during which previously adsorbed CO2 and H2O are desorbed. The sample is then cooled to 25°C and this temperature is maintained for 60 minutes.This is followed by adsorption under isothermal conditions (25°C) with a constant volume flow of humid (60% RH) adsorption air of 200 ml / min for 10 h. Desorption is carried out at the same volume flow at 80°C within 2 h.

[0045] Since the adsorbed amounts of CO2 cannot be determined gravimetrically due to the binary adsorption of CO2 and H2O, the adsorbed CO2 is measured during desorption using an Emerson X-Stream Enhanced XEGP (see Marc P. Vocht et al., in "Macromol. Mater. Eng.", 2022, 307, 223093, pp. 1-19, therein 2.2. Methods). The H2O adsorption capacity is also determined using the aforementioned thermogravimetry. The difference in material weight before and after adsorption is determined.

[0046] The invention will be explained in more detail below using various examples:

[0047] Example 1:

[0048] The production of an inventive amine-functionalized cellulose material is described, in which a nonwoven fabric (VS) is used as the cellulose carrier. The finishing and reaction take place in a batch process in immersion baths (30 cm x 30 cm x 5 cm). For functionalization with a branched poly(ethyleneimine) (bPEI), a nonwoven fabric (thickness 0.7 mm) consisting of round regenerated cellulose fibers (diameter 12 pm / dtex value: 1.7) is initially introduced and washed with ethanol. The nonwoven fabric is soaked for 15 minutes with a 2 wt.% ethanolic glutaraldehyde solution. A 10 wt.% ethanolic bPEI solution (molecular weight 25,000) is then added to this solution. The mixture is then allowed to stand for 30 minutes. Water (20 wt.% water to the total mass of the solution) is added to start the reaction. The fleeces are stored in the reaction solution for 24 hours at room temperature.The weight ratio of the nonwoven fabric (VS) to the reaction solution is 1:70. The nonwoven fabric is then dried at 60°C under reduced pressure (<200 mbar). To remove unreacted bPEI, it is then washed with water and ethanol and then dried again (60°C, <200 mbar). The CO2 adsorption is 48 mg. CO2 / gAdsorb er(1.1 mmol CO2 / G Adsorber ), the H2O adsorption at 18 wt.%.

[0049] Example 2:

[0050] Example 1 is repeated. The amine-functional cellulose material according to the invention is also produced using a nonwoven fabric (VS). The molecular weight of the PEI is reduced to 10,000. The CO2 adsorption of the resulting adsorber is 56 mg. CO2 / G Adsorb er (1.3 mmol CO2 / G Adsorber ), the H2O adsorption at 24 wt.%.

[0051] Example 3:

[0052] Example 1 is repeated. The production of the inventive amine-functional cellulose material is also carried out using a nonwoven fabric (VS). The molecular weight of the PEI is reduced to 2,000. Here, a microfiber (0.5 dtex) is used to produce the inventive amine-functionalized cellulose material. The CO2 adsorption of the resulting adsorber is 66 mg. CO2 / G Adsorber (1.5 mmol CO2 / G Adsorber ), the H2O adsorption at 21 wt%.

[0053] Example 4:

[0054] The preparation of an amine-functionalized cellulose material according to the invention is described. Production is carried out using microfiber nonwovens (0.5 dtex). The procedure is as described in Example 1 using bPEI (molecular weight: 25,000). The CO2 adsorption of the adsorber is 68 mg. CO2 / G Adsorb er (1.5 mmol CO2 / G Adsorber ), the H2O adsorption at 20 wt%.

[0055] Example 5:

[0056] Here, the amine-functionalized cellulose material according to the invention is obtained from microfiber nonwovens (0.5 dtex). The procedure is as described in Example 1 using bPEI (molecular weight: 10,000). The CO2 adsorption of the resulting adsorbent is 53 mg. C / O G 2Adsorber (1.2 mmol CO2 / G Adsorbens ), the H2O adsorption at 17 wt%.

[0057] Example 6:

[0058] The amine-functionalized cellulose material according to the invention is produced using a nonwoven fabric with microfibers (0.5 dtex). The procedure is as described in Example 1 using bPEI (molecular weight: 2,000). The CO2 adsorption of the resulting material is 73 mg. CO2 / G Adsorber (1.7 mmol CO2 / G Adsorbens ), the H2O adsorption at 25 wt%.

[0059] Example 7:

[0060] Here, the amine-functionalized cellulose material according to the invention is produced using a nonwoven fabric with trilobal fibers (2.2 dtex). The procedure is as described in Example 1 using bPEI (molecular weight: 25,000). The CO2 adsorption of this material is 48 mg. C o2 / g Adsor- ber (1.1 mmol CO2 / G Adsorber ), the H2O adsorption at 16 wt%.

[0061] Example 8:

[0062] The fabric is made from a trilobal fiber nonwoven (2.2 dtex). The procedure is as described in Example 1 using bPEI (molecular weight: 10,000). The CO2 adsorption is 55 mg. CO2 / G Adsorber (1.2 mmol CO2 / G Adsorber ), the H2O adsorption at 16 wt%.

[0063] Example 9:

[0064] Here, nonwovens made of trilobal fibers (2.2 dtex) are used as the starting material for the cellulose carrier. The procedure is as described in Example 1 using bPEI (molecular weight: 2,000). The CO2 adsorption here is 65 mg. CO2 / G Adsorber (1.5 mmol / g Adsorber ), the H2O adsorption at 23 wt.%. Example 10:

[0065] The preparation of an amine-functionalized cellulose material according to the invention is described. Production is carried out using nonwovens made of trilobal fibers (2.2 dtex). The procedure is as described in Example 1 using bPEI (molecular weight: 25,000). The concentration of the crosslinker in the form of glutaraldehyde was 1 wt.%. The CO2 adsorption of this material is 47 mg / g. Adsorber (1.1 mmol CO2 / G Adsorbens ), the H2O adsorption at 20 wt.%.

[0066] Example 11:

[0067] To produce the amine-functionalized cellulose material according to the invention, nonwoven fabrics made of trilobal fibers (2.2 dtex) were used. The procedure was as described in Example 1 using bPEI (molecular weight: 25,000). The concentration of the crosslinker in the form of glutaraldehyde was 3 wt.%. The CO2 adsorption of this material was 42 mg / g. Adsorber (1.0 m mol CO2 / G Adsorber ), the H2O adsorption at 18 wt%.

[0068] Example 12:

[0069] The production of an inventive amine-functionalized cellulose material is described, in which a nonwoven fabric (VS) is used as the cellulose carrier. The finishing takes place in a continuous process using a padding machine. For functionalization with a branched poly(ethyleneimine) (bPEI), a nonwoven fabric (thickness 0.7 mm) consisting of round regenerated cellulose fibers (diameter 12 pm / dtex value: 1.7) is introduced and washed with ethanol. The nonwoven fabric is impregnated with a 2 wt.% ethanolic glutaraldehyde solution on the padding machine at a roller speed of 1 m / min and a contact pressure of 1 bar at room temperature. The still-wet nonwoven impregnated with glutaraldehyde solution is then impregnated once more with a 10 wt% ethanolic bPEI solution (molecular weight 25,000) under the same conditions. The liquor absorption of the nonwoven is approximately 40%.The nonwoven fabric is then dried under normal (laboratory) conditions, preferably at a temperature of approximately 60°C under a vacuum of approximately 150 mbar. The crosslinking reaction begins as soon as sufficient ethanol has evaporated. To remove unreacted bPEI, it is then washed with water and ethanol and dried again under normal (laboratory) conditions, specifically at a temperature of approximately 60°C under a vacuum of approximately 150 mbar.

[0070] Example 13 (Reversing the fleet load):

[0071] The production of an inventive amine-functionalized cellulose material is described, in which a nonwoven fabric (VS) is used as the cellulose carrier. The finishing takes place in a continuous process using a padding machine. For functionalization with a branched polyethyleneimine (bPEI), a nonwoven fabric (thickness 0.7 mm) consisting of round regenerated cellulose fibers (diameter 12 pm / dtex value: 1.7) is introduced and washed with ethanol. The nonwoven fabric is impregnated with a 10 wt.% ethanolic bPEI solution (molecular weight 25,000) on the padding machine at a roller speed of 1 m / min and a contact pressure of 1 bar at room temperature. The still-wet, bPEI-impregnated nonwoven is then impregnated with a 2 wt% ethanolic glutaraldehyde solution under the same conditions. The liquor pick-up of the nonwoven is approximately 40%.The nonwoven fabric is then dried at a temperature of approximately 60°C under a vacuum of approximately 150 mbar. The crosslinking reaction begins as soon as sufficient ethanol has evaporated. To remove unreacted bPEI, it is then washed with water and ethanol and dried again under normal (laboratory) conditions, specifically at a temperature of approximately 60°C under a vacuum of approximately 150 mbar.

[0072] Example 14:

[0073] The production of an inventive amine-functionalized cellulose material is described, in which a nonwoven fabric (VS) is used as the cellulose carrier. Finishing takes place in a continuous process using a padding machine. For functionalization with a branched poly(ethyleneimine) (bPEI), a nonwoven fabric (thickness 0.7 mm) consisting of trilobal regenerated cellulose fibers (dtex value: 3.3) is introduced and washed with ethanol. The nonwoven fabric is impregnated on the padding machine at a roller speed of 1 m / min and a contact pressure of 1 bar with an ethanolic solution containing 2 wt.% glutaraldehyde and 12.5 wt.% bPEI solution (molecular weight 10,000) at room temperature. This impregnation process can be repeated as required, although two repetitions are preferred. The liquor absorption of the nonwoven fabric is approximately 42%.The nonwoven fabric is then dried, preferably at a temperature of 60°C under a vacuum of approximately 150 mbar. The crosslinking reaction begins as soon as sufficient ethanol has evaporated. To remove unreacted bPEI, it is then washed with water and ethanol and dried again at a temperature of 60°C and under a vacuum of approximately 150 mbar.

[0074] * * *

Claims

AMENDED CLAIMS received by the International Bureau on 15 July 2024 (15.07.2024) 1. Amine-functionalized cellulose material containing a cellulose carrier coated with a crosslinked polyalkyleneamine, characterized in that the cellulose carrier is based on cellulose fibers in the form of textile fabrics, and in that the crosslinked polyalkyleneamine is derived from a crosslinking of polyalkyleneamine with a dialdehyde.

2. Amine-functionalized cellulose material according to claim 1, characterized in that the fiber of the textile fabric is present as a microfiber, in particular as a continuous fiber.

3. Amine-functionalized cellulose material according to claim 1 or 2, characterized in that the fiber is a round fiber whose diameter is in particular between about 4 and about 20 pm and particularly preferably between about 6 and 12 pm, or a trilobal fiber whose dtex value is in particular between about 2 and 5 dtex and particularly preferably between about 2.5 and 3.5 dtex.

4. Amine-functionalized cellulose material according to claim 1, characterized in that the cellulose carrier is in the form of a nonwoven.

5. Amine-functionalized cellulose material according to claim 4, characterized in that the basis weight of the nonwoven is between about 150 and 600 g / m 2 and in particular between about 250 and 440 g / m 2 and / or the thickness of the fleece is between about 0.5 and 15 mm, in particular between about 0.7 and 13 mm.

6. Amine-functionalized cellulose material according to at least one of the preceding claims, characterized in that the polyalkyleneamine is linear, branched or cyclic.

7. Amine-functionalized cellulose material according to at least one of the preceding claims, characterized in that the polyalkyleneamine is a polyethyleneamine (PEI), polypropyleneamine, polybutyleneamine, polypentyleneamine, tetraethylenepentamine (TEPA), diethylenetriamine (DETA) and / or pentaethylenehexamine (PEHA).

8. Amine-functionalized cellulose material according to at least one of the preceding claims, characterized in that the polyalkyleneamine has a molecular weight (M w ) of about 600 to 100,000, in particular of about 1,000 to 50,000, most preferably of about 1,500 to 30,000.

9. Amine-functionalized cellulose material according to at least one of the preceding claims, characterized in that the crosslinked polyalkyleneamine is based on a crosslinking of polyalkyleneamine with a dialdehyde of the formula CHO(CH2) n CH2CHO, where n is an integer between 2 and 9, in particular between 2 and 6, in particular in the form of oxaldialdehyde, glutardialdehyde, alipindialdehyde, succinaldehyde, malondialdehyde and / or 1,9-nonanedialdehyde.

10. Amine-functionalized cellulose material according to at least one of the preceding claims, characterized in that the coating of the cellulose carrier with crosslinked polyalkyleneamines has a thickness of about 0.1 to 10 pm, in particular of 1.0 to 7.5 pm.

11. Process A for the preparation of the amine-functionalized cellulose material according to at least one of claims 1 to 10, characterized in that 1) the cellulose carrier is placed in an alcoholic, in particular ethanolic, solution of a compound crosslinking the polyalkyleneamine, wherein the crosslinking compound is at least bifunctional with respect to the crosslinking reaction and is present as a dialdehyde, 2) the polyalkyleneamine is added to an alcoholic, especially ethanolic, solution and 3) the alcoholic solutions from step 1) and step 2) are mixed, 4) water is added to the resulting mixture, in particular in an amount of about 10 to 40% by weight, based on the total reaction system, to initiate a crosslinking reaction, whereby a layer of a crosslinked polyalkyleneamine is formed on the cellulose support and 5) after completion of the cross-linking reaction, the amine-functionalized cellulose material is obtained.

12. The method according to claim 11, characterized in that water is added in step 4) in such an amount that about 1 to 5 parts by weight of alcohol, in particular about 3 to 4 parts by weight of alcohol, in particular ethanol, are added to 1 part by weight of water.

13. The method according to claim 11 or 12, characterized in that the crosslinking reaction is carried out at a temperature of about 15°C to 50°C, in particular about 20°C to 30°C.

14. The method according to any one of claims 11 to 13, characterized in that the amine-functionalized cellulose material obtained is dried at a temperature of about 20°C to 100°C, in particular of about 50°C to 70°C, in particular under vacuum of about 20 mbar to 300 mbar, particularly preferably of about 50 mbar to 150 mbar.

15. The method according to at least one of claims 11 to 14, characterized in that the amine-functionalized cellulose material obtained is washed at about 40°C to 80°C, in particular at about 50°C to 70°C, in particular with water and / or ethanol, and dried again.

16. The method according to claim 15, characterized in that the washing is carried out in two steps, wherein in the first step the washing is carried out with water and in the second step with alcohol, in particular with ethanol, in order to remove unreacted polyalkyleneamine, and is then dried at an elevated temperature, in particular at a temperature of about 50°C to 70°C.

17. The process according to at least one of claims 11 to 16, characterized in that about 5 to 50, in particular about 10 to 25 parts by weight of polyalkyleneamine, in particular polyethyleneimine, are used per 1 part by weight of crosslinking compound.

18. The method according to at least one of claims 11 to 17, characterized in that the liquor ratio of cellulose carrier to the remaining cellulose coating batch is about 1:20 to 1:100, in particular about 1:60 to 1:

80.

19. Process B for the production of the amine-functionalized cellulose material according to at least one of claims 1 to 10 with a textile fabric as cellulose carrier, in particular in the form of a nonwoven, characterized in that 1 the textile fabric is impregnated in the dipping tank of a padding machine with an alcoholic, in particular ethanolic, solution of a polyalkyleneamine crosslinking compound (crosslinker) in the form of a dialdehyde, in particular in the form of glutaraldehyde, and the thus impregnated textile fabric is pressed in a subsequent pair of rollers of the padding machine and 2 subsequently, the wet impregnated textile fabric of step 1 is impregnated in a further dip tank of the padding machine with an alcoholic, in particular ethanolic, polyalkyleneamine solution, in particular a polyethyleneimine solution, and 3 this impregnated textile fabric obtained after steps 1 and 2 is pressed over a further pair of rollers of the padding machine to a liquor pick-up of about 20 to 50% by weight, in particular about 35 to 45% by weight, and 4 subsequently, optionally with heating, the crosslinking reaction between the crosslinker and the polyalkyleneamine is effected to form a layer of crosslinked polyalkyleneamine on the surface of the textile fabric.

20. A method according to claim 19, characterized in that the roller pairs of the padding machine are rotated at a speed of about 0.2 to 5 m / min, in particular about 0.5 to 2 m / min and very particularly preferably about 1 m / min, and / or the contact pressure of the rollers is set between about 0.2 to 5 bar, in particular between about 0.5 and 2.5 bar, particularly preferably to about 1 bar.

21. The method according to claim 19 or 20, characterized in that the mass fraction of crosslinker, in particular glutaraldehyde, in the liquor of step 1 is about 0.3 to 6 wt.%, in particular about 1 to 3 wt.%, and particularly preferably about 2 wt.%, and / or the mass fraction of polyalkyleneamine in the liquor of step 2 is about 3 to 18 wt.%, in particular about 7 to 14 wt.%, and particularly preferably about 10 wt.%.

22. The method according to at least one of claims 19 to 21, characterized in that steps 1 and 2 are combined and the textile fabric is treated with an impregnation solution containing the required reactants, and the impregnated textile fabric is subjected to steps 3 and 4 to form the amine-functionalized cellulose material.

23. The method according to claim 22, characterized in that the liquor ratio of textile fabric to the remaining coating mixture (alcohol, crosslinker, polyalkyleneamine) is about 1:20 to 1:100, in particular about 1:60 to 1:

80.

24. Process according to at least one of claims 19 to 23, characterized in that about 5 to 50, in particular about 10 to 25 parts by weight of polyalkyleneamine are used for 1 part by weight of crosslinking compound (crosslinker).

25. Amine-functionalized cellulose material according to at least one of the preceding claims 1 to 9, characterized in that the amine-functionalized cellulose material (adsorbent) has a CO2 adsorption capacity of at least about 0.50 mmol CO2 / g adsorbent, preferably at least about 0.6 mmol CO2 / G Adsorbens , in particular of at least about 0.7 mmol CO2 / G Adsorbens and most preferably of at least about 0.8 mmol CO2 / G Adsorbens obtainable by the process according to at least one of claims 10 to 18 or according to at least one of claims 19 to 24.

26. Am i n-functionalized cellulose material according to claim 25, characterized by a H 2 O adsorption capacity of about 15 to 35 wt.%, in particular of 20 to 30 wt.%.

27. Use of the amine-functionalized cellulose material according to at least one of claims 1 to 10 and 25 for the direct adsorption of CO2 from air.

28. Use according to claim 27, characterized in that the amine-functionalized cellulose material is used in the form of textile tapes or textile fabrics, in particular in the form of a nonwoven, for the continuous adsorption of CO2, in particular at room temperature of about 20°C.

29. Use according to claim 27 or 28, characterized in that the CO2-loaded amine-functionalized cellulose material is subjected to a desorption of CO2 under heating, in particular at a temperature of up to about 100°C, preferably from about 60°C to 85°C, particularly preferably from about 75°C to 85°C, and / or under reduced pressure of 100 mbar to 900 mbar, in particular from 200 mbar to 800 mbar and particularly preferably from 400 mbar to 600 mbar, in order to put the desorbed CO2 to useful use.

30. Use according to claim 29, characterized in that the desorbed CO2 is further processed into chemicals, in particular fuels and plastics, or is used to promote the growth of plants in greenhouses. * * *

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