CO2 adsorbents, their preparation methods, and applications

Abstract

The application relates to the technical field of CO2 capture, in particular to a CO2 adsorbent and a preparation method and application thereof. The preparation method of the CO2 adsorbent comprises the following steps: impregnating a carrier with an impregnation solution; wherein the impregnation solution comprises an organic amine and an aromatic hydrocarbon polycyclic epoxide compound, the aromatic hydrocarbon polycyclic epoxide compound comprises at least two epoxy functional groups, the aromatic hydrocarbon polycyclic epoxide compound further comprises at least one of benzene rings, biphenyl rings and naphthalene rings, and the carrier has pores; and heating and cross-linking; the organic amine and the aromatic hydrocarbon polycyclic epoxide compound are cross-linked in the pores of the carrier to form a network structure, and the CO2 adsorbent is obtained. The organic amine in the CO2 adsorbent has a network structure, the anti-leaching performance and stability of the network structure organic amine are improved, and the stability of the CO2 adsorbent is enhanced.

Description

Technical Field

[0001] This application relates to the field of CO2 capture technology, and in particular to CO2 adsorbents, their preparation methods, and applications. Background Technology

[0002] Solid amine CO2 adsorbents adsorb CO2 through an acid-base neutralization reaction between organic amines and CO2. However, the organic amines in these adsorbents are easily lost during repeated adsorption-desorption cycles, shortening the adsorbent's lifespan. Summary of the Invention

[0003] This application discloses a CO2 adsorbent, its preparation method, and its application, in order to improve the stability of solid amine CO2 adsorbents and extend their service life.

[0004] To achieve the above objectives, firstly, this application discloses a method for preparing a CO2 adsorbent, the method comprising:

[0005] Impregnating the carrier with an impregnation solution: wherein the impregnation solution comprises an organic amine and an aromatic hydrocarbon polyepoxide compound, the aromatic hydrocarbon polyepoxide compound comprising at least two epoxy functional groups, and the aromatic hydrocarbon polyepoxide compound further comprising at least one of a benzene ring, a biphenyl ring, and a naphthalene ring, and the carrier having pores;

[0006] Heating crosslinking: The organic amine and the aromatic hydrocarbon polyepoxide compound are crosslinked in the pores of the support to form a network structure, thereby obtaining the CO2 adsorbent.

[0007] Furthermore, there is a physical force between the network structure and the carrier; and / or,

[0008] The network structure can be a two-dimensional network structure or a three-dimensional network structure.

[0009] Furthermore, in the heating crosslinking step, the reaction temperature is 45℃~90℃, and the reaction time is 2 h~24 h.

[0010] Further, the molar ratio of the epoxy functional group in the aromatic hydrocarbon polyepoxide to the amino group in the organic amine is (0.80~2.00):1; and / or,

[0011] The mass ratio of the organic amine to the carrier is (0.25~2.30):1.

[0012] Furthermore, the aromatic hydrocarbon polyepoxide includes at least one of aromatic hydrocarbon diepoxide, aromatic hydrocarbon triepoxide, and aromatic hydrocarbon tetraepoxide;

[0013] The aromatic hydrocarbon diepoxy compound includes at least one of resorcinol diglycidyl ether, diglycidyl phthalate, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, 1,6-bis(2,3-epoxypropoxy)naphthalene, and 4,4'-bis(2,3-epoxypropoxy)biphenyl.

[0014] The aromatic hydrocarbon triepoxide includes at least one of the following: triglycidyl p-aminophenol, F51 bisphenol A type phenolic epoxy resin having the structure of formula (1), and o-cresol epoxy resin having the structure of formula (2).

[0015] The aromatic hydrocarbon tetraepoxide includes at least one of N,N,N',N'-tetraglycidyl-m-phenylenediamine, F51 bisphenol A type phenolic epoxy resin having the structure of formula (3), and o-cresol epoxy resin having the structure of formula (4).

[0016] Equation (1);

[0017] Equation (2);

[0018] Equation (3);

[0019] Equation (4).

[0020] Further, the carrier comprises at least one of nano-silica, nano-alumina, zeolite molecular sieve, resin, or metal-organic framework compound; and / or,

[0021] The organic amine includes at least one of tetraethylenepentamine, pentaethylenehexamine, triethylenetetramine, and polyethyleneimine.

[0022] Furthermore, in the step of impregnating the carrier with the impregnation solution, the method for preparing the impregnation solution includes: dissolving the organic amine and the aromatic hydrocarbon polyepoxide compound in a solvent to obtain the impregnation solution;

[0023] The solvent includes at least one of methanol, ethanol, isopropanol, n-butanol, and ethylene glycol.

[0024] Furthermore, after the heating crosslinking step, the preparation method further includes a post-treatment step: drying the solvent at 60℃~80℃ in a vacuum or non-reactive gas environment for 3 h~6 h.

[0025] Secondly, this application discloses a CO2 adsorbent, which is prepared by the preparation method of the first aspect.

[0026] Thirdly, this application discloses the application of a CO2 adsorbent, wherein the CO2 adsorbent is the same as the CO2 adsorbent in the second aspect.

[0027] Compared with the prior art, the beneficial effects of this application are as follows:

[0028] This application describes the preparation of a novel CO2 adsorbent. The adsorbent is prepared by first impregnating an organic amine and an aromatic hydrocarbon polyepoxide into a porous support, followed by a heating and cross-linking reaction. This process allows the organic amine and the aromatic hydrocarbon polyepoxide to cross-link within the confined space of the support's pores, forming a network structure with a larger spatial volume and containing specific functional groups than the organic amine alone. This network structure effectively improves the anti-leakage performance and stability of the cross-linked organic amine, thereby enhancing the stability of the CO2 adsorbent.

[0029] In the preparation process of the CO2 adsorbent of this application, the amino group in the organic amine undergoes a ring-opening addition reaction with the epoxy functional group in the aromatic hydrocarbon polyepoxide. Since the aromatic hydrocarbon polyepoxide contains at least two epoxy functional groups, the organic amine and the aromatic hydrocarbon polyepoxide can form a network structure after crosslinking. The volume of the crosslinked network structure organic amine is larger than that before crosslinking, which reduces the possibility of the network structure organic amine leaking from the carrier pores, thereby improving the anti-leakage performance of the crosslinked organic amine in the CO2 adsorbent.

[0030] Furthermore, the introduction of aromatic hydrocarbon polyepoxides results in the presence of at least one of benzene, biphenyl, or naphthalene rings with a rigid framework within the network structure. This rigid framework further restricts the movement of molecular chains within the network structure, reducing the likelihood of volume reduction in the organic amines caused by bending and deformation. On one hand, this alleviates the problem of leakage from the support pores; on the other hand, it better preserves the porosity of the network structure, providing new channels for CO2 molecule diffusion and mitigating the decrease in diffusion rate caused by cross-linking. This rigid framework further reduces the possibility of chemical bond breakage in the organic amines within the network structure, preventing the migration of these organic amines into the support pores due to network structure disruption, thus preventing organic amine leakage. The hydrophobicity of the benzene, biphenyl, and naphthalene rings reduces swelling and leakage of organic amines caused by hydrothermal effects, further enhancing the anti-leakage performance of organic amines in the CO2 adsorbent and thereby improving its stability. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a process flow diagram of the preparation method of the CO2 adsorbent of this application;

[0033] Figure 2 This is a schematic diagram of the structure before and after heating and crosslinking during the preparation of the CO2 adsorbent in this application. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] The terms "first," "second," etc., are primarily used to distinguish different devices, components, or parts (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, components, or parts. Unless otherwise stated, "a plurality of" means two or more.

[0036] The technical solutions provided in this application will be further described below with reference to the embodiments and accompanying drawings.

[0037] Among various carbon reduction technologies, carbon capture technology is one of the core directions, effectively removing low concentrations of CO2 from the atmosphere. Solid amine adsorption capture technology, in particular, shows promising application prospects due to its advantages such as high adsorption capacity, low regeneration energy consumption, and low equipment corrosivity. The core of this technology is the solid amine CO2 adsorbent, a composite solid adsorbent material with organic amines as the active component, loaded within a porous matrix material. The organic amines act as active sites, reacting with CO2 and achieving efficient CO2 adsorption through Lewis acid-base interactions.

[0038] Solid amine CO2 adsorbents can be prepared using the physical impregnation method, which is simple to operate, low in cost, and allows for high amine loading. However, the physical impregnation method also has significant limitations: the physical interaction between the organic amine molecules and the support in the prepared adsorbent is relatively weak. During high-temperature desorption and regeneration, this interaction is easily disrupted, leading to increased migration of organic amine molecules within the support and subsequent loss. Furthermore, when used in an aqueous environment, the organic amines can react with water and dissolve.

[0039] like Figure 1 This application provides a method for preparing a CO2 adsorbent, the method comprising:

[0040] The carrier is impregnated with an impregnation solution: wherein the impregnation solution includes organic amines and aromatic hydrocarbon polyepoxides, the aromatic hydrocarbon polyepoxides contain at least two epoxy functional groups, and the aromatic hydrocarbon polyepoxides also include at least one of benzene rings, biphenyl rings, and naphthalene rings, and the carrier has pores;

[0041] Heating crosslinking: Organic amines and aromatic hydrocarbon polyepoxides are crosslinked in the pores of the support to form a network structure, resulting in a CO2 adsorbent. Schematic diagrams of the structure before and after heating crosslinking are shown below. Figure 2 As shown.

[0042] This application provides a novel CO2 adsorbent structure prepared by first impregnating an organic amine and an aromatic hydrocarbon polyepoxide into a porous support, followed by a heating and cross-linking reaction. This process allows the organic amine and aromatic hydrocarbon polyepoxide to cross-link within the limited space of the support's pores, forming a network structure with a larger spatial volume and an aromatic ring framework than that of pure organic amine. This network structure effectively improves the anti-leakage performance and stability of the cross-linked organic amine, thereby enhancing the stability of the CO2 adsorbent.

[0043] In the preparation process of the CO2 adsorbent of this application, the amino group in the organic amine undergoes a ring-opening addition reaction with the epoxy functional group in the aromatic hydrocarbon polyepoxide. Since the aromatic hydrocarbon polyepoxide contains at least two epoxy functional groups, the organic amine and the aromatic hydrocarbon polyepoxide can form a network structure after crosslinking. The volume of the crosslinked network structure organic amine is larger than that before crosslinking, which reduces the possibility of the network structure organic amine leaking from the carrier pores, thereby improving the anti-leakage performance of the crosslinked organic amine in the CO2 adsorbent.

[0044] In addition, the introduction of aromatic hydrocarbon polyepoxides results in the presence of at least one of benzene, biphenyl, or naphthalene rings with a rigid framework in the network structure. This rigid framework further restricts the movement of molecular chains within the network structure, reducing the likelihood of volume reduction of the organic amines in the network structure due to bending and deformation. On one hand, this alleviates the problem of their loss from the support pores; on the other hand, it better preserves the porosity of the network structure, providing new channels for CO2 molecule diffusion and mitigating the decrease in diffusion rate caused by cross-linking. This rigid framework further reduces the possibility of chemical bond breakage in the organic amines in the network structure, preventing the migration of the aforementioned organic amines in the support pores due to network structure destruction, thus preventing the loss of organic amines. The hydrophobicity of the benzene, biphenyl, and naphthalene rings reduces the swelling and loss of organic amines caused by hydrothermal effects, further improving the anti-loss performance of organic amines in the CO2 adsorbent, thereby enhancing its stability.

[0045] Furthermore, there are physical forces between the network structure and the carrier. These physical forces include at least one of hydrogen bonds, van der Waals forces, and electrostatic interactions. In the embodiments of this application, the network structure formed by organic amines and aromatic hydrocarbon polyepoxides is attached to the carrier pores through physical forces, and there are no chemical bonds between the network structure and the carrier.

[0046] Furthermore, the network structure can be a two-dimensional or three-dimensional network structure. Specifically, when the number of amino groups in the organic amine is less than or equal to two, the network structure formed by the reaction of the organic amine and the aromatic hydrocarbon polyepoxide is a two-dimensional network structure; when the number of amino groups in the organic amine is greater than two, the network structure formed by the reaction of the organic amine and the aromatic hydrocarbon polyepoxide is a three-dimensional network structure. Preferably, the network structure is a three-dimensional network structure, which has a higher crosslinking density and better stability.

[0047] Further, the aromatic hydrocarbon polyepoxide includes at least one of aromatic hydrocarbon diepoxide, aromatic hydrocarbon triepoxide, and aromatic hydrocarbon tetraepoxide. Specifically, the aromatic hydrocarbon diepoxide includes at least one of resorcinol diglycidyl ether, diglycidyl phthalate, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, 1,6-bis(2,3-epoxypropoxy)naphthalene, and 4,4'-bis(2,3-epoxypropoxy)biphenyl; the aromatic hydrocarbon triepoxide includes at least one of triglycidyl-p-aminophenol, F51 bisphenol A type phenolic epoxy resin having the structure of formula (1), and o-cresol phenolic epoxy resin having the structure of formula (2); the aromatic hydrocarbon tetraepoxide includes at least one of N,N,N',N'-tetraglycidyl-m-phenylenediamine, F51 bisphenol A type phenolic epoxy resin having the structure of formula (3), and o-cresol phenolic epoxy resin having the structure of formula (4).

[0048] Equation (1);

[0049] Equation (2);

[0050] Equation (3);

[0051] Equation (4).

[0052] Preferably, the aromatic hydrocarbon polyepoxide is N,N,N',N'-tetraglycidyl-m-phenylenediamine. In the embodiments of this application, N,N,N',N'-tetraglycidyl-m-phenylenediamine has four epoxy functional groups, resulting in more crosslinking sites for the organic amine and the aromatic hydrocarbon polyepoxide, leading to a higher crosslinking density in the formed network structure. This further reduces the likelihood of the network structure organic amine bending and folding, thereby reducing the migration rate of the network structure organic amine in the carrier pores, alleviating the problem of its loss from the carrier pores, and improving the anti-loss performance of the network structure organic amine.

[0053] Furthermore, the organic amine includes at least one of tetraethylenepentamine, pentaethylenehexamine, triethylenetetramine, and polyethyleneimine. Preferably, the organic amine is polyethyleneimine.

[0054] Further, the weight-average molecular weight (Mw) of polyethyleneimine is 300 Da to 1200 Da. Exemplarily, the weight-average molecular weight of polyethyleneimine is 300 Da, 600 Da, 900 Da, or 1200 Da. Preferably, the weight-average molecular weight of polyethyleneimine is 600 Da. In the embodiments of this application, when the weight-average molecular weight of polyethyleneimine is between 300 Da and 1200 Da, the organic amine in the network structure achieves a better balance between stability and cross-linking effect.

[0055] Further, the support includes at least one of nano-silica, nano-alumina, zeolite molecular sieve, resin, or metal-organic framework compound. Exemplarily, the resin can be NKA-9 resin, HP20 resin, X-5 resin, D500 resin, XAD-4 resin, etc. Preferably, the support is nano-silica. In the embodiments of this application, the surface of the nano-silica has silanol groups, and the amino groups in the network structure can form hydrogen bonds with the silanol groups. Simultaneously, the Si-O framework of the nano-silica can form van der Waals forces with the carbon chains in the network structure. These hydrogen bonds and van der Waals forces create physical interactions between the support and the network structure.

[0056] Further, the molar ratio of the epoxy functional group in the aromatic hydrocarbon polyepoxide to the amino group in the organic amine is (0.80~2.00):1. Wherein, the amino group in the organic amine is a reactive functional group (i.e., primary and secondary amines), and its molar amount is 70% of the molar amount of the amino group. Exemplarily, the molar ratio of the epoxy functional group in the aromatic hydrocarbon polyepoxide to the amino group in the organic amine is 0.80:1, 0.85:1, 1.00:1, 1.15:1, 1.20:1, 1.30:1, 1.45:1, 1.50:1, 1.63:1, 1.70:1, 1.86:1, 1.90:1, or 2.00:1. Preferably, the molar ratio of the epoxy functional group in the aromatic hydrocarbon polyepoxide to the amino group in the organic amine is 0.85:1.

[0057] In this embodiment, when the molar ratio of aromatic hydrocarbon polyepoxide to organic amine is within this range, the degree to which primary and secondary amines in the network structure of the organic amine further convert into tertiary amines without adsorption capacity can be reduced. More importantly, it can result in a higher crosslinking density of the crosslinked network formed by the organic amine and aromatic hydrocarbon polyepoxide, thus improving the adsorption performance of the CO2 adsorbent. Furthermore, it can prevent the amine from solidifying, thereby ensuring the number of adsorption sites for the organic amine, resulting in good adsorption performance of the adsorbent.

[0058] Further, the mass ratio of organic amine to support is (0.25~2.30):1. Exemplarily, the mass ratio of organic amine to support is 0.25:1, 0.50:1, 0.74:1, 0.90:1, 1.42:1, 1.73:1, or 2.30:1. Preferably, the mass ratio of organic amine to support is 0.90:1. In the embodiments of this application, when the mass ratio of organic amine to support is within this range, while ensuring the amine loading of the CO2 adsorbent, the possibility of amine agglomeration clogging the support pores is reduced, thus ensuring the adsorption performance of the CO2 adsorbent.

[0059] Further, in the step of impregnating the carrier with the impregnation solution, the impregnation solution is prepared by dissolving the organic amine and the aromatic hydrocarbon polyepoxide compound in a solvent to obtain the impregnation solution. The solvent includes at least one selected from methanol, ethanol, isopropanol, n-butanol, and ethylene glycol. Preferably, the organic amine is first dissolved in the solvent, and the aromatic hydrocarbon polyepoxide compound is added and stirred until homogeneous after complete dissolution. In the embodiments of this application, the organic amine and the aromatic hydrocarbon polyepoxide compound are mixed more uniformly, which is beneficial for the subsequent formation of a more uniform and cross-linked network structure of the organic amine in the carrier pores, reducing the possibility of it leaking out of the pores.

[0060] Further, in the heating crosslinking step, the reaction temperature is 45℃~90℃, and the reaction time is 2 h~24 h. Exemplarily, the reaction temperature is 45℃, 50℃, 60℃, 70℃, 80℃, 85℃, or 90℃. Exemplarily, the reaction time is 2 h, 4 h, 7 h, 10 h, 13 h, 18 h, or 24 h. In the embodiments of this application, the reaction temperature and time allow for a more complete crosslinking reaction between the aromatic hydrocarbon polyepoxide and the organic amine, resulting in a larger volume of the network structure organic amine. This further reduces the possibility of the network structure organic amine leaking from the carrier pores, improves the anti-leakage performance of the network structure organic amine, and enhances the stability of the solid amine CO2 adsorbent.

[0061] Furthermore, after the heating crosslinking step, the preparation method also includes post-treatment: drying the second solvent at 60℃~80℃ in a vacuum or non-reactive gas environment for 3 h~6 h. The non-reactive gas includes nitrogen and / or argon. Preferably, the second solvent is removed in a vacuum environment. Exemplarily, the temperature for removing the second solvent is 60℃, 65℃, 70℃, 75℃, or 80℃, and the drying time is 3 h, 4 h, 5 h, or 6 h. In this embodiment, controlling the temperature at 60℃~80℃ and removing the second solvent in a vacuum or non-reactive gas environment can prevent the primary and / or secondary amines in the amine molecules from being oxidized to tertiary amines without adsorption capacity, further ensuring the adsorption performance of the CO2 adsorbent.

[0062] This application also provides a CO2 adsorbent, which is prepared by the above-described preparation method.

[0063] This application also provides an application of a CO2 adsorbent for capturing CO2.

[0064] The technical solution of this application will be further explained below with reference to more specific embodiments and experimental test results.

[0065] Example 1

[0066] S1. Dissolve 1.8 g polyethyleneimine (Mw=600 Da) in 10 mL of ethanol, stir until completely dissolved, add 6.2 mmol of N,N,N',N'-tetraglycidyl m-phenylenediamine and stir until homogeneous to obtain the impregnation solution;

[0067] S2. Add 2.0 g of mesoporous silica carrier (SBA-15) to the impregnation solution and stir to impregnate. React in a vacuum oven at 80℃ for 6 h.

[0068] S3. Dry under vacuum at 60℃ for 6 h to remove ethanol and obtain the CO2 adsorbent.

[0069] Example 2

[0070] The difference between this embodiment and Embodiment 1 is that:

[0071] S2. Replace 6.2 mmol N,N,N',N'-tetraglycidyl-m-phenylenediamine with 8.3 mmol triglycidyl-p-aminophenol, and react at 50 °C for 3 h.

[0072] Example 3

[0073] The difference between this embodiment and Embodiment 1 is that:

[0074] S2. Replace 6.2 mmol N,N,N',N'-tetraglycidyl-m-phenylenediamine with 12.5 mmol resorcinol diglycidyl ether, and react at 60 °C for 4 h.

[0075] Example 4

[0076] The difference between this embodiment and Embodiment 1 is that:

[0077] S2. Replace 6.2 mmol N,N,N',N'-tetraglycidyl-m-phenylenediamine with 12.5 mmol bisphenol A diglycidyl ether, and react at 90 °C for 8 h.

[0078] Example 5

[0079] The difference between this embodiment and Embodiment 1 is that an equimolar amount of polyethyleneimine with Mw=300 Da is replaced with polyethyleneimine with Mw=600 Da.

[0080] Example 6

[0081] The difference between this embodiment and Embodiment 1 is that an equimolar amount of polyethyleneimine with Mw=1000 Da is replaced with polyethyleneimine with Mw=600 Da.

[0082] Comparative Example

[0083] The only difference between the comparative example and Example 1 is that N,N,N',N'-tetraglycidyl m-phenylenediamine is replaced with ethylene glycol diglycidyl ether.

[0084] Performance testing

[0085] 1. Anti-loss performance test

[0086] 0.5 g of each CO2 adsorbent from Examples 1 to 6 and the comparative example were weighed as test samples. The samples were boiled in water at 90℃ for 10 h, and the pH value of the soaking solution was measured. The pH meter used was a ST3100 pH meter from Ohaus Instruments (Changzhou) Co., Ltd.

[0087] The test results of Examples 1 to 6 and the comparative examples are shown in Table 1.

[0088] 2. Adsorption performance test

[0089] 10 mg of each CO2 adsorbent from Examples 1-6 and the comparative example were weighed as test samples. The samples were placed in a crucible within a thermogravimetric analyzer. Under an argon flow of 50 mL / min, the sample temperature was increased to 110°C at a rate of 10°C / min and maintained for 30 min to remove impurities. The system was then cooled to the adsorption temperature of 30°C at a rate of -5°C / min and stabilized for 35 min. Afterward, the system was switched to a CO2 atmosphere (equilibrated with argon at a concentration of 15 vol.%) and isothermal adsorption was performed at a flow rate of 50 mL / min for 60 min. The thermogravimetric analyzer was a Setsys EVO Easy 1750.

[0090] The test results of Examples 1 to 6 and the comparative examples are shown in Table 2.

[0091] Table 1. Test results of anti-leaching performance of Examples 1-6 and comparative examples

[0092]

[0093] Table 2. Adsorption performance test results of Examples 1-6 and the comparative examples

[0094]

[0095] As shown in Table 1, the pH values ​​of the soaking solutions in Examples 1 to 6 are all lower than those in the comparative example. The pH value of the pure water before soaking is 7.00, and the change in pH value of the soaking solutions before and after soaking in Examples 1 to 6 is smaller. In Examples 1 to 6, the volume of the network-structured organic amine is larger than that in the comparative example, which reduces the migration of the network-structured organic amine in the carrier pores and decreases the possibility of loss from the carrier pores, thereby improving the anti-loss performance of the network-structured organic amine in the CO2 adsorbent. In the CO2 adsorbents obtained in Examples 1 to 6, the network-structured organic amine also contains benzene rings. On the one hand, the rigid skeleton of the benzene rings can further restrict the movement of molecular chains in the network structure, reducing the possibility of volume reduction of the network-structured organic amine caused by bending and folding of the network structure, and improving the anti-loss performance of the network-structured organic amine; on the other hand, the presence of benzene rings improves the hydrophobicity of the network-structured organic amine, thus improving the problem of organic amine dissolution after water soaking, and ultimately improving the stability of the CO2 adsorbent. As can be seen from the data in Table 2, the CO2 adsorption capacity of Examples 2 to 4 is greater than that of the comparative example, and its adsorption performance is improved. Example 1 is a tetraepoxy crosslinking. When the molar ratio of epoxy functional groups to amino groups is the same, the crosslinking agent has more epoxy functional groups, the crosslinking structure is more compact, and the steric hindrance and mass transfer resistance are stronger. Its adsorption performance is slightly reduced, but its anti-loss performance is significantly improved. Therefore, Example 1 has better overall performance.

[0096] As shown in Table 1, in the preparation processes of Examples 3 and 4, the aromatic hydrocarbon polyepoxides contained two epoxy functional groups. The bisphenol A diglycidyl ether used in Example 4 had rotatable chemical bonds between its benzene rings. Compared to the resorcinol diglycidyl ether used in Example 3, the overall structure of bisphenol A diglycidyl ether was more flexible and bendable, resulting in a greater change in the pH value of the soaking solution and poorer anti-leakage performance. In the preparation process of Example 2, the aromatic hydrocarbon polyepoxide contained three epoxy functional groups, while in the preparation process of Example 1, the aromatic hydrocarbon polyepoxide contained four epoxy functional groups. The network structure organic amine of Example 1 exhibited superior anti-leakage performance. The anti-leakage performance of the network structure organic amine increased with the increase in the number of epoxy functional groups in the aromatic hydrocarbon polyepoxide. A higher number of epoxy functional groups resulted in more cross-linking sites between the organic amine and the aromatic hydrocarbon polyepoxide, leading to a higher cross-linking density in the formed network structure. This further reduced the possibility of bending and deformation of the network structure organic amine, and the smaller volume change of the network structure organic amine reduced the possibility of it leaching from the carrier pores. As shown in Tables 1 and 2, compared with Examples 5 and 6, the weight-average molecular weight of polyethyleneimine in Example 1 is moderate, and the resulting network structure organic amine has better balance stability and cross-linking effect. Moreover, its cross-linking reaction success rate is higher, so its overall effect of anti-loss performance and adsorption performance is better.

[0097] The above provides a detailed description of a CO2 adsorbent, its preparation method, and its application as disclosed in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the technical solutions and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for preparing a CO2 adsorbent, characterized in that, The preparation method includes: Impregnating the carrier with an impregnation solution: wherein the impregnation solution comprises an organic amine and an aromatic hydrocarbon polyepoxide compound, the aromatic hydrocarbon polyepoxide compound comprising at least two epoxy functional groups, and the aromatic hydrocarbon polyepoxide compound further comprising at least one of a benzene ring, a biphenyl ring, and a naphthalene ring, and the carrier having pores; Heating crosslinking: The organic amine and the aromatic hydrocarbon polyepoxide are crosslinked in the pores of the support to form a network structure, thereby obtaining the CO2 adsorbent. The network structure has physical interaction with the support. The aromatic hydrocarbon polyepoxide includes at least one of aromatic hydrocarbon diepoxide, aromatic hydrocarbon triepoxide, and aromatic hydrocarbon tetraepoxide. The aromatic hydrocarbon diepoxy compound includes at least one of resorcinol diglycidyl ether, diglycidyl phthalate, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, 1,6-bis(2,3-epoxypropoxy)naphthalene, and 4,4'-bis(2,3-epoxypropoxy)biphenyl. The aromatic hydrocarbon triepoxide includes at least one of the following: triglycidyl p-aminophenol, F51 bisphenol A type phenolic epoxy resin having the structure of formula (1), and o-cresol epoxy resin having the structure of formula (2). The aromatic hydrocarbon tetraepoxide includes at least one of N,N,N',N'-tetraglycidyl-m-phenylenediamine, F51 bisphenol A type phenolic epoxy resin having the structure of formula (3), and o-cresol epoxy resin having the structure of formula (4). Equation (1); Equation (2); Equation (3); Equation (4).

2. The preparation method according to claim 1, characterized in that, The network structure can be a two-dimensional network structure or a three-dimensional network structure.

3. The preparation method according to claim 1, characterized in that, In the heating crosslinking step, the reaction temperature is 45℃~90℃ and the reaction time is 2 h~24 h.

4. The preparation method according to claim 1, characterized in that, The molar ratio of the epoxy functional group in the aromatic hydrocarbon polyepoxide to the amino group in the organic amine is (0.80~2.00):1; and / or, The mass ratio of the organic amine to the carrier is (0.25~2.30):

1.

5. The preparation method according to claim 1, characterized in that, The carrier comprises at least one of nano-silica, nano-alumina, zeolite molecular sieve, resin, or metal-organic framework compound; and / or, The organic amine includes at least one of tetraethylenepentamine, pentaethylenehexamine, triethylenetetramine, and polyethyleneimine.

6. The preparation method according to any one of claims 1-5, characterized in that, In the step of impregnating the carrier with the impregnation solution, the method for preparing the impregnation solution includes: dissolving the organic amine and the aromatic hydrocarbon polyepoxide compound in a solvent to obtain the impregnation solution; The solvent includes at least one of methanol, ethanol, isopropanol, n-butanol, and ethylene glycol.

7. The preparation method according to claim 6, characterized in that, After the heating crosslinking step, the preparation method further includes a post-processing step: drying the solvent at 60℃~80℃ in a vacuum or non-reactive gas environment for 3h~6h.

8. A CO2 adsorbent, characterized in that, The CO2 adsorbent is prepared by the preparation method according to any one of claims 1-7.

9. An application of a CO2 adsorbent, characterized in that, The CO2 adsorbent is the CO2 adsorbent according to claim 8, and the CO2 adsorbent is used to capture CO2.

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