Amino adsorption material for separating CO2 from waste gas as well as preparation and application of amino adsorption material

Abstract

The invention discloses an amino adsorption material for separating CO2 from waste gas as well as preparation and application of the amino adsorption material. The preparation method of the adsorption material comprises the following steps: obtaining a double-site porous polymer carrier with cyano and chloromethyl; carrying out substitution reaction on a hydroxyl compound and the double-site porous polymer carrier to obtain an intermediate product; an amino compound and the intermediate product are subjected to an addition reaction, and the amino adsorption material for separating CO2 from waste gas is obtained; according to the amino adsorption material controllably grafted with the hydroxyl group and the amino group, the CO2 adsorption capacity and adsorption rate of the amino adsorption material are improved, and the stability is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of CO2 separation, and in particular to an amino adsorption material for separating CO2 from waste gas, and its preparation and application. Background Art

[0002] With the acceleration of global industrialization, the greenhouse effect caused by carbon dioxide (CO2) emissions is becoming increasingly severe. The development of efficient CO2 adsorbents has become a core requirement for mitigating climate change. Solid amine adsorbents are considered one of the most promising solutions due to their high CO2 adsorption capacity and selectivity. However, the preparation technology of traditional solid amine adsorbents still faces significant bottlenecks. Especially in low-humidity environments, existing materials are difficult to achieve the synergistic optimization of adsorption capacity, kinetic rate, and long-term stability, which seriously restricts their large-scale industrial application.

[0003] At present, the existing technology has the following key defects: First, under low CO2 concentration or low humidity conditions, the adsorbent has insufficient or uneven amino group loading, resulting in a significant reduction in effective adsorption sites and a significant reduction in adsorption capacity. For example, due to the aggregation of amine groups, the adsorbent based on a simple impregnation method has a sharp drop in adsorption efficiency in low-concentration CO2 gas streams, making it difficult to achieve rapid dynamic adsorption. Secondly, the stability of existing materials is difficult to meet actual needs, especially in the cyclic adsorption-desorption process, where the amine groups are prone to oxidative degradation or collapse of the carrier structure, resulting in a significant attenuation of the adsorption capacity with increasing cycle times. Some adsorbents have weak interfacial bonding between the carrier and the amine group in a low humidity environment, further exacerbating the problem of active component loss. In addition, although the low humidity environment avoids competitive adsorption of water vapor, existing adsorbents still face challenges such as thermal migration of amine groups or destruction of the carrier pore structure, making it difficult to maintain stable adsorption performance in long-term operation.

[0004] In summary, existing technologies urgently need to overcome the performance challenge of balancing adsorption capacity, adsorption rate, and stability in low-humidity environments. Developing a CO2 adsorption material with high amine group utilization, rapid mass transfer kinetics, and resistance to degradation is a key technical direction for achieving efficient operation in scenarios such as industrial waste gas treatment and direct air capture. Summary of the Invention

[0005] In view of this, the present application provides an amino adsorption material for separating CO2 from exhaust gas, and its preparation and application, to solve the problem of how to simultaneously improve the adsorption amount, adsorption rate and stability of amino adsorption material for CO2.

[0006] In order to achieve the above technical objectives, this application adopts the following technical solutions:

[0007] In a first aspect, the present application provides a method for preparing an amino adsorbent material for separating CO2 from exhaust gas, comprising the following steps:

[0008] A dual-site porous polymer support with cyano and chloromethyl groups was obtained;

[0009] The hydroxy compound is subjected to a substitution reaction with the dual-site porous polymer support to obtain an intermediate product;

[0010] The amino compound is subjected to an addition reaction with the intermediate product to obtain an amino adsorbent material for separating CO2 from exhaust gas.

[0011] Preferably, the steps for obtaining a dual-site porous polymer support having cyano and chloromethyl groups are as follows:

[0012] A porous polymer carrier containing cyano groups is obtained by carrying out an oil-in-water suspension polymerization reaction using a mixture of water, a dispersant, and an inorganic salt as the aqueous phase and a mixture of a cyano functional monomer, an auxiliary monomer, a crosslinking agent, a porogen, and an initiator as the oil phase;

[0013] The invention adopts Lewis acid as catalyst, a porous polymer support containing cyano group and chloromethyl ether or chloroacetyl chloride as raw materials to carry out chloromethylation reaction to obtain a dual-site porous polymer support.

[0014] Preferably, the temperature of the oil-in-water suspension polymerization reaction is and the stirring speed is 100-300 r / min.

[0015] Preferably, the temperature of the chloromethylation reaction is 30-50°C.

[0016] Preferably, the cyano functional monomer includes one or more of acrylonitrile, cyanophenylcyclohexylethylene, and 3-fluoro-4-cyanophenylcyclohexylethylene, and styrene serves as an auxiliary monomer and can provide a benzene ring as a chloromethyl site; the crosslinking agent includes one or more of divinylbenzene, trimethylolpropane triacrylate, and ethylene glycol dimethacrylate; the initiator includes one or more of tert-butyl peroxide, benzoyl peroxide, and azobisisobutyronitrile; the porogen includes one or more of toluene, n-heptane, methyl isobutyl carbinol, chlorobenzene, and polyethylene glycol; the dispersant includes one or more of gelatin, polyvinyl alcohol, hydroxyethyl methyl cellulose, and carboxymethyl cellulose; and the inorganic salt includes one or more of sodium chloride, calcium chloride, sodium sulfate, and potassium sulfate.

[0017] Preferably, the molar ratio of the cyano functional monomer to the chloromethyl functional group is 0.5-3.0:1.0.

[0018] Preferably, the hydroxy compound includes one or more of ethylene glycol, glycerol, tris(hydroxymethyl)aminomethane, ascorbic acid, pentaerythritol, and meglumine; the substitution reaction temperature is 60-80° C., and the molar ratio of the hydroxy compound to the chloromethyl functional group is 1.0-3.0:1.0.

[0019] Preferably, the amino compound includes one or more of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, polyethyleneimine, methylamine, and ethylamine; the temperature of the addition reaction is 120-140° C., and the molar ratio of the amino compound to the cyano functional group is 1.0-3.0:1.0.

[0020] In a second aspect, the present application provides an amino adsorption material for separating CO2 from exhaust gas.

[0021] In a third aspect, the present application provides an application of an amino adsorption material for separating CO2 from exhaust gas under conditions of air humidity of 5-80%.

[0022] The beneficial effects of the present application are as follows: In the present application, a porous polymer carrier containing two different reactive sites (cyano and chloromethyl) is prepared. Based on the principle that the reactivity of chloromethyl is significantly better than that of cyano, a hydroxyl compound is first subjected to a substitution reaction with the chloromethyl group on the porous polymer carrier, so that the functional group (monohydroxy or polyhydroxy) of the hydroxyl compound is grafted onto the porous polymer carrier. Then, an amino compound is subjected to an addition reaction with the unreacted cyano group, so that the amino group is grafted onto the porous polymer carrier. The grafting method is optimized, and an amino adsorption material with controllable grafting of hydroxyl groups and amino groups is obtained, thereby achieving an increase in the adsorption amount and adsorption rate of CO2 by the amino adsorption material and an improvement in its stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the preparation process of the amino resin of the present invention;

[0024] Figure 2 Comparison of the adsorption and penetration curves of the amino resin of Comparative Example 2 and the amino resin of Example 4;

[0025] Figure 3 This is a diagram showing the adsorption speed of the amino resin of Comparative Example 1 and the amino resin of Example 1. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0027] like Figure 1 As shown, the present application provides a method for preparing an amino adsorbent material for separating CO2 from exhaust gas, comprising the following steps:

[0028] S1. Obtaining a dual-site porous polymer support with cyano and chloromethyl groups;

[0029] S2. performing a substitution reaction between the hydroxy compound and the dual-site porous polymer support to obtain an intermediate product;

[0030] S3. performing an addition reaction on the amino compound and the intermediate product to obtain an amino adsorbent material for separating CO2 from exhaust gas.

[0031] The polymer carrier obtained by traditional suspension polymerization usually contains only one active site, such as epoxy, ester, cyano, etc. In the subsequent functionalized reaction process, since functional groups such as hydroxyl and amino have similar reactivity, it is usually difficult to control the reaction degree of each functional monomer separately, so that it is difficult to obtain a polymer carrier with functional group modification of the required ratio. In the present application, a porous polymer carrier containing two different reactive sites (cyano and chloromethyl) is prepared, and the reactivity of chloromethyl is significantly better than the reactivity of cyano. First, a hydroxy compound is subjected to a substitution reaction with the chloromethyl on the porous polymer carrier, so that the functional group (monohydroxy or polyhydroxy) of the hydroxy compound is grafted on the porous polymer carrier, and then an amino compound is subjected to an addition reaction with the cyano group that has not yet reacted, so that the amino group is grafted on the porous polymer carrier, and the grafting method is optimized. An amino adsorbent material having a quantitatively controllable content and ratio of grafted hydroxyl groups and amino groups is obtained, and the adsorption capacity, adsorption rate and stability of the amino adsorbent material to CO2 are improved.

[0032] Specifically, due to the controllable grafting of hydroxyl groups and amino groups on the porous polymer carrier, the amino adsorption material obtained in this application has the following advantages:

[0033] 1. The synergistic improvement of the adsorption capacity and adsorption rate of CO2 by amino adsorbent materials is due to the following reasons: on the one hand, the introduction of hydroxyl groups changes the hydrophilicity of the carrier surface, so that when the subsequent macromolecular amine is grafted onto the carrier, the surface hydroxyl sites and amino sites produce hydrogen bond interactions, reducing the gas diffusion resistance, which will promote the relaxation of amino groups, especially long-chain macromolecular amines such as PEI, avoid the entanglement and accumulation of amine molecular chains, reduce the resistance of gas diffusion to the inner amino group, and promote the diffusion of CO2, thereby improving the utilization rate of amino groups, significantly improving the adsorption kinetics, and being able to achieve a higher adsorption capacity in a shorter time, thereby improving C O2 capture efficiency; on the other hand, the hydroxyl group will participate in the reaction with CO2 together with the amino group, thereby increasing the adsorption capacity of the amino resin under dry conditions. For example, in a high humidity environment, water, carbon dioxide and amino groups will react in a ratio of 1:1:1 to capture carbon dioxide. In an extremely cold or high temperature environment with low humidity, amino groups and carbon dioxide will react in a ratio of 2:1 to capture carbon dioxide, resulting in a decrease in adsorption capacity. However, the introduction of hydroxyl groups can replace the role of water molecules and cooperate with amino groups to adsorb carbon dioxide, ensuring that the adsorption capacity of the material can maintain a high adsorption capacity even under dry conditions.

[0034] 2. The stability of amino adsorption materials is improved because, on the one hand, the amine group and the carrier are connected by a stable chemical bond, which can effectively resist structural changes during the cyclic adsorption-desorption process; on the other hand, the hydroxyl group and the amino group form hydrogen bonds, reducing the risk of oxidative degradation of the amine group when exposed to oxygen.

[0035] The steps for obtaining a dual-site porous polymer carrier having cyano and chloromethyl groups in this application are as follows:

[0036] S11. A mixture of water, a dispersant, and an inorganic salt as the aqueous phase and a mixture of a cyano-functional monomer, an auxiliary monomer, a crosslinking agent, a porogen, and an initiator as the oil phase are subjected to an oil-in-water suspension polymerization reaction to obtain a porous polymer carrier containing a cyano group;

[0037] S12. Using Lewis acid as a catalyst, a porous polymer support containing a cyano group and chloromethyl ether or chloroacetyl chloride as raw materials, a chloromethylation reaction is carried out to obtain a dual-site porous polymer support.

[0038] As known to those skilled in the art, it is difficult to simultaneously obtain a porous polymer carrier containing two active sites during the synthesis of porous polymers due to the differences in reactivity and polymerization rate between monomers. In order to controllably graft amino groups and hydroxyl groups on the carrier, the present application adopts a two-step method so that the porous polymer carrier contains two active sites (cyano and chloromethyl) with large activity differences after secondary functionalization. Chloromethyl is a highly active site with much greater reactivity than cyano. The reaction temperature of cyano is usually greater than 120°C, and that of chloromethyl is usually less than 80°C. Therefore, under mild conditions, chloromethyl reacts with various groups, such as hydroxyl, to ensure the controlled and accurate introduction of hydroxyl groups, while avoiding the reaction between hydroxyl compounds and cyano groups, leaving cyano reaction active sites for the subsequent introduction of amino groups. In addition, the advantages of the two-step method for preparing porous polymer carriers in the present application are: 1. From the perspective of group introduction, the introduction order of the present application is to introduce cyano group first and then introduce chloromethyl group. Because the reaction activity of cyano group is relatively low, by controlling the lower reaction temperature, such as below 50°C, better stability can be guaranteed when introducing chloromethyl group at the second active site, avoiding side reactions, thereby leaving sufficient sites for subsequent amino functionalization; 2. From the perspective of preparation method, the present application uses water-in-oil suspension polymerization reaction to introduce cyano group, which is beneficial to the subsequent chloromethylation reaction. The introduction of cyano group by this method can form a uniform porous structure. Its high specific surface area and open pores provide sufficient diffusion channels for chloromethylation, thereby promoting the success rate of subsequent modification.

[0039] In some embodiments, the temperature of the oil-in-water suspension polymerization reaction is 60-90° C., and the stirring speed is 100-300 r / min.

[0040] If the temperature is too high, polymerization will tend to be too rapid, leading to polymer adhesion and poor molding. If the temperature is too low, the degree of polymerization will be insufficient, the pore structure will be poor, and the particle strength will be low. The stirring rate of this application is combined with the selection of porogens such as toluene and methyl isobutyl carbinol to achieve a particle size range of 100-1000μm for the adsorption resin material obtained. This particle size range is conducive to the subsequent use of this material in carbon capture equipment, ensuring that the adsorption bed has a low pressure drop and high adsorption efficiency. Too small a particle size will lead to excessive pressure in the adsorption bed, while too large a particle size will lead to loose layer stacking, too short a residence time of the airflow on the material surface, and reduced CO2 capture efficiency.

[0041] In some embodiments, the temperature of the chloromethylation reaction is 30-50° C., preferably, the temperature of the chloromethylation reaction is 40° C. At this temperature, the cyano group maintains a high stability, and the introduction of the chloromethyl group does not lead to the deactivation of the cyano group, providing a guarantee for the subsequent secondary functionalization of the cyano group.

[0042] In this embodiment, the Lewis acid includes but is not limited to one or more of aluminum chloride, zinc chloride, and ferric chloride. Under the action of a catalyst and a certain temperature, chloromethyl ether or chloroacetyl chloride reagent is used to chloromethylate the benzene ring structure in the porous polymer support. The benzene ring structure comes from the auxiliary monomer styrene in the suspension polymerization step, thereby introducing chloromethyl active sites on the resin surface; if the temperature is too high, it is easy to induce a cyanide side reaction, resulting in the inactivation of the cyanide group; if the temperature is too low, the degree of chloromethylation is not high, which affects the subsequent introduction of hydroxyl functional groups.

[0043] In some embodiments, the cyano-functional monomer includes one or more of acrylonitrile, cyanophenylcyclohexylethylene, and 3-fluoro-4-cyanophenylcyclohexylethylene, and styrene is an auxiliary monomer that can provide a benzene ring to serve as an additional chloromethylation site; the cross-linking agent includes one or more of divinylbenzene, trimethylolpropane triacrylate, and ethylene glycol dimethacrylate; the initiator includes one or more of tert-butyl peroxide, benzoyl peroxide, and azobisisobutyronitrile; the porogen includes one or more of toluene, n-heptane, methyl isobutyl carbinol, chlorobenzene, and polyethylene glycol; the dispersant includes one or more of gelatin, polyvinyl alcohol, hydroxyethyl methyl cellulose, and carboxymethyl cellulose; and the inorganic salt includes one or more of sodium chloride, calcium chloride, sodium sulfate, and potassium sulfate.

[0044] The cyano functional monomer of the present application is a compound or mixture containing a double bond at one end and a cyano active site at the other end that can react secondary. Preferably, the cyano functional monomer is cyanophenylcyclohexylethylene or acrylonitrile. The crosslinker of the present application is a divinyl or trivinyl containing free radical polymerization. Preferably, the crosslinker is divinylbenzene; the initiator of the present application is an organic peroxide or azo compound, and the amount of the initiator is 1-2% of the total mass of the oil phase; the porogen of the present application is an organic solvent that does not participate in the polymerization; the dispersant of the present application is a water-soluble polymer. In the aqueous phase of the present application, the mass ratio of water, dispersant, and inorganic salt is 100:1:2, and in the oil phase, the mass ratio of cyano functional monomer, auxiliary monomer, crosslinker, porogen, and initiator is 20-60:70-30:10:100:1; by controlling the ratio of each raw material in the oil phase, the ratio of cyano to chloromethyl is controlled, and then the grafting ratio of amino and hydroxyl groups is controlled.

[0045] In this application, the ratio of cyano groups to chloromethyl groups grafted onto a porous polymer support is controlled by controlling the amounts of cyano-functional monomers and chloromethyl ether. The molar ratio of cyano groups to chloromethyl groups is 0.5-3.0:1.0. The amount of cyano groups determines the amount of subsequent functionalized amino groups, while the amount of chloromethyl groups determines the amount of subsequent functionalized hydroxyl groups. Too few cyano groups will result in too few amino groups on the support surface, leading to low CO2 adsorption capacity. Too low a chloromethyl content will result in too few hydroxyl groups on the support surface, making it impossible to control the surface properties of the adsorbent, affecting adsorption efficiency.

[0046] The hydroxy compound of the present application includes one or more of ethylene glycol, glycerol, tris(hydroxymethyl)aminomethane, ascorbic acid, pentaerythritol, and meglumine; the temperature of the substitution reaction is 60-80° C., and the molar ratio of the hydroxy compound to the chloromethyl active site is 1.0-3.0:1.0.

[0047] In some embodiments, the hydroxyl compound is meglumine and / or glycerol. The hydroxyl compound of the present application contains a monohydroxyl group or a polyhydroxyl group, and can undergo a substitution reaction with a chloromethyl group at 60-80° C. If the reaction temperature is too high, the hydroxyl compound will react with the cyano group, affecting the subsequent amino functionalization of the cyano group; if the reaction temperature is too low, the chloromethyl group will not react sufficiently, resulting in too little hydroxyl content, and the surface properties of the carrier cannot be adjusted.

[0048] The amino compound of the present application includes one or more of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, polyethyleneimine, methylamine, and ethylamine; the temperature of the addition reaction is 120-140° C., and the molar ratio of the amino compound to the cyano active site is 1.0-3.0:1.0.

[0049] In the addition reaction of the present application, if the reaction temperature is too low, the amino functionalization efficiency is low, resulting in a low amino content on the carrier surface, which in turn affects the CO2 capture efficiency.

[0050] The present application provides an amino adsorption material for separating CO2 from exhaust gas.

[0051] The present application provides an application of an amino adsorption material for separating CO2 from exhaust gas under conditions of air humidity of 5-80%.

[0052] This application optimizes the grafting method to uniformly and densely introduce amino groups and hydroxyl groups on the surface of the adsorption material, greatly increasing the effective adsorption sites for CO2 and significantly improving the adsorption capacity, adsorption rate and stability of CO2 under low concentration and dry conditions.

[0053] The present invention is further described below through specific examples.

[0054] Example 1

[0055] A method for preparing an amino adsorbent material for separating CO2 from exhaust gas comprises the following steps:

[0056] S1. Take 40g of styrene, 10g of divinylbenzene, 50g of acrylonitrile, 60g of toluene, 40g of n-heptane, and 1.0g of benzoyl peroxide to form the oil phase, and take 900g of water, 18g of gelatin, and 18g of calcium chloride to form the aqueous phase; after dissolving and mixing the aqueous phase at 60°C, add the oil phase, mechanically stir at 200rpm, keep warm at 65°C for 2h, keep warm at 75°C for 2h, and keep warm at 90°C for 5h. After the reaction is completed, use ethanol to remove the unreacted raw materials and solvent to obtain a porous polymer carrier containing cyano sites; take 5.0g of the dried porous polymer carrier containing cyano groups, add 50ml of chloromethyl ether to swell overnight, add 5g of zinc chloride as a catalyst, react at 45°C for 8h, wash with alcohol and dry to obtain a dual-active site resin carrier containing chloromethyl and cyano groups, i.e., a dual-site porous polymer carrier.

[0057] S2. 5 g of the dual-site porous polymer support was added to 25 ml of glycerol, 1.0 g of sodium hydroxide catalyst was added, and the reaction was carried out at 80 ° C for 8 hours to obtain an intermediate product;

[0058] S3. The intermediate product is then placed in 25 ml of tetraethylenepentamine solution, the reaction temperature is controlled at 120°C for 8 hours, and then washed with ethanol to remove unreacted small molecular amines to obtain an amino adsorption material.

[0059] Example 2

[0060] A method for preparing an amino adsorbent material for separating CO2 from waste gas, the other contents of which are the same as those of Example 1, except that glycerol is replaced by meglumine, and tetraethylenepentamine is replaced by triethylenetetramine.

[0061] Example 3

[0062] A method for preparing an amino adsorbent material for separating CO2 from exhaust gas, the other contents of which are the same as those of Example 1, except that glycerol is replaced by pentaerythritol, and tetraethylene pentamine is replaced by polyethyleneimine.

[0063] Example 4

[0064] A method for preparing an amino adsorbent material for separating CO2 from waste gas, the other contents of which are the same as those of Example 1, except that glycerol is replaced by meglumine.

[0065] Example 5

[0066] A method for preparing an amino adsorbent material for separating CO2 from exhaust gas, the other contents of which are the same as those of Example 3, except that acrylonitrile in step S1 is replaced by cyanophenylcyclohexylethylene.

[0067] Comparative Example 1

[0068] A method for preparing an amino adsorption material, the other contents of which are the same as those of Example 1, except that step S2 is not included.

[0069] Comparative Example 2

[0070] A method for preparing an amino adsorption material, the other contents are the same as those of Example 3, except that step S2 is not included.

[0071] Comparative Example 3

[0072] A method for preparing an amino adsorption material, the other contents of which are the same as those of Example 1, except that step S3 is not included.

[0073] Comparative Example 4

[0074] A method for preparing an amino adsorption material, the other contents are the same as those in Example 3, except that in step S1, the amount of acrylonitrile used is 20 g, and the amount of styrene used is 70 g.

[0075] Comparative Example 5

[0076] A method for preparing an amino adsorption material, the other contents are the same as those in Example 3, except that in step S1, the amount of acrylonitrile used is 55 g, and the amount of styrene used is 35 g.

[0077] Testing and Evaluation

[0078] Figure 2 Comparison of the adsorption and penetration curves of the amino resin of Comparative Example 2 and the amino resin of Example 4. Figure 3 This is a diagram showing the adsorption capacity change of the amino resin of Comparative Example 1 and the amino resin of Example 1.

[0079] The carbon dioxide adsorption performance of various amino adsorbent materials was tested: 1. In a fixed-bed adsorption apparatus, amino resin was packed into an adsorption column. Air was introduced at a constant temperature of 25°C. The carbon dioxide concentration in the inlet and outlet gases was monitored using a gas analyzer to calculate the carbon dioxide adsorption capacity of the amino resin. The desorption temperature was 90°C, and the vacuum was maintained for 30 minutes. These adsorption and desorption conditions were repeated 10 times. 2. Rapid thermogravimetric testing was performed on 10 mg of the prepared adsorbent. The adsorption temperature and atmosphere were 30°C, 15% CO2, and the adsorption time was 60 minutes. The desorption temperature and atmosphere were 90°C, 100% Ar, and the desorption time was 30 minutes. The results of adsorption capacity, adsorption rate, and adsorption stability are shown in Table 1.

[0080] Table 1 Test results

[0081]

[0082]

[0083] According to the analysis and comparison of the above test data, the adsorption material of Example 1 contains both propylene glycol and tetraethylene pentamine functional groups, the adsorption material of Comparative Example 1 contains only tetraethylene pentamine, and Comparative Example 3 contains only propylene glycol. Compared with the three, Example 1 has the highest CO2 adsorption capacity, and the adsorption capacity under low humidity and high humidity conditions is not much different. Under high humidity conditions, the adsorption capacity of Comparative Example 1 is slightly lower, but the adsorption rate is slower. Under low humidity conditions, the adsorption capacity is significantly reduced, indicating that the presence of hydroxyl groups on the carrier surface can significantly improve the utilization rate of amino groups under high humidity and low humidity conditions. When there are only hydroxyl groups on the surface of the material, it can hardly adsorb CO2; the adsorption material of Example 4 contains more Comparative Example 2 contains hydroxyl meglumine and tetraethylenepentamine, while Comparative Example 2 contains only macromolecular polyethyleneimine. The adsorption data of the two show that more hydroxyl groups can improve the efficiency of amino groups to a certain extent, especially under low humidity conditions. The comparison is more obvious, and more hydroxyl groups significantly increase the adsorption rate of amino groups, so that the adsorption reaches equilibrium faster. The adsorption data of Comparative Examples 4 and 5 also show that only when the amount of amino groups and hydroxyl groups is within a certain range, the CO2 adsorption capacity of the material has an optimal value. Too few amino groups lead to a significant decrease in the adsorption capacity. Too many amino groups and fewer hydroxyl groups will also reduce the adsorption rate of the material and reduce the synergistic effect of hydroxyl groups. Especially under low humidity conditions, the result gap is more obvious.

[0084] The above are only preferred specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or replacements that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing an amino adsorbent material for separating CO2 from exhaust gas, characterized in that: The following steps are involved: A dual-site porous polymer support with cyano and chloromethyl groups was obtained; performing a substitution reaction between the hydroxy compound and the dual-site porous polymer support to obtain an intermediate product; The amino compound is subjected to an addition reaction with the intermediate product to obtain the amino adsorption material for separating CO2 from exhaust gas.

2. The method for preparing an amino adsorbent material for separating CO2 from exhaust gas according to claim 1, characterized in that: The steps for obtaining the dual-site porous polymer carrier having cyano and chloromethyl groups are as follows: A porous polymer carrier containing cyano groups is obtained by carrying out an oil-in-water suspension polymerization reaction using a mixture of water, a dispersant, and an inorganic salt as the aqueous phase and a mixture of a cyano functional monomer, an auxiliary monomer, a crosslinking agent, a porogen, and an initiator as the oil phase; A Lewis acid is used as a catalyst, and the porous polymer carrier containing a cyano group and chloromethyl ether or chloroacetyl chloride are used as raw materials to carry out a chloromethylation reaction to obtain the dual-site porous polymer carrier.

3. The method for preparing an amino adsorbent material for separating CO2 from exhaust gas according to claim 2, characterized in that: The temperature of the oil-in-water suspension polymerization reaction is 60-90° C., and the stirring speed is 100-300 r / min.

4. The method for preparing an amino adsorbent material for separating CO2 from exhaust gas according to claim 2, characterized in that: The temperature of the chloromethylation reaction is 30-50°C.

5. The method for preparing an amino adsorbent material for separating CO2 from exhaust gas according to claim 2, characterized in that: The cyano functional monomer includes one or more of acrylonitrile, cyanophenylcyclohexylethylene, and 3-fluoro-4-cyanophenylcyclohexylethylene; the auxiliary monomer is styrene; the crosslinking agent includes one or more of divinylbenzene, trimethylolpropane triacrylate, and ethylene glycol dimethacrylate; the initiator includes one or more of tert-butyl peroxide, benzoyl peroxide, and azobisisobutyronitrile; the porogen includes one or more of toluene, n-heptane, methyl isobutyl carbinol, chlorobenzene, and polyethylene glycol; the dispersant includes one or more of gelatin, polyvinyl alcohol, hydroxyethyl methyl cellulose, and carboxymethyl cellulose; and the inorganic salt includes one or more of sodium chloride, calcium chloride, sodium sulfate, and potassium sulfate.

6. The method for preparing an amino adsorbent material for separating CO2 from exhaust gas according to claim 2, characterized in that: The molar ratio of the cyano functional group to the chloromethyl functional group is 0.5-3.0:1.

0.

7. The method for preparing an amino adsorbent material for separating CO2 from exhaust gas according to claim 1, characterized in that: The hydroxy compound includes one or more of ethylene glycol, glycerol, tris(hydroxymethyl)aminomethane, ascorbic acid, pentaerythritol, and meglumine; the temperature of the substitution reaction is 60-80° C., and the molar ratio of the hydroxy compound to the chloromethyl functional group is 1.0-3.0:1.

0.

8. The method for preparing an amino adsorbent material for separating CO2 from exhaust gas according to claim 1, characterized in that: The amino compound includes one or more of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, polyethyleneimine, methylamine, and ethylamine; the temperature of the addition reaction is 120-140° C., and the molar ratio of the amino compound to the cyano functional group is 1.0-3.0:1.

0.

9. An amino adsorption material for separating CO2 from exhaust gas obtained by the preparation method according to any one of claims 1 to 8.

10. Use of the amino adsorbent material according to claim 9 for separating CO2 from exhaust gas under conditions of air humidity of 5-80%.

Images