A hollow porous amino resin for separating CO2 from the atmosphere and its preparation and application

Abstract

The present invention discloses a hollow porous amino-based resin for separating CO2 from the atmosphere, and its preparation and application. The preparation method comprises the following steps: dispersing a template and a polyhydroxy biomass compound into an alcohol solution, adding a porogen, and performing a template-directed synthesis reaction to obtain an emulsion containing micelles; adding an alcohol solution of an organic amine into the emulsion, performing an aggregation and assembly reaction, and then centrifuging and washing to obtain a hollow amino-based resin precursor material; adding the hollow amino-based resin precursor material into a curing agent solution, performing a cross-linking and curing reaction to obtain a cured material; dispersing the cured material in a solvent, heating the reaction, and obtaining a hollow porous amino-based resin for separating CO2 from the atmosphere. By combining the steps of the present application, an amino-based resin with a large amine loading and a stable hollow porous structure is finally obtained, and the hollow porous amino-based resin achieves the effect of taking into account the adsorption capacity, adsorption rate and adsorption stability of the solid amine.

Description

Technical Field

[0001] The present invention relates to the technical field of separating CO2 from air, and in particular to a hollow porous amino-based resin for separating CO2 from the atmosphere, and its preparation and application. Background Art

[0002] Carbon capture, utilization, and storage (CCUS) is considered one of the key technologies for achieving carbon neutrality. CCUS technology can capture CO2 from industrial point sources, reducing greenhouse gas emissions. However, traditional point-source capture technologies for power plants and industrial flue gases cannot capture all emitted CO2. In addition, CO2 emissions from mobile emission sources, such as the transportation sector, account for approximately 50% of total emissions, and carbon reduction cannot be achieved through traditional carbon capture devices. Developing direct air capture (DAC) technology to capture excess CO2 from the atmosphere is an important means to achieve carbon neutrality. DAC technology has the advantages of flexible site selection, low energy consumption and transportation costs, and can solve the problem of distributed CO2 emissions. By achieving net negative CO2 emissions through DAC technology and then using the captured CO2 to form a closed carbon cycle, net zero CO2 emissions can be achieved.

[0003] Solid-state amine adsorption is a novel carbon capture technology. It boasts advantages such as high adsorption capacity, strong selectivity, easy material preparation, mild operating conditions, and potentially low energy consumption. It is considered the most promising air carbon capture technology for large-scale application. The most important evaluation criteria for solid-state amine performance are adsorption capacity and rate, particularly in low CO₂ concentration environments, where high adsorption rate is even more crucial. Currently, solid-state amines prepared by impregnation methods suffer from issues such as amine loss and poor stability. These issues can be avoided by preparing solid-state amines via grafting (or in-situ loading). However, solid-state amines prepared by grafting methods present several challenges. For example, low amine loading leads to decreased adsorption capacity, while increasing the amine loading can lead to clogging of the amine's internal pore structure, resulting in slow adsorption rates and inefficient utilization of the amine functional groups. Consequently, existing technologies for preparing solid-state amines for atmospheric CO₂ separation struggle to balance adsorption capacity, rate, and stability.

[0004] Therefore, it is necessary to provide a solution that can take into account the adsorption capacity, adsorption rate and adsorption stability of solid amines. Summary of the Invention

[0005] In view of this, the present application provides a hollow porous amine-based resin for separating CO2 from the atmosphere, and its preparation and application, to solve the problem of how to balance the adsorption capacity, adsorption rate and adsorption stability of solid amines.

[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 a hollow porous amino resin for separating CO2 from the atmosphere, comprising the following steps:

[0008] S1. Dispersing the template and the polyhydroxy biomass compound into an alcohol solution, adding a porogen, and performing a template-directed synthesis reaction to obtain an emulsion containing micelles;

[0009] S2. An alcoholic solution of an organic amine is added to the emulsion to perform an aggregation assembly reaction, followed by centrifugation and washing to obtain a hollow amino resin precursor material;

[0010] S3. The hollow amino resin precursor material is added to the curing agent solution to undergo a cross-linking curing reaction to obtain a cured material;

[0011] S4. The solidified material is dispersed in a solvent and heated to react, thereby obtaining a hollow porous amino resin for separating CO2 from the atmosphere.

[0012] Preferably, the template includes one or more of F127, P123, and AEO9; and / or, the porogen includes one or more of trimethylbenzene and N,N-dimethylbenzylamine; and / or, the polyhydroxy biomass compound includes one or more of tannic acid, catechol, and gallic acid.

[0013] Preferably, the organic amine includes one or more of tetraethylenepentamine, pentaethylenehexamine, triethylenetetramine, and polyethyleneimine.

[0014] Preferably, in step S2, the washing step is: washing with ethanol and water alternately.

[0015] Preferably, the molar ratio of the porogen to the polyhydroxy biomass compound is 0.01-0.1:1; the molar ratio of the porogen to the alcohol solution is 1-5:500; and the molar ratio of the template to the porogen is 1-10:1.

[0016] Preferably, the temperature of the template-directed synthesis reaction is 25-45°C.

[0017] Preferably, the temperature of the aggregation assembly reaction is 25-65°C.

[0018] Preferably, the temperature of the curing reaction is 30-60°C, the curing agent includes one or more of formaldehyde, glutaraldehyde, and trioxymethylene; and the temperature of the heating reaction is 80-140°C.

[0019] In a second aspect, the present application provides a hollow porous amino resin for separating CO2 from the atmosphere.

[0020] In a third aspect, the present application provides an application of a hollow porous amino-based resin for separating CO2 from the atmosphere and for capturing CO2 in the air.

[0021] The beneficial effects of the present application are as follows: through the coordination of the various steps of the present application, an amino resin with a large and stable hollow porous structure is finally obtained, thereby ensuring the amino loading and its stability, and the mesoporous structure can overcome the defect of blockage of the internal pore structure of the solid amine due to the increase in the amino loading, thereby improving the adsorption rate of the material, and finally achieving the effect of the hollow porous amino resin taking into account the adsorption capacity, adsorption rate and adsorption stability of the solid amine. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the SEM image of the material obtained in Example 1 of this application. DETAILED DESCRIPTION

[0023] 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.

[0024] The inventor unexpectedly discovered that

[0025] The present application provides a method for preparing a hollow porous amino resin for separating CO2 from the atmosphere, comprising the following steps:

[0026] S1. Dispersing the template and the polyhydroxy biomass compound into an alcohol solution, adding a porogen, and performing a template-directed synthesis reaction to obtain an emulsion containing micelles;

[0027] S2. An alcoholic solution of an organic amine is added to the emulsion to perform an aggregation assembly reaction, followed by centrifugation and washing to obtain a hollow amino resin precursor material;

[0028] S3. The hollow amino resin precursor material is added to the curing agent solution to undergo a cross-linking curing reaction to obtain a cured material;

[0029] S4. The solidified material is dispersed in a solvent and heated to react, thereby obtaining a hollow porous amino resin for separating CO2 from the atmosphere.

[0030] The reaction process of this application is as follows:

[0031] The template, polyhydroxy biomass compound, and porogen in step S1 interact with each other to form a micelle structure with the porogen inside and the template-polyhydroxy biomass compound complex outside. As time goes by, the polyhydroxy biomass compound continues to distribute at the micelle interface to form a composite emulsion. In step S2, the micelles (emulsion droplets) in the composite emulsion have high surface energy and need to adsorb substances from the outside to reduce the surface energy. Therefore, driven by the interfacial energy of the emulsion and the hydroxyl-amine group effect, the organic amine aggregates and assembles at the interface of the composite emulsion and further reacts with the polyhydroxy compound to obtain small-sized nanoparticles. As time goes by, large-sized nanoparticles with a core-shell structure are continuously formed, and the interfacial energy of the emulsion also continues to decrease. Finally, the nanoparticles are precipitated. Then, the template and porogen are removed by washing to form a hollow and porous amino resin precursor material.

[0032] After the curing in step S3, the stability of the amino groups can be ensured to prevent the amino groups from falling off;

[0033] Finally, in step S4, a low-temperature solvent thermal treatment transforms the interaction between the amino groups and the hydroxyl groups from hydrogen bonds to chemical bonds, more stably facilitating the loading of the amino groups into the material and preventing amine loss. It is worth noting that the solvent thermal treatment does not alter the adsorbent's morphology; it maintains a hollow, porous structure. Furthermore, the surface hydrophobicity of the material increases after solvent thermal treatment, preventing a decrease in adsorption capacity caused by excessive water absorption.

[0034] The functions of each step of the present application are as follows: Step S1 provides the necessary environment for forming an amino resin with a hollow structure and increasing the amino loading capacity; the organic amine in Step S2 is loaded on the emulsion interface under the action of interfacial energy and hydroxyl groups, and forms nanoparticles with large particle size; the template and porogen are then removed by washing, thereby forming an amino resin precursor material with a hollow structure and a large amino loading capacity; the purpose of Step S3 and Step S4 is to prevent the loss of amino groups and the collapse of the hollow structure, and to increase the hydrophobicity of the material to overcome the defect of decreased adsorption capacity caused by excessive washing. Among them, the template is an amphiphilic, hydrophobic-hydrophilic type. The hydrophilic group is combined with the polyhydroxy compound; the internal hydrophobic group is combined with the porogen to form a composite micelle, and finally the porogen is washed out by washing to form a hollow structure.

[0035] Therefore, through the coordination of the various steps of the present application, a hollow porous amino resin with a large and stable amine loading capacity is finally obtained, thereby ensuring the amine loading capacity and stability, and the mesoporous structure can overcome the defect of blockage of the internal pore structure of the solid amine due to the increase in the amine loading capacity, thereby improving the adsorption rate of the material, and finally achieving the effect of the hollow porous amino resin taking into account the adsorption capacity, adsorption rate and adsorption stability of the solid amine.

[0036] In some embodiments, the template includes one or more of F127, P123, and AEO9; and / or the porogen includes one or more of trimethylbenzene and N,N-dimethylbenzylamine; and / or the polyhydroxy biomass compound includes one or more of tannic acid, catechol, and gallic acid.

[0037] Among them, F127 and P123 are polyethylene oxide-polypropylene oxide-polyethylene oxide; AEO9 is fatty alcohol polyoxyethylene ether.

[0038] In this application, the polyol has the following characteristics: 1. It is a biomass derivative, which helps reduce the environmental burden of material preparation and realizes the utilization of renewable resources; 2. It has abundant hydroxyl sites, which helps increase the loading capacity of amine groups; 3. It contains benzene rings, which helps improve the backbone stability through π-π conjugation; 4. It contains phenolic hydroxyl groups, which facilitates hydrogen bonding with the template and can also interact with the porogen through π electrons. The template has the following characteristics: 1. It is an amphiphilic macromolecule with polyether groups, which can form strong hydrogen bonds with the polyol; 2. It has a hydrophobic alkyl chain segment (such as the polypropylene chain of F127, the polypropoxy chain of P123, and the C9 alkyl chain of AEO9). This hydrophobic segment can synergistically assemble with the long alkane chain of the porogen through hydrophobic interactions. At the same time, the hydrophilic-hydrophobic microphase separation characteristics of its block structure are used to induce the formation of micelles with a core-shell structure, which helps to cooperate with the porogen to form micelles with a specific structure. The porogen has the following characteristics: it is a hydrophobic organic compound, with typical characteristics of containing long alkane chains and aromatic structures in the molecule, being hydrophobic, with a β value greater than 0.1 and a π* value close to 0.4 in the Kamlet-Taft parameter, which is conducive to enhancing the aggregation of the micelle core through the hydrophobic association of the long alkane chain, while stabilizing the micelle interface by utilizing the π-π stacking effect of the aromatic structure, and regulating the polarity matching between the micelle and the polyhydroxy compound through the hydrogen bond acceptor capacity corresponding to the β value, and accurately controlling the degree of micelle microphase separation by combining the medium polarity characteristics of the π value. Therefore, the template, porogen, and polyhydroxy biomass compound of the present application cooperate with each other, and the polyhydroxy compound and the porogen form emulsion droplets (micelles) through hydrophobic interaction and π electron interaction respectively. The template and the polyhydroxy compound interact through strong hydrogen bonds, and an emulsion containing micelles can be formed under multiple forces, and the structure of the micelle is an ordered porous core-shell structure.

[0039] In some embodiments, the organic amine includes one or more of tetraethylenepentamine, pentaethylenehexamine, triethylenetetramine, and polyethyleneimine.

[0040] In some embodiments, in step S2, the washing step is: washing with ethanol and water alternately.

[0041] The washing step of the present application achieves the removal of the porogen and the template to form a hollow and porous structured material.

[0042] In some embodiments, the molar ratio of the porogen to the polyhydroxy biomass compound is 0.01-0.1:1; the molar ratio of the porogen to the alcohol solution is 1-5:500; and the molar ratio of the template to the porogen is 1-10:1.

[0043] In the present application, the size of the emulsion droplets is controlled by regulating the amount of porogen, organic solvent, and the ratio of porogen to polyhydroxy compound, thereby precisely controlling the pore structure of the material. Among them, under the condition of limiting the molar ratio of porogen to polyhydroxy biomass compound, it is beneficial to control the size of the micelle core through the volume effect of the hydrophobic microregion of the porogen. If the porogen is relatively high, the micelles will aggregate excessively due to excessive hydrophobic effect, forming agglomerates with uneven cavity structure. If the porogen is relatively low, the hydrophobic driving force of the micelle core is insufficient, resulting in the collapse of the mesoporous structure or too small pore size. Under the condition of limiting the molar ratio of porogen to alcohol solution, it is beneficial to regulate the solvation effect of the micelle interface through the polarity of the alcohol solution. If the porogen content is relatively too high, the uniformity of the micelle structure will be destroyed. If the porogen content is relatively too low, the micelle expansion will be restricted, resulting in the densification of the mesoporous structure. Under the condition of limiting the molar ratio of the template to the porogen, it is beneficial to form a stable core-shell structure through the hydrophobic-hydrophilic synergistic effect of the template polyether chain segment and the porogen. If the porogen content is relatively too high, the template shell is not enough to wrap the porogen core, resulting in the instability of the micelle structure. If the porogen content is relatively too low, the excessive template will cause excessive hydrogen bond cross-linking between micelles, resulting in pore blockage.

[0044] In some embodiments, the temperature of the template-directed synthesis reaction is 25-45°C.

[0045] In some embodiments, the temperature of the aggregation assembly reaction is 25-65°C.

[0046] In some embodiments, the temperature of the curing reaction is 30-60°C, and the curing agent includes one or more of formaldehyde, glutaraldehyde, and trioxymethylene; the temperature of the heating reaction is 80-140°C.

[0047] In this application, under the conditions of limiting the parameters of the aggregation assembly reaction, it is beneficial to accelerate the assembly efficiency of the amino resin precursor on the micelle surface. If the temperature is too low, the reaction rate is too slow, and if the temperature is too high, some side reactions such as oxidation will occur.

[0048] The present application provides a hollow porous amino resin for separating CO2 from the atmosphere.

[0049] The hollow porous amino resin of the present application is a hollow porous nanoparticle structure with a particle size of 100-800nm, an average pore size of the porous structure of 10-30nm, and a size of the hollow channel of 50-300nm. The size of the amino resin is regulated by optimizing the composite micelle structure or the emulsion structure. The core is that the template and the porogen coordinately regulate the size of the micelle, thereby regulating the size of the cavity of the amino resin. By controlling the concentration of the biomass hydroxyl compound and the organic amine, the assembly of the amino resin on the micelle surface is achieved, and then the thickness of the hollow shell in the regulation material and the size of the amino resin particles are regulated.

[0050] The present application provides an application of a hollow porous amino-based resin for separating CO2 from the atmosphere and for capturing CO2 in the air.

[0051] The present invention is further described below through specific examples.

[0052] Example 1

[0053] A method for preparing a hollow porous amino resin for separating CO2 from the atmosphere comprises the following steps:

[0054] S1. Dissolve F127 and tannic acid in 100 ml of 50% ethanol and stir at 25°C for 3 h. Then, add trimethylbenzene for template-directed synthesis to obtain an emulsion containing micelles. The molar ratio of trimethylbenzene to tannic acid is 0.05, the molar ratio of F127 to trimethylbenzene is 5:1, and the molar ratio of trimethylbenzene to alcohol solution is 2:500.

[0055] S2. Dissolve triethylenetetramine in 10 ml of ethanol and add it to the micelle-containing emulsion obtained in step S1. Aggregation and assembly reaction is carried out at 35°C. The mixture is then centrifuged and the precipitate is washed with ethanol and then water to obtain a hollow amino resin precursor material. The molar ratio of triethylenetetramine to tannic acid is 5:1.

[0056] S3. The hollow amino resin precursor material 100ml was dispersed in a 50wt% ethanol aqueous solution, and then added to a curing agent glutaraldehyde solution, and a cross-linking curing reaction was carried out at 40°C to obtain a cured material;

[0057] S4. The solidified material was dispersed in a 50wt% ethanol-water solution at a solid-to-liquid ratio of 1:10. The mixture was heated at 100°C for 24 hours. The mixture was then washed with water, filtered, and vacuum-dried to obtain a hollow porous amino resin for separating CO2 from the atmosphere.

[0058] Example 2

[0059] A method for preparing a hollow porous amino resin for separating CO2 from the atmosphere. Other contents are the same as those in Example 1, except that F127 is replaced by P123; trimethylbenzene is replaced by N,N-dimethylbenzylamine; tannic acid is replaced by catechol; and triethylenetetramine is replaced by tetraethylenepentamine.

[0060] Examples 3-4

[0061] A method for preparing a hollow porous amino resin for separating CO2 from the atmosphere, the other contents are the same as those in Example 1, except that the molar ratios of the porogen and the polyhydroxy biomass compound are 0.01:1 and 0.1:1, respectively.

[0062] Examples 5-6

[0063] A method for preparing a hollow porous amino resin for separating CO2 from the atmosphere, the other contents are the same as those in Example 1, except that the molar ratios of the porogen to the alcohol solution are 1:500 and 5:500.

[0064] Examples 7-8

[0065] A method for preparing a hollow porous amino resin for separating CO2 from the atmosphere, the other contents are the same as those in Example 1, except that the molar ratios of the template and the porogen are 1:1 and 10:1.

[0066] Examples 9-10

[0067] A method for preparing a hollow porous amino resin for separating CO2 from the atmosphere, the other contents are the same as those in Example 1, except that the reaction temperature of the template-directed synthesis is 10 and 60°C.

[0068] Examples 11-12

[0069] A method for preparing a hollow porous amino resin for separating CO2 from the atmosphere, the other contents are the same as those in Example 1, except that the temperatures for the aggregation assembly reaction are 10 and 60°C.

[0070] Example 13

[0071] A method for preparing a hollow porous amino resin for separating CO2 from the atmosphere, the other contents are the same as those in Example 1, except that the reaction temperature is 160°C.

[0072] Comparative Example 1

[0073] A method for preparing an amino resin is the same as that of Example 1 except that step S3 is not included.

[0074] Comparative Example 2

[0075] A method for preparing an amino resin is the same as that of Example 1 except that step S4 is not included.

[0076] Comparative Example 3

[0077] A method for preparing an amino resin is the same as that of Example 1 except that no template is used in step S1.

[0078] Comparative Example 4

[0079] A method for preparing an amino resin is the same as that of Example 1 except that, in step S1, no polyhydroxy biomass compound is used.

[0080] Comparative Example 5

[0081] A method for preparing an amino resin is the same as that of Example 1 except that, in step S1, no template agent and polyhydroxy biomass compound are used.

[0082] Comparative Examples 6-7

[0083] A method for preparing an amino resin is the same as Example 1 except that the template is replaced by CTAB and sodium dodecylsulfonate in sequence.

[0084] Comparative Examples 8-9

[0085] A method for preparing an amino resin is the same as Example 1 except that the porogen is replaced by hexadecane and benzene in sequence.

[0086] Testing and Evaluation

[0087] The SEM images of different amino resins were tested, and the SEM images of the amino resin obtained in Example 1 were as follows: Figure 1 shown.

[0088] The cavity diameter and amine loading of different amino resins were tested, and the adsorption capacity, average adsorption rate and cyclic stability of CO2 of different amino resins were tested at 25°C. The results are shown in Figure 1.

[0089] Table 1 Test results

[0090]

[0091] The adsorbent materials prepared in Examples 1 and 2 exhibited superior performance, attributed to optimal process formulation. Excessive polyol content in Example 3 resulted in compression of the hollow cavity and a decrease in adsorption rate, while insufficient polyol content in Example 4 reduced organic amine loading and adsorption capacity. Excessive or insufficient alcohol content can lead to excessively low or high template concentrations, affecting the size of the hollow cavity. Excessively small cavity size results in slow adsorption rate (Example 5), while excessively large cavity size easily breaks the material and results in poor cyclic stability (Example 6). Excessive or insufficient template content can also lead to similar problems (Examples 7 and 8).

[0092] In Examples 9 and 11, the reaction temperature was too low, resulting in low organic amine loading and low adsorption capacity. In Examples 10, 12, and 13, the reaction temperature was too high, which easily led to overreaction, causing some amino functional groups to be oxidized, resulting in a low content of effective adsorption groups and a decrease in adsorption capacity.

[0093] In Comparative Examples 1 and 2, the curing and heat treatment parts are lacking, the amino functional group is unstable, and although the adsorption capacity is high, the cyclic stability is poor. In Comparative Example 3, no template is added, and a solid structure material is obtained, and the adsorption rate is slow. In Comparative Examples 4 and 5, no solid material is formed. In Comparative Examples 6 and 7, the template is replaced by anionic and cationic surfactants, which makes it difficult to form micelles with a core-shell structure. The cavity structure of the material is small and the adsorption rate is slow. The porogen is replaced by smaller hydrophobic alkyl and benzene. The micelle size formed is smaller, the cavity structure of the material is also relatively small, and the adsorption rate is slow.

[0094] 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 a hollow porous amino resin for separating CO2 from the atmosphere, characterized in that: The following steps are involved: S1. Dispersing the template and the polyhydroxy biomass compound into an alcohol solution, adding a porogen, and performing a template-directed synthesis reaction to obtain an emulsion containing micelles; S2. An alcoholic solution of an organic amine is added to the emulsion to perform an aggregation assembly reaction, followed by centrifugation and washing to obtain a hollow amino resin precursor material; S3. The hollow amino resin precursor material is added to the curing agent solution, cross-linking and curing reaction is performed to obtain a cured material; S4. The solidified material is dispersed in a solvent and heated to react to obtain a hollow porous amino resin for separating CO2 from the atmosphere; The template includes one or more of F127 and P123; the porogen includes one or more of trimethylbenzene and N,N-dimethylbenzylamine; the polyhydroxy biomass compound is tannic acid or catechol; the molar ratio of the porogen to the polyhydroxy biomass compound is 0.01-0.05:1; the molar ratio of the porogen to the alcohol solution is 2:500; the molar ratio of the template to the porogen is 5:1; the temperature of the heating reaction is 100°C; the organic amine includes one or more of tetraethylenepentamine, pentaethylenehexamine, triethylenetetramine, and polyethyleneimine; the temperature of the template-directed synthesis reaction is 25-45°C; the temperature of the aggregation assembly reaction is 35°C; and the curing agent includes one or more of formaldehyde, glutaraldehyde, and trioxymethylene.

2. The method for preparing a hollow porous amino resin for separating CO2 from the atmosphere according to claim 1, characterized in that: In step S2, the washing step is: washing with ethanol and water alternately.

3. The method for preparing a hollow porous amino resin for separating CO2 from the atmosphere according to claim 1, characterized in that: The temperature of the curing reaction is 30-60°C.

4. A hollow porous amino resin for separating CO2 from the atmosphere obtained by the preparation method according to any one of claims 1 to 3.

5. Use of the hollow porous amino resin for separating CO2 from the atmosphere as claimed in claim 4 in capturing CO2 in the air.

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