A low-concentration CO2 adsorbent material and its preparation method

Abstract

The application discloses a kind of low-concentration CO2 adsorption material and preparation method thereof, belong to CO2 capture technical field.The method includes respectively preparing porous polymer spherical particles with uniform interpenetration macroporous structure, metal salt solution, pyrazine solution and ligand solution;The porous polymer spherical particles are vacuum impregnated with the metal salt solution and then dried, to obtain intermediate product one;The intermediate product one is vacuum impregnated with the pyrazine solution and then carries out first heating reaction, subsequently removed and washed, dried, to obtain intermediate product two;The intermediate product two is vacuum impregnated with the ligand solution, and the solid separation product is separated and subjected to second heating reaction, subsequently removed and washed, dried, and obtained.The application solves the problem of MOF powder accumulation, while ensuring good CO2 adsorption performance at low concentration, improves the adsorption efficiency and water stability.

Description

Technical Field

[0001] This invention belongs to the field of CO2 capture technology, and particularly relates to a low-concentration CO2 adsorption material and its preparation method. Background Technology

[0002] Global warming has sparked widespread concern and reflection on CO2 emissions worldwide. To achieve global warming targets, CO2 emission reduction is imperative. Currently, CCUS (Carbon Capture, Utilization, and Storage) is one of the key technologies for addressing global climate change. The main source of CO2 emissions is coal-based power generation, and developing carbon capture technologies for large-scale coal-fired flue gas is considered an effective means of achieving clean energy. Current carbon capture technologies mainly include chemical absorption, membrane separation, and solid adsorption. However, compared to chemical absorption and membrane separation, solid adsorption offers advantages such as energy saving, environmental friendliness, and lightweight, flexible equipment. Therefore, solid adsorption is considered one of the most promising methods for carbon capture in power plant flue gas. The core of adsorption separation lies in finding solid adsorbents that are highly effective, stable, easily regenerated, non-toxic, and inexpensive. Commonly used solid porous materials for CO2 capture include zeolite molecular sieves, carbon-based adsorbents, silicon-based materials, solid amine materials, and metal-organic frameworks (MOFs).

[0003] Zeolite molecular sieves are artificially synthesized hydrated aluminosilicates (zeolite) or natural zeolites that have sieving properties for molecules. Zeolite molecular sieves possess advantages such as large specific surface area, diverse structures and channels, and adjustable pore size, making them widely used as matrix materials for CO2 solid adsorbents. However, since flue gas from coal-fired power plants often contains 9-12% water vapor by volume, its presence inhibits the adsorption effect of zeolite molecular sieves. Furthermore, at low CO2 concentrations, the adsorption capacity of zeolite molecular sieves is low, making them unsuitable for separating CO2 from power plant flue gas. Carbon-based adsorbent materials, including activated carbon, activated coke, and activated carbon fibers, offer advantages such as low cost, high specific surface area, and easy regeneration. However, carbon adsorption is typically physical adsorption, with weak adsorption capacity and high temperature sensitivity. It also exhibits poor selectivity for CO2, and the presence of other gases such as nitrogen in the flue gas further reduces CO2 adsorption capacity. Therefore, modification is necessary before carbon materials can be used for flue gas separation. Silicon-based materials mainly refer to SiO2. Research on silicon-based materials for CO2 adsorption mainly focuses on two aspects: one is the use of different types of SiO2, including nanoparticles, hollow microspheres, nanotubes, aerogels, etc.; the other is the use of SiO2 as a substrate, selecting a suitable ammonia source, and loading amines into the material to improve the material's CO2 adsorption capacity. Solid amine adsorbents are made by loading organic amines into the porous carrier channels of a solid adsorbent with well-developed pore structure, large specific surface area, and good thermal stability. Both types of adsorbents and solid amine adsorbents share the problem of insufficient amine stability.

[0004] Metal-organic frameworks (MOFs) are a class of crystalline porous materials with microporous network structures, formed by the self-assembly of metal ions and multidentate organic ligands containing oxygen and nitrogen. Compared to other solid adsorbents, MOFs do not corrode equipment, and their abundant active sites facilitate interaction with CO2, resulting in higher adsorption selectivity. Applying MOFs to CO2 capture and storage technologies can broaden the range of adsorbents, improving selectivity while reducing costs. Hybrid ultraporous materials (HUMs) have attracted particular attention for trace carbon capture because their selectivity for CO2 is higher than that for N2 and CH4. However, they also have many drawbacks. For example, TiFSIX-3-Ni, a pyrazine-linked HUM, is an excellent physical adsorbent for capturing CO2 under dry conditions, but its strong affinity for water reduces its carbon capture performance under humid conditions. ZIF (zeolite-like imidazole ester) framework materials, composed of transition metal cations (most commonly Zn or Co) and imidazole ligands, not only possess the advantages of general MOFs such as large specific surface area and tunable pore size, but also exhibit good thermal and chemical stability. Among them, ZIF-7, composed of Zn metal clusters linked with benzimidazole, is one of the earliest reported and most promising ZIFs for the separation of various light gases. It has strong hydrophobicity and good water stability. However, due to the presence of two different pore sizes in ZIF-7, a phase transition occurs during adsorption, resulting in gate opening or breathing effects, leading to lower CO2 adsorption capacity at low concentrations.

[0005] While MOFs show promising potential in gas capture, they also have several drawbacks. For example, in practical applications, MOF powders need to be bonded together, and under high packing conditions, the adsorption capacity, selectivity, and kinetic properties of the material are significantly reduced. Furthermore, some MOFs suffer from insufficient thermal, water, and hydrothermal stability, limiting their applicability to specific scenarios rather than general applications.

[0006] In view of this, the present invention is hereby proposed. Summary of the Invention

[0007] The purpose of this invention is to provide a low-concentration CO2 adsorption material and its preparation method, which solves the problem of MOF powder accumulation and improves adsorption efficiency and water stability while ensuring good CO2 adsorption performance at low concentrations.

[0008] To achieve the above objectives, the present invention adopts the following specific technical solution:

[0009] This invention provides a method for preparing a low-concentration CO2 adsorbent material, comprising:

[0010] Porous polymeric spherical particles, metal salt solutions, pyrazine solutions, and ligand solutions with uniformly interpenetrating macroporous structures were prepared respectively.

[0011] The porous polymer spherical particles were vacuum impregnated with the metal salt solution and then dried to obtain intermediate product one.

[0012] The intermediate product one was vacuum impregnated with the pyrazine solution and then subjected to a first heating reaction. After that, it was taken out, washed and dried to obtain intermediate product two.

[0013] The intermediate product 2 was vacuum impregnated with the ligand solution to separate the solid isolate, which was then subjected to a second heating reaction. The solid isolate was then removed, washed, and dried to obtain the final product.

[0014] Furthermore, the method for preparing porous polymeric spherical particles with a uniformly interpenetrating macroporous structure includes:

[0015] Acrylamide monomer, emulsifier, crosslinking agent and initiator are dissolved in deionized water to form an aqueous phase;

[0016] The aqueous phase and the oil phase are mixed and stirred to obtain an oil-in-water emulsion;

[0017] The oil-in-water emulsion is mixed and stirred with the third phase, and a reducing agent is added to carry out a polymerization reaction to obtain polyacrylamide spherical particles (i.e., the porous polymerized spherical particles). The particles are then washed, filtered, and dried at 60℃-100℃ for 24-48 hours to obtain the final product.

[0018] Optionally, the crosslinking agent is N,N-methylenebisacrylamide.

[0019] Optionally, the emulsifier is Span80 and / or polyoxyethylene polyoxypropylene ether.

[0020] Optionally, the initiator is one or more of ammonium persulfate, benzoyl peroxide, or azobisisobutyronitrile.

[0021] Further, the acrylamide monomer, emulsifier, crosslinking agent, and initiator are respectively 50-64 parts, 3-5 parts, 30-40 parts, and 3-5 parts by mass; the deionized water is 1-2 times the total mass of the acrylamide monomer, emulsifier, crosslinking agent, and initiator.

[0022] Optionally, the oil phase comprises cyclohexane.

[0023] Furthermore, the mass of the oil phase is 1-4 times the mass of the aqueous phase.

[0024] Preferably, the mixing and stirring rate of the aqueous phase and the oil phase is 3000-9000 r / min.

[0025] Preferably, the mixing time between the aqueous phase and the oil phase is 3-10 minutes.

[0026] Preferably, the polymerization reaction takes 10-30 minutes.

[0027] Preferably, the reducing agent is tetramethylethylenediamine and / or N,N-dimethylaniline.

[0028] Preferably, the amount of reducing agent added is 0.2-0.6 times the mass of the initiator.

[0029] Furthermore, the preparation method of the third phase includes: dissolving the dispersant in the dispersed phase and heating to 40-80℃ to obtain the third phase.

[0030] The dispersant is selected from one or more of sodium carboxymethyl cellulose, ethyl cellulose, or polyvinylpyrrolidone.

[0031] The dispersed phase is selected from one or more of toluene, cyclohexane, or carbon tetrachloride.

[0032] Preferably, the dispersant accounts for 0.05%-0.20% of the total mass of the dispersed phase.

[0033] Preferably, the mass of the third phase is 30-60 times the total mass of the acrylamide monomer, emulsifier, crosslinking agent and initiator in the aqueous phase.

[0034] Further, the method for preparing the metal salt solution includes dissolving an organonickel salt and an organozinc salt in water. Optionally, the organonickel salt includes nickel acetate tetrahydrate, and the concentration of the nickel acetate tetrahydrate solution is 0.42-0.5 g / mL; the organozinc salt includes zinc acetate dihydrate, and the concentration of the zinc acetate dihydrate solution is 0.18-0.25 g / mL.

[0035] Furthermore, the pyrazine solution is obtained by dissolving pyrazine in H2TiF6 solution, with a mass ratio of pyrazine to H2TiF6 of 1:(0.8-1.2).

[0036] Furthermore, the ligand solution is obtained by dissolving benzimidazole in dimethylformamide, with a concentration of 0.2-0.5 g / mL.

[0037] Furthermore, the temperature of the first heating reaction is 80-90℃, and the time is 24-72h.

[0038] Preferably, the drying temperature after the first heating reaction and washing is 55-65°C.

[0039] Preferably, the separation involves allowing the solution to stand and then aspirating it dry; more preferably, the standing time is 5-10 minutes.

[0040] Furthermore, the temperature of the second heating reaction is 80-90℃, and the time is 12-36h.

[0041] The present invention also provides a low-concentration CO2 adsorbent material, which is prepared by the aforementioned preparation method.

[0042] This invention modifies Ni-MOF by coating it with ZIF, fully utilizing the advantages of both materials. While maintaining CO2 adsorption performance at low concentrations, it reduces the water absorption of the composite material, enabling stable separation of low-concentration CO2. Furthermore, by preparing porous polymeric spherical particles with an interlocking macroporous structure, Ni-MOF crystals are uniformly dispersed on the inner walls of the pores of the porous polymer material, while ZIF crystals are distributed on the outer layer of the Ni-MOF crystals. This solves the problem of MOF powder accumulation and the resulting low adsorption efficiency, significantly improving the material's adsorption efficiency and kinetic performance. Utilizing the confined space of the spherical porous polyacrylamide polymer material, the particle size of the grown MOF crystals is reduced, thereby enhancing the crystal's adsorption performance.

[0043] Ni-MOF crystals exhibit excellent adsorption performance for low-concentration CO2, but their water stability is poor, leading to a decrease in CO2 adsorption performance in humid flue gas. ZIF crystals, on the other hand, possess good water stability and strong hydrophobicity. By incorporating ZIF onto the outer surface of Ni-MOF crystals, the adsorption performance of the crystals is maintained while the hydrophobic properties of ZIF can block water molecules from entering the Ni-MOF crystals, thereby reducing the impact of water molecules on the CO2 adsorption performance of Ni-MOF and improving its water stability. Experimental results demonstrate that the Ni-MOF / ZIF@porous polymeric spherical particle composite material exhibits good CO2 adsorption performance, hydrophobicity, and hydrothermal stability at low concentrations.

[0044] The invention is further characterized by the use of suspension polymerization to prepare porous polymeric spherical materials with a uniformly interpenetrating macroporous structure, and using these materials as a matrix, a Ni-MOF / ZIF@porous polymeric spherical particle composite material was prepared by solvothermal synthesis. This composite material solves the problem of MOF powder accumulation, and while ensuring good CO2 adsorption performance at low concentrations, it also improves adsorption efficiency and water stability. Attached Figure Description

[0045] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0046] Figure 1 The images shown are characterization diagrams or photographs of the porous polymer spherical particles in Embodiment 1 of the present invention; wherein, a is a physical image of the porous polymer spherical particles; b is an external morphology image of the porous polymer spherical particles; c is a surface pore structure diagram of the porous polymer spherical particles; and d is a scanning electron microscope image of the internal pore structure of the porous polymer spherical particles.

[0047] Figure 2 These are scanning electron microscope (SEM) images showing the interior of the material in Example 1 of the present invention; wherein, a and b are SEM images showing the interior of TiFSIX-3-Ni@polyacrylamide spherical particles at different magnifications; c and d are SEM images showing the interior of TiFSIX-3-Ni / ZIF-7@polyacrylamide spherical particle composite material at different magnifications.

[0048] Figure 3 In Figure 3 a and Figure 3 b are scanning electron microscope images of the TiFSIX-3-Ni / ZIF-7@polyacrylamide spherical particle composite material of Example 1 of the present invention, displayed at different magnifications.

[0049] Figure 4 The images show the XRD patterns of the polyacrylamide spherical particles, ZIF-7, TiFSIX-3-Ni, TiFSIX-3-Ni@polyacrylamide spherical particles, and TiFSIX-3-Ni / ZIF-7@polyacrylamide spherical particle composites of Example 1 of the present invention.

[0050] Figure 5 The CO2 adsorption curves of the TiFSIX-3-Ni@polyacrylamide spherical particle material and the TiFSIX-3-Ni / ZIF-7@polyacrylamide spherical particle composite material prepared in Comparative Example 1 of this invention are shown at 25℃ and 0-0.1 bar.

[0051] Figure 6 The CO2 adsorption curves of TiFSIX-3-Ni@polyacrylamide spherical particles and TiFSIX-3-Ni / ZIF-7@polyacrylamide spherical particle composites in Example 1 of this invention are shown at 25°C and 0-0.1 bar. Figure 6 a) and H2O adsorption curves at 0-0.03 bar ( Figure 6 b).

[0052] Figure 7 The TiFSIX-3-Ni@polyacrylamide spherical particles of Example 1 of this invention ( Figure 7 a) and TiFSIX-3-Ni / ZIF-7@polyacrylamide spherical particle composite material ( Figure 7 b) CO2 adsorption curves at 25℃ and 0-0.1 bar before and after the hydrothermal experiment.

[0053] Figure 8 In Figure 8 a represents the CO2 adsorption curves of ZIF-7 powder, TiFSIX-3-Ni powder, polyacrylamide spherical particles, TiFSIX-3-Ni@polyacrylamide spherical particles, and TiFSIX-3-Ni / ZIF-7@polyacrylamide spherical particle composite materials in Example 2 of this invention at 25°C and 0-0.1 bar. Figure 8 b shows the H2O adsorption curves of TiFSIX-3-Ni@polyacrylamide spherical particles and TiFSIX-3-Ni / ZIF-7@polyacrylamide spherical particle composites in Example 2 at 25°C.

[0054] Figure 9 The CO2 adsorption curves at 25℃ and 0-0.1 bar before and after the hydrothermal stability test of the TiFSIX-3-Ni / ZIF-7@polyacrylamide spherical particle composite material in Example 2 of the present invention are shown. Detailed Implementation

[0055] The embodiments of the present invention will be described in detail below with reference to specific examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0056] It should be noted that any proportions not specified in the embodiments of this invention are arbitrary proportions.

[0057] Example 1

[0058] A method for preparing a low-concentration CO2 adsorbent:

[0059] (1) Dissolve 8g of deionized water, 1.5g of acrylamide, 0.9g of N,N-methylenebisacrylamide, 0.1g of emulsifier Span80, and 0.1g of initiator ammonium persulfate by sonication. The oil phase consists of 15g of cyclohexane; the third phase consists of 60mL of toluene and 140mL of cyclohexane, added to 0.3g of ethyl cellulose, placed in a 250mL three-necked flask with a stirrer to form a dispersed phase, and purged with nitrogen for 10min under stirring until the temperature reaches 60℃.

[0060] (2) The oil phase was added dropwise to the aqueous phase at a speed of 5000 r / min. The speed was increased to 9000 r / min, 1 mL of reducing agent tetramethylethylenediamine was added, and the mixture was stirred at high speed for 5 min to prepare a uniform O / W emulsion.

[0061] (3) The prepared emulsion was poured into the third phase solution and dispersed into spheres at a stirring speed of 250 r / min. After the polymerization reaction was carried out for 10 min, the synthesized microspheres were taken out, washed and filtered in methanol, and dried in an oven at 60℃ for 24 h to obtain spherical polymer material polyacrylamide spherical particles.

[0062] (4) Dissolve 4.8 g of nickel acetate tetrahydrate and 1.98 g of zinc acetate dihydrate in 10 mL of deionized water to obtain a metal salt solution. Dissolve 4 g of pyrazine in 4 g of H2TiF6 solution to obtain a clear solution, which is the pyrazine solution. Dissolve 2.13 g of benzimidazole in 5 mL of dimethylformamide to obtain a clear solution, which is the ligand solution.

[0063] (5) Take 0.2 g of polyacrylamide spherical particles and place them in a 25 mL round-bottom flask. After vacuuming for 1 h, impregnate the spherical particles with a metal salt solution. After impregnation, drain the solution and dry the flask. Impregnate a second time with a pyrazine solution. After impregnation, transfer the spherical particles and the pyrazine solution together into a hydrothermal reactor and grow them in an oven at 85 °C for 48 h. After the reaction, wash the obtained sample with deionized water and dry it at 60 °C to obtain TiFSIX-3-Ni@polyacrylamide spherical particles. After vacuuming the TiFSIX-3-Ni@polyacrylamide spherical particles for a period of time, impregnate the TiFSIX-3-Ni@polyacrylamide spherical particle material with a ligand solution. After standing at room temperature for 8 min, absorb the solution and transfer the moist sample to a polytetrafluoroethylene reactor and heat it at 85 °C for 24 h. After cooling to room temperature, the product is washed with deionized water and ethanol and dried in air to obtain TiFSIX-3-Ni / ZIF-7@polyacrylamide spherical particle composite material.

[0064] The prepared spherical polymer was cut open with a knife, and the microstructure and surface pore structure of the sample cross-section were observed using a scanning electron microscope. Gold sputtering was required before structural observation to obtain... Figure 1 a, Figure 1 b、 Figure 1 c and Figure 1 d, etc. By Figure 1 a- Figure 1 As can be seen from d, the spherical particles have a uniform particle size distribution; the synthesized spherical particles are regular spheres with a well-developed porous structure on the surface, which can provide channels for the entry of TiFSIX-3-Ni and ZIF-7 precursor solutions. The internal interconnected pores are well-distributed and almost uniformly distributed, which provides a unique confinement space for the growth of MOF grains.

[0065] See Figure 2 a, Figure 2 b、 Figure 2 c and Figure 2 As shown in Figure d, TiFSIX-3-Ni crystals are uniformly dispersed on the inner walls of the spherical particles in the composite material, while ZIF-7 crystals are uniformly distributed on the outer layer of TiFSIX-3-Ni crystals.

[0066] See Figure 3 a and Figure 3 As can be seen from the attached figure, TiFSIX-3-Ni crystals and ZIF-7 crystals did not grow on the outside of the composite material.

[0067] See Figure 4 It can be seen that TiFSIX-3-Ni and ZIF-7 were successfully composited in polyacrylamide spherical particles.

[0068] See Figure 6 a and Figure 6 b. It can be seen that with the change of ZIF-7 crystallization conditions, the ZIF-7 crystallization process has little effect on the crystals of TiFSIX-3-Ni, and the water absorption rate of the composite material has been greatly reduced.

[0069] See Figure 7 a and Figure 7 b. It can be seen that the hydrothermal stability of the composite material has been significantly improved, but after treatment at 80℃, the adsorption capacity is still reduced.

[0070] Comparative Example 1

[0071] The difference from Example 1 is that in step (5), after the TiFSIX-3-Ni@polyacrylamide spherical particles are vacuumed for a period of time, the spherical particles are impregnated with a ligand solution. After standing at room temperature for 5-10 minutes, the solution is dried, the moistened sample is transferred to a polytetrafluoroethylene reactor, and heated at 130°C for 48 hours. After cooling to room temperature, the product is washed with deionized water and ethanol, and dried in air to obtain the TiFSIX-3-Ni / ZIF-7@polyacrylamide spherical particle composite material.

[0072] See Figure 5 It can be seen that the crystallization process of ZIF-7 destroys the TiFSIX-3-Ni crystal, which leads to a significant reduction in its CO2 adsorption capacity.

[0073] Performance tests were conducted on the above materials: CO2 adsorption tests were performed on the samples at 25℃. The TiFSIX-3-Ni@polyacrylamide spherical particle composite material showed good CO2 adsorption performance, with a CO2 adsorption capacity of 1.46 mmol / g at 0.005 bar. However, after being combined with ZIF-7, the CO2 adsorption performance of the TiFSIX-3-Ni / ZIF-7@polyacrylamide spherical particle composite material was only 0.38 mmol / g.

[0074] Compared to Comparative Example 1, Example 1 adjusted the growth method of ZIF-7, lowered the crystallization temperature of ZIF-7, and shortened the crystallization time. The adsorption of CO2 and H2O on the prepared sample was tested at 25℃. It was found that the CO2 adsorption capacity of the TiFSIX-3-Ni / ZIF-7@polyacrylamide spherical particle composite material at 25℃ and 0.005 bar was 1.42 mmol·g. -1 It is evident that the adsorption performance of the composite material was significantly improved, and its water absorption capacity was substantially reduced. The CO2 adsorption curve of the TiFSIX-3-Ni / ZIF-7@polyacrylamide spherical particle composite material after high-temperature water treatment shows that the composite material has poor water stability. After water treatment at 80℃, the adsorption capacity of the TiFSIX-3-Ni / ZIF-7@polyacrylamide spherical particle composite material at 25℃ and 0.005 bar was 0.88 mmol·g. -1 This represents a decrease of 43.5%.

[0075] Example 2

[0076] The difference from Example 1 is that the amount of zinc acetate dihydrate added is 2.50 g; 2.13 g of benzimidazole is dissolved in 10 mL of dimethylformamide to obtain a clear solution, which is a ligand solution.

[0077] Performance tests were conducted on the above materials: Compared to Example 1, Example 2 increased the mass fraction of zinc acetate dihydrate (metal salt) and decreased the concentration of benzimidazole ligand. Adsorption tests of CO2 and H2O on the composite material were performed at 25°C. The CO2 adsorption capacity of the TiFSIX-3-Ni / ZIF-7@polyacrylamide spherical particle composite material at 25°C and 0.005 bar was 1.45 mmol·g. -1 This greatly ensures the material's CO2 adsorption capacity at low concentrations. Furthermore, the H2O absorption rate of the TiFSIX-3-Ni / ZIF-7@polyacrylamide spherical particle composite material is only 12.6%. After water treatment at 80℃, the adsorption capacity of the TiFSIX-3-Ni / ZIF-7@polyacrylamide spherical particle composite material remains at 1.45 mmol·g at 25℃ and 0.005 bar. -1 This indicates that the TiFSIX-3-Ni / ZIF-7@polyacrylamide spherical particle composite material has good water stability.

[0078] See Figure 8 ,from Figure 8 As shown in Figure a, the composite TiFSIX-3-Ni / ZIF-7@polyacrylamide spherical particles maintain good adsorption capacity for low-concentration CO2, thus solving the problem of low CO2 adsorption efficiency; from Figure 8 As can be seen from b, the water absorption performance of the composite material is reduced, indicating that ZIF-7 in the composite material plays a hydrophobic protective role and reduces the water adsorption capacity of TiFSIX-3-Ni.

[0079] See Figure 9 It can be seen that the composite TiFSIX-3-Ni / ZIF-7@polyacrylamide spherical particle composite material has excellent hydrothermal stability.

[0080] Example 3

[0081] A method for preparing a low-concentration CO2 adsorbent:

[0082] (1) Dissolve 8g of deionized water, 1.5g of acrylamide, 0.9g of N,N-methylenebisacrylamide, 0.1g of emulsifier Span80, and 0.1g of initiator ammonium persulfate by sonication. The oil phase consists of 15g of cyclohexane; the third phase consists of 60mL of toluene and 140mL of cyclohexane, added to 0.3g of ethyl cellulose, placed in a 250mL three-necked flask with a stirrer to form a dispersed phase, and purged with nitrogen for 10min under stirring until the temperature reaches 40℃.

[0083] (2) The oil phase was added dropwise to the aqueous phase at a speed of 5000 r / min, and then 1 mL of reducing agent tetramethylethylenediamine was added and stirred at high speed for 5 min to prepare a uniform O / W emulsion.

[0084] (3) The prepared emulsion was poured into the third phase solution and dispersed into spheres at a stirring speed of 250 r / min. After the polymerization reaction was carried out for 10 min, the synthesized microspheres were taken out, washed and filtered in methanol, and dried in an oven at 60℃ for 24 h to obtain spherical polymer material polyacrylamide spherical particles.

[0085] (4) Dissolve 4.8 g of nickel acetate tetrahydrate and 1.98 g of zinc acetate dihydrate in 10 mL of deionized water to obtain a metal salt solution. Dissolve 4 g of pyrazine in 4 g of H2TiF6 solution to obtain a clear solution, which is the pyrazine solution. Dissolve 2.13 g of benzimidazole in 5 mL of dimethylformamide to obtain a clear solution, which is the ligand solution.

[0086] (5) Take 0.2 g of polyacrylamide spherical particles and place them in a 25 mL round-bottom flask. After vacuuming for 1 h, impregnate the spherical particles with a metal salt solution. After impregnation, drain the solution and dry the flask. Impregnate a second time with a pyrazine solution. After impregnation, transfer the spherical particles and the pyrazine solution together into a hydrothermal reactor and grow them in an oven at 85 °C for 48 h. After the reaction, wash the obtained sample with deionized water and dry it at 60 °C to obtain TiFSIX-3-Ni@polyacrylamide spherical particles. After vacuuming the TiFSIX-3-Ni@polyacrylamide spherical particles for a period of time, impregnate them with a ligand solution. After standing at room temperature for 8 min, absorb the solution and transfer the moistened sample to a polytetrafluoroethylene reactor and heat it at 85 °C for 24 h. After cooling to room temperature, the product is washed with deionized water and ethanol and dried in air to obtain TiFSIX-3-Ni / ZIF-7@polyacrylamide spherical particle composite material.

[0087] Example 4

[0088] A method for preparing a low-concentration CO2 adsorbent:

[0089] (1) Dissolve 8g of deionized water, 1.8g of acrylamide, 0.9g of N,N-methylenebisacrylamide, 0.1g of emulsifier Span80, and 0.1g of initiator ammonium persulfate by sonication. The oil phase consists of 15g of cyclohexane; the third phase consists of 60mL of toluene, 140mL of cyclohexane, and 0.3g of sodium carboxymethyl cellulose, placed in a 250mL three-necked flask with a stirrer to form a dispersed phase. Purge with nitrogen for 10min while stirring, and raise the temperature to 80℃.

[0090] (2) The oil phase was added dropwise to the aqueous phase at a speed of 3000 r / min. The speed was increased to 8000 r / min, 1 mL of reducing agent tetramethylethylenediamine was added, and the mixture was stirred at high speed for 10 min to prepare a uniform O / W emulsion.

[0091] (3) The prepared emulsion was poured into the third phase solution and dispersed into spheres at a stirring speed of 250 r / min. After the polymerization reaction was carried out for 10 min, the synthesized microspheres were taken out, washed and filtered in methanol, and dried in an oven at 80℃ for 28 h to obtain spherical polymer material polyacrylamide spherical particles.

[0092] (4) Dissolve 4.8 g of nickel acetate tetrahydrate and 1.98 g of zinc acetate dihydrate in 10 mL of deionized water to obtain a metal salt solution. Dissolve 4 g of pyrazine in 4 g of H2TiF6 solution to obtain a clear solution, which is the pyrazine solution. Dissolve 2.13 g of benzimidazole in 5 mL of dimethylformamide to obtain a clear solution, which is the ligand solution.

[0093] (5) Take 0.2 g of polyacrylamide spherical particles and place them in a 25 mL round-bottom flask. After vacuuming for 1 h, impregnate the spherical particles with a metal salt solution. After impregnation, drain the solution and dry the flask. Impregnate a second time with a pyrazine solution. After impregnation, transfer the spherical particles and the pyrazine solution together into a hydrothermal reactor and grow them in an oven at 85 °C for 48 h. After the reaction, wash the obtained sample with deionized water and dry it at 60 °C to obtain TiFSIX-3-Ni@polyacrylamide spherical particles. After vacuuming the TiFSIX-3-Ni@polyacrylamide spherical particles for a period of time, impregnate them with a ligand solution. After standing at room temperature for 8 min, absorb the solution and transfer the moistened sample to a polytetrafluoroethylene reactor and heat it at 85 °C for 24 h. After cooling to room temperature, the product is washed with deionized water and ethanol and dried in air to obtain TiFSIX-3-Ni / ZIF-7@polyacrylamide spherical particle composite material.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

[0095] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are meant to be within the scope of the invention and form different embodiments. For example, in the foregoing claims, any of the claimed embodiments can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of the invention and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

Claims

1. A method for producing a low concentration CO2 adsorbent material, characterized by, The application relates to a method for preparing polyacrylamide spherical particles with a uniform interpenetrating macroporous structure. The polyacrylamide spherical particles with a uniform interpenetrating macroporous structure are prepared by the following steps: preparing a polyacrylamide spherical particle, a metal salt solution, a pyrazine solution and a ligand solution respectively; the metal salt solution is prepared by dissolving organic nickel salt and organic zinc salt in water; the pyrazine solution is prepared by dissolving pyrazine in H2TiF6 solution; the ligand solution is prepared by dissolving benzimidazole in dimethylformamide; The polyacrylamide spherical particles are vacuum-impregnated with the metal salt solution and dried to obtain intermediate product one; The intermediate product one is vacuum-impregnated with the pyrazine solution, and then a first heating reaction is carried out; after the first heating reaction, the intermediate product one is taken out, washed and dried to obtain intermediate product two; the first heating reaction is carried out at 80-90 DEG C for 24-72 h; the drying is carried out at 55-65 DEG C; The intermediate product two is vacuum-impregnated with the ligand solution, and then a solid separation product is separated and a second heating reaction is carried out; after the second heating reaction, the intermediate product two is taken out, washed and dried to obtain the polyacrylamide spherical particles with a uniform interpenetrating macroporous structure; the second heating reaction is carried out at 80-90 DEG C for 12-36 h.

2. The production method according to claim 1, characterized by, The method for preparing the polyacrylamide spherical particles with a uniform interpenetrating macroporous structure comprises the following steps: The acrylamide monomer, the emulsifier, the crosslinking agent and the initiator are dissolved in deionized water to form an aqueous phase; The aqueous phase and an oil phase are mixed and stirred to obtain an oil-in-water emulsion; The oil-in-water emulsion and a third phase are mixed and stirred, and a reducing agent is added to carry out a polymerization reaction, so that the polyacrylamide spherical particles are obtained; the polyacrylamide spherical particles are washed, filtered and dried at 60 DEG C-100 DEG C for 24-48 h.

3. The production method according to claim 2, characterized by, The method for preparing the polyacrylamide spherical particles with a uniform interpenetrating macroporous structure satisfies one or more of the following conditions: a. The crosslinking agent is N,N-methylene bisacrylamide; b. The emulsifier is span 80 and / or polyoxyethylene polyoxypropylene ether; c. The initiator is one or more of ammonium persulfate, benzoyl peroxide or azobisisobutyronitrile; d. The acrylamide monomer, the emulsifier, the crosslinking agent and the initiator are 50-64 parts, 3-5 parts, 30-40 parts and 3-5 parts respectively in terms of mass; the deionized water is 1-2 times the total mass of the acrylamide monomer, the emulsifier, the crosslinking agent and the initiator; e. The oil phase comprises cyclohexane; f. The mass of the oil phase is 1-4 times the mass of the aqueous phase; g. The preparation method of the third phase comprises the following steps: a dispersant is dissolved in a dispersion phase, and the temperature is raised to 40-80 DEG C, so that the third phase is obtained; h. The stirring rate of the aqueous phase and the oil phase is 3000-9000 r / min; i. The stirring time of the aqueous phase and the oil phase is 3-10 min; j. The reducing agent is tetramethylethylenediamine and / or N,N-dimethylaniline; k. The adding amount of the reducing agent is 0.2-0.6 times the mass of the initiator.

4. The production method according to claim 3, characterized by, The dispersant is one or more of carboxymethyl cellulose sodium, ethyl cellulose or polyvinylpyrrolidone; And / or, the dispersion phase is one or more of toluene, cyclohexane or carbon tetrachloride; And / or, the dispersant accounts for 0.05%-0.20% of the total mass of the dispersion phase. And / or, the mass of the third phase is 30-60 times of the total mass of acrylamide monomer, emulsifier, crosslinking agent and initiator in the aqueous phase.

5. The preparation method according to claim 1, characterized in that, The organic nickel salt comprises nickel acetate tetrahydrate; the organic zinc salt comprises zinc acetate dihydrate.

6. The method of claim 1, wherein, The separation is that the solution is absorbed after standing for 5-10 min.

7. A low concentration CO2 adsorbent material, characterized by, Prepared by the preparation method of any one of claims 1-6.

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