Amino-modified porous organic cage material, mixed matrix membrane as well as preparation method and application of amido-modified porous organic cage material and mixed matrix membrane

Abstract

The invention provides an amido-modified porous organic cage material, a mixed matrix membrane and a preparation method and application thereof, and belongs to the technical field of gas separation. When the amido-modified porous organic cage material is used for preparing a mixture matrix membrane,-NH2 in the amido-modified porous organic cage material can interact with an H bond in a polymer-based membrane, so that the free volume and the chain mobility are increased, the compatibility between the porous organic cage material and the polymer-based membrane can be improved, and the porous organic cage material and the polymer-based membrane can form a homogeneous solution; meanwhile, the modified porous organic cage material does not cause structural collapse or decomposition in the subsequent solvent removal process, and a mixed matrix membrane which is uniform in thickness and good in surface can be formed; and the amino group can significantly improve the affinity to CO2, can be subjected to a reversible reaction with CO2, and can be used as a CO2 transmission site to improve the CO2 permeability and CO2 selectivity, so that the application prospect of the porous organic cage material in the aspect of gas separation is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of gas separation, and particularly relates to an amine-modified porous organic cage material, a mixed matrix membrane, and a preparation method and application thereof. Background Art

[0002] Compared with pressure swing adsorption, cryogenic distillation, absorption, etc., gas separation membranes have the advantages of high energy efficiency, small volume, low cost, easy maintenance, easy operation, etc. Membrane materials and microstructures are the main factors affecting CO2 gas absorption. Porous organic cages (POCs) are a relatively new class of low-density crystalline materials and have become a multifunctional platform for studying molecular recognition, gas storage and separation, proton conduction, etc. They have potential application values in fields such as porous liquids, highly permeable membranes, heterogeneous catalysis, and microreactors. They have the advantages of high specific surface area, porosity, open pores, adjustable structure, and chemical stability, making them excellent candidate materials for gas separation. Although POC materials are soluble in some organic solvents (such as dichloromethane and insoluble in solvents such as ethanol and N-methylpyrrolidone), these soluble solvents are volatile at room temperature and volatilize rapidly under heating conditions, which easily affects the rigid structure of POC materials. As a result, it is impossible to obtain a matrix membrane with uniform thickness and good surface, and there are defects in poor CO2 separation effect. Summary of the Invention

[0003] The purpose of the present invention is to provide an amine-modified porous organic cage material, a mixed matrix membrane, and a preparation method and application thereof. The present invention uses an amine-modified porous organic cage material to prepare a mixed matrix membrane, which has uniform thickness and good surface morphology, and has a good separation effect on CO2.

[0004] To achieve the purpose of the present invention, the present invention provides the following technical solutions:

[0005] An amine-modified porous organic cage material, comprising a porous organic cage material and an amine-containing compound loaded on the surface and in the pores of the porous organic cage material; the mass ratio of the amine-containing compound to the porous organic cage material is 2.4 - 3:0.3 - 0.6.

[0006] Preferably, the amine-containing compound includes one or more of polyethyleneimine, silane coupling agent, alkanolamine compounds, and polyethylenepolyamine compounds.

[0007] Preferably, the silane coupling agent is one or more of N-methylaminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and 2-(2-pyridyl)ethyltrimethoxysilane; the alkanolamine compound is N-methyldiethanolamine; the polyethylenepolyamine compound is diethylenetriamine and / or tetraethylenepentamine.

[0008] Preferably, the porous organic cage material includes one or more of CC1, CC2, CC3, CC5, and CC9.

[0009] The present invention also provides a mixed matrix membrane, including a polymer-based membrane and the amino group-modified porous organic cage material described in the above technical solution dispersed in the polymer-based membrane.

[0010] Preferably, the polymer-based membrane includes one or more of polyethylene, polypropylene, polystyrene, polyvinyl chloride, nylon, polyvinylidene fluoride, polyethersulfone, polyoxymethylene, and polyether block polyamide.

[0011] Preferably, the loading amount of the amino group-modified porous organic cage material is 1.5-15 wt%.

[0012] The present invention also provides a preparation method of the mixed matrix membrane described in the above technical solution, including the following steps:

[0013] Mix the amino group-modified porous organic cage material, the polymer-based membrane, and a polar organic solvent to obtain a casting solution; after forming and drying the casting solution, the mixed matrix membrane is obtained.

[0014] Preferably, the polar organic solvent includes one or more of methanol, ethanol, N,N-dimethylformamide, dimethyl sulfoxide, acetone, and N-methylpyrrolidone.

[0015] The present invention also provides the application of the amino group-modified porous organic cage material described in the above technical solution or the mixed matrix membrane described in the above technical solution in adsorptive separation of CO2 in a mixed gas.

[0016] The present invention provides an amino group-modified porous organic cage material, including a porous organic cage material and an amino group-containing compound loaded on the surface and in the pores of the porous organic cage material; the mass ratio of the amino group-containing compound to the porous organic cage material is 2.4-3:0.3-0.6. The present invention also provides a mixed matrix membrane, including a polymer-based membrane and the amino group-modified porous organic cage material dispersed in the polymer-based membrane. In the porous organic cage material modified by the amino group in the present invention, -NH2 can interact with the H bond in the polymer-based membrane, resulting in an increase in free volume and chain mobility, which can improve the compatibility between the porous organic cage material and the polymer-based membrane, and thus is conducive to processing into a matrix membrane. At the same time, the modified porous organic cage material will not cause the collapse or decomposition of the POC material structure during the subsequent solvent removal process, and a mixed matrix membrane with uniform thickness and good surface can be formed; and the amino group can significantly improve the affinity for CO2 and undergo a reversible reaction with CO2, which can be used as a CO2 transport site to improve CO2 permeability and CO2 / N2 selectivity, and improve the application prospect of the porous organic cage material in gas separation. Description of the Drawings

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 Scanning electron microscope images of the unmodified material CC3, the modified material PEI@CC3 obtained in Example 1, and the modified material DETA@CC3 obtained in Example 2; among them, (a) is CC3, (b) is PEI@CC3, and (c) is DETA@CC3;

[0019] Figure 2 Infrared spectra of Pebax / PEI@CC3-5 obtained in Example 1, Pebax / DETA@CC3-3 obtained in Example 2, and Pebax obtained in Comparative Example 1; among them, (a) is Pebax / PEI@CC3-5 and Pebax, and (b) is Pebax / DETA@CC3-3 and Pebax;

[0020] Figure 3 X-ray diffraction spectra of Pebax / PEI@CC3-5 obtained in Example 1, Pebax / DETA@CC3-3 obtained in Example 2, and Pebax obtained in Comparative Example 1; among them, (a) is Pebax / PEI@CC3-5 and Pebax, and (b) is Pebax / DETA@CC3-3 and Pebax;

[0021] Figure 4 Surface scanning electron microscope images of Pebax / PEI@CC3-5 obtained in Example 1, Pebax / DETA@CC3-3 obtained in Example 2, and Pebax obtained in Comparative Example 1; among them, (a) is Pebax, (b) is Pebax / PEI@CC3-5, and (c) is Pebax / DETA@CC3-3;

[0022] Figure 5 Cross-section scanning electron microscope images of Pebax / PEI@CC3-5 obtained in Example 1, Pebax / DETA@CC3-3 obtained in Example 2, and Pebax obtained in Comparative Example 1; among them, (a) is Pebax, (b) is Pebax / PEI@CC3-5, and (c) is Pebax / DETA@CC3-3;

[0023] Figure 6CO2 / N2 gas separation diagrams of Pebax / PEI@CC3-X obtained in Example 1, Pebax / DETA@CC3-X obtained in Example 2, and Pebax obtained in Comparative Example 1, where (a) is Pebax / PEI@CC3-5 and Pebax, and (b) is Pebax / DETA@CC3-3 and Pebax. Detailed implementation manners

[0024] The present invention provides an amine-modified porous organic cage material, comprising a porous organic cage material and an amine-containing compound loaded on the surface and in the pores of the porous organic cage material; the mass ratio of the amine-containing compound to the porous organic cage material is 2.4 - 3:0.3 - 0.6.

[0025] In the present invention, unless otherwise specified, all preparation raw materials are commercially available products well-known to those skilled in the art.

[0026] In the present invention, the amine-containing compound includes one or more of polyethyleneimine (PEI), silane coupling agent, alkanolamine compounds, and polyethylenepolyamine compounds; the silane coupling agent is one or more of N-methylaminopropyltrimethoxysilane (MAPS), 3-aminopropyltriethoxysilane (APTES), and 2-(2-pyridyl)ethyltrimethoxysilane; the alkanolamine compound is N-methyldiethanolamine (MDEA); the polyethylenepolyamine compound is diethylenetriamine (DETA) and / or tetraethylenepentamine (TEPA). In specific embodiments of the present invention, it can be polyethyleneimine or diethylenetriamine. The amine groups rich in the amine-containing compound in the present invention can interact with the CC3 and Pebax polymer chains through hydrogen bonds, enabling good interfacial compatibility between the filler and the mixed matrix membrane. And the amine groups can provide rich carriers to increase the CO2 permeation amount and promote gas transmission.

[0027] In the present invention, the porous organic cage material includes one or more of CC1, CC2, CC3, CC5, and CC9. In specific embodiments, it can be CC3. In a specific embodiment of the present invention, CC3 is a covalent cage 3 covalent organic cage, which has an octahedral spatial configuration, a simple preparation method, and sub-nanometer-sized windows that can screen gases of different sizes, thus obtaining the advantages of high CO2 selectivity and high gas flux.

[0028] In the present invention, the mass ratio of the amine-containing compound to the porous organic cage material is 2.4 - 3:0.3 - 0.6. In specific embodiments, it can be 3:0.4 or 2.6:0.5.

[0029] In the present invention, the preparation method of the amine-modified porous organic cage material includes the following steps:

[0030] Mix an amine - containing compound, a POC material and water to obtain a mixed solution;

[0031] Perform solid - liquid separation and drying on the mixed solution to obtain the amine - modified porous organic cage material.

[0032] In the present invention, the water is deionized water.

[0033] In the present invention, the mixing includes first mixing and second mixing in sequence; the first mixing is carried out under ultrasonic conditions at room temperature for 5 - 20 min, and in specific embodiments, it can be 10 min or 15 min; the second mixing is carried out under stirring conditions at room temperature; there are no special limitations on the frequency of ultrasonic waves and the stirring rate in the present invention.

[0034] In the present invention, the method of solid - liquid separation is centrifugation; the reagent used for centrifugation is ethanol; the rotation speed of centrifugation is 6000 - 8000 rpm; the number of centrifugation times is 1 - 3 times; the drying is vacuum drying at a temperature of 60 - 80 °C for 12 - 24 h.

[0035] The present invention also provides a mixed matrix membrane, which includes a polymer - based membrane and the amine - modified porous organic cage material described in the above technical solution dispersed in the polymer - based membrane.

[0036] In the present invention, the polymer - based membrane includes one or more of polyethylene, polypropylene, polystyrene, polyvinyl chloride, nylon, polyvinylidene fluoride, polyethersulfone, polyoxymethylene and polyether - block polyamide, and in specific embodiments, it can be polyether - block polyamide (Pebax). In the present invention, Pebax is a rubber - like high - molecular polymer of polyether copolymer amide, which is composed of a polyether segment (PE) providing high gas permeability and a polyamide segment (PA) providing mechanical strength, and has high gas separation selectivity and high gas permeability. The polymer powder is the base - film body of the mixed matrix membrane and can be used as a scaled - up base - film for further industrialization.

[0037] In the present invention, the loading amount of the amine - modified porous organic cage material is 1.5 - 15 wt%, and in specific embodiments, it can be 2 wt%, 5 wt%, 8 wt% or 11 wt%. By controlling the amine - modified porous organic cage material within the above range in the present invention, it is possible to prevent the excessive amount of the amine - modified porous organic cage material from causing its agglomeration in the polymer - based membrane and affecting the gas separation performance of the membrane; at the same time, it can prevent the insufficient amount from failing to play the role of a CO2 transport channel.

[0038] The present invention also provides a preparation method of the mixed matrix membrane described in the above technical solution, including the following steps:

[0039] Mix an amino-modified porous organic cage material, a polymer-based membrane, and a polar organic solvent to obtain a casting solution; after forming and drying the casting solution, obtain the mixed matrix membrane.

[0040] In the present invention, the polar organic solvent includes one or more of methanol, ethanol, N,N-dimethylformamide, dimethyl sulfoxide, acetone, and N-methylpyrrolidone. In a specific embodiment, it can be N-methylpyrrolidone (NMP).

[0041] In the present invention, dissolve the amino-modified porous organic cage material in an organic solvent to obtain an amino-modified porous organic cage material solution; dissolve the polymer-based membrane in an organic solvent to obtain a polymer solution; mix the amino-modified porous organic cage material solution and the polymer solution to obtain a casting solution; the temperature for dissolving the amino-modified porous organic cage material is room temperature, and the time is 2 - 4 h; the temperature for dissolving the polymer-based membrane is 60 - 80 °C, and the time is 2 - 4 h; the temperature for mixing the amino-modified porous organic cage material solution and the polymer solution is 60 - 80 °C;

[0042] In the present invention, after forming and drying the casting solution, obtain the mixed matrix membrane; the drying method is evaporation, the temperature is 40 - 60 °C, and the time is 12 - 24 h.

[0043] The present invention also provides the application of the amino-modified porous organic cage material described in the above technical solution or the mixed matrix membrane described in the above technical solution in adsorbing and separating CO2 in a mixed gas.

[0044] In the present invention, the mixed gas includes a N2 and CO2 mixture, a CH4 and CO2 mixture.

[0045] To further illustrate the present invention, the following describes in detail the amino-modified porous organic cage material, the mixed matrix membrane, and their preparation methods and applications provided by the present invention with reference to the accompanying drawings and examples, but they should not be construed as limiting the protection scope of the present invention.

[0046] Example 1

[0047] Dissolve 3 g of polyethyleneimine in 120 mL of deionized water, stir for 10 min to obtain a PEI solution; add 0.4 g of CC3 powder to the above PEI solution, ultrasonically treat the obtained suspension for 10 min, and stir overnight at room temperature to obtain a mixed solution; centrifuge the obtained mixed solution with ethanol at 8000 rpm for 5 min, centrifuge the obtained solid again under the same conditions, centrifuge a total of 3 times, and transfer the obtained solid to a vacuum drying oven at 80 °C and dry for 12 h to obtain an amino-modified porous organic cage material powder, denoted as PEI@CC3.

[0048] Respectively place 0.01 g, 0.03 g, 0.05 g, and 0.07 g of the above PEI@CC3 powders into 5 g of NMP solvent, and stir the resulting mixture at room temperature for 4 h to obtain a dispersion;

[0049] Meanwhile, place 0.6 g of polyether block polyamide (Pebax1657) pellets into 15 g of NMP solvent, and stir at 80 °C for 4 h to obtain a casting solution; mix the dispersion with the casting solution, stir the resulting mixture at 80 °C overnight, and finally add the mixture to a clean polytetrafluoroethylene petri dish (diameter 10 cm) using a pipette, and evaporate at 60 °C for 24 h to obtain mixed matrix membranes, denoted as Pebax / PEI@CC3-1, Pebax / PEI@CC3-3, Pebax / PEI@CC3-5, and Pebax / PEI@CC3-7, respectively. The thickness of all membranes is approximately 85 - 150 μm.

[0050] Example 2

[0051] Dissolve 3 g of diethylenetriamine in 120 mL of deionized water, stir for 10 min to obtain a DETA solution; add 0.4 g of CC3 powder to the above DETA solution, sonicate the resulting suspension for 10 min, and stir overnight at room temperature to obtain a mixture; centrifuge the resulting mixture with ethanol at 8000 rpm for 5 min, centrifuge the resulting solid again under the same conditions, centrifuge a total of 3 times, and transfer the resulting solid to a vacuum drying oven at 80 °C and dry for 12 h to obtain an amino-modified porous organic cage material powder, denoted as DETA@CC3.

[0052] Respectively place 0.01 g, 0.03 g, and 0.05 g of the above DETA@CC3 powders into 5 g of NMP solvent, and stir the resulting mixture at room temperature for 4 h to obtain a dispersion;

[0053] Meanwhile, place 0.6 g of polyether block polyamide (Pebax1657) pellets into 15 g of NMP solvent, and stir at 80 °C for 4 h to obtain a casting solution; mix the dispersion with the casting solution, stir the resulting mixture at 80 °C overnight, and finally add the mixture to a clean polytetrafluoroethylene petri dish (diameter 10 cm) using a pipette, and evaporate at 60 °C for 24 h to obtain mixed matrix membranes, denoted as Pebax / DETA@CC3-1, Pebax / DETA@CC3-3, and Pebax / DETA@CC3-5, respectively. The thickness of all membranes is approximately 85 - 150 μm.

[0054] Comparative Example 1

[0055] 0.6 g of Pebax1657 was placed in 20 g of NMP solvent and stirred overnight at 80 °C to obtain a casting solution. The casting solution was added to a clean polytetrafluoroethylene petri dish (10 cm in diameter) by a pipette and evaporated at 60 °C for 24 h to obtain a pure polymer membrane, denoted as Pebax.

[0056] Comparative Example 2

[0057] 0.6 g of PES was placed in 20 g of NMP solvent and stirred overnight at 80 °C to obtain a casting solution. The casting solution was added to a clean polytetrafluoroethylene petri dish (10 cm in diameter) by a pipette and evaporated at 60 °C for 24 h to obtain a pure polymer membrane, denoted as PES.

[0058] Comparative Example 3

[0059] 0.6 g of Pebax1657 was placed in 20 g of ethanol solvent and stirred overnight at 80 °C to obtain a casting solution. The casting solution was added to a clean polytetrafluoroethylene petri dish (10 cm in diameter) by a pipette and evaporated at 60 °C for 24 h to obtain a pure polymer membrane, denoted as EtOH / Pebax.

[0060] Test Example

[0061] Characterization and testing of the membranes:

[0062] Figure 1 are the scanning electron microscope images of the unmodified material CC3, the modified material PEI@CC3 obtained in Example 1, and the modified material DETA@CC3 obtained in Example 2. From Figure 1 the results, it can be seen that the CC3 crystals exhibit a regular octahedral structure with a smooth surface. After modification with PEI and DETA, it can be clearly seen that there are debris on the octahedral surface, but the crystal structure remains intact.

[0063] Figure 2 are the infrared spectra of Pebax / PEI@CC3-5 obtained in Example 1, Pebax / DETA@CC3-3 obtained in Example 2, and Pebax obtained in Comparative Example 1. From Figure 2 the results, it can be seen that after blending the amine-modified POC material in the polymer-based membrane, the main characteristic peaks corresponding to PA and PEO in the membrane have not changed, which proves that the addition of the modified POC filler has not changed the properties of the membrane; at the same time, it can be observed that the characteristic peak corresponding to -NH2 has increased and the characteristic peak of the membrane has shifted slightly towards higher intensity, which proves the successful modification of the amine-containing compounds.

[0064] Figure 3X-ray diffraction patterns of Pebax / PEI@CC3-5 obtained in Example 1, Pebax / DETA@CC3-3 obtained in Example 2, and Pebax obtained in Comparative Example 1. From Figure 3 the results, it can be seen that the characteristic peaks corresponding to the filler CC3 can be clearly observed in the mixed matrix membrane, while the positions of the characteristic peaks corresponding to PA and PEO have not changed, which proves the successful addition of the filler without changing the basic properties of the membrane.

[0065] Figure 4 Surface scanning electron micrographs of Pebax / PEI@CC3-5 obtained in Example 1, Pebax / DETA@CC3-3 obtained in Example 2, and Pebax obtained in Comparative Example 1; Figure 5 Cross-section scanning electron micrographs of Pebax / PEI@CC3-5 obtained in Example 1, Pebax / DETA@CC3-3 obtained in Example 2, and Pebax obtained in Comparative Example 1. From Figure 4 the results, it can be seen that the surface of the Pebax / PEI@CC3-5 membrane becomes more porous, providing more and faster gas transport paths, while the uniformly distributed filler particles can be clearly seen on the surface of Pebax / DETA@CC3-3, indicating the successful loading of the amine-modified POC material. And from Figure 5 the comparison of the cross-section electron micrographs, it can be found that the mixed matrix membrane becomes more uniform and dense, and a few filler particles can be seen in the cross-section but no obvious agglomeration phenomenon is found. This shows that the addition of the modified filler increases the interfacial compatibility of the membrane.

[0066] Single gas permeation experiments of CO2 and N2 were carried out under the conditions of 30 °C and 1 bar pressure. Figure 6 CO2 / N2 gas separation diagrams of Pebax / PEI@CC3-X obtained in Example 1, Pebax / DETA@CC3-X obtained in Example 2, and Pebax obtained in Comparative Example 1, as Figure 6 shown. In Comparative Example 1, the CO2 permeability of the pure polymer membrane Pebax is 89 Barrer, and the CO2 / N2 selectivity is 11.8; for the Pebax / PEI@CC3-5 with the best performance among the mixed matrix membranes obtained in Example 1, the CO2 permeation flux is 307.71 Barrer, and the CO2 / N2 selectivity is 30.61; for the Pebax / DETA@CC3-3 with the best performance among the mixed matrix membranes obtained in Example 2, the CO2 permeation flux is 248 Barrer, and the CO2 / N2 selectivity is 34.37.

[0067] First, the rich porosity and unique sub-nanostructure of CC3 itself provide a transport path for CO2 transportation, reducing the transport resistance. Second, after amine modification, the amine groups can significantly enhance the adsorption of C O2The affinity with CO2 and the reversible reaction with CO2 can serve as CO2 transmission sites to enhance CO2 permeability. Moreover, the -NH2 in the modified PEI@CC3 and DETA@CC3 interacts with the H bond in the C=O of the PA segment in Pebax, resulting in an increase in free volume and chain mobility, which can improve the compatibility between the amine-modified POC material and the membrane and reduce the gas transmission resistance. The addition of the amine-modified POC material significantly improves the CO2 permeability and CO2 / N2 selectivity of the polymer membrane. The amine-modified POC material has broad application prospects in gas separation. In Examples 1 and 2, the preparation method used is the blending method, mainly changing the types of amine-containing compounds, and in Example 1, the main change is the dosage of PEI@CC3; in Example 2, the main change is the dosage of DETA@CC3, but in both cases, a mixed matrix membrane with good performance and a flat surface can be prepared.

[0068] In addition, from the test results, it can be found that the CO2 permeability of the pure polymer membrane Pebax in Comparative Example 1 is 89 Barrer, and the CO2 / N2 selectivity is 11.8; the CO2 permeation flux of the pure polymer membrane PES in Comparative Example 2 is 37.23 Barrer, and the CO2 / N2 selectivity is 20.78; the CO2 permeation flux of the pure polymer membrane EtOH / Pebax in Comparative Example 3 is 105.95 Barrer, and the CO2 / N2 selectivity is 8.07. In comparison, the Pebax membrane in Comparative Example 1 has the best gas separation performance. In Comparative Examples 2 and 3, the preparation method used is the co-solvent method. In Comparative Example 2, the main change is the type of polymer material, and in Comparative Example 3, the main change is the choice of solvent. By comparing with Comparative Example 1, it can be concluded that Pebax and NMP are the most suitable polymer material and solvent.

[0069] From the above examples and comparative examples, it can be seen that the mixed matrix membrane prepared by introducing the amine-modified POC material into the polymer in the present invention has excellent CO2 / N2 separation performance, and the amine-modified POC material is introduced into various different types of polymer-based membranes by using the simple preparation method of the blending method, making its large-scale preparation possible and further broadening its practical application field. The membrane prepared in the present invention has excellent CO2 / N2 separation performance and has broad application prospects in aspects such as CO2 adsorption and separation.

[0070] Although the above examples have described the present invention in detail, they are only a part of the embodiments of the present invention, not all embodiments. People can also obtain other embodiments based on these embodiments without creative efforts, and these embodiments all belong to the protection scope of the present invention.

Claims

1. An amine-modified porous organic cage material, characterized in that: The invention comprises a porous organic cage material and an amine-containing compound loaded on the surface and in the pores of the porous organic cage material; the mass ratio of the amine-containing compound to the porous organic cage material is 2.4-3:0.3-0.

6.

2. The amino-modified porous organic cage material according to claim 1, characterized in that: The amine-containing compound includes one or more of polyethyleneimine, silane coupling agent, alcoholamine compound and polyethylene polyamine compound.

3. The amino-modified porous organic cage material according to claim 2, characterized in that: The silane coupling agent is one or more of N-methylaminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane and 2-(2-pyridyl)ethyltrimethoxysilane; the alcoholamine compound is N-methyldiethanolamine; and the polyethylenepolyamine compound is diethylenetriamine and / or tetraethylenepentamine.

4. The amino-modified porous organic cage material according to claim 1, characterized in that: The porous organic cage material includes one or more of CC1, CC2, CC3, CC5 and CC9.

5. A mixed matrix membrane, characterized in that The invention comprises a polymer-based film and the amine-modified porous organic cage material according to any one of claims 1 to 4 dispersed in the polymer-based film.

6. The mixed matrix membrane according to claim 5, characterized in that: The polymer base film includes one or more of polyethylene, polypropylene, polystyrene, polyvinyl chloride, nylon, polyvinylidene fluoride, polyether sulfone, polyoxymethylene and polyether block polyamide.

7. The mixed matrix membrane according to claim 5, characterized in that: The loading amount of the amine-modified porous organic cage material is 1.5-15 wt %.

8. The method for preparing a mixed matrix membrane according to any one of claims 5 to 7, characterized in that: The following steps are involved: The amine-modified porous organic cage material, the polymer-based membrane and the polar organic solvent are mixed to obtain a casting solution; the casting solution is formed into a film and dried to obtain the mixed matrix membrane.

9. The preparation method according to claim 8, characterized in that: The polar organic solvent includes one or more of methanol, ethanol, N,N-dimethylformamide, dimethyl sulfoxide, acetone and N-methylpyrrolidone.

10. Use of the amino-modified porous organic cage material according to any one of claims 1 to 4 or the mixed matrix membrane according to any one of claims 5 to 7 in the adsorption and separation of CO2 in mixed gases.

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