A gas separation membrane based on a covalent organic framework and its preparation method and application

Abstract

The present invention relates to the field of gas separation membrane technology, and in particular to a covalent organic framework-based gas separation membrane and its preparation method and application, comprising the following steps: preparing a mixed solution containing a polyamine monomer, a polyaldehyde monomer, and an organic solvent, reacting to obtain a COF material; preparing an aqueous solution of small amine molecules, adding the COF material, and mixing until adsorption equilibrium is obtained to obtain NH2-COF; preparing an aqueous phase reaction liquid containing NH2-COF and an organic phase reaction liquid containing polyacyl chlorides; contacting the aqueous phase reaction liquid with the surface of a support membrane, removing excess liquid, and then contacting it with the organic phase reaction liquid to react to obtain a nascent COF membrane; and heat-treating the nascent COF membrane at 30-90°C for 1-30 minutes to obtain a COF gas separation membrane. The gas separation membrane prepared by the present invention can achieve efficient separation of carbon dioxide / nitrogen and carbon dioxide / methane, solving the problem of low selectivity of COF membranes in carbon dioxide / nitrogen and carbon dioxide / methane separation in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of gas separation membranes, and in particular to a gas separation membrane based on a covalent organic framework, and a preparation method and application thereof. Background Art

[0002] CO2 is the most prominent greenhouse gas, primarily derived from industrial coal-fired flue gases. Carbon capture technology, short for carbon dioxide capture, utilization, and storage, separates, enriches, and utilizes the CO2 produced by fossil fuel combustion, thereby reducing the greenhouse gas effect. Industrial applications of CO2 separation also include hydrogen purification (CO2 / H2 separation) and natural gas purification (CO2 / CH4 separation).

[0003] Currently, the main CO2 capture technologies include absorption, adsorption, and membrane separation. Membrane separation utilizes the pressure difference across a membrane as a driving force, separating gases based on the varying permeation rates of the components within the membrane. Compared to traditional CO2 capture technologies, gas separation membrane technology is an environmentally friendly separation technology with advantages such as low energy consumption, low cost, high efficiency, no phase change of the permeated material, high operational continuity, and a high degree of equipment integration, making it a representative second-generation carbon capture technology.

[0004] Polymer membranes, with their advantages of easy processing, excellent film-forming properties, and high toughness, have become common gas separation membrane materials in industrial applications. However, there is often a trade-off between gas permeability and selectivity in polymer membranes. Therefore, the development of high-performance gas separation membrane materials is crucial for achieving efficient CO2 / N2 and CO2 / Methane separations, and for promoting the industrialization of CO2 emissions reduction and methane purification.

[0005] Covalent organic frameworks (COFs) are crystalline porous materials with two- or three-dimensional structures formed by covalently linking light elements (such as carbon, nitrogen, oxygen, boron, and hydrogen) through thermodynamically controlled reversible polymerization reactions. Compared to traditional amorphous polymer membranes, COFs membranes possess well-ordered pores, promising to overcome the trade-off between permeability and selectivity, enabling ultrafast gas transport and separation. However, the pore size of existing COFs (>1 nm) is much larger than the kinetic diameter of common gas molecules (such as H₂, N₂, CO₂, and CH₄), making selective gas separation difficult. Summary of the Invention

[0006] The purpose of the present invention is to provide a gas separation membrane based on a covalent organic framework, a preparation method and application thereof. The prepared gas separation membrane can achieve efficient separation of carbon dioxide / nitrogen and carbon dioxide / methane, and solve the problem of low selectivity of COF membranes in carbon dioxide / nitrogen and carbon dioxide / methane separation in the prior art.

[0007] To achieve the above objectives, the present invention provides a method for preparing a gas separation membrane based on a covalent organic framework, comprising the following steps:

[0008] (1) preparing a mixed solution containing a polyamine monomer, a polyaldehyde monomer, and an organic solvent, reacting the mixture at 50-200 °C for 12-72 h, and then washing and drying the mixture to obtain a COF material;

[0009] (2) Prepare an aqueous solution of amine small molecules, add COF material, mix until adsorption equilibrium, centrifuge and dry to obtain the aminated COF material NH2-COF;

[0010] (3) uniformly dispersing NH2-COF in water to obtain an aqueous phase reaction solution containing NH2-COF; dissolving the polyacyl chloride monomer in an organic solvent to obtain an organic phase reaction solution containing polyacyl chloride;

[0011] (4) After the aqueous phase reaction liquid contacts the support membrane surface for 1-30 min, the excess liquid is removed and then contacted with the organic phase reaction liquid for 5-60 min to obtain the primary COF membrane;

[0012] (5) The nascent COF membrane was heat treated at 30-90 °C for 1-30 min to obtain a COF gas separation membrane.

[0013] Preferably, the concentration of the polyamine monomer in the mixed solution of step (1) is in the range of 0.1 to 5 mol·L -1 The concentration of polyaldehyde monomers ranges from 0.1 to 5 mol·L -1 .

[0014] Preferably, in step (1), the polyamine monomer includes one or more of p-phenylenediamine, piperazine, 2,5-dimethyl-p-phenylenediamine, 1,3,5-triaminobenzene, 1,2,4-triaminobenzene, 2-sulfonic acid-1,4-phenylenediamine, m-phenylenediamine and o-phenylenediamine.

[0015] Preferably, in step (1), the polyaldehyde monomer includes one or more of 2,4,6-triformylphloroglucinol, 2,5-dimethoxybenzene-1,4-dicarboxaldehyde, 4,4'-biphenyldicarboxaldehyde, 2,2'-bipyridine-5,5'-dicarboxaldehyde, 2,5-dihydroxyterephthalaldehyde, 1,4-dialdehyde-2,5-divinylbenzene, 2,3,5,6-tetrafluorobenzaldehyde, glyoxal, glutaraldehyde, adipaldehyde, 1,3-butanedialdehyde, terephthalaldehyde, 2,5-dichloroterephthalaldehyde and 3,3',5,5'-tetralyl-4,4'-dihydroxybiphenyl.

[0016] Preferably, the organic solvents in step (1) and step (3) include one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, benzene, toluene, mesitylene, ethanol, acetone, acetonitrile, n-hexane, ethyl acetate, dichloromethane and chloroform.

[0017] Preferably, in step (2), the amine small molecule includes one or more of ethylenediamine, propylenediamine, polyethyleneimine, monoethanolamine, diethanolamine, polyoxyethylenediamine, triethanolamine, m-phenylenediamine, adipic acid diamine, piperazine, o-phenylenediamine, polyethylene polyamine, p-phenylenediamine, and polyvinylamine;

[0018] The concentration of amine small molecules in the aqueous solution is 0.1~5 mol·L -1 The adsorption equilibrium time is 0.5~24 h.

[0019] Preferably, in step (3), the polyvalent acyl chloride monomer includes one or more of o-phthaloyl disulfonyl chloride, isophthaloyl disulfonyl chloride, 4,4'-biphenyl disulfonyl chloride, 2,6-pyridine dicarbonyl chloride, p-phthaloyl disulfonyl chloride, fumaroyl chloride, 1,3,5-trimesoyl chloride, terephthaloyl chloride, octafluoroadipoyl chloride, o-phthaloyl chloride, azelayl chloride, isophthaloyl chloride, oxalyl chloride, hexafluoroglutaryl chloride, malonyl chloride, methylmalonyl chloride, succinoyl chloride, tetrafluorosuccinoyl chloride, glutaryl chloride, adipoyl chloride, pimeloyl chloride, suberyl chloride, and sebacoyl chloride.

[0020] Preferably, in step (3), the mass concentration of NH2-COF in the aqueous reaction solution is 0.1~5 g·L -1 The mass concentration of polyacyl chloride in the organic phase reaction solution is 0.1~5 g·L -1 .

[0021] A gas separation membrane based on a covalent organic framework is prepared by the above-mentioned preparation method of a gas separation membrane based on a covalent organic framework.

[0022] An application of a gas separation membrane based on a covalent organic framework for the separation of carbon dioxide / nitrogen and carbon dioxide / methane systems.

[0023] Mechanism of the present invention:

[0024] The present invention uses an aminated COF material as an aqueous phase reaction monomer and a polyacyl chloride as an organic phase reaction monomer to produce a gas separation membrane based on a covalent organic framework through an interfacial reaction. The COF material has an ordered pore structure of a specific size, providing a fast and selective channel for gas transmission. The aminated COF material obtained by adsorbing small amine molecules contains a large number of amino groups in the pores, which can reduce the COF pore size on the one hand and increase the adsorption amount of CO2 in the COF pores on the other hand. Therefore, the aminated COF membrane constructed by the above method is suitable for the selective and rapid transmission of CO2 molecules, thereby achieving efficient separation of carbon dioxide / nitrogen and carbon dioxide / methane.

[0025] Beneficial effects of the present invention:

[0026] (1) A gas separation membrane based on a covalent organic framework of the present invention has excellent structural stability and good long-term operational stability;

[0027] (2) A gas separation membrane based on a covalent organic framework of the present invention has a high carbon dioxide permeation rate and a moderate carbon dioxide / nitrogen selectivity, and can be used for carbon dioxide capture in flue gas;

[0028] (3) A gas separation membrane based on a covalent organic framework of the present invention has a high carbon dioxide permeation rate and a moderate carbon dioxide / methane selectivity, and can be used for methane purification in natural gas, shale gas, coalbed methane and other systems;

[0029] (4) The present invention provides a method for preparing a gas separation membrane based on a covalent organic framework. The method is simple, the preparation conditions are mild, and it is easy to realize industrial production.

[0030] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a surface scanning electron microscope image of the polysulfone-based membrane in Example 1 of the present invention;

[0032] Figure 2 This is a surface scanning electron microscope image of the COF gas separation membrane in Example 1 of the present invention. DETAILED DESCRIPTION

[0033] The present invention is further described below with reference to the accompanying drawings and examples. Unless otherwise defined, technical or scientific terms used herein shall have the same meanings as those commonly understood by persons of ordinary skill in the art to which the present invention pertains. The above-mentioned features or features described in the specific examples of the present invention may be combined in any manner. These specific examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention.

[0034] There is no particular limitation on the sources of all raw materials in the present invention and the following examples, and any commercially available raw materials may be used.

[0035] The method for detecting the gas permeation rate in the embodiment of the present invention is as follows:

[0036] The membrane permeation selectivity test system was used to test the membrane permeation rate of CO2, N2 and CH4. The test system includes a membrane pool, pipeline, regulating valve, pressure gauge, soap film flow meter and gas chromatograph. The effective membrane area tested is 4.91 cm 2 , the test pressure is 1~6 bar, and the test temperature is 20±1 ℃.

[0037] The calculation formula for gas permeation rate is as follows:

[0038] R i =Q i / (A·△P i ),

[0039] where R i is the penetration rate of component i, in GPU (1 GPU = 10 -6 cm 3 (STP) cm -2 ·s -1 cmHg -1 ), Q i is the volume flow rate of component i at standard temperature and pressure (STP), in cm 3 (STP) / s; ΔP i is the partial pressure difference of component i on both sides of the membrane, in cmHg; A is the effective membrane area, in cm 2 .

[0040] The selectivity of separation membranes is often evaluated by separation selectivity, or separation factor (α). Commonly used separation factors include ideal separation factor and true separation factor.

[0041] When using pure gas for testing, the ideal separation factor of components i and j is α * i / j The definition is:

[0042]

[0043] Where, R i and R j are the permeation rates of components i and j, respectively.

[0044] For a gas mixture containing two components i and j, the true separation factor is α' i / j The definition is:

[0045]

[0046] Where, y i 、y j are the mole fractions of components i and j in the permeate gas, respectively; x i 、x j are the mole fractions of components i and j in the feed gas, respectively.

[0047] Example 1

[0048] The present invention provides a gas separation membrane based on a covalent organic framework, and a preparation method thereof comprises the following steps:

[0049] (1) Prepare 0.2 mol·L -1 Piperazine and 0.1 mol·L -1 The toluene solution of terephthalaldehyde was reacted at 100 °C for 72 h, washed three times with toluene and ethanol, and dried at 80 °C for 24 h to obtain the COF material.

[0050] (2) Prepare the solution at a concentration of 1 mol·L -1 The COF material powder was mixed with the monoethanolamine aqueous solution, stirred for 8 h, centrifuged and dried to obtain NH2-COF material.

[0051] (3) Prepare a mixture containing 0.5 g·L -1 The aqueous reaction solution of NH2-COF material was prepared to contain 0.5 g·L -1 A n-hexane solution of 1,3,5-trimethylbenzyl chloride was used as the organic phase reaction solution.

[0052] (4) The aqueous reaction liquid was brought into contact with the surface of the polysulfone-based membrane for 10 minutes. After removing the excess solution on the surface, the aqueous reaction liquid was brought into contact with the organic reaction liquid. After reacting for 10 minutes, the excess reaction liquid was removed and the residual organic phase monomer on the surface was washed with n-hexane to obtain the primary COF membrane.

[0053] (5) The prepared nascent COF membrane was heat treated at 80 °C for 10 min to obtain a COF gas separation membrane.

[0054] After testing, the COF gas separation membrane produced has a CO2 permeability rate of 1000 GPU, a CO2 / N2 separation factor of 28, and a CO2 / CH4 separation factor of 17.

[0055] Figure 1 is a surface scanning electron microscope image of the polysulfone base membrane in Example 1 of the present invention, Figure 1 It can be seen that the surface of the polysulfone-based membrane is smooth; Figure 2 is a surface scanning electron microscope image of the COF gas separation membrane in Example 1 of the present invention, Figure 2 It can be seen that the surface of the COF gas separation membrane shows accumulated NH2-COF nanoparticles.

[0056] Example 2

[0057] The present invention provides a gas separation membrane based on a covalent organic framework, and a preparation method thereof comprises the following steps:

[0058] (1) Prepare 0.3 mol·L -1 2,5-dimethyl-p-phenylenediamine and 0.1 mol·L -1 A toluene solution of 2,5-dimethoxybenzene-1,4-dicarbaldehyde was reacted at 100 °C for 72 h, washed three times with toluene and ethanol, and dried at 80 °C for 24 h to obtain the COF material.

[0059] (2) Prepare the solution at a concentration of 1 mol·L -1 The COF material powder was mixed with the polyethylene polyamine aqueous solution, stirred for 8 h, centrifuged and dried to obtain NH2-COF material.

[0060] (3) Prepare a mixture containing 0.3 g·L -1 The aqueous reaction solution of NH2-COF material was prepared to contain 1.5 g·L -1 A n-heptane solution of terephthaloyl chloride was used as the organic phase reaction liquid.

[0061] (4) The aqueous reaction liquid was brought into contact with the surface of the polyacrylonitrile-based membrane for 5 minutes. After removing the excess solution on the surface, the aqueous reaction liquid was brought into contact with the organic reaction liquid. After reacting for 5 minutes, the excess reaction liquid was removed and the residual organic phase monomer on the surface was washed with n-heptane to obtain the primary COF membrane.

[0062] (5) The prepared nascent COF membrane was heat treated at 80 °C for 5 min to obtain a COF gas separation membrane.

[0063] After testing, the CO2 permeation rate of the prepared COF gas separation membrane reached 800 GPU, the CO2 / N2 separation factor was 35, and the CO2 / CH4 separation factor was 23.

[0064] Example 3

[0065] The present invention provides a gas separation membrane based on a covalent organic framework, and a preparation method thereof comprises the following steps:

[0066] (1) Prepare 0.2 mol·L -1 1,3,5-triaminobenzene and 0.1 mol·L -1 The toluene solution of terephthalaldehyde was reacted at 100 °C for 72 h, washed three times with toluene and ethanol, and dried at 80 °C for 24 h to obtain the COF material.

[0067] (2) Prepare the solution at a concentration of 1 mol·L -1 The COF material powder was mixed with the polyethyleneimine aqueous solution, stirred for 20 h, centrifuged and dried to obtain NH2-COF material.

[0068] (3) Prepare a mixture containing 0.5 g·L -1 The aqueous reaction solution of NH2-COF material was prepared to contain 1.0 g·L -1 Isophthaloyl chloride in n-heptane was used as the organic phase reaction solution.

[0069] (4) The aqueous reaction liquid was brought into contact with the surface of the polyethersulfone-based membrane for 5 minutes. After removing the excess solution on the surface, the aqueous reaction liquid was brought into contact with the organic reaction liquid. After reacting for 5 minutes, the excess reaction liquid was removed and the residual organic phase monomer on the surface was washed with n-heptane to obtain the primary COF membrane.

[0070] (5) The prepared nascent COF membrane was heat treated at 80 °C for 5 min to obtain a COF gas separation membrane.

[0071] After testing, the CO2 permeation rate of the prepared COF gas separation membrane reached 1100 GPU, the CO2 / N2 separation factor was 40, and the CO2 / CH4 separation factor was 26.

[0072] Example 4

[0073] The present invention provides a gas separation membrane based on a covalent organic framework, and a preparation method thereof comprises the following steps:

[0074] (1) Prepare 0.2 mol·L -1 p-phenylenediamine and 0.1 mol·L -1The toluene solution of terephthalaldehyde was reacted at 100 °C for 72 h, washed three times with toluene and ethanol, and dried at 80 °C for 24 h to obtain the COF material.

[0075] (2) Prepare the solution at a concentration of 1 mol·L -1 The COF powder was mixed with the adipamide aqueous solution, stirred for 10 h, centrifuged and dried to obtain NH2-COF material.

[0076] (3) Prepare a mixture containing 0.5 g·L -1 The aqueous reaction solution of NH2-COF material was prepared to contain 1.0 g·L -1 Suberoyl chloride in n-heptane was used as the organic phase reaction solution.

[0077] (4) The aqueous reaction liquid was brought into contact with the surface of the polyethersulfone-based membrane for 5 minutes. After removing the excess solution on the surface, the aqueous reaction liquid was brought into contact with the organic reaction liquid. After reacting for 5 minutes, the excess reaction liquid was removed and the residual organic phase monomer on the surface was washed with n-heptane to obtain the primary COF membrane.

[0078] (5) The prepared nascent COF membrane was heat treated at 80 °C for 5 min to obtain a COF gas separation membrane.

[0079] After testing, the COF gas separation membrane produced has a CO2 permeability rate of 1200 GPU, a CO2 / N2 separation factor of 32, and a CO2 / CH4 separation factor of 25.

[0080] Example 5

[0081] The present invention provides a gas separation membrane based on a covalent organic framework, and a preparation method thereof comprises the following steps:

[0082] (1) Prepare 0.2 mol·L -1 p-phenylenediamine and 0.1 mol·L -1 The toluene solution of terephthalaldehyde was reacted at 100 °C for 72 h, washed three times with toluene and ethanol, and dried at 80 °C for 24 h to obtain the COF material.

[0083] (2) Prepare a mixture containing 0.5 g·L -1 The aqueous reaction solution of pure COF material was prepared to contain 1.0 g·L -1 Suberoyl chloride in n-heptane was used as the organic phase reaction solution.

[0084] (3) The aqueous reaction liquid was brought into contact with the surface of the polyethersulfone-based membrane for 5 minutes. After removing the excess solution on the surface, the aqueous reaction liquid was brought into contact with the organic reaction liquid. After reacting for 5 minutes, the excess reaction liquid was removed and the residual organic phase monomer on the surface was washed with n-heptane to obtain the primary COF membrane.

[0085] (4) The prepared nascent COF membrane was heat treated at 80 °C for 5 min to obtain an unaminated COF gas separation membrane.

[0086] After testing, the CO2 permeation rate of the unaminated COF gas separation membrane prepared reached 400 GPU, the CO2 / N2 separation factor was 18, and the CO2 / CH4 separation factor was 8.

[0087] In summary, the covalent organic framework membrane prepared by the present invention has a high carbon dioxide permeation rate, good structural stability and long-term operational stability, and can achieve efficient separation of carbon dioxide / nitrogen and carbon dioxide / methane.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a gas separation membrane based on a covalent organic framework, characterized in that: The following steps are involved: (1) preparing a mixed solution containing a polyamine monomer, a polyaldehyde monomer, and an organic solvent, reacting the mixture at 50 to 200° C. for 12 to 72 hours, and then washing and drying the mixture to obtain a COF material; The polyamine monomer includes one or more of p-phenylenediamine, piperazine, 2,5-dimethyl-p-phenylenediamine, 1,3,5-triaminobenzene, 1,2,4-triaminobenzene, 2-sulfonic acid-1,4-phenylenediamine, m-phenylenediamine and o-phenylenediamine; The polyaldehyde monomer includes one or more of 2,4,6-triformylphloroglucinol, 2,5-dimethoxybenzene-1,4-dicarboxaldehyde, 4,4'-biphenyldicarboxaldehyde, 2,2'-bipyridine-5,5'-dicarboxaldehyde, 2,5-dihydroxyterephthalaldehyde, 1,4-dialdehyde-2,5-divinylbenzene, 2,3,5,6-tetrafluorobenzaldehyde, glyoxal, glutaraldehyde, adipaldehyde, 1,3-butanedialdehyde, terephthalaldehyde, 2,5-dichloroterephthalaldehyde and 3,3',5,5'-tetralyl-4,4'-dihydroxybiphenyl; (2) preparing an aqueous solution of amine small molecules, adding the COF material, mixing until adsorption equilibrium, centrifuging, and drying to obtain the aminated COF material NH2-COF; Amine small molecules include one or more of ethylenediamine, propylenediamine, polyethyleneimine, monoethanolamine, diethanolamine, polyoxyethylenediamine, triethanolamine, m-phenylenediamine, adipic acid diamine, piperazine, o-phenylenediamine, polyethylene polyamine, p-phenylenediamine, and polyvinylamine; (3) uniformly dispersing NH2-COF in water to obtain an aqueous phase reaction solution containing NH2-COF; dissolving a polyacyl chloride monomer in an organic solvent to obtain an organic phase reaction solution containing polyacyl chloride; (4) The aqueous phase reaction liquid is in contact with the support membrane surface for 1 to 30 minutes, and after removing the excess liquid, it is in contact with the organic phase reaction liquid for 5 to 60 minutes to react and obtain a nascent COF membrane; (5) heat treating the nascent COF membrane at 30-90° C. for 1-30 min to obtain a COF gas separation membrane; Gas separation membranes based on covalent organic frameworks are used for the separation of carbon dioxide / nitrogen and carbon dioxide / methane systems.

2. The method for preparing a gas separation membrane based on a covalent organic framework according to claim 1, characterized in that: The concentration of the polyamine monomer in the mixed solution of step (1) is in the range of 0.1 to 5 mol·L -1 The concentration of polyaldehyde monomers ranges from 0.1 to 5 mol·L -1 .

3. The method for preparing a gas separation membrane based on a covalent organic framework according to claim 1, characterized in that: The organic solvents in step (1) and step (3) include one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, benzene, toluene, mesitylene, ethanol, acetone, acetonitrile, n-hexane, ethyl acetate, dichloromethane and chloroform.

4. The method for preparing a gas separation membrane based on a covalent organic framework according to claim 1, wherein: In step (2), the concentration of the amine small molecule in the amine small molecule aqueous solution is 0.1 to 5 mol·L -1 The adsorption equilibrium time is 0.5 to 24 hours.

5. The method for preparing a gas separation membrane based on a covalent organic framework according to claim 1, characterized in that: In step (3), the polyvalent acid chloride monomer includes one or more of o-phthaloyl disulfonyl chloride, isophthaloyl disulfonyl chloride, 4,4'-biphenyl disulfonyl chloride, 2,6-pyridine dicarbonyl chloride, p-phthaloyl disulfonyl chloride, fumaroyl chloride, 1,3,5-trimesoyl chloride, terephthaloyl chloride, octafluoroadipoyl chloride, o-phthaloyl chloride, azelayl chloride, isophthaloyl chloride, oxalyl chloride, hexafluoroglutaryl chloride, malonyl chloride, methylmalonyl chloride, succinoyl chloride, tetrafluorosuccinoyl chloride, glutaryl chloride, adipoyl chloride, pimeloyl chloride, suberyl chloride, and sebacoyl chloride.

6. The method for preparing a gas separation membrane based on a covalent organic framework according to claim 1, characterized in that: In step (3), the mass concentration of NH2-COF in the aqueous reaction solution is 0.1-5 g·L -1 The mass concentration of polyacyl chloride in the organic phase reaction solution is 0.1~5g·L -1 .

7. A gas separation membrane based on a covalent organic framework, characterized in that: The gas separation membrane is prepared by the preparation method of the covalent organic framework-based gas separation membrane according to any one of claims 1 to 6.

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