Porous ammonia-hydrogen separation membrane and preparation method thereof

Abstract

The preparation method comprises the following steps: S1, taking chloromethylated polyether sulfone as a raw material, and dissolving the chloromethylated polyether sulfone in an organic solvent to obtain a membrane casting solution; s2, uniformly coating a clean glass plate with the membrane casting solution to obtain a porous CMPES base membrane; s3, the CMPES base membrane is soaked in a polyamine solution for crosslinking, quaternization modification is conducted on the CMPES base membrane through alkyl halide, and a modified membrane is obtained; and S4, soaking the modified membrane in a metal chloride solution for chelation reaction to introduce adsorption sites, then taking out the membrane, and repeatedly cleaning the membrane with deionized water to obtain the porous ammonia-hydrogen separation membrane. The obtained separation membrane has an efficient ammonia separation effect, and when the separation membrane is used for separating ammonia-containing gas, the ammonia permeability reaches up to 7777 Barrer, and the ammonia / hydrogen selectivity reaches up to 706.

Description

Technical Field

[0001] The present invention relates to the technical field of new materials, and in particular to a porous ammonia-hydrogen separation membrane and a preparation method thereof. Background Art

[0002] Ammonia is a compound with multiple importance, and has extremely broad applications in agriculture, chemical industry, energy, medical treatment and environmental protection. At present, the industrial methods for producing ammonia include natural gas ammonia production method, heavy oil ammonia production method, coal (coke) ammonia production method and Haber-Bosch synthesis method, among which Haber-Bosch method is the current mainstream industrial method for producing ammonia. This method is to react hydrogen and nitrogen under high temperature and high pressure to generate ammonia, but the conversion rate of the reaction is low, at about 20%. And the generated ammonia is mainly collected by condensation and liquefaction. Due to the existence of saturated vapor pressure, about 3% of ammonia exists in the atmosphere, which causes product loss to a certain extent. In addition, ammonia is an alkaline gas and has certain corrosiveness. Therefore, a large amount of ammonia discharged into the air will aggravate the severity of environmental pollution problems, so it is necessary to separate and recover this part of ammonia.

[0003] Common ammonia separation methods include adsorption, absorption, low-pressure distillation and membrane separation. Among them, membrane separation has attracted widespread attention in recent years due to its advantages of low energy consumption, high separation efficiency and no pollution to the environment. However, the ammonia selectivity and ammonia permeation flux of existing ammonia separation membranes are relatively low. So far, it is still a severe technical challenge to develop ammonia separation membranes with both high performance and low cost. Summary of the invention

[0004] In view of the problems of low ammonia selectivity and low ammonia permeation flux of ammonia separation membranes in the prior art, the present invention provides a porous ammonia-hydrogen separation membrane and a preparation method thereof. Based on the special microstructure of the porous membrane, its large free space volume greatly improves the molecular transmission rate.

[0005] The present invention adopts the following technical solution:

[0006] A method for preparing a porous ammonia-hydrogen separation membrane comprises the following steps:

[0007] S1, using chloromethylated polyethersulfone (CMPES) as a raw material, dissolving it in an organic solvent to obtain a casting solution;

[0008] S2, uniformly coating the casting solution on a clean glass plate, and preparing a porous CMPES-based membrane by a non-solvent-induced phase inversion method;

[0009] S3, soaking the CMPES base film in a polyamine solution for cross-linking, and then quaternizing it with a halide to obtain a modified film;

[0010] S4. Immerse the modified membrane in a metal chloride solution to carry out a chelating reaction to introduce adsorption sites, then take out the membrane and repeatedly wash it with deionized water for 3 times or more to obtain a porous ammonia-hydrogen separation membrane.

[0011] Preferably, in step S1, the chloromethylation degree of CMPES is 30%-80%, and it is composed of repeating units with chloromethyl groups and repeating units without chloromethyl groups, and its structural formula is:

[0012]

[0013] The organic solvent for dissolving CMPES in step S1 is one of chloroform, dichloromethane, tetrahydrofuran, N,N-dimethylformamide, dimethyl sulfoxide, N,N-dimethylacetamide, 1-methylpyrrolidone and toluene.

[0014] Preferably, the concentration of the casting solution in step S1 is 10%-40%.

[0015] The thickness of the base film in step S2 is 0.1-0.25 μm.

[0016] In step S3, the polyamine solution is an amine containing two primary amine groups or secondary amine groups.

[0017] The cross-linking conditions in step S3 are: the concentration of the polyamine solution is 0.1-4 mol·L -1 , soaking time is 0.5-48h, soaking temperature is 25-80℃.

[0018] In step S3, the quaternization agent is an alkyl halide; the quaternization modification is: the concentration of the alkyl halide solution is 0.1-2 mol·L -1 , modification time is 0.5-48h, temperature is 30-80℃.

[0019] Preferably, the alkyl halide is one of methyl iodide, ethyl bromide and propyl chloroethane.

[0020] The metal chloride solution in step S4 is one of ZnCl2, NaCl, KCl, MgCl2, LiCl2, CoCl2, NiCl2, and CuCl2.

[0021] The chelating reaction conditions in step S4 are: the concentration of the metal chloride solution is 0.1-2 mol·L -1 , the soaking temperature is 30-120℃, and the soaking time is 1-48h.

[0022] A porous ammonia-hydrogen separation membrane prepared according to the above preparation method.

[0023] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0024] The present invention prepares the base membrane by a non-solvent phase transformation method, and the membrane formation is relatively simple. Then, the base membrane is cross-linked and quaternized, and finally, metal ions are introduced to carry out chelation reaction. The functional groups are highly adjustable, and a variety of metal ions and Lewis acids can be introduced as adsorption sites. As the degree of CMPES chloromethylation increases, more reactive groups can be introduced, and the adsorption sites will be further increased. At the same time, thanks to the special porous structure of the porous membrane itself, the permeation flux of gas molecules is improved. DETAILED DESCRIPTION

[0025] The present invention can be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. Instead, these embodiments are provided so that the present disclosure will be thorough and complete and will fully convey the concept of the present invention to those skilled in the art. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present invention.

[0026] Embodiment 1:

[0027] This embodiment provides a method for preparing a porous ammonia-hydrogen separation membrane, comprising the following steps:

[0028] S1, dissolving polyethersulfone with a chloromethylation degree of 50% in N,N-dimethylformamide to obtain a casting solution with a concentration of 30%;

[0029] S2, uniformly coating the casting solution on a clean glass plate, and preparing a porous CMPES base membrane by a non-solvent induced phase inversion method. Specifically, uniformly coating the casting solution on the glass plate, scraping the film on the glass plate with a scraper, and then immersing the glass plate in deionized water for phase inversion to obtain a CMPES porous base membrane;

[0030] S3, soak the CMPES base film in a water bath with a temperature of 30°C and a concentration of 1 mol·L -1 The cross-linking was carried out in a diethylenetriamine solution of 0.5 h, and then immersed in a 0.5 mol·L -1 The modified membrane is obtained by quaternization in a halide solution.

[0031] S4, immerse the modified membrane in a solution with a concentration of 0.1 mol·L -1 , and a NiCl2 solution at 30°C for 1 h to carry out a chelating reaction, and then the membrane was taken out and washed repeatedly with deionized water for 3 times to obtain a porous ammonia-hydrogen separation membrane.

[0032] A gas separation device was used to separate the mixed gas containing ammonia and hydrogen. The test results showed that the ammonia permeability was 1223.9 Barrer and the ammonia / hydrogen selectivity was 100.1.

[0033] Embodiment 2:

[0034] This embodiment provides a method for preparing a porous ammonia-hydrogen separation membrane, comprising the following steps:

[0035] S1, dissolving polyethersulfone with a chloromethylation degree of 55% in N,N-dimethylformamide to obtain a casting solution with a concentration of 30%;

[0036] S2, uniformly coating the casting solution on a clean glass plate, and preparing a porous CMPES base membrane by a non-solvent induced phase inversion method. Specifically, uniformly coating the casting solution on the glass plate, scraping the film on the glass plate with a scraper, and then immersing the glass plate in deionized water for phase inversion to obtain a CMPES porous base membrane;

[0037] S3, soak the CMPES base film at a temperature of 30°C and a concentration of 1 mol·L -1 The cross-linking was carried out in a triethylenetetramine solution of 30 °C for 3 h, and then immersed in a 0.5 mol·L -1 The modified membrane is obtained by quaternization in a halide solution.

[0038] S4, soak the modified membrane in a solution with a concentration of 0.5 mol·L -1 , and a NiCl2 solution at 35°C for 8 h to carry out a chelating reaction, and then the membrane was taken out and washed repeatedly with deionized water for 3 times to obtain a porous ammonia-hydrogen separation membrane.

[0039] A gas separation device was used to separate the mixed gas containing ammonia and hydrogen. The test results showed that the ammonia permeability was 2231.9 Barrer and the ammonia / hydrogen selectivity was 156.8.

[0040] Embodiment 3:

[0041] This embodiment provides a method for preparing a porous ammonia-hydrogen separation membrane, comprising the following steps:

[0042] S1, dissolving polyethersulfone with a chloromethylation degree of 30% in N,N-dimethylformamide to obtain a casting solution with a concentration of 20%;

[0043] S2, uniformly coating the casting solution on a clean glass plate, and preparing a porous CMPES base membrane by a non-solvent induced phase inversion method. Specifically, uniformly coating the casting solution on the glass plate, scraping the film on the glass plate with a scraper, and then immersing the glass plate in deionized water for phase inversion to obtain a CMPES porous base membrane;

[0044] S3, soak the CMPES base film at a temperature of 30°C and a concentration of 1 mol·L -1The crosslinking was carried out in tetraethylenepentamine solution for 6 h, and then immersed in a solution at a temperature of 35 °C and a concentration of 1 mol·L -1 The modified membrane is obtained by quaternization in a halide solution.

[0045] S4, soak the modified membrane in a solution with a concentration of 0.5 mol·L -1 , and a CuCl2 solution at 35°C for 8 h to carry out a chelating reaction, and then the membrane was taken out and washed repeatedly with deionized water for 3 times to obtain a porous ammonia-hydrogen separation membrane.

[0046] A gas separation device was used to separate the mixed gas containing ammonia and hydrogen. The test results showed that the ammonia permeability was 2885 Barrer and the ammonia / hydrogen selectivity was 266.4.

[0047] Embodiment 4:

[0048] This embodiment provides a method for preparing a porous ammonia-hydrogen separation membrane, comprising the following steps:

[0049] S1, dissolving polyethersulfone with a chloromethylation degree of 55% in N,N-dimethylformamide to obtain a casting solution with a concentration of 10%;

[0050] S2, uniformly coating the casting solution on a clean glass plate, and preparing a porous CMPES base membrane by a non-solvent induced phase inversion method. Specifically, uniformly coating the casting solution on the glass plate, scraping the film on the glass plate with a scraper, and then immersing the glass plate in deionized water for phase inversion to obtain a CMPES porous base membrane;

[0051] S3, soak the CMPES base film at a temperature of 40°C and a concentration of 4 mol·L -1 The crosslinking was carried out in a diethylenetriamine solution for 6 h, and then immersed in a 0.5 mol·L -1 The modified membrane is obtained by quaternization in a halide solution.

[0052] S4, soak the modified membrane in a solution with a concentration of 0.5 mol·L -1 , and a ZnCl2 solution at 35°C for 12 h to carry out a chelating reaction, and then the membrane was taken out and washed repeatedly with deionized water for 4 times to obtain a porous ammonia-hydrogen separation membrane.

[0053] A gas separation device was used to separate the mixed gas containing ammonia and hydrogen. The test results showed that the ammonia permeability was 3232.3 Barrer and the ammonia / hydrogen selectivity was 301.4.

[0054] Embodiment 5:

[0055] This embodiment provides a method for preparing a porous ammonia-hydrogen separation membrane, comprising the following steps:

[0056] S1, dissolving polyethersulfone with a chloromethylation degree of 75% in N,N-dimethylformamide to obtain a casting solution with a concentration of 35%;

[0057] S2, uniformly coating the casting solution on a clean glass plate, and preparing a porous CMPES base membrane by a non-solvent induced phase inversion method. Specifically, uniformly coating the casting solution on the glass plate, scraping the film on the glass plate with a scraper, and then immersing the glass plate in deionized water for phase inversion to obtain a CMPES porous base membrane;

[0058] S3, soak the CMPES base film at a temperature of 40°C and a concentration of 2 mol·L -1 The cross-linking was carried out in a triethylenetetramine solution of 1 mol·L -1 The modified membrane is obtained by quaternization in a halide solution.

[0059] S4, soak the modified membrane in a solution with a concentration of 0.5 mol·L -1 , and a ZnCl2 solution at 35°C for 12 h to carry out a chelating reaction, and then the membrane was taken out and washed repeatedly with deionized water for three times to obtain a porous ammonia-hydrogen separation membrane.

[0060] A gas separation device was used to separate the mixed gas containing ammonia and hydrogen. The test results showed that the ammonia permeability was 3480.1 Barrer and the ammonia / hydrogen selectivity was 358.2.

[0061] Embodiment 6:

[0062] This embodiment provides a method for preparing a porous ammonia-hydrogen separation membrane, comprising the following steps:

[0063] S1, dissolving polyethersulfone with a chloromethylation degree of 80% in N,N-dimethylformamide to obtain a casting solution with a concentration of 35%;

[0064] S2, uniformly coating the casting solution on a clean glass plate, and preparing a porous CMPES base membrane by a non-solvent induced phase inversion method. Specifically, uniformly coating the casting solution on the glass plate, scraping the film on the glass plate with a scraper, and then immersing the glass plate in deionized water for phase inversion to obtain a CMPES porous base membrane;

[0065] S3, soak the CMPES base film at a temperature of 60°C and a concentration of 2 mol·L -1 The cross-linking was carried out in a pentaethylenehexamine solution of 1 mol·L -1 The modified membrane is obtained by quaternization in a halide solution.

[0066] S4, immerse the modified membrane in a solution with a concentration of 2 mol·L-1 , and a CoCl2 solution at 120°C for 48 hours to carry out a chelating reaction, and then the membrane was taken out and washed repeatedly with deionized water three times to obtain a porous ammonia-hydrogen separation membrane.

[0067] A gas separation device was used to separate the mixed gas containing ammonia and hydrogen. The test results showed that the ammonia permeability was 3880.1 Barrer and the ammonia / hydrogen selectivity was 258.8.

[0068] Embodiment 7:

[0069] This embodiment provides a method for preparing a porous ammonia-hydrogen separation membrane, comprising the following steps:

[0070] S1, dissolving polyethersulfone with a chloromethylation degree of 55% in N,N-dimethylformamide to obtain a casting solution with a concentration of 35%;

[0071] S2, uniformly coating the casting solution on a clean glass plate, and preparing a porous CMPES base membrane by a non-solvent induced phase inversion method. Specifically, uniformly coating the casting solution on the glass plate, scraping the film on the glass plate with a scraper, and then immersing the glass plate in deionized water for phase inversion to obtain a CMPES porous base membrane;

[0072] S3, soak the CMPES base film at a temperature of 70°C and a concentration of 2 mol·L -1 The crosslinking was carried out in a diethylenetriamine solution for 10 h, and then immersed in a solution at a temperature of 70 °C and a concentration of 1 mol·L -1 The modified membrane is obtained by quaternization in a halide solution.

[0073] S4, soak the modified membrane in a solution with a concentration of 0.5 mol·L -1 , and a CoCl2 solution at 60°C for 16 h to carry out a chelating reaction, and then the membrane was taken out and washed repeatedly with deionized water for 3 times to obtain a porous ammonia-hydrogen separation membrane.

[0074] A gas separation device was used to separate the mixed gas containing ammonia and hydrogen. The test results showed that the ammonia permeability was 4586.5 Barrer and the ammonia / hydrogen selectivity was 315.

[0075] Embodiment 8:

[0076] This embodiment provides a method for preparing a porous ammonia-hydrogen separation membrane, comprising the following steps:

[0077] S1, dissolving polyethersulfone with a chloromethylation degree of 55% in N,N-dimethylformamide to obtain a casting solution with a concentration of 35%;

[0078] S2, uniformly coating the casting solution on a clean glass plate, and preparing a porous CMPES base membrane by a non-solvent induced phase inversion method. Specifically, uniformly coating the casting solution on the glass plate, scraping the film on the glass plate with a scraper, and then immersing the glass plate in deionized water for phase inversion to obtain a CMPES porous base membrane;

[0079] S3, soak the CMPES base film at a temperature of 70°C and a concentration of 2 mol·L -1 The cross-linking was carried out in a triethylenetetramine solution of 100 μg / ml for 12 h, and then immersed in a 0.5 mol·L -1 The modified membrane is obtained by quaternization in a halide solution.

[0080] S4, immerse the modified membrane in a solution with a concentration of 2 mol·L -1 , and a NiCl2 solution at 60°C for 16 hours to carry out a chelating reaction, and then the membrane was taken out and washed repeatedly with deionized water for three times to obtain a porous ammonia-hydrogen separation membrane.

[0081] A gas separation device was used to separate the mixed gas containing ammonia and hydrogen. The test results showed that the ammonia permeability was 5223.1 Barrer and the ammonia / hydrogen selectivity was 554.4.

[0082] Embodiment 9:

[0083] This embodiment provides a method for preparing a porous ammonia-hydrogen separation membrane, comprising the following steps:

[0084] S1, dissolving polyethersulfone with a chloromethylation degree of 55% in N,N-dimethylformamide to obtain a casting solution with a concentration of 35%;

[0085] S2, uniformly coating the casting solution on a clean glass plate, and preparing a porous CMPES base membrane by a non-solvent induced phase inversion method. Specifically, uniformly coating the casting solution on the glass plate, scraping the film on the glass plate with a scraper, and then immersing the glass plate in deionized water for phase inversion to obtain a CMPES porous base membrane;

[0086] S3, soak the CMPES base film at a temperature of 70°C and a concentration of 4 mol·L -1 The cross-linking was carried out in tetraethylenepentamine solution for 20 h, and then immersed in a solution at a temperature of 45 °C and a concentration of 1 mol·L -1 The modified membrane is obtained by quaternization in a halide solution.

[0087] S4, immerse the modified membrane in a solution with a concentration of 2 mol·L -1 , and a CuCl2 solution at a temperature of 80°C for 24 hours to carry out a chelating reaction, and then the membrane was taken out and washed repeatedly with deionized water for 5 times to obtain a porous ammonia-hydrogen separation membrane.

[0088] A gas separation device was used to separate the mixed gas containing ammonia and hydrogen. The test results showed that the ammonia permeability was 6525.9 Barrer and the ammonia / hydrogen selectivity was 628.9.

[0089] Embodiment 10:

[0090] This embodiment provides a method for preparing a porous ammonia-hydrogen separation membrane, comprising the following steps:

[0091] S1, dissolving polyethersulfone with a chloromethylation degree of 55% in N,N-dimethylformamide to obtain a casting solution with a concentration of 35%;

[0092] S2, uniformly coating the casting solution on a clean glass plate, and preparing a porous CMPES base membrane by a non-solvent induced phase inversion method. Specifically, uniformly coating the casting solution on the glass plate, scraping the film on the glass plate with a scraper, and then immersing the glass plate in deionized water for phase inversion to obtain a CMPES porous base membrane;

[0093] S3, soak the CMPES base film at a temperature of 80°C and a concentration of 2 mol·L -1 The product was cross-linked in tetraethylenepentamine solution for 24 h, and then immersed in a 0.5 mol·L -1 The modified membrane is obtained by quaternization in a halide solution.

[0094] S4, immerse the modified membrane in a solution with a concentration of 2 mol·L -1 , and a FeCl2 solution at a temperature of 80°C for 24 hours to carry out a chelating reaction, and then the membrane was taken out and washed repeatedly with deionized water for three times to obtain a porous ammonia-hydrogen separation membrane.

[0095] A gas separation device was used to separate the mixed gas containing ammonia and hydrogen. The test results showed that the ammonia permeability was 6973.2 Barrer and the ammonia / hydrogen selectivity was 687.

[0096] Embodiment 11:

[0097] This embodiment provides a method for preparing a porous ammonia-hydrogen separation membrane, comprising the following steps:

[0098] S1, dissolving polyethersulfone with a chloromethylation degree of 55% in N,N-dimethylformamide to obtain a casting solution with a concentration of 35%;

[0099] S2, uniformly coating the casting solution on a clean glass plate, and preparing a porous CMPES base membrane by a non-solvent induced phase inversion method. Specifically, uniformly coating the casting solution on the glass plate, scraping the film on the glass plate with a scraper, and then immersing the glass plate in deionized water for phase inversion to obtain a CMPES porous base membrane;

[0100] S3, soak the CMPES base film at a temperature of 80°C and a concentration of 2 mol·L -1 The cross-linking was carried out in a diethylenetriamine solution of 1 mol·L -1 The modified membrane is obtained by quaternization in a halide solution.

[0101] S4, immerse the modified membrane in a solution with a concentration of 2 mol·L -1 , and a ZnCl2 solution at 100°C for 36 hours to carry out a chelating reaction. The membrane was then taken out and washed repeatedly with deionized water three times to obtain a porous ammonia-hydrogen separation membrane.

[0102] A gas separation device was used to separate the mixed gas containing ammonia and hydrogen. The test results showed that the ammonia permeability was 7128 Barrer and the ammonia / hydrogen selectivity was 691.

[0103] Embodiment 12:

[0104] This embodiment provides a method for preparing a porous ammonia-hydrogen separation membrane, comprising the following steps:

[0105] S1, dissolving polyethersulfone with a chloromethylation degree of 65% in N,N-dimethylformamide to obtain a casting solution with a concentration of 35%;

[0106] S2, uniformly coating the casting solution on a clean glass plate, and preparing a porous CMPES base membrane by a non-solvent induced phase inversion method. Specifically, uniformly coating the casting solution on the glass plate, scraping the film on the glass plate with a scraper, and then immersing the glass plate in deionized water for phase inversion to obtain a CMPES porous base membrane;

[0107] S3, soak the CMPES base film at a temperature of 80°C and a concentration of 2 mol·L -1 The cross-linking was carried out in tetraethylenepentamine solution for 48 h, and then immersed in a solution at a temperature of 50 °C and a concentration of 2 mol·L -1 The modified membrane is obtained by quaternization in a halide solution.

[0108] S4, immerse the modified membrane in a solution with a concentration of 2 mol·L -1 , and a CoCl2 solution at 80°C for 24 hours to carry out a chelating reaction, and then the membrane was taken out and washed repeatedly with deionized water three times to obtain a porous ammonia-hydrogen separation membrane.

[0109] A gas separation device was used to separate the mixed gas containing ammonia and hydrogen. The test results showed that the ammonia permeability was 7564 Barrer and the ammonia / hydrogen selectivity was 700.

[0110] Embodiment 13:

[0111] This embodiment provides a method for preparing a porous ammonia-hydrogen separation membrane, comprising the following steps:

[0112] S1, dissolving polyethersulfone with a chloromethylation degree of 55% in N,N-dimethylformamide to obtain a casting solution with a concentration of 30%;

[0113] S2, uniformly coating the casting solution on a clean glass plate, and preparing a porous CMPES base membrane by a non-solvent induced phase inversion method. Specifically, uniformly coating the casting solution on the glass plate, scraping the film on the glass plate with a scraper, and then immersing the glass plate in deionized water for phase inversion to obtain a CMPES porous base membrane;

[0114] S3, soak the CMPES base film at a temperature of 80°C and a concentration of 2 mol·L -1 The product was immersed in a pentaethylenehexamine solution for 48 h to achieve synchronous cross-linking quaternization, and then immersed in a 50 °C, 2 mol·L -1 The modified membrane is obtained by quaternization in a halide solution.

[0115] S4, immerse the modified membrane in a solution with a concentration of 2 mol·L -1 , and a CoCl2 solution at 80°C for 24 hours to carry out a chelating reaction, and then the membrane was taken out and washed repeatedly with deionized water three times to obtain a porous ammonia-hydrogen separation membrane.

[0116] A gas separation device was used to separate the mixed gas containing ammonia and hydrogen. The test results showed that the ammonia permeability was 7777 Barrer and the ammonia / hydrogen selectivity was 706.

[0117] In summary, the present invention prepares the base membrane by a non-solvent phase transformation method, the film formation is relatively simple, and then cross-linking and quaternization modification are performed on it, and finally metal ions are introduced to carry out chelation reaction. The functional groups are highly adjustable, and a variety of metal ions and Lewis acids can be introduced as adsorption sites. As the degree of CMPES chloromethylation increases, more reactive groups can be introduced, and the adsorption sites will be further increased. At the same time, thanks to the special porous structure of the porous membrane itself, the permeation flux of gas molecules is improved.

[0118] Anything not described in the present invention is applicable to the prior art.

[0119] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. However, the obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A method for preparing a porous ammonia-hydrogen separation membrane, characterized in that: The steps include: S1, using chloromethylated polyethersulfone (CMPES) as a raw material, dissolving it in an organic solvent to obtain a casting solution; S2, uniformly coating the casting solution on a clean glass plate, and preparing a porous CMPES-based membrane by a non-solvent-induced phase inversion method; S3, soaking the CMPES base film in a polyamine solution for cross-linking, and then quaternizing it with a halide to obtain a modified film; S4. The modified membrane is immersed in a metal chloride solution to carry out a chelating reaction to introduce adsorption sites, and then the membrane is taken out and repeatedly washed with deionized water to obtain a porous ammonia-hydrogen separation membrane.

2. The preparation method according to claim 1, characterized in that: In the step S1, the chloromethylation degree of CMPES is 30%-80%, and it is composed of repeating units with chloromethyl groups and repeating units without chloromethyl groups, and its structural formula is:

3. The preparation method according to claim 1, characterized in that: The organic solvent for dissolving CMPES in step S1 is one of chloroform, dichloromethane, tetrahydrofuran, N,N-dimethylformamide, dimethyl sulfoxide, N,N-dimethylacetamide, 1-methylpyrrolidone and toluene.

4. The preparation method according to claim 1, characterized in that: The concentration of the casting solution in step S1 is 10%-40%.

5. The preparation method according to claim 1, characterized in that: The thickness of the base film in step S2 is 0.1-0.25 μm.

6. The preparation method according to claim 1, characterized in that: In step S3, the polyamine solution is an amine containing two primary amine groups or secondary amine groups.

7. The preparation method according to claim 1, characterized in that: The cross-linking conditions in step S3 are: the concentration of the polyamine solution is 0.1-4 mol·L -1 , soaking time is 0.5-48h, soaking temperature is 25-80℃.

8. The preparation method according to claim 1, characterized in that: In step S3, the quaternization agent is an alkyl halide; the quaternization modification is: the concentration of the alkyl halide solution is 0.1-2 mol·L -1 , modification time is 0.5-48h, temperature is 30-80℃.

9. The preparation method according to claim 9, characterized in that: The alkyl halide is one of methyl iodide, ethyl bromide and propyl chloroethane.

10. The preparation method according to claim 1, characterized in that: The metal chloride solution in step S4 is one of ZnCl2, NaCl, KCl, MgCl2, LiCl2, CoCl2, NiCl2, and CuCl2.

11. The preparation method according to claim 1, characterized in that: The chelating reaction conditions in step S4 are: the concentration of the metal chloride solution is 0.1-2 mol·L -1 , the soaking temperature is 30-120℃, and the soaking time is 1-48h.

12. A porous ammonia-hydrogen separation membrane obtained by the preparation method according to any one of claims 1 to 11.

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