Ammonia-hydrogen separation membrane based on self-contained microporous polymer and preparation method of ammonia-hydrogen separation membrane

Abstract

The invention discloses an ammonia hydrogen separation membrane based on an intrinsic microporous polymer and a preparation method thereof, and the preparation method comprises the following steps: S1, carrying out condensation polymerization on TTSBI-M and TFTPN at a high temperature to synthesize an intrinsic microporous polymer PIM-M containing benzyl methyl; s2, after PIM-M is completely dissolved in chlorobenzene, liquid bromine is added, and a bromomethylated polymer PIM-Br with intrinsic micropores is prepared through a reaction; s3, dissolving PIM-Br in an organic solvent to obtain a membrane casting solution, dripping the membrane casting solution on an ultra-flat culture dish, and volatilizing the solvent to obtain a PIM-Br-based membrane; s4, soaking the base membrane in a polyamine solution to obtain an amine cross-linked polymer membrane with intrinsic micropores, and then soaking the amine cross-linked polymer membrane in an alkyl halide solution to realize quaternization modification to obtain a modified membrane; s5, the modified membrane is soaked in a metal chloride solution for a chelation reaction, then the membrane is taken out and washed with deionized water, and the ammonia-hydrogen separation membrane based on the self-contained microporous polymer is obtained. The self-microporous polymer membrane prepared by the invention has excellent ammonia-hydrogen separation capacity, and also has excellent mechanical properties.

Description

Technical Field

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

[0002] Ammonia is an important chemical raw material with extremely important applications in industrial and agricultural production. It is mainly used to manufacture ammonium salts, ammonia water, nitrogen fertilizers, compound fertilizers, etc. Ammonia is also used to produce nitric acid. It is converted into nitric oxide through catalytic oxidation and then generates nitric acid. In addition, as the most abundant alkaline gas in the atmospheric environment, it plays a very important role in the ecosystem. On the one hand, ammonia can promote the formation of sulfates and nitrates and increase the concentration of fine particles in the atmosphere. On the other hand, it can neutralize acidic substances in the atmosphere, thereby reducing the impact of acid rain on the ecological environment. However, the wanton emission of ammonia will lead to air pollution. The secondary particles of PM2.5 such as ammonium sulfate and ammonium nitrate generated by the reaction with sulfur oxides and nitrogen oxides in the atmosphere are one of the important reasons for the formation of haze. By recycling ammonia, the emission of these pollutants can be effectively reduced, the air quality can be improved, and the recycling of resources can be realized at the same time, the demand for new resources can be reduced, and resource consumption can be reduced.

[0003] There are many methods for separating and recovering ammonia, such as electrochemical method, ionic liquid method, improved absorption method, gas membrane separation method, etc. Among them, membrane separation generally does not require high temperature or high pressure operation, can significantly reduce energy consumption, and has received extensive attention in recent years. 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 an ammonia separation membrane 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 an ammonia-hydrogen separation membrane based on a self-microporous polymer and a preparation method thereof. The self-microporous polymer is a high molecular compound containing a rigid twisted segment structure. Due to the stacking of molecular chains, a large free space volume is generated, and thus it has a high specific surface area, which is beneficial to the transmission of molecules. By modifying the self-microporous polymer, the separation ability of ammonia and hydrogen is enhanced.

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

[0006] A method for preparing an ammonia-hydrogen separation membrane based on a self-microporous polymer comprises the following steps:

[0007] S1, 5,5',6,6'-tetrahydroxy-3,3,3',3',4,4'-hexamethyl-1,1'-spirobiindane (TTSBI-M) and tetrafluoroterephthalonitrile (TFTPN) were subjected to polycondensation reaction at a molar ratio of 1:1 at 155° C. to synthesize a self-microporous polymer PIM-M containing benzyl methyl groups;

[0008] S2, after PIM-M is completely dissolved in chlorobenzene, liquid bromine is added to react to obtain a bromomethylated self-microporous polymer PIM-Br;

[0009] S3, dissolving PIM-Br in an organic solvent, filtering to remove insoluble matter to obtain a casting solution, dropping the casting solution on an ultra-flat culture dish, and obtaining a PIM-Br base film after the solvent evaporates;

[0010] S4, soaking the base film in a solution of a polyamine containing two or more primary amine groups, controlling the soaking time and temperature, to obtain an amine-crosslinked self-microporous polymer membrane, and then soaking it in a halide solution to achieve quaternary ammonium modification to obtain a modified membrane;

[0011] S5. 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 rinsed with deionized water to obtain an ammonia-hydrogen separation membrane based on a self-microporous polymer.

[0012] The bromomethylated self-microporous polymer PIM-Br in step S2 is composed of repeating units containing bromomethyl and benzyl, and its structural formula is as follows:

[0013]

[0014] Preferably, the bromination degree of the PIM-Br is 10%-100%.

[0015] The reaction conditions of PIM-M and liquid bromine in step S2 are: reaction temperature 140-155° C., reaction time 2-6 h.

[0016] The concentration of the casting solution in step S3 is 2%-10%.

[0017] The organic solvent for dissolving PIM-Br in step S3 is one of N,N-dimethylformamide, N,N-dimethylacetamide, chloroform, tetrahydrofuran, dimethyl sulfoxide, and 1-methylpyrrolidone.

[0018] The polyamine containing two or more primary amine groups in step S4 is one of ethylenediamine, 1,3-propylenediamine, 1,4-butylenediamine, polyethyleneimine, and pentaethylenehexamine.

[0019] The conditions for the amine cross-linking reaction in step S4 are: the concentration of the amine solution is 0.1-3 mol·L-1 The soaking time in the amine solution is 0.5-24h, and the soaking temperature is 25-60℃.

[0020] In step S4, the alkyl halide is one of methyl iodide, ethyl bromide and propyl chloride.

[0021] The conditions for quaternization modification in step S4 are: the concentration of the alkyl halide solution is 0.5-2 mol·L -1 , the modification time is 1-48h, and the temperature is 30-80℃.

[0022] In step S5, the metal chloride is one of NiCl2, MgCl2, MnCl2, FeCl2, FeCl3 and ZnCl2.

[0023] The chelating reaction conditions in step S5 are as follows: the concentration of the metal chloride solution is 0.5-2 mol·L -1 The metal chelation reaction time is 0.5-12h and the temperature is 30-80℃.

[0024] An ammonia-hydrogen separation membrane based on a self-microporous polymer prepared according to the above preparation method.

[0025] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0026] The present invention innovatively introduces benzyl bromide groups into a self-microporous polymer with a large intrinsic free space volume through liquid bromine modification, thereby performing amine cross-linking and quaternization modification, and finally using the chelation reaction of metal chloride to prepare a self-microporous polymer membrane for ammonia hydrogen separation. The functional groups of the self-microporous polymer ammonia hydrogen separation membrane are highly adjustable, and as the degree of PIM-Br bromomethyl increases, more adsorption sites are introduced. The ammonia hydrogen separation membrane based on the self-microporous polymer has a high ammonia permeation flux, excellent ammonia hydrogen selectivity, and good industrial application potential. DETAILED DESCRIPTION

[0027] 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.

[0028] Embodiment 1:

[0029] This embodiment provides a method for preparing a brominated self-microporous polymer ammonia hydrogen separation membrane, comprising the following steps:

[0030] S1, 5,5',6,6'-tetrahydroxy-3,3,3',3',4,4'-hexamethyl-1,1'-spirobiindane (TTSBI-M) and tetrafluoroterephthalonitrile (TFTPN) were subjected to polycondensation reaction at 155°C to synthesize a self-microporous polymer PIM-M containing benzyl methyl groups;

[0031] S2. After PIM-M is completely dissolved in chlorobenzene, liquid bromine is added and reacted at 140° C. for 6 hours to obtain a bromomethylated self-microporous polymer PIM-Br; when the molar ratio of liquid bromine to benzyl in the repeating unit is controlled to be 1:4.6, the degree of bromomethylation is 30%;

[0032] S3, dissolving PIM-Br in chloroform, filtering to remove insoluble matter, dropping it on an ultra-flat culture dish, and obtaining a PIM-Br base film after the solvent evaporates;

[0033] S4, soak the base film in a solution with a temperature of 25°C and a concentration of 0.5 mol / L -1 The amine-crosslinked self-microporous polymer membrane was then immersed in a diethylenetriamine solution at a temperature of 30°C and a concentration of 0.5 mol / L -1 The modified membrane was prepared by placing the membrane in a halide solution for 12 hours to achieve quaternary ammonium modification.

[0034] S5. Soak the modified membrane in 0.5 molL -1 The chelating reaction was carried out in a CuCl2 solution at 40°C for 12 hours, and then the membrane was taken out and rinsed with deionized water to obtain an ammonia-hydrogen separation membrane with microporous polymer.

[0035] A gas separation device was used to separate the mixed gas containing ammonia and hydrogen. The test results showed that the ammonia permeability was 1134.9 Barrer and the ammonia / hydrogen selectivity was 250.9.

[0036] Embodiment 2:

[0037] This embodiment provides a method for preparing a brominated self-microporous polymer ammonia hydrogen separation membrane, comprising the following steps:

[0038] S1, 5,5',6,6'-tetrahydroxy-3,3,3',3',4,4'-hexamethyl-1,1'-spirobiindane (TTSBI-M) and tetrafluoroterephthalonitrile (TFTPN) were subjected to polycondensation reaction at 155°C to synthesize a self-microporous polymer PIM-M containing benzyl methyl groups;

[0039] S2. After PIM-M is completely dissolved in chlorobenzene, liquid bromine is added and reacted at 140° C. for 6 hours to obtain a bromomethylated self-microporous polymer PIM-Br; when the molar ratio of liquid bromine to benzyl in the repeating unit is controlled to be 1:1, the degree of bromomethylation is close to 100%;

[0040] S3, dissolving PIM-Br in chloroform, filtering to remove insoluble matter, dropping it on an ultra-flat culture dish, and obtaining a PIM-Br base film after the solvent evaporates;

[0041] S4, soak the base film in a solution with a temperature of 30°C and a concentration of 1 molL -1 The amine-crosslinked self-microporous polymer membrane was then immersed in a 1 mol / L ethylenediamine solution at 35 °C for 12 h. -1 The modified membrane was prepared by placing the membrane in a halide solution for 12 hours to achieve quaternary ammonium modification.

[0042] S5. Soak the modified membrane in 0.5 molL -1 The chelating reaction was carried out in a CuCl2 solution at 40°C for 12 hours, and then the membrane was taken out and rinsed with deionized water to obtain an ammonia-hydrogen separation membrane with microporous polymer.

[0043] A gas separation device was used to separate the mixed gas containing ammonia and hydrogen. The test results showed that the ammonia permeability was 1325.9 Barrer and the ammonia / hydrogen selectivity was 270.4.

[0044] Embodiment 3:

[0045] This embodiment provides a method for preparing a brominated self-microporous polymer ammonia hydrogen separation membrane, comprising the following steps:

[0046] S1, 5,5',6,6'-tetrahydroxy-3,3,3',3',4,4'-hexamethyl-1,1'-spirobiindane (TTSBI-M) and tetrafluoroterephthalonitrile (TFTPN) were subjected to polycondensation reaction at 155°C to synthesize a self-microporous polymer PIM-M containing benzyl methyl groups;

[0047] S2, after PIM-M is completely dissolved in chlorobenzene, liquid bromine is added, and the mixture is reacted at 150° C. for 4 h to obtain a self-microporous polymer PIM-Br with a bromomethylation degree of 50%;

[0048] S3, dissolving PIM-Br in chloroform, filtering to remove insoluble matter, dropping it on an ultra-flat culture dish, and obtaining a PIM-Br base film after the solvent evaporates;

[0049] S4, soak the base film in a solution with a temperature of 30°C and a concentration of 1 molL -1The amine-crosslinked self-microporous polymer membrane was then immersed in a 1,3-propylenediamine solution at a temperature of 35 °C and a concentration of 0.5 mol L -1 The modified membrane was prepared by placing the membrane in a halide solution for 12 hours to achieve quaternary ammonium modification.

[0050] S5, soak the modified membrane in 1.5molL -1 The chelating reaction was carried out in a FeCl2 solution at 60°C for 6 hours, and then the membrane was taken out and rinsed with deionized water to obtain an ammonia-hydrogen separation membrane with microporous polymer.

[0051] A gas separation device was used to separate the mixed gas containing ammonia and hydrogen. The test results showed that the ammonia permeability was 1762.1 Barrer and the ammonia / hydrogen selectivity was 279.5.

[0052] Embodiment 4:

[0053] This embodiment provides a method for preparing a brominated self-microporous polymer ammonia hydrogen separation membrane, comprising the following steps:

[0054] S1, 5,5',6,6'-tetrahydroxy-3,3,3',3',4,4'-hexamethyl-1,1'-spirobiindane (TTSBI-M) and tetrafluoroterephthalonitrile (TFTPN) were subjected to polycondensation reaction at 155°C to synthesize a self-microporous polymer PIM-M containing benzyl methyl groups;

[0055] S2. After PIM-M is completely dissolved in chlorobenzene, liquid bromine is added and reacted at 140° C. for 6 hours to obtain a bromomethylated self-microporous polymer PIM-Br; when the molar ratio of liquid bromine to benzyl in the repeating unit is controlled to be 1:1, the degree of bromomethylation is close to 100%;

[0056] S3, dissolving PIM-Br in chloroform, filtering to remove insoluble matter, dropping it on an ultra-flat culture dish, and obtaining a PIM-Br base film after the solvent evaporates;

[0057] S4, soak the base film in a solution with a temperature of 30°C and a concentration of 1 molL -1 The amine-crosslinked self-microporous polymer membrane was then immersed in a 1,4-butanediamine solution at a temperature of 35 °C and a concentration of 0.5 mol L -1 The modified membrane was prepared by placing the membrane in a halide solution for 12 hours to achieve quaternary ammonium modification.

[0058] S5. Soak the modified membrane in 1 molL -1 The chelating reaction was carried out in a NaCl solution at 60°C for 12 hours, and then the membrane was taken out and rinsed with deionized water to obtain an ammonia-hydrogen separation membrane with microporous polymer.

[0059] A gas separation device was used to separate the mixed gas containing ammonia and hydrogen. The test results showed that the ammonia permeability was 1818.3 Barrer and the ammonia / hydrogen selectivity was 286.7.

[0060] Embodiment 5:

[0061] This embodiment provides a method for preparing a brominated self-microporous polymer ammonia hydrogen separation membrane, comprising the following steps:

[0062] S1, 5,5',6,6'-tetrahydroxy-3,3,3',3',4,4'-hexamethyl-1,1'-spirobiindane (TTSBI-M) and tetrafluoroterephthalonitrile (TFTPN) were subjected to polycondensation reaction at 155°C to synthesize a self-microporous polymer PIM-M containing benzyl methyl groups;

[0063] S2, after PIM-M is completely dissolved in chlorobenzene, liquid bromine is added, and the mixture is reacted at 155°C for 2 hours to obtain a self-microporous polymer PIM-Br with a bromomethylation degree of 80%;

[0064] S3, dissolving PIM-Br in chloroform, filtering to remove insoluble matter, dropping it on an ultra-flat culture dish, and obtaining a PIM-Br base film after the solvent evaporates;

[0065] S4, soak the base film in a solution with a temperature of 30°C and a concentration of 1 molL -1 The amine-crosslinked self-microporous polymer membrane was then immersed in a diethylenetriamine solution at a temperature of 80 °C and a concentration of 1.5 mol / L -1 The modified membrane was prepared by placing the membrane in a halide solution for 6 hours to achieve quaternary ammonium modification.

[0066] S5. Soak the modified membrane in 0.5 molL -1 The chelating reaction was carried out in a NiCl2 solution at 60°C for 12 hours, and then the membrane was taken out and rinsed with deionized water to obtain an ammonia-hydrogen separation membrane with microporous polymer.

[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 1820.6 Barrer and the ammonia / hydrogen selectivity was 278.

[0068] Embodiment 6:

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

[0070] S1, 5,5',6,6'-tetrahydroxy-3,3,3',3',4,4'-hexamethyl-1,1'-spirobiindane (TTSBI-M) and tetrafluoroterephthalonitrile (TFTPN) were subjected to polycondensation reaction at 155°C to synthesize a self-microporous polymer PIM-M containing benzyl methyl groups;

[0071] S2. After PIM-M is completely dissolved in chlorobenzene, liquid bromine is added and reacted at 145°C for 3 hours to obtain a bromomethylated self-microporous polymer PIM-Br; when the molar ratio of liquid bromine to benzyl in the repeating unit is controlled to be 1:1, the degree of bromomethylation is close to 100%;

[0072] S3, dissolving PIM-Br in chloroform, filtering to remove insoluble matter, dropping it on an ultra-flat culture dish, and obtaining a PIM-Br base film after the solvent evaporates;

[0073] S4, soak the base film in a solution with a temperature of 60°C and a concentration of 0.5 mol / L -1 The amine-crosslinked self-microporous polymer membrane was obtained by immersing it in a polyethyleneimine solution for 24 h, and then soaking it in a 0.5 mol / L -1 The modified membrane was prepared by placing the membrane in a halide solution for 12 hours to achieve quaternary ammonium modification.

[0074] S5, soak the modified membrane in 1.5 mol L -1 The chelating reaction was carried out in a CoCl2 solution at 70°C for 12 hours, and then the membrane was taken out and rinsed with deionized water to obtain an ammonia-hydrogen separation membrane with a microporous polymer.

[0075] A gas separation device was used to separate the mixed gas containing ammonia and hydrogen. The test results showed that the ammonia permeability was 2235.8 Barrer and the ammonia / hydrogen selectivity was 309.

[0076] Embodiment 7:

[0077] This embodiment provides a method for preparing a brominated self-microporous polymer ammonia hydrogen separation membrane, comprising the following steps:

[0078] S1, 5,5',6,6'-tetrahydroxy-3,3,3',3',4,4'-hexamethyl-1,1'-spirobiindane (TTSBI-M) and tetrafluoroterephthalonitrile (TFTPN) were subjected to polycondensation reaction at 155°C to synthesize a self-microporous polymer PIM-M containing benzyl methyl groups;

[0079] S2. After PIM-M is completely dissolved in chlorobenzene, liquid bromine is added and reacted at 140° C. for 6 hours to obtain a bromomethylated self-microporous polymer PIM-Br; when the molar ratio of liquid bromine to benzyl in the repeating unit is controlled to be 1:1, the degree of bromomethylation is close to 100%;

[0080] S3, dissolving PIM-Br in chloroform, filtering to remove insoluble matter, dropping it on an ultra-flat culture dish, and obtaining a PIM-Br base film after the solvent evaporates;

[0081] S4, soak the base film in a solution with a temperature of 60°C and a concentration of 0.5 mol L -1 The amine-crosslinked self-microporous polymer membrane was obtained by immersing it in a polyethyleneimine solution for 24 h, and then soaking it in a 0.5 mol / L -1 The modified membrane was prepared by placing the membrane in a halide solution for 12 hours to achieve quaternary ammonium modification.

[0082] S5. Soak the modified membrane in 2 molL -1 The chelating reaction is carried out in a CuCl2 solution at 80°C for 0.5, and then the membrane is taken out and rinsed with deionized water to obtain an ammonia-hydrogen separation membrane with microporous polymer.

[0083] A gas separation device was used to separate the mixed gas containing ammonia and hydrogen. The test results showed that the ammonia permeability was 2207.5 Barrer and the ammonia / hydrogen selectivity was 302.

[0084] Embodiment 8:

[0085] This embodiment provides a method for preparing a brominated self-microporous polymer ammonia hydrogen separation membrane, comprising the following steps:

[0086] S1, 5,5',6,6'-tetrahydroxy-3,3,3',3',4,4'-hexamethyl-1,1'-spirobiindane (TTSBI-M) and tetrafluoroterephthalonitrile (TFTPN) were subjected to polycondensation reaction at 155°C to synthesize a self-microporous polymer PIM-M containing benzyl methyl groups;

[0087] S2. After PIM-M is completely dissolved in chlorobenzene, liquid bromine is added and reacted at 140° C. for 5 h to obtain a bromomethylated self-microporous polymer PIM-Br; when the molar ratio of liquid bromine to benzyl in the repeating unit is controlled to be 1:1, the degree of bromomethylation is close to 100%;

[0088] S3, dissolving PIM-Br in chloroform, filtering to remove insoluble matter, dropping it on an ultra-flat culture dish, and obtaining a PIM-Br base film after the solvent evaporates;

[0089] S4, soak the base film in a solution with a temperature of 60°C and a concentration of 1.5 mol L-1 The amine-crosslinked self-microporous polymer membrane was obtained by immersing it in a polyethyleneimine solution for 24 h, and then soaking it in a 2 mol / L -1 The modified membrane was prepared by placing the membrane in a halide solution for 0.5 h to achieve quaternary ammonium modification.

[0090] S5. Soak the modified membrane in 1 molL -1 The chelating reaction was carried out in a NiCl2 solution at 70°C for 12 hours, and then the membrane was taken out and rinsed with deionized water to obtain an ammonia-hydrogen separation membrane with microporous polymer.

[0091] A gas separation device was used to separate the mixed gas containing ammonia and hydrogen. The test results showed that the ammonia permeability was 2856.2 Barrer and the ammonia / hydrogen selectivity was 302.

[0092] Embodiment 9:

[0093] This embodiment provides a method for preparing a brominated self-microporous polymer ammonia hydrogen separation membrane, comprising the following steps:

[0094] S1, 5,5',6,6'-tetrahydroxy-3,3,3',3',4,4'-hexamethyl-1,1'-spirobiindane (TTSBI-M) and tetrafluoroterephthalonitrile (TFTPN) were subjected to polycondensation reaction at 155°C to synthesize a self-microporous polymer PIM-M containing benzyl methyl groups;

[0095] S2. After PIM-M is completely dissolved in chlorobenzene, liquid bromine is added and reacted at 140° C. for 6 hours to obtain a bromomethylated self-microporous polymer PIM-Br; when the molar ratio of liquid bromine to benzyl in the repeating unit is controlled to be 1:1, the degree of bromomethylation is close to 100%;

[0096] S3, dissolving PIM-Br in chloroform, filtering to remove insoluble matter, dropping it on an ultra-flat culture dish, and obtaining a PIM-Br base film after the solvent evaporates;

[0097] S4, soak the base film in a solution with a temperature of 60°C and a concentration of 2 mol L -1 The amine-crosslinked self-microporous polymer membrane was obtained by immersing it in a polyethyleneimine solution for 24 h, and then soaking it in a 0.5 mol / L -1 The modified membrane was prepared by placing the membrane in a halide solution for 12 hours to achieve quaternary ammonium modification.

[0098] S5. Soak the modified membrane in 0.5 molL -1 The chelating reaction was carried out in a ZnCl2 solution at 70°C for 6 hours, and then the membrane was taken out and rinsed with deionized water to obtain an ammonia-hydrogen separation membrane with microporous polymer.

[0099] A gas separation device was used to separate the mixed gas containing ammonia and hydrogen. The test results showed that the ammonia permeability was 3123.6 Barrer and the ammonia / hydrogen selectivity was 309.

[0100] Embodiment 10:

[0101] This embodiment provides a method for preparing a brominated self-microporous polymer ammonia hydrogen separation membrane, comprising the following steps:

[0102] S1, 5,5',6,6'-tetrahydroxy-3,3,3',3',4,4'-hexamethyl-1,1'-spirobiindane (TTSBI-M) and tetrafluoroterephthalonitrile (TFTPN) were subjected to polycondensation reaction at 155°C to synthesize a self-microporous polymer PIM-M containing benzyl methyl groups;

[0103] S2. After PIM-M is completely dissolved in chlorobenzene, liquid bromine is added and reacted at 155° C. for 6 hours to obtain a bromomethylated self-microporous polymer PIM-Br; when the molar ratio of liquid bromine to benzyl in the repeating unit is controlled to be 1:1, the degree of bromomethylation is close to 100%;

[0104] S3, dissolving PIM-Br in chloroform, filtering to remove insoluble matter, dropping it on an ultra-flat culture dish, and obtaining a PIM-Br base film after the solvent evaporates;

[0105] S4, soak the base film in a solution with a temperature of 50°C and a concentration of 3 mol L -1 The amine-crosslinked self-microporous polymer membrane was obtained by immersing it in a polyethyleneimine solution for 24 h, and then soaking it in a 1 mol / L -1 The modified membrane was prepared by placing the membrane in a halide solution for 12 hours to achieve quaternary ammonium modification.

[0106] S5. Soak the modified membrane in 2 molL -1 The chelating reaction was carried out in a NiCl2 solution at 80°C for 12 hours, and then the membrane was taken out and rinsed with deionized water to obtain an ammonia-hydrogen separation membrane with microporous polymer.

[0107] A gas separation device was used to separate the mixed gas containing ammonia and hydrogen. The test results showed that the ammonia permeability was 2855.1 Barrer and the ammonia / hydrogen selectivity was 301.

[0108] Embodiment 11:

[0109] This embodiment provides a method for preparing a brominated self-microporous polymer ammonia hydrogen separation membrane, comprising the following steps:

[0110] S1, 5,5',6,6'-tetrahydroxy-3,3,3',3',4,4'-hexamethyl-1,1'-spirobiindane (TTSBI-M) and tetrafluoroterephthalonitrile (TFTPN) were subjected to polycondensation reaction at 155°C to synthesize a self-microporous polymer PIM-M containing benzyl methyl groups;

[0111] S2, after PIM-M is completely dissolved in chlorobenzene, liquid bromine is added, and the mixture is reacted at 140°C for 6 hours to obtain a self-microporous polymer PIM-Br with a bromomethylation degree of 10%;

[0112] S3, dissolving PIM-Br in chloroform, filtering to remove insoluble matter, dropping it on an ultra-flat culture dish, and obtaining a PIM-Br base film after the solvent evaporates;

[0113] S4, soak the base film in a solution with a temperature of 60°C and a concentration of 0.5 mol / L -1 The amine-crosslinked self-microporous polymer membrane was then immersed in a diethylenetriamine solution at a temperature of 30 °C and a concentration of 0.5 mol / L -1 The modified membrane was prepared by placing the membrane in a halide solution for 12 hours to achieve quaternary ammonium modification.

[0114] S5. Soak the modified membrane in 0.5 molL -1 The chelating reaction was carried out in a CuCl2 solution at 40°C for 4 hours, and then the membrane was taken out and rinsed with deionized water to obtain an ammonia-hydrogen separation membrane with microporous polymer.

[0115] A gas separation device was used to separate the mixed gas containing ammonia and hydrogen. The test results showed that the ammonia permeability was 1110.3 Barrer and the ammonia / hydrogen selectivity was 245.6.

[0116] In summary, the present invention innovatively introduces benzyl bromide groups into a self-microporous polymer with a large intrinsic free space volume through liquid bromine modification, thereby performing amine cross-linking and quaternization modification, and finally using the chelation reaction of metal chloride to prepare a self-microporous polymer membrane for ammonia hydrogen separation. The functional groups of the self-microporous polymer ammonia hydrogen separation membrane are highly adjustable, and as the degree of PIM-Br bromomethyl increases, more adsorption sites are introduced. The ammonia hydrogen separation membrane based on the self-microporous polymer has a high ammonia permeation flux, excellent ammonia hydrogen selectivity, and good potential for industrial application.

[0117] Anything not described in the present invention is applicable to the prior art.

[0118] 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 an ammonia-hydrogen separation membrane based on a self-microporous polymer, characterized in that: The steps include: S1, 5,5',6,6'-tetrahydroxy-3,3,3',3',4,4'-hexamethyl-1,1'-spirobiindane (TTSBI-M) and tetrafluoroterephthalonitrile (TFTPN) were subjected to polycondensation reaction at a molar ratio of 1:1 at 155° C. to synthesize a self-microporous polymer PIM-M containing benzyl methyl groups; S2, after PIM-M is completely dissolved in chlorobenzene, liquid bromine is added to react to obtain a bromomethylated self-microporous polymer PIM-Br; S3, dissolving PIM-Br in an organic solvent, filtering to remove insoluble matter to obtain a casting solution, dropping the casting solution on an ultra-flat culture dish, and obtaining a PIM-Br base membrane after the solvent evaporates; S4, soaking the base film in a solution of a polyamine containing two or more primary amine groups, controlling the soaking time and temperature, to obtain an amine-crosslinked self-microporous polymer membrane, and then soaking it in a halide solution to achieve quaternary ammonium modification to obtain a modified membrane; S5. 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 rinsed with deionized water to obtain an ammonia-hydrogen separation membrane based on a self-microporous polymer.

2. The preparation method according to claim 1, characterized in that: The bromomethylated self-microporous polymer PIM-Br in step S2 is composed of repeating units containing bromomethyl and benzyl, and its structural formula is as follows: The bromination degree of PIM-Br is 10%-100%.

3. The preparation method according to claim 1, characterized in that: The reaction conditions of PIM-M and liquid bromine in step S2 are: reaction temperature 140-155° C., reaction time 2-6 h.

4. The preparation method according to claim 1, characterized in that: In step S3, the concentration of the casting solution is 2%-10%; the organic solvent for dissolving PIM-Br is one of N,N-dimethylformamide, N,N-dimethylacetamide, chloroform, tetrahydrofuran, dimethyl sulfoxide, and 1-methylpyrrolidone.

5. The preparation method according to claim 1, characterized in that: The polyamine containing two or more primary amine groups in step S4 is one of ethylenediamine, 1,3-propylenediamine, 1,4-butylenediamine, polyethyleneimine, and pentaethylenehexamine.

6. The preparation method according to claim 1, characterized in that: The conditions for the amine cross-linking reaction in step S4 are: the concentration of the amine solution is 0.1-3 mol·L -1 The soaking time in the amine solution is 0.5-24h, and the soaking temperature is 25-60℃.

7. The preparation method according to claim 1, characterized in that: In step S4, the alkyl halide is one of methyl iodide, ethyl bromide and propyl chloroethane.

8. The preparation method according to claim 1, characterized in that: The conditions for quaternization modification in step S4 are: the concentration of the alkyl halide solution is 0.5-2 mol·L -1 , the modification time is 1-48h, and the temperature is 30-80℃.

9. The preparation method according to claim 1, characterized in that: In step S5, the metal chloride is one of NiCl2, MgCl2, MnCl2, FeCl2, FeCl3 and ZnCl2.

10. The preparation method according to claim 1, characterized in that: The chelating reaction conditions in step S5 are as follows: the concentration of the metal chloride solution is 0.5-2 mol·L -1 The metal chelation reaction time is 0.5-12h and the temperature is 30-80℃.

11. An ammonia-hydrogen separation membrane based on a self-microporous polymer obtained by the preparation method according to any one of claims 1 to 10.

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