An ammonia-hydrogen separation membrane based on a self-microporous polymer and a preparation method thereof

Abstract

The application discloses a kind of based on self-porous polymer's ammonia hydrogen separation membrane and preparation method thereof, comprising the following steps: S1, TTSBI-M is reacted with TFTPN at high temperature, and synthesis contains benzyl methyl self-porous polymer PIM-M;S2, after PIM-M is completely dissolved in chlorobenzene, bromine is added, and ammonia hydrogen separation membrane based on self-porous polymer is prepared by reaction;S3, PIM-Br is dissolved in organic solvent, and casting solution is obtained, which is dropped on super flat culture dish, and PIM-Br base film is obtained after solvent volatilization;S4, base film is soaked in polyamine solution, and the self-porous polymer membrane of amine crosslinking is obtained, then it is soaked in halogenated alkane solution to realize quaternary ammonium modification, and modified membrane is obtained;S5, modified membrane is soaked in metal chloride solution and chelated, then the membrane is taken out and washed with deionized water, and ammonia hydrogen separation membrane based on self-porous polymer is obtained.The self-porous polymer membrane prepared by the application has excellent ammonia hydrogen separation capacity, and also has excellent mechanical properties.

Description

TECHNICAL FIELD

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

[0002] Ammonia is an important chemical raw material, which has extremely important application in industrial and agricultural production, mainly used for manufacturing ammonium salt, ammonia water, nitrogen fertilizer, compound fertilizer, etc. Ammonia is also used for producing nitric acid, which is converted into nitric oxide through catalytic oxidation, and then generates nitric acid. In addition, as the most abundant alkaline gas in the atmosphere, ammonia plays a very important role in the ecological system. On the one hand, ammonia can promote the generation of sulfate and nitrate to increase the concentration of atmospheric fine particulate matter, and 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 uncontrolled emission of ammonia will lead to air pollution, and the secondary particulate matter of sulfur ammonium and nitrate ammonium generated by the reaction of sulfur oxide and nitrogen oxide in the atmosphere is one of the important reasons for the formation of haze. By recovering ammonia, the emission of these pollutants can be effectively reduced to improve air quality, and at the same time, resource recycling can be realized to reduce the demand for new resources and reduce resource consumption.

[0003] The separation and recovery method of ammonia includes electrochemical method, ionic liquid method, improved absorption method, gas membrane separation method, etc. Among them, membrane separation generally does not need high temperature or high pressure operation, which can significantly reduce energy consumption, and has received extensive attention in recent years. However, the ammonia selectivity and ammonia permeation flux of the existing ammonia separation membrane are relatively low. So far, ammonia separation membranes with high performance and low cost still pose a serious technical challenge. SUMMARY

[0004] In view of the low ammonia selectivity and low ammonia permeation flux of the ammonia separation membrane in the prior art, the present application 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 continuous segment structure. Due to the stacking of the molecular chain, a large free space volume is generated, so that the specific surface area is high, which is beneficial to the transmission of molecules. By modifying the self-microporous polymer, the separation capacity of ammonia and hydrogen can be further enhanced.

[0005] The present application adopts the following technical solutions:

[0006] A preparation method of an ammonia-hydrogen separation membrane based on a self-microporous polymer, comprising the following steps:

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

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

[0009] S3, PIM-Br is dissolved in an organic solvent, insoluble substances are removed by filtration to obtain a casting solution, the casting solution is dropped on an ultraplan culture dish, and the solvent is volatilized to obtain a PIM-Br-based film;

[0010] S4, the film is soaked in a solution of a polyamine containing two or more primary amine groups, the soaking time and temperature are controlled to obtain an amine-crosslinked self-porous polymer film, which is then soaked in a halogenated alkane solution to realize quaternary ammonium modification to obtain a modified film;

[0011] S5, the modified film is soaked in a metal chloride solution to introduce adsorption sites by chelation reaction, and then the film is taken out and washed with deionized water to obtain an ammonia-hydrogen separation membrane based on a self-porous polymer.

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

[0013]

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

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

[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-propanediamine, 1, 4-butanediamine, polyethyleneimine and pentaethylenehexamine.

[0019] The conditions for amine crosslinking reaction in step S4 are as follows: 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] The halogenated alkane in the step S4 is one of methyl iodide, ethyl bromide, and propyl chloride.

[0021] The concentration of the halogenated alkane solution in the step S4 is 0.5-2mol·L -1 , the modification time is 1-48h, and the temperature is 30-80℃.

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

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

[0024] A self-porous polymer-based ammonia-hydrogen separation membrane prepared according to the above preparation method.

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

[0026] The self-porous polymer with a large intrinsic free space volume is modified by liquid bromine to introduce benzyl bromide groups, then subjected to amine crosslinking and quaternary ammonium modification, and finally subjected to chelation reaction with metal chloride to prepare a self-porous polymer membrane for ammonia-hydrogen separation. The functional groups of the self-porous polymer ammonia-hydrogen separation membrane are highly adjustable. As the degree of PIM-Br bromomethyl groups increases, the number of introduced adsorption sites also increases. The self-porous polymer-based ammonia-hydrogen separation membrane has a high ammonia permeation flux, excellent ammonia-hydrogen selectivity, and good industrial application potential. DETAILED DESCRIPTION

[0027] The present application can be implemented in many different forms, and should not be understood as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the inventive concept to those skilled in the art. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0028] Example 1:

[0029] The present embodiment provides a preparation method of a brominated self-porous polymer ammonia-hydrogen separation membrane, comprising the following steps:

[0030] S1. Equimolar amounts of 5,5',6,6'-tetrahydroxy-3,3,3',3',4,4'-hexamethyl-1,1'-spirobisindane (TTSBI-M) and tetrafluoroterephthalonitrile (TFTPN) were subjected to a polycondensation reaction at 155 °C to synthesize a microporous polymer PIM-M containing benzylmethyl.

[0031] S2. After completely dissolving PIM-M in chlorobenzene, liquid bromine is added, and the mixture is reacted at 140℃ for 6 hours to obtain the bromomethylated microporous polymer PIM-Br. When the molar ratio of liquid bromine to benzyl in the repeating unit is controlled at 1:4.6, the degree of bromomethylation is 30%.

[0032] S3. Dissolve PIM-Br in chloroform, filter to remove insoluble matter, drop it onto an ultra-flat culture dish, and obtain the PIM-Br base film after the solvent evaporates.

[0033] S4. Immerse the base film at a temperature of 25℃ and a concentration of 0.5 mol / L. -1 A self-corrosive microporous polymer membrane was obtained by immersing the membrane in a diethylenetriamine solution for 0.5 h. The membrane was then immersed in a solution at 30 °C with a concentration of 0.5 mol / L. -1 Quaternization modification was achieved by immersing the membrane in a haloalkane solution for 12 hours to obtain a modified membrane;

[0034] S5. Immerse the modified membrane in 0.5 mol / L water. -1 The chelation reaction was carried out in CuCl2 solution at 40°C for 12 hours. The membrane was then removed and rinsed with deionized water to obtain an ammonia-hydrogen separation membrane with microporous polymer.

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

[0036] Example 2:

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

[0038] S1. Equimolar amounts of 5,5',6,6'-tetrahydroxy-3,3,3',3',4,4'-hexamethyl-1,1'-spirobisindane (TTSBI-M) and tetrafluoroterephthalonitrile (TFTPN) were subjected to a polycondensation reaction at 155 °C to synthesize a microporous polymer PIM-M containing benzylmethyl.

[0039] S2. After completely dissolving PIM-M in chlorobenzene, liquid bromine was added, and the mixture was reacted at 140°C for 6 hours to obtain the bromomethylated microporous polymer PIM-Br. When the molar ratio of liquid bromine to benzyl group in the repeating unit was controlled at 1:1, the degree of bromomethylation was close to 100%.

[0040] S3. Dissolve PIM-Br in chloroform, filter to remove insoluble matter, drop it onto an ultra-flat culture dish, and obtain the PIM-Br base film after the solvent evaporates.

[0041] S4. Immerse the base film at a temperature of 30℃ and a concentration of 1 mol / L. -1 A amine-crosslinked microporous polymer membrane was obtained by immersing the membrane in an ethylenediamine solution for 12 hours. The membrane was then immersed in an ethylenediamine solution at 35°C with a concentration of 1 mol / L. -1 Quaternization modification was achieved by immersing the membrane in a haloalkane solution for 12 hours to obtain a modified membrane;

[0042] S5. Immerse the modified membrane in 0.5 mol / L water. -1 The chelation reaction was carried out in CuCl2 solution at 40°C for 12 hours. The membrane was then removed and rinsed with deionized water to obtain an ammonia-hydrogen separation membrane with microporous polymer.

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

[0044] Example 3:

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

[0046] S1. Equimolar amounts of 5,5',6,6'-tetrahydroxy-3,3,3',3',4,4'-hexamethyl-1,1'-spirobisindane (TTSBI-M) and tetrafluoroterephthalonitrile (TFTPN) were subjected to a polycondensation reaction at 155 °C to synthesize a microporous polymer PIM-M containing benzylmethyl.

[0047] S2. After completely dissolving PIM-M in chlorobenzene, liquid bromine was added, and the mixture was reacted at 150°C for 4 hours to obtain PIM-Br, a microporous polymer with a bromomethylation degree of 50%.

[0048] S3. Dissolve PIM-Br in chloroform, filter to remove insoluble matter, drop it onto an ultra-flat culture dish, and obtain the PIM-Br base film after the solvent evaporates.

[0049] S4. Immerse the base film at a temperature of 30℃ and a concentration of 1 mol / L. -1A amine-crosslinked microporous polymer membrane was obtained by immersing the membrane in a 1,3-propanediamine solution for 6 hours. The membrane was then immersed in a solution at 35°C with a concentration of 0.5 mol / L. -1 Quaternization modification was achieved by immersing the membrane in a haloalkane solution for 12 hours to obtain a modified membrane;

[0050] S5. Immerse the modified membrane in 1.5 mol / L water. -1 The chelation reaction was carried out in FeCl2 solution at 60°C for 6 hours. The membrane was then removed and rinsed with deionized water to obtain an ammonia-hydrogen separation membrane with microporous polymer.

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

[0052] Example 4:

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

[0054] S1. Equimolar amounts of 5,5',6,6'-tetrahydroxy-3,3,3',3',4,4'-hexamethyl-1,1'-spirobisindane (TTSBI-M) and tetrafluoroterephthalonitrile (TFTPN) were subjected to a polycondensation reaction at 155 °C to synthesize a microporous polymer PIM-M containing benzylmethyl.

[0055] S2. After completely dissolving PIM-M in chlorobenzene, liquid bromine was added, and the mixture was reacted at 140°C for 6 hours to obtain the bromomethylated microporous polymer PIM-Br. When the molar ratio of liquid bromine to benzyl group in the repeating unit was controlled at 1:1, the degree of bromomethylation was close to 100%.

[0056] S3. Dissolve PIM-Br in chloroform, filter to remove insoluble matter, drop it onto an ultra-flat culture dish, and obtain the PIM-Br base film after the solvent evaporates.

[0057] S4. Immerse the base film at a temperature of 30℃ and a concentration of 1 mol / L. -1 A amine-crosslinked microporous polymer membrane was obtained by immersing the membrane in a 1,4-butanediamine solution for 12 hours. The membrane was then immersed in a solution at 35°C with a concentration of 0.5 mol / L. -1 Quaternization modification was achieved by immersing the membrane in a haloalkane solution for 12 hours to obtain a modified membrane;

[0058] S5. Immerse the modified membrane in 1 mol / L water. -1 The chelation reaction was carried out in NaCl solution at 60°C for 12 hours. The membrane was then removed and rinsed with deionized water to obtain an ammonia-hydrogen separation membrane with microporous polymer.

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

[0060] Example 5:

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

[0062] S1. Equimolar amounts of 5,5',6,6'-tetrahydroxy-3,3,3',3',4,4'-hexamethyl-1,1'-spirobisindane (TTSBI-M) and tetrafluoroterephthalonitrile (TFTPN) were subjected to a polycondensation reaction at 155 °C to synthesize a microporous polymer PIM-M containing benzylmethyl.

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

[0064] S3. Dissolve PIM-Br in chloroform, filter to remove insoluble matter, drop it onto an ultra-flat culture dish, and obtain the PIM-Br base film after the solvent evaporates.

[0065] S4. Immerse the base film at a temperature of 30℃ and a concentration of 1 mol / L. -1 A self-corrosive microporous polymer membrane was obtained by immersing the membrane in a diethylenetriamine solution for 12 hours. The membrane was then immersed in a solution of 1.5 mol / L at 80 °C. -1 Quaternization modification was achieved by immersing the modified film in a haloalkane solution for 6 hours to obtain a modified film.

[0066] S5. Immerse the modified membrane in 0.5 mol / L water. -1 The membrane was subjected to a chelation reaction in a NiCl2 solution at 60°C for 12 hours. The membrane was then removed and rinsed with deionized water to obtain an ammonia-hydrogen separation membrane with a microporous polymer.

[0067] A gas separation device was used to separate a mixture of ammonia and hydrogen. The test results showed that the ammonia permeability was 1820.6 Barrer and the ammonia / hydrogen selectivity was 278.

[0068] Example 6:

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

[0070] S1. Equimolar amounts of 5,5',6,6'-tetrahydroxy-3,3,3',3',4,4'-hexamethyl-1,1'-spirobisindane (TTSBI-M) and tetrafluoroterephthalonitrile (TFTPN) were subjected to a polycondensation reaction at 155 °C to synthesize a microporous polymer PIM-M containing benzylmethyl.

[0071] S2. After completely dissolving PIM-M in chlorobenzene, liquid bromine was added, and the mixture was reacted at 145°C for 3 hours to obtain the bromomethylated microporous polymer PIM-Br. When the molar ratio of liquid bromine to benzyl group in the repeating unit was controlled at 1:1, the degree of bromomethylation was close to 100%.

[0072] S3. Dissolve PIM-Br in chloroform, filter to remove insoluble matter, drop it onto an ultra-flat culture dish, and obtain the PIM-Br base film after the solvent evaporates.

[0073] S4. Immerse the base film at a temperature of 60℃ and a concentration of 0.5 mol / L. -1 A amine-crosslinked microporous polymer membrane was obtained by immersing the membrane in a polyethyleneimine solution for 24 hours. The membrane was then immersed in a solution at 35°C with a concentration of 0.5 mol / L. -1 Quaternization modification was achieved by immersing the membrane in a haloalkane solution for 12 hours to obtain a modified membrane;

[0074] S5. Immerse the modified membrane in 1.5 mol L... -1 The chelation reaction was carried out in a CoCl2 solution at 70°C for 12 hours. The membrane was then removed 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 a mixture of ammonia and hydrogen. The test results showed that the ammonia permeability was 2235.8 Barrer and the ammonia / hydrogen selectivity was 309.

[0076] Example 7:

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

[0078] S1. Equimolar amounts of 5,5',6,6'-tetrahydroxy-3,3,3',3',4,4'-hexamethyl-1,1'-spirobisindane (TTSBI-M) and tetrafluoroterephthalonitrile (TFTPN) were subjected to a polycondensation reaction at 155 °C to synthesize a microporous polymer PIM-M containing benzylmethyl.

[0079] S2. After completely dissolving PIM-M in chlorobenzene, liquid bromine was added, and the mixture was reacted at 140°C for 6 hours to obtain the bromomethylated microporous polymer PIM-Br. When the molar ratio of liquid bromine to benzyl group in the repeating unit was controlled at 1:1, the degree of bromomethylation was close to 100%.

[0080] S3. Dissolve PIM-Br in chloroform, filter to remove insoluble matter, drop it onto an ultra-flat culture dish, and obtain the PIM-Br base film after the solvent evaporates.

[0081] S4. Immerse the base film at a temperature of 60℃ and a concentration of 0.5 mol / L. -1 A amine-crosslinked microporous polymer membrane was obtained by immersing the membrane in a polyethyleneimine solution for 24 hours. The membrane was then immersed in a solution at 35°C with a concentration of 0.5 mol / L. -1 Quaternization modification was achieved by immersing the membrane in a haloalkane solution for 12 hours to obtain a modified membrane;

[0082] S5. Immerse the modified membrane in 2 mol / L water. -1 The chelation reaction was carried out in CuCl2 solution at 80℃ for 0.5 hours. The membrane was then removed and rinsed with deionized water to obtain an ammonia-hydrogen separation membrane with microporous polymer.

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

[0084] Example 8:

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

[0086] S1. Equimolar amounts of 5,5',6,6'-tetrahydroxy-3,3,3',3',4,4'-hexamethyl-1,1'-spirobisindane (TTSBI-M) and tetrafluoroterephthalonitrile (TFTPN) were subjected to a polycondensation reaction at 155 °C to synthesize a microporous polymer PIM-M containing benzylmethyl.

[0087] S2. After completely dissolving PIM-M in chlorobenzene, liquid bromine is added, and the mixture is reacted at 140℃ for 5 hours to obtain the bromomethylated microporous polymer PIM-Br. When the molar ratio of liquid bromine to benzyl in the repeating unit is controlled at 1:1, the degree of bromomethylation is close to 100%.

[0088] S3. Dissolve PIM-Br in chloroform, filter to remove insoluble matter, drop it onto an ultra-flat culture dish, and obtain the PIM-Br base film after the solvent evaporates.

[0089] S4. Immerse the base film at a temperature of 60℃ and a concentration of 1.5 mol / L.-1 A amine-crosslinked microporous polymer membrane was obtained by immersing the membrane in a polyethyleneimine solution for 24 hours. The membrane was then immersed in a solution at 60°C with a concentration of 2 mol / L. -1 Quaternization modification was achieved by immersing the modified membrane in a haloalkane solution for 0.5 h to obtain a modified membrane;

[0090] S5. Immerse the modified membrane in 1 mol / L water. -1 The membrane was subjected to a chelation reaction in a NiCl2 solution at 70°C for 12 hours. The membrane was then removed and rinsed with deionized water to obtain an ammonia-hydrogen separation membrane with a microporous polymer.

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

[0092] Example 9:

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

[0094] S1. Equimolar amounts of 5,5',6,6'-tetrahydroxy-3,3,3',3',4,4'-hexamethyl-1,1'-spirobisindane (TTSBI-M) and tetrafluoroterephthalonitrile (TFTPN) were subjected to a polycondensation reaction at 155 °C to synthesize a microporous polymer PIM-M containing benzylmethyl.

[0095] S2. After completely dissolving PIM-M in chlorobenzene, liquid bromine was added, and the mixture was reacted at 140°C for 6 hours to obtain the bromomethylated microporous polymer PIM-Br. When the molar ratio of liquid bromine to benzyl group in the repeating unit was controlled at 1:1, the degree of bromomethylation was close to 100%.

[0096] S3. Dissolve PIM-Br in chloroform, filter to remove insoluble matter, drop it onto an ultra-flat culture dish, and obtain the PIM-Br base film after the solvent evaporates.

[0097] S4. Immerse the base film at a temperature of 60℃ and a concentration of 2 mol / L. -1 A amine-crosslinked microporous polymer membrane was obtained by immersing the membrane in a polyethyleneimine solution for 24 hours. The membrane was then immersed in a solution at 35°C with a concentration of 0.5 mol / L. -1 Quaternization modification was achieved by immersing the membrane in a haloalkane solution for 12 hours to obtain a modified membrane;

[0098] S5. Immerse the modified membrane in 0.5 mol / L water. -1 The chelation reaction was carried out in a ZnCl2 solution at 70°C for 6 hours. The membrane was then removed and rinsed with deionized water to obtain an ammonia-hydrogen separation membrane with a microporous polymer.

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

[0100] Example 10:

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

[0102] S1. Equimolar amounts of 5,5',6,6'-tetrahydroxy-3,3,3',3',4,4'-hexamethyl-1,1'-spirobisindane (TTSBI-M) and tetrafluoroterephthalonitrile (TFTPN) were subjected to a polycondensation reaction at 155 °C to synthesize a microporous polymer PIM-M containing benzylmethyl.

[0103] S2. After completely dissolving PIM-M in chlorobenzene, liquid bromine was added, and the mixture was reacted at 155°C for 6 hours to obtain the bromomethylated microporous polymer PIM-Br. When the molar ratio of liquid bromine to benzyl group in the repeating unit was controlled at 1:1, the degree of bromomethylation was close to 100%.

[0104] S3. Dissolve PIM-Br in chloroform, filter to remove insoluble matter, drop it onto an ultra-flat culture dish, and obtain the PIM-Br base film after the solvent evaporates.

[0105] S4. Immerse the base film at 50℃ with a concentration of 3 mol / L. -1 A amine-crosslinked microporous polymer membrane was obtained by immersing the membrane in a polyethyleneimine solution for 24 hours. The membrane was then immersed in a solution at 40°C with a concentration of 1 mol / L. -1 Quaternization modification was achieved by immersing the membrane in a haloalkane solution for 12 hours to obtain a modified membrane;

[0106] S5. Immerse the modified membrane in 2 mol / L water. -1 The membrane was subjected to a chelation reaction in a NiCl2 solution at 80°C for 12 hours. The membrane was then removed and rinsed with deionized water to obtain an ammonia-hydrogen separation membrane with a microporous polymer.

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

[0108] Example 11:

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

[0110] S1. Equimolar amounts of 5,5',6,6'-tetrahydroxy-3,3,3',3',4,4'-hexamethyl-1,1'-spirobisindane (TTSBI-M) and tetrafluoroterephthalonitrile (TFTPN) were subjected to a polycondensation reaction at 155 °C to synthesize a microporous polymer PIM-M containing benzylmethyl.

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

[0112] S3. Dissolve PIM-Br in chloroform, filter to remove insoluble matter, drop it onto an ultra-flat culture dish, and obtain the PIM-Br base film after the solvent evaporates.

[0113] S4. Immerse the base film at a temperature of 60℃ and a concentration of 0.5 mol / L. -1 A self-corrosive microporous polymer membrane was obtained by immersing the membrane in a diethylenetriamine solution for 12 hours. The membrane was then immersed in a solution of 0.5 mol / L at 30°C. -1 Quaternization modification was achieved by immersing the membrane in a haloalkane solution for 12 hours to obtain a modified membrane;

[0114] S5. Immerse the modified membrane in 0.5 mol / L water. -1 The chelation reaction was carried out in CuCl2 solution at 40°C for 4 hours. The membrane was then removed and rinsed with deionized water to obtain an ammonia-hydrogen separation membrane with microporous polymer.

[0115] A gas separation device was used to separate a mixture of 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, this invention innovatively introduces benzyl bromide groups into a self-porous polymer with a large intrinsic free space volume through liquid bromine modification, followed by amine crosslinking and quaternization modification. Finally, a chelation reaction with metal chlorides is used to prepare a self-porous polymer membrane for ammonia-hydrogen separation. The functional groups of the self-porous polymer ammonia-hydrogen separation membrane are highly tunable; the more methyl groups are introduced, the more adsorption sites are introduced. The ammonia-hydrogen separation membrane based on the self-porous polymer exhibits high ammonia permeation flux and excellent ammonia-hydrogen selectivity, demonstrating good potential for industrial application.

[0117] Any aspects not described in this invention are applicable to existing technologies.

[0118] Obviously, the above embodiments are merely example for clearly illustrating but not limitation to the embodiments. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the embodiments need not and can not be enumerated. The obvious changes or variations derived from the above description are still within the protection scope of the present application.

Claims

1. A method for preparing an ammonia-hydrogen separation membrane based on a self-porous polymer, characterized in that, Includes the following steps: S1. 5,5',6,6'-tetrahydroxy-3,3,3',3',4,4'-hexamethyl-1,1'-spirobisindane (TTSBI-M) and tetrafluoroterephthalonitrile (TFTPN) were subjected to a polycondensation reaction at 155°C in a molar ratio of 1:1 to synthesize a microporous polymer PIM-M containing benzylmethyl. S2. After completely dissolving PIM-M in chlorobenzene, liquid bromine is added, and the reaction is carried out to obtain the bromomethylated microporous polymer PIM-Br. S3. Dissolve PIM-Br in an organic solvent, filter to remove insoluble matter to obtain casting solution, drop the casting solution onto an ultra-flat culture dish, and obtain PIM-Br base film after the solvent evaporates; S4. The base membrane is immersed in a solution of a polyamine containing two or more primary amine groups, and the immersion time and temperature are controlled to obtain an amine crosslinked self-porous polymer membrane. Then, it is immersed in a haloalkane solution to achieve quaternization modification to obtain a modified membrane. The haloalkane is one of iodomethane, bromoethane, and chloropropane. S5. The modified membrane is immersed in a metal chloride solution to carry out a chelation reaction to introduce adsorption sites. Then the membrane is taken out and rinsed with deionized water to obtain an ammonia-hydrogen separation membrane based on a self-porous polymer. The metal chloride is one of MgCl2 and ZnCl2.

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

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

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-propanediamine, 1,4-butanediamine, polyethyleneimine, and pentaethylenehexamine.

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

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

8. The preparation method according to claim 1, characterized in that: The chelation reaction conditions in step S5 are as follows: the concentration of the metal chloride solution is 0.5-2 mol·L⁻¹. -1 The metal chelation reaction takes 0.5-12 hours and is carried out at a temperature of 30-80℃.

9. An ammonia-hydrogen separation membrane based on a self-porous polymer prepared by the preparation method according to any one of claims 1-8.

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