Brominated self-microporous polymer ammonia-hydrogen separation membrane and preparation method thereof

Abstract

The application discloses a kind of brominated self-porous polymer 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, PIM-M is completely dissolved in chlorobenzene, then liquid bromine is added, and bromomethylated self-porous polymer PIM-Br is prepared by reaction;S3, PIM-Br is dissolved in organic solvent to obtain casting solution, the casting solution is uniformly coated on clean glass plate, and PIM-Br base film is obtained after solvent volatilization;S4, the base film is soaked in the solution of amine containing two or more tertiary amine groups to carry out synchronous crosslinking quaternary ammonium reaction, and modified membrane is obtained;S5, the modified membrane is soaked in metal chloride solution to carry out chelation reaction, then the membrane is taken out and washed with deionized water, and ammonia hydrogen separation membrane based on brominated self-porous polymer is obtained.The obtained separation membrane has high ammonia separation effect, and when separating ammonia-containing gas, ammonia permeability is as high as 7145.3 Barrer, and ammonia / hydrogen selectivity is as high as 668.5.

Description

Technical Field

[0001] This invention relates to the field of new materials technology, specifically to a brominated self-porous polymer ammonia-hydrogen separation membrane and its preparation method. Background Technology

[0002] The main uses of ammonia include nitrogen fertilizer production in agriculture and as a raw material and synthetic intermediate in the chemical industry. Meanwhile, hydrogen is considered an important component of future clean energy and is widely used in fuel cells, hydrogen-powered vehicles, and industrial emission reduction. The efficient separation of ammonia and hydrogen can not only ensure a sustainable supply of hydrogen but also promote the resource utilization of ammonia.

[0003] Common ammonia separation methods include adsorption, absorption, low-pressure distillation, and membrane separation. Among these, membrane separation has received widespread attention in recent years due to its advantages such as low energy consumption, high separation efficiency, and no environmental pollution. However, existing ammonia separation membranes have relatively low ammonia selectivity and ammonia permeation flux. To date, developing ammonia separation membranes that combine high performance and low cost remains a significant technical challenge. Summary of the Invention

[0004] To address the problems of low ammonia selectivity and low ammonia permeation flux in existing ammonia separation membranes, this invention provides a brominated self-microporous polymer ammonia-hydrogen separation membrane and its preparation method. Self-microporous polymers, as a novel membrane material, possess unique microporous structures and high specific surface areas. They can be synthesized through high-temperature polycondensation reactions and have a large intrinsic free space volume, thereby enhancing the ammonia-hydrogen separation capability.

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

[0006] A method for preparing a brominated self-microporous polymer ammonia-hydrogen separation membrane includes the following steps:

[0007] 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.

[0008] 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.

[0009] S3. Dissolve PIM-Br in an organic solvent to obtain a casting solution. Coat the casting solution evenly on a clean glass plate. After the solvent evaporates, a PIM-Br base film is obtained.

[0010] S4. The base membrane is immersed in a solution of an amine containing two or more tertiary amine groups to carry out a simultaneous cross-linking quaternization reaction to obtain a modified membrane.

[0011] S5. The modified membrane is immersed in a metal chloride solution for chelation reaction, and then the membrane is taken out and rinsed with deionized water to obtain an ammonia-hydrogen separation membrane based on a brominated self-porous polymer.

[0012] In step S2, the degree of bromination of the microporous polymer PIM-Br is 10%-100%.

[0013] The reaction conditions for PIM-M and liquid bromine in step S2 are: reaction temperature 140-155℃, reaction time 2h-6h.

[0014] The mass fraction of the casting solution in step S3 is 1%-10%.

[0015] The organic solvent used to dissolve PIM-Br in step S3 is one of chloroform (CHCl3), tetrahydrofuran (THF), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), and N-methylpyrrolidone (NMP).

[0016] The amine containing two or more tertiary amine groups in step S4 is one of pentamethyldiethylenetriamine, 1,4-diazidobicyclo[2.2.2.]octane, and 1,4-dimethylpiperazine.

[0017] The conditions for the simultaneous cross-linking quaternization reaction in step S4 are: the concentration of the amine solution is 0.5-2 mol·L⁻¹. -1 The modification time is 1-48 hours, and the temperature is 30-80℃.

[0018] In step S5, the metal chloride is one of CoCl2, MgCl2, NiCl2, MnCl2, FeCl2, FeCl3, ZnCl2, and CuCl2.

[0019] The chelation reaction conditions in step S5 are as follows: the concentration of the metal chloride solution is 0.5-3 mol·L⁻¹. -1 The metal chelation reaction takes 6-24 hours and is carried out at a temperature of 40-90℃.

[0020] A brominated self-porous polymer ammonia-hydrogen separation membrane prepared according to the above preparation method.

[0021] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0022] This invention innovatively introduces benzyl bromide groups into a self-porous polymer with a large intrinsic free space volume as the base material. The polymer undergoes an amine crosslinking reaction to form a three-dimensional network structure, enhancing the material's mechanical properties and stability. The functional groups of the self-porous polymer ammonia-hydrogen separation membrane are highly tunable; as the degree of bromination increases, more metal ions and Lewis acids can be introduced as adsorption sites. This not only provides a large intrinsic free space volume, promoting gas permeation, but also significantly improves the selective separation capability of ammonia / hydrogen, offering a new solution for the development of ammonia-hydrogen separation technology and possessing broad application prospects. Detailed Implementation

[0023] This invention can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the inventive concept to those skilled in the art. All other embodiments derived by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0024] Example 1:

[0025] This embodiment provides a method for preparing a brominated microporous polymer ammonia-hydrogen separation membrane, comprising the following steps:

[0026] 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.

[0027] 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 50%.

[0028] S3. Dissolve PIM-Br in chloroform to obtain a casting solution. Coat the casting solution evenly on a clean glass plate. After the solvent evaporates, a PIM-Br base film is obtained.

[0029] S4. Immerse the base film at a temperature of 30℃ and a concentration of 0.5 mol / L. -1 The modified membrane was obtained by simultaneous cross-linking quaternization reaction in a pentamethyldiethylenetriamine solution for 4 hours.

[0030] S5. Immerse the modified membrane at a temperature of 40℃ and a concentration of 0.5 mol / L. -1The membrane was immersed in NiCl2 solution for 2 hours to introduce metal chloride for chelation reaction. Then the membrane was taken out and rinsed with deionized water to obtain an ammonia-hydrogen separation membrane based on brominated self-porous polymer.

[0031] A gas separation device was used to separate a mixture of ammonia and hydrogen. The test results showed that the ammonia permeability was 968.2 Barrer and the ammonia / hydrogen selectivity was 272.5.

[0032] Example 2:

[0033] The preparation method in this embodiment is the same as in Example 1, except that the degree of bromination of PIM-Br is increased to 80%. The mixed gas containing ammonia and hydrogen was separated using a gas separation device. The test results showed that the ammonia permeability was 1056.9 Barrer and the ammonia / hydrogen selectivity was 295.5.

[0034] Example 3:

[0035] The preparation method in this embodiment is the same as in Example 1, except that the degree of bromination of PIM-Br is increased to 100%. The mixed gas containing ammonia and hydrogen was separated using a gas separation device. The test results showed that the ammonia permeability was 1821.1 Barrer and the ammonia / hydrogen selectivity was 321.4.

[0036] Example 4:

[0037] The preparation method in this embodiment is the same as in Example 3, except that a PIM-Br base film with a bromination degree of 100% is immersed in an atmosphere at a temperature of 40°C and a concentration of 0.5 mol / L. -1 Simultaneous cross-linking quaternization reaction was carried out in a pentamethyldiethylenetriamine solution for 4 hours. The mixture containing ammonia and hydrogen was separated using a gas separation device. The test results showed that the ammonia permeability was 2623.6 Barrer and the ammonia / hydrogen selectivity was 389.9.

[0038] Example 5:

[0039] The preparation method in this embodiment is the same as in Example 3, except that the PIM-Br base film is immersed in a solution at a temperature of 50°C and a concentration of 1 mol / L. -1 Simultaneous cross-linking quaternization reaction was carried out in a pentamethyldiethylenetriamine solution for 8 hours. The mixture containing ammonia and hydrogen was separated using a gas separation device. The test results showed that the ammonia permeability was 2985.2 Barrer and the ammonia / hydrogen selectivity was 415.7.

[0040] Example 6:

[0041] The preparation method in this embodiment is the same as in Example 3, except that the PIM-Br base film is immersed in water at a temperature of 80°C and a concentration of 1.5 mol / L. -1Simultaneous cross-linking quaternization reaction was carried out in a pentamethyldiethylenetriamine solution for 1 hour. The mixture containing ammonia and hydrogen was separated using a gas separation device. The test results showed that the ammonia permeability was 3198.1 Barrer and the ammonia / hydrogen selectivity was 444.4.

[0042] Example 7:

[0043] The preparation method in this embodiment is the same as in Example 3, except that the PIM-Br base film is immersed in a solution at a temperature of 30°C and a concentration of 2 mol / L. -1 Simultaneous crosslinking quaternization reaction was carried out in a pentamethyldiethylenetriamine solution for 48 hours. The mixture containing ammonia and hydrogen was separated using a gas separation device. The test results showed that the ammonia permeability was 3758.6 Barrer and the ammonia / hydrogen selectivity was 456.8.

[0044] Example 8:

[0045] The preparation method in this embodiment is the same as in Example 3, except that the PIM-Br base film is immersed in water at a temperature of 50°C and a concentration of 1.5 mol / L. -1 Simultaneous crosslinking quaternization reaction was carried out in a pentamethyldiethylenetriamine solution for 24 hours. The mixture containing ammonia and hydrogen was separated using a gas separation device. The test results showed that the ammonia permeability was 4000 Barrer and the ammonia / hydrogen selectivity was 473.5.

[0046] Example 9:

[0047] The preparation method in this embodiment is the same as in Example 8, except that the membrane is immersed in water at a temperature of 40°C and a concentration of 0.5 mol / L. -1 The ammonia-hydrogen mixture was introduced into a NiCl2 solution for 6 hours to induce a chelation reaction with metal chlorides. A gas separation device was used to separate the ammonia-hydrogen mixture. The test results showed that the ammonia permeability was 4175.3 Barrer and the ammonia / hydrogen selectivity was 513.8.

[0048] Example 10:

[0049] The preparation method in this embodiment is the same as in Example 9, except that the membrane is immersed in a solution at a temperature of 60°C and a concentration of 1 mol / L. -1 The ammonia-hydrogen mixture was introduced into a NiCl2 solution for 16 hours to induce a chelation reaction with metal chlorides. A gas separation device was used to separate the ammonia-hydrogen mixture. The test results showed that the ammonia permeability was 4258.4 Barrer and the ammonia / hydrogen selectivity was 605.5.

[0050] Example 11:

[0051] The preparation method in this embodiment is the same as in Example 10, except that the base film is immersed in water at a temperature of 50°C and a concentration of 1.5 mol / L. -1Simultaneous crosslinking quaternization reaction was carried out in 1,4-diazidobicyclo[2.2.2.]octane solution for 24 h. The mixture containing ammonia and hydrogen was separated using a gas separation device. The test results showed that the ammonia permeability was 5358.1 Barrer and the ammonia / hydrogen selectivity was 619.2.

[0052] Example 12:

[0053] The preparation method in this embodiment is the same as in Example 11, except that the base film is immersed in water at a temperature of 50°C and a concentration of 1.5 mol / L. -1 Simultaneous crosslinking quaternization reaction was carried out in 1,4-diazidobicyclo[2.2.2.]octane solution for 36 h. The mixture containing ammonia and hydrogen was separated using a gas separation device. The test results showed that the ammonia permeability was 5958.6 Barrer and the ammonia / hydrogen selectivity was 636.8.

[0054] Example 13:

[0055] The preparation method in this embodiment is the same as in Example 11, except that the base film is immersed in water at a temperature of 65°C and a concentration of 1.5 mol / L. -1 Simultaneous crosslinking quaternization reaction was carried out in 1,4-diazidobicyclo[2.2.2.]octane solution for 48 h. The mixture containing ammonia and hydrogen was separated using a gas separation device. The test results showed that the ammonia permeability was 6565.6 Barrer and the ammonia / hydrogen selectivity was 641.1.

[0056] Example 14:

[0057] The preparation method in this embodiment is the same as in Example 11, except that the membrane is immersed in water at a temperature of 90°C and a concentration of 1.5 mol / L. -1 The metal chloride was introduced into the CoCl2 solution for chelation reaction at 20 h. The mixture of ammonia and hydrogen was separated using a gas separation device. The test results showed that the ammonia permeability was 6963.2 Barrer and the ammonia / hydrogen selectivity was 658.8.

[0058] Example 15:

[0059] The preparation method in this embodiment is the same as in Example 11, except that the membrane is immersed in a solution at a temperature of 80°C and a concentration of 3 mol / L. -1 The metal chloride was introduced into the CoCl2 solution for 24 hours to carry out a chelation reaction. The mixture of ammonia and hydrogen was separated using a gas separation device. The test results showed that the ammonia permeability was 7145.3 Barrer and the ammonia / hydrogen selectivity was 668.5.

[0060] Example 16:

[0061] The preparation method in this embodiment is the same as in Example 1, except that the degree of bromination of PIM-Br is reduced to 10%. The mixture containing ammonia and hydrogen was separated using a gas separation device. The test results showed that the ammonia permeability was 893.5 Barrer and the ammonia / hydrogen selectivity was 138.

[0062] Example 17:

[0063] The preparation method in this embodiment is the same as in Example 1, except that the reaction temperature of PIM-M with liquid bromine in step S2 is adjusted to 155°C and the reaction time is adjusted to 2 hours. A gas separation device was used to separate the ammonia-hydrogen mixture. The test results showed that the ammonia permeability was 6947.5 Barrer and the ammonia / hydrogen selectivity was 659.2.

[0064] In summary, a novel approach was taken to introduce benzyl bromide groups into a self-porous polymer with a large intrinsic free space volume as the base material. The polymer undergoes an amine crosslinking reaction to form a three-dimensional network structure, enhancing the material's mechanical properties and stability. The functional groups of the self-porous polymer ammonia-hydrogen separation membrane are highly tunable; with increasing bromination degree, more metal ions and Lewis acids can be introduced as adsorption sites. This not only provides a large intrinsic free space volume, promoting gas permeation, but also significantly improves the selective separation capability of ammonia / hydrogen, offering a new solution for the development of ammonia-hydrogen separation technology and demonstrating broad application prospects.

[0065] Any aspects not described in this invention are applicable to existing technologies.

[0066] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a brominated self-porous polymer ammonia-hydrogen separation membrane, characterized in that, Includes the following steps: 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. 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, wherein the degree of bromination of the bromomethylated microporous polymer PIM-Br is 10%-100%; S3. Dissolve PIM-Br in an organic solvent to obtain a casting solution, uniformly coat the casting solution onto a clean glass plate, and obtain a PIM-Br base film after the solvent evaporates, wherein the mass fraction of PIM-Br in the casting solution is 1%-10%; S4. The base membrane is immersed in a solution of an amine containing two or more tertiary amine groups to carry out a simultaneous crosslinking quaternization reaction to obtain a modified membrane, wherein the amine containing two or more tertiary amine groups is one of pentamethyldiethylenetriamine, 1,4-diazidobicyclo[2.2.2]octane and 1,4-dimethylpiperazine; S5. The modified membrane is immersed in a metal chloride solution for chelation reaction, and then the membrane is taken out and rinsed with deionized water to obtain an ammonia-hydrogen separation membrane based on a brominated self-microporous polymer. The metal chloride is one of CoCl2, MgCl2, NiCl2, MnCl2, FeCl2, FeCl3, ZnCl2, and CuCl2.

2. 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.

3. The preparation method according to claim 1, characterized in that: The organic solvent used to dissolve PIM-Br in step S3 is one of chloroform (CHCl3), tetrahydrofuran (THF), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), and N-methylpyrrolidone (NMP).

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

5. 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 0.5-3 mol·L⁻¹. -1 The metal chelation reaction takes 6-24 hours and is carried out at a temperature of 40-90℃.

6. A brominated self-porous polymer ammonia-hydrogen separation membrane prepared by the preparation method according to any one of claims 1-5.