An anion exchange membrane that combines selectivity for monovalent anions and solvent resistance

Abstract

This invention relates to the field of polymer materials, specifically disclosing anion exchange membrane that combines monovalent anion selectivity and solvent resistance. It utilizes brominated polyphenylene ether as the main chain, adds a crosslinking agent to construct a three-dimensional crosslinked network, and the main chain and crosslinking agent become entangled to form a dense membrane structure, thereby preparing an ion exchange membrane with high thermal, mechanical, and dimensional stability resistant to organic solvents. Simultaneously, side chains are added to the main chain to charge the polymer, thus giving the prepared ion exchange membrane high monovalent / divalent separation performance. This homogeneous structure of the ion exchange membrane is beneficial to the stability of long-term operation in electrodialysis processes. The crosslinked imidazole-containing anion exchange membrane prepared by this invention has advantages such as good ion conductivity, good monovalent anion selectivity, and good solvent resistance, and has broad application prospects, especially in electrodialysis applications and ion resource recovery.

Description

Technical Field

[0001] This invention relates to the field of polymer materials, and specifically to an anion exchange membrane that combines monovalent anion selectivity and solvent resistance. Background Technology

[0002] In recent years, resource scarcity and environmental pollution have become severe challenges facing the world. The discharge of industrial wastewater is particularly significant, causing not only energy waste but also considerable harm to the environment and human health. The development of wastewater treatment technologies has greatly mitigated environmental pollution. Currently, electrodialysis technology mainly focuses on aqueous systems. Separating ions from mixed salt systems is a crucial practical application of electrodialysis, but actual industrial processes often involve organic solvent systems. For specific mixed salt systems to be separated, the selection of ion exchange membranes is critical, and the solvent resistance of the membranes is also essential. Traditional commercial ion exchange membrane materials (such as polysulfone, polyethersulfone, and polystyrene) are prone to chemical degradation and other harmful changes in aqueous environments containing organic solvents, thus greatly limiting the application of electrodialysis technology in complex industrial environments.

[0003] In organic solvents, polymers dissolve due to the principle of "like dissolves like," primarily through two processes: (1) diffusion of the solvent into the polymer; and (2) dissociation of the polymer chains. This dissociation leads to changes in the membrane surface structure, resulting in a loss of separation performance and limiting the application of organic membranes in organic solvent systems. Therefore, maintaining membrane stability and long-term high efficiency in organic solvents over a wide range is crucial. Developing organic solvent-resistant separation membranes and properly coordinating the relationship between membrane solubility, diffusivity, and physicochemical stability to achieve high separation selectivity while maintaining a certain permeate flux holds great promise. Summary of the Invention

[0004] To improve the solvent resistance of ion exchange membranes, a three-dimensional cross-linked network structure is constructed. This invention uses brominated polyphenylene ether as the main chain, adds a cross-linking agent, and constructs a three-dimensional cross-linked network. The main chain and the cross-linking agent become entangled to form a dense membrane structure, thereby preparing an ion exchange membrane with high thermal, mechanical, and dimensional stability resistant to organic solvents. Simultaneously, side chains are added to the main chain to charge the polymer, thus giving the prepared ion exchange membrane high selectivity. This homogeneous ion exchange membrane structure is beneficial for the stability of long-term operation of the electrodialysis process.

[0005] The purpose of this invention is to provide a method for preparing homogeneous brominated polyphenylene ether anion exchange membranes that combine monovalent anion selectivity and solvent resistance.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for preparing an anion exchange membrane that combines monovalent anion selectivity and solvent resistance includes the following steps:

[0008] (1) Take a certain amount of brominated polyphenylene ether (I), N-butylimidazolium (II), and polyethyleneimine (PEI) (III) respectively, and dissolve the brominated polyphenylene ether and polyethyleneimine in a certain amount of solvent to obtain a dilute solution of a certain concentration.

[0009]

[0010] (2) The solution of N-butylimidazolium shown in formula (II) is added to the solution of brominated polyphenylene ether shown in formula (I) and reacted at 25-60℃ for 8-24 hours to obtain imidazolium-functionalized brominated polyphenylene ether. Then, the solution of polyethyleneimine shown in formula (III) is added to the imidazolium-functionalized brominated polyphenylene ether and stirred to react to obtain an imidazolium-functionalized PEI blended brominated polyphenylene ether solution. The molar ratio of brominated polyphenylene ether (I), N-butylimidazolium (II) to polyethyleneimine (III) is 1:(0-0.44):(0-0.04).

[0011] (3) The imidazole-functionalized PEI blended brominated polyphenylene ether casting solution obtained in step (2) is filtered to remove impurities, then vacuum degassed, and then cast onto a clean glass plate and dried at 80°C for 12-36 hours to obtain a homogeneous brominated polyphenylene ether anion exchange membrane.

[0012] The homogeneous brominated polyphenylene ether anion exchange membrane prepared in this invention is composed of brominated polyphenylene ether. Due to the uncertainty of the bromination sites, there are multiple possible polymer structures, one of which is shown below:

[0013]

[0014] The structure has X = 0, 0.01, 0.02, 0.03, 0.04; Y = 0.11, 0.22, 0.33, 0.44.

[0015] As can be seen from the structure of imidazole-functionalized brominated polyphenylene ether, this invention introduces N-butylimidazole and polyethyleneimine and controls the ratio of the two crosslinking agents. The crosslinking agents are tightly entangled with the main chain to form a three-dimensional network structure and new chemical bonds are generated during the crosslinking process, thereby enabling the membrane to have solvent resistance and selectivity while ensuring low membrane surface resistance.

[0016] Preferably, in step (1), the N-butylimidazolium, brominated polyphenylene ether, and polyethyleneimine are stirred in an organic solvent for 2-8 hours until completely dissolved.

[0017] As a further preferred option, in step (1), the organic solvent is one or more of dimethylformamide (DMF), dimethylacetamide (DMAc), and N-methylpyrrolidone (NMP) (more preferably N-methylpyrrolidone).

[0018] As a further preferred embodiment, in step (1), the N-butylimidazole has a purity of 99%, and the brominated polyphenylene ether and the polyethyleneimine solution have mass concentrations of 6 wt% and 3 wt%, respectively.

[0019] As a preferred embodiment, step (2) is carried out as follows: a certain amount of dissolved brominated polyphenylene ether solution is placed in a round-bottom single-necked flask, a certain amount of N-methylimidazole is added and stirred until the reaction is complete, and then a certain amount of polyethyleneimine solution is added and stirred on a magnetic stirrer. The resulting casting solution is filtered using a sand core funnel to remove impurities and dust, thus obtaining an imidazole-functionalized brominated polyphenylene ether solution.

[0020] As a further preferred option, in step (2), the molar ratio of brominated polyphenylene ether (Ⅰ), N-butylimidazolium (Ⅱ) to polyethyleneimine (Ⅲ) is 1:(0-0.44):(0-0.04).

[0021] As a further preferred option, in step (2), the reaction temperature of N-butylimidazole added to the brominated polyphenylene ether solution is 0-60°C (more preferably 25°C), and the reaction time is 4-24 hours (more preferably 24 hours).

[0022] As a further preferred embodiment, in step (2), the reaction temperature of adding polyethyleneimine to the brominated polyphenylene ether solution is 0-60°C (more preferably 0°C), and the reaction time is 1-24 hours (more preferably 5 hours).

[0023] As a preferred embodiment, step (3) is carried out as follows: after the polymer solution reaction is completed, the polymer solution is filtered with a sand core filter funnel to remove dust and impurities, the casting solution is degassed under vacuum and then poured onto a clean glass plate, and then dried in a vacuum drying oven to finally obtain a homogeneous brominated polyphenylene ether anion exchange membrane.

[0024] As a further preferred option, in step (3), the drying conditions for the ion exchange membrane are set to vacuum drying at 80°C for 24 hours.

[0025] As a further preferred option, in step (3), the amount of casting solution poured into the glass plate is controlled so that the thickness of the homogeneous brominated polyphenylene ether anion exchange membrane is 80-160 μm.

[0026] The cross-linked imidazole-containing anion exchange membrane prepared by this invention has advantages such as good ion conductivity, good monovalent selectivity, and good solvent resistance, and has broad application prospects, especially in the field of electrodialysis.

[0027] Compared with the prior art, the advantages of this invention are:

[0028] (1) The present invention uses branched polyacetylimide to crosslink imidazole functionalized polyphenylene ether containing benzyl bromide to form a three-dimensional polymer anion exchange membrane with low sheet resistance, insoluble in strong polar solvents (such as DMF, DMAc, DMSO, etc.) and can maintain low liquid absorption and swelling rate, thus exhibiting good solvent resistance.

[0029] (2) The cross-linked anion exchange membrane prepared by the present invention maintains good solvent resistance while exhibiting high monovalent anion permeation selectivity due to its dense and unique microstructure. It can realize the ion resource utilization of waste salt in solution systems containing organic solvents, thus having good industrial application prospects. Attached Figure Description

[0030] Figure 1 and Figure 2 The images show actual photos of the AEMs prepared in Example 8 of this invention before and after soaking in different solvents with a concentration of 60% for 30 days.

[0031] Figure 3 These are physical images of the solvent-resistant crosslinked structure AEMs obtained in Examples 2, 5, 8 and 11 of this invention. Detailed Implementation

[0032] To further illustrate the technical solution of the present invention, the preferred embodiments of the present invention are described below in conjunction with specific examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the claims of the present invention.

[0033] Example 1:

[0034] Preparation of modified brominated polyphenylene ether: Weigh 3.2 g (16 mmol) of brominated polyphenylene ether into a 100 mL round-bottom flask, then add 40 mL of N-methylpyrrolidone (NMP) and stir at 25 °C until the solid is completely dissolved to obtain a clear solution of brominated polyphenylene ether. Weigh 0.2182 g (1.7574 mmol) of N-butylimidazole into a 100 mL round-bottom flask, then add 10 mL of N-methylpyrrolidone (NMP) and stir evenly at 25 °C to obtain a clear solution of N-butylimidazole. Prepare a 3 wt% polyethyleneimine solution in a 100 mL round-bottom flask to obtain a clear polyethyleneimine solution.

[0035] Preparation of the cross-linked anion exchange membrane: 40 mL of clear brominated polyphenylene ether solution was transferred to a 250 mL single-necked round-bottom flask and stirred rapidly. Then, 10 mL of clear N-butylimidazole solution was added to the same flask, and the mixture was stirred evenly at 25 °C for 24 h. Next, 2132 μL (0.144 mmol) of polyethyleneimine was transferred using a 1000 μL pipette and added to the 250 mL single-necked round-bottom flask. The mixture was stirred rapidly at 0 °C for 5 h. The reaction solution was then filtered through a sintered glass filter funnel to obtain the casting solution. The casting solution was degassed and poured onto a clean glass mold. The mold was then vacuum-dried at 60 °C for 24 h to form a homogeneous imidazole-functionalized PEI blended brominated polyphenylene ether anion exchange membrane with a thickness of 152 μm and a resistivity of 102 Ω·cm. 2 .

[0036] The thickness, ion exchange capacity, tensile strength, water swelling rate, and organic solvent swelling rate of the prepared monovalent anion-selective anion exchange membrane were experimentally tested using national standard methods. The sheet resistance, transport number, and permeation selectivity of the ion exchange membrane were tested using a self-made apparatus. The results are shown in Table 1. (For specific testing methods, please refer to the literature reports: Journal of Membrane Science 574(2019)181–195; Journal of Membrane Science 577(2019)153–164).

[0037] Example 2:

[0038] The preparation of modified brominated polyphenylene ether is the same as in Example 1.

[0039] Preparation of the cross-linked anion exchange membrane: 40 mL of clear brominated polyphenylene ether solution was transferred to a 250 mL single-necked round-bottom flask and stirred rapidly. Then, 10 mL of clear N-butylimidazole solution was added to the same flask, and the mixture was stirred evenly at 25 °C for 24 h. Next, 3198 μL (0.216 mmol) of polyethyleneimine was transferred using a 1000 μL pipette and added to the 250 mL single-necked round-bottom flask. The mixture was stirred rapidly at 0 °C for 5 h. The reaction solution was then filtered through a sintered glass filter funnel to obtain the casting solution. The casting solution was degassed and poured onto a clean glass mold. The mold was then vacuum-dried at 60 °C for 24 h to form a homogeneous imidazole-functionalized PEI blended brominated polyphenylene ether anion exchange membrane with a thickness of 153 μm and a resistivity of 96 Ω·cm. 2 .

[0040] The thickness, ion exchange capacity, tensile strength, water swelling rate, and organic solvent swelling rate of the prepared monovalent anion-selective anion exchange membrane were experimentally tested using national standard methods. The sheet resistance, transport number, and permeation selectivity of the ion exchange membrane were tested using a self-made apparatus. The results are shown in Table 1. (For specific testing methods, please refer to the literature reports: Journal of Membrane Science 574(2019)181–195; Journal of Membrane Science 577(2019)153–164).

[0041] Example 3:

[0042] The preparation of modified brominated polyphenylene ether is the same as in Example 1.

[0043] Preparation of the cross-linked anion exchange membrane: 40 mL of clear brominated polyphenylene ether solution was transferred to a 250 mL single-necked round-bottom flask and stirred rapidly. Then, 10 mL of clear N-butylimidazole solution was added to the same flask, and the mixture was stirred at 25 °C for 24 h. Next, 4264 μl (0.288 mmol) of polyethyleneimine was transferred using a 1000 μL pipette and added to the 250 mL single-necked round-bottom flask. The mixture was stirred rapidly at 0 °C for 5 h. The reaction solution was then filtered through a sintered glass filter funnel to obtain the casting solution. The casting solution was degassed and poured onto a clean glass mold. The mold was then vacuum-dried at 60 °C for 24 h to form a homogeneous imidazole-functionalized PEI blended brominated polyphenylene ether anion exchange membrane with a thickness of 156 μm and a resistivity of 88 Ω·cm. 2 .

[0044] The thickness, ion exchange capacity, tensile strength, water swelling rate, and organic solvent swelling rate of the prepared monovalent anion-selective anion exchange membrane were experimentally tested using national standard methods. The sheet resistance, transport number, and permeation selectivity of the ion exchange membrane were tested using a self-made apparatus. The results are shown in Table 1. (For specific testing methods, please refer to the literature reports: Journal of Membrane Science 574(2019)181–195; Journal of Membrane Science 577(2019)153–164).

[0045] Example 4:

[0046] Preparation of modified brominated polyphenylene ether: Weigh 3.2 g (16 mmol) of brominated polyphenylene ether into a 100 mL round-bottom flask, then add 40 mL of N-methylpyrrolidone (NMP) and stir at 25 °C until the solid is completely dissolved, obtaining a clear solution of brominated polyphenylene ether. Weigh 0.4364 g (3.5184 mmol) of N-butylimidazole into a 100 mL round-bottom flask, then add 10 mL of N-methylpyrrolidone (NMP) and stir evenly at 25 °C, obtaining a clear solution of N-butylimidazole. Prepare a 3 wt% polyethyleneimine solution in a 100 mL round-bottom flask, obtaining a clear polyethyleneimine solution.

[0047] The preparation process of the cross-linked anion exchange membrane is the same as in Example 1. The resulting anion exchange membrane has a thickness of 155 μm and a resistivity of 4.8 Ω·cm. 2 .

[0048] The thickness, ion exchange capacity, tensile strength, water swelling rate, and organic solvent swelling rate of the prepared monovalent anion-selective anion exchange membrane were experimentally tested using national standard methods. The sheet resistance, transport number, and permeation selectivity of the ion exchange membrane were tested using a self-made apparatus. The results are shown in Table 1. (For specific testing methods, please refer to the literature reports: Journal of Membrane Science 574(2019)181–195; Journal of Membrane Science 577(2019)153–164).

[0049] Example 5:

[0050] The preparation of modified brominated polyphenylene ether is the same as in Example 4.

[0051] The preparation process of the cross-linked anion exchange membrane is the same as in Example 2. The resulting anion exchange membrane has a thickness of 156 μm and a resistivity of 3.2 Ω·cm. 2 .

[0052] The thickness, ion exchange capacity, tensile strength, water swelling rate, and organic solvent swelling rate of the prepared monovalent anion-selective anion exchange membrane were experimentally tested using national standard methods. The sheet resistance, transport number, and permeation selectivity of the ion exchange membrane were tested using a self-made apparatus. The results are shown in Table 1. (For specific testing methods, please refer to the literature reports: Journal of Membrane Science 574(2019)181–195; Journal of Membrane Science 577(2019)153–164).

[0053] Example 6:

[0054] The preparation of modified brominated polyphenylene ether is the same as in Example 4.

[0055] The preparation process of the cross-linked anion exchange membrane is the same as in Example 3. The thickness of the obtained anion exchange membrane is 156 μm and the resistance is 4.8 Ω·cm2.

[0056] The thickness, ion exchange capacity, tensile strength, water swelling rate, and organic solvent swelling rate of the prepared monovalent anion-selective anion exchange membrane were experimentally tested using national standard methods. The sheet resistance, transport number, and permeation selectivity of the ion exchange membrane were tested using a self-made apparatus. The results are shown in Table 1. (For specific testing methods, please refer to the literature reports: Journal of Membrane Science 574(2019)181–195; Journal of Membrane Science 577(2019)153–164).

[0057] Example 7:

[0058] Preparation of modified brominated polyphenylene ether: Weigh 3.2 g (16 mmol) of brominated polyphenylene ether into a 100 mL round-bottom flask, then add 40 mL of N-methylpyrrolidone (NMP) and stir at 25 °C until the solid is completely dissolved, obtaining a clear solution of brominated polyphenylene ether. Weigh 0.6546 g (5.2722 mmol) of N-butylimidazole into a 100 mL round-bottom flask, then add 10 mL of N-methylpyrrolidone (NMP) and stir evenly at 25 °C, obtaining a clear solution of N-butylimidazole. Prepare a 3 wt% polyethyleneimine solution in a 100 mL round-bottom flask, obtaining a clear polyethyleneimine solution.

[0059] The preparation process of the cross-linked anion exchange membrane is the same as in Example 1. The resulting anion exchange membrane has a thickness of 155 μm and a resistivity of 4.9 Ω·cm. 2 .

[0060] The thickness, ion exchange capacity, tensile strength, water swelling rate, and organic solvent swelling rate of the prepared monovalent anion-selective anion exchange membrane were experimentally tested using national standard methods. The sheet resistance, transport number, and permeation selectivity of the ion exchange membrane were tested using a self-made apparatus. The results are shown in Table 1. (For specific testing methods, please refer to the literature reports: Journal of Membrane Science 574(2019)181–195; Journal of Membrane Science 577(2019)153–164).

[0061] Example 8:

[0062] The preparation of modified brominated polyphenylene ether is the same as in Example 7.

[0063] The preparation process of the cross-linked anion exchange membrane is the same as in Example 2. The resulting anion exchange membrane has a thickness of 153 μm and a resistivity of 3.3 Ω·cm. 2 .

[0064] The thickness, ion exchange capacity, tensile strength, water swelling rate, and organic solvent swelling rate of the prepared monovalent anion-selective anion exchange membrane were experimentally tested using national standard methods. The sheet resistance, transport number, and permeation selectivity of the ion exchange membrane were tested using a self-made apparatus. The results are shown in Table 1. (For specific testing methods, please refer to the literature reports: Journal of Membrane Science 574(2019)181–195; Journal of Membrane Science 577(2019)153–164).

[0065] Example 9:

[0066] The preparation of modified brominated polyphenylene ether is the same as in Example 7.

[0067] The preparation process of the cross-linked anion exchange membrane is the same as in Example 3. The resulting anion exchange membrane has a thickness of 154 μm and a resistivity of 4.6 Ω·cm. 2 .

[0068] The thickness, ion exchange capacity, tensile strength, water swelling rate, and organic solvent swelling rate of the prepared monovalent anion-selective anion exchange membrane were experimentally tested using national standard methods. The sheet resistance, transport number, and permeation selectivity of the ion exchange membrane were tested using a self-made apparatus. The results are shown in Table 1. (For specific testing methods, please refer to the literature reports: Journal of Membrane Science 574(2019)181–195; Journal of Membrane Science 577(2019)153–164).

[0069] Example 10:

[0070] Preparation of modified brominated polyphenylene ether: Weigh 3.2 g (16 mmol) of brominated polyphenylene ether into a 100 mL round-bottom flask, then add 40 mL of N-methylpyrrolidone (NMP) and stir at 25 °C until the solid is completely dissolved to obtain a clear solution of brominated polyphenylene ether. Weigh 0.8728 g (7.0296 mmol) of N-butylimidazole into a 100 mL round-bottom flask, then add 10 mL of N-methylpyrrolidone (NMP) and stir evenly at 25 °C to obtain a clear solution of N-butylimidazole. Prepare a 3 wt% polyethyleneimine solution in a 100 mL round-bottom flask to obtain a clear polyethyleneimine solution.

[0071] The preparation process of the cross-linked anion exchange membrane is the same as in Example 1. The resulting anion exchange membrane has a thickness of 153 μm and a resistivity of 4.6 Ω·cm. 2 .

[0072] The thickness, ion exchange capacity, tensile strength, water swelling rate, and organic solvent swelling rate of the prepared monovalent anion-selective anion exchange membrane were experimentally tested using national standard methods. The sheet resistance, transport number, and permeation selectivity of the ion exchange membrane were tested using a self-made apparatus. The results are shown in Table 1. (For specific testing methods, please refer to the literature reports: Journal of Membrane Science 574(2019)181–195; Journal of Membrane Science 577(2019)153–164).

[0073] Example 11:

[0074] The preparation of modified brominated polyphenylene ether is the same as in Example 10.

[0075] The preparation process of the cross-linked anion exchange membrane is the same as in Example 2. The resulting anion exchange membrane has a thickness of 154 μm and a resistivity of 2.3 Ω·cm. 2 .

[0076] The thickness, ion exchange capacity, tensile strength, water swelling rate, and organic solvent swelling rate of the prepared monovalent anion-selective anion exchange membrane were experimentally tested using national standard methods. The sheet resistance, transport number, and permeation selectivity of the ion exchange membrane were tested using a self-made apparatus. The results are shown in Table 1. (For specific testing methods, please refer to the literature reports: Journal of Membrane Science 574(2019)181–195; Journal of Membrane Science 577(2019)153–164).

[0077] Example 12:

[0078] The preparation of modified brominated polyphenylene ether is the same as in Example 10.

[0079] The preparation process of the cross-linked anion exchange membrane is the same as in Example 3. The resulting anion exchange membrane has a thickness of 156 μm and a resistivity of 4.6 Ω·cm. 2 .

[0080] The thickness, ion exchange capacity, tensile strength, water swelling rate, and organic solvent swelling rate of the prepared monovalent anion-selective anion exchange membrane were experimentally tested using national standard methods. The sheet resistance, transport number, and permeation selectivity of the ion exchange membrane were tested using a self-made apparatus. The results are shown in Table 1. (For specific testing methods, please refer to the literature reports: Journal of Membrane Science 574(2019)181–195; Journal of Membrane Science 577(2019)153–164).

[0081]

[0082] Table 1. Performance comparison of the anion exchange membranes prepared in Examples 1-12 and the commercial anion exchange membrane Neosepta ACS.

Claims

1. A method for preparing an anion exchange membrane that combines selectivity for monovalent anions and solvent resistance, comprising the following steps: Step (1) Take a certain amount of brominated polyphenylene ether (I), N-butylimidazolium (II), and polyethyleneimine (PEI) (III) respectively, and dissolve the brominated polyphenylene ether and polyethyleneimine in a certain amount of organic solvent to obtain a dilute solution of a certain concentration. (2) The solution of N-butylimidazole is added to the solution of brominated polyphenylene ether and reacted at 25-60℃ for 8-24 hours to obtain imidazole-functionalized brominated polyphenylene ether. Then, the solution of polyethyleneimine is added to the imidazole-functionalized brominated polyphenylene ether and stirred to react to obtain an imidazole-functionalized PEI blended brominated polyphenylene ether solution. The molar ratio of brominated polyphenylene ether, N-butylimidazole and polyethyleneimine is 1:0-0.44:0-0.

04. (3) The imidazole-functionalized PEI blend brominated polyphenylene ether casting solution obtained in step (2) is filtered to remove impurities, then vacuum degassed, and then cast onto a clean glass plate and dried at 80°C for 12-36 hours to obtain a homogeneous brominated polyphenylene ether anion exchange membrane.

2. The method for preparing anion exchange membrane with both monovalent anion selectivity and solvent resistance according to claim 1, characterized in that: One structure of the homogeneous brominated polyphenylene ether anion exchange membrane is shown below: The structure has X = 0, 0.01, 0.02, 0.03, 0.04; Y = 0.11, 0.22, 0.33, 0.

44.

3. The method for preparing anion exchange membrane with both monovalent anion selectivity and solvent resistance according to claim 1, characterized in that: In step (1), the N-butylimidazole, brominated polyphenylene ether, and polyethyleneimine are stirred in an organic solvent for 2-8 hours until completely dissolved.

4. The method for preparing anion exchange membrane with both monovalent anion selectivity and solvent resistance according to claim 1, characterized in that: In step (1), the organic solvent is one or more of dimethylformamide (DMF), dimethylacetamide (DMAc), and N-methylpyrrolidone (NMP).

5. The method for preparing anion exchange membrane with both monovalent anion selectivity and solvent resistance according to claim 1, characterized in that: In step (1), the N-butylimidazole has a purity of 99%, and the mass concentrations of the brominated polyphenylene ether and the polyethyleneimine solution are 6 wt% and 3 wt%, respectively.

6. The method for preparing anion exchange membrane with both monovalent anion selectivity and solvent resistance according to claim 1, characterized in that: Step (2) is carried out as follows: Take a certain amount of dissolved brominated polyphenylene ether solution into a round-bottom single-necked flask, add a certain amount of N-methylimidazole and stir until the reaction is complete, then add a certain amount of polyethyleneimine solution and stir on a magnetic stirrer. The resulting casting solution is filtered using a sand core funnel to remove impurities and dust, thus obtaining an imidazole-functionalized brominated polyphenylene ether solution.

7. The method for preparing anion exchange membrane with both monovalent anion selectivity and solvent resistance according to claim 6, characterized in that: In step (2), the reaction temperature of N-butylimidazole added to the brominated polyphenylene ether solution is 0-60℃ and the reaction time is 4-24 hours; the reaction temperature of polyethyleneimine added to the brominated polyphenylene ether solution is 0-60℃ and the reaction time is 1-24 hours.

8. The method for preparing anion exchange membrane with both monovalent anion selectivity and solvent resistance according to claim 1, characterized in that: Step (3) is carried out as follows: the casting solution is degassed under vacuum and then poured onto a clean glass plate, and then dried in a vacuum drying oven to finally obtain a homogeneous brominated polyphenylene ether anion exchange membrane.

9. The method for preparing anion exchange membrane with both monovalent anion selectivity and solvent resistance according to claim 8, characterized in that: In step (3), the drying conditions for the ion exchange membrane are set to vacuum drying at 80°C for 24 hours.

10. The method for preparing anion exchange membrane with both monovalent anion selectivity and solvent resistance according to claim 8, characterized in that: In step (3), the amount of casting solution poured into the glass plate is controlled so that the thickness of the homogeneous brominated polyphenylene ether anion exchange membrane is 80-160 μm.

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