Preparation method of anion exchange membrane for cross-chain transportation

Abstract

The invention relates to a preparation method of an anion exchange membrane for cross-chain transportation. The anion exchange membrane has the advantages of small resistance, high ion transmission rate and good desalting performance. Specifically, a crown ether structure is introduced, so that a direct and efficient ion transmission path is provided; the introduction of crown ether not only improves the chemical stability of the anion exchange membrane, so that the membrane can stably work in a wider chemical environment, but also enhances the ion selectivity; the crown ether structure is chemically modified, so that the properties of an ion channel can be further regulated and optimized, such as changing the size and shape of the channel or the characteristics of a functional group, so as to adapt to specific ion screening requirements. In addition, the anion exchange membrane also achieves a remarkable effect on optimization of transmittance and resistance. Due to the characteristics, the membrane material can show higher efficiency and reliability in various industrial applications.

Description

Technical Field

[0001] The invention relates to the field of membrane materials, in particular to a method for preparing a cross-chain transport anion exchange membrane. Background Art

[0002] Traditional anion exchange membrane technology, although playing a key role in multiple industrial and environmental fields, faces a series of technical challenges. One of the main issues is the efficiency and controllability of ion transmission. In the prior art, ions are usually transmitted through ion clusters formed on the side chains of polymers. The ion channels caused by this method are often tortuous and difficult to accurately control. The complexity of this structure makes the ion transmission process mainly exchange, which greatly reduces the efficiency of ions passing through the membrane and limits the performance of the membrane in high-efficiency ion separation applications.

[0003] In order to overcome these limitations and improve the functionality of ion exchange membranes, the present invention uses supramolecular responsive channels based on crown ether structures. Crown ethers, a type of cyclic supramolecular compound, can effectively enhance the cross-chain transport capacity of ions in the membrane due to its unique cavity structure. This structure provides a more direct and efficient ion transport path through the optimized configuration of its internal space. In addition, the crown ether unit is integrated into the polymer main chain, which increases the hydrophilicity of the main chain and enables the main chain to form a more direct connection with the functional groups on the side chain. This design improvement allows ions to no longer be transported through the separation of the gaps in the polymer main chain, but to be directly guided through the supramolecular responsive channels connected by the crown ether units, thereby achieving more efficient ion transport.

[0004] The introduction of crown ethers also brings significant improvements in chemical stability and ion selectivity to anion exchange membranes. In terms of chemical stability, the introduction of supramolecular structures enables the membrane to work stably in a wider range of chemical environments, greatly expanding its scope of application. In terms of ion selectivity, the cavity structure of crown ethers can specifically identify and transport ions of specific size and charge, which enables the membrane to show excellent performance in specific industrial applications, such as accurately removing or recovering specific ions in complex solutions.

[0005] In addition, by chemically modifying the crown ether structure, the properties of ion channels can be further regulated and optimized, such as changing the size, shape or characteristics of the functional groups of the channel to meet specific ion screening requirements. This flexible design can be applied to a wide range of applications, including water treatment, resource recovery, separation and purification of biopharmaceutical products, etc.

[0006] Through these supramolecular innovations, the performance of the anion exchange membrane of the present invention has surpassed traditional membrane materials in all aspects. The optimization of transmittance and resistance shows that this membrane material has made significant technological progress, not only with higher chemical stability and ion selectivity, but also with higher efficiency and reliability in various industrial applications. These technological advances not only demonstrate the huge application potential of supramolecular chemistry in membrane material science, but also provide a solid foundation for the development of future technologies and a wide range of practical applications. Summary of the invention

[0007] The object of the present invention is to provide a method for preparing an anion exchange membrane with low resistance, high ion transmission rate and good desalination performance.

[0008] In order to achieve the above-mentioned invention object, the present invention adopts the following technical scheme: A method for preparing an anion exchange membrane for cross-chain transport, the preparation method comprising the following steps: (1) First, take 3-5 g of biphenyl, 0.5-1 g of dibenzo-18-crown-6, and 4-5 mL of N-methylpiperidone and dissolve them in 5-20 mL of dichloromethane; (2) In an ice bath, add 1-3 mL of trifluoroacetic acid (TFA) at a constant rate, then add 10-33 mL of TFSA (trifluoromethanesulfonic acid), and continue the reaction for 3-5 hours. (3) pouring the viscous mixture obtained in step (2) into deionized water for elution, and then placing it in a vacuum drying oven at 60-80° C. for 10-24 hours to obtain a white polymer; (4) Take 0.5-1 g of the above white polymer and dissolve it in 10-15 mL of dimethyl sulfoxide (DMSO), add 1-3 mmol 1-bromobutane, react at 60-80 °C for 10-24 h, and then elute with ether to obtain a quaternized polymer; (5) Dissolve 0.5-1 g of the quaternized polymer in 10-15 mL of dimethyl sulfoxide (DMSO) to obtain a transparent solution; (6) Pour the above transparent solution onto a glass plate, place it in a vacuum drying oven, and dry it at 60-80 °C for 10-24 h to obtain an anion exchange membrane with cross-chain transport.

[0009] Furthermore, the dimethyl sulfoxide (DMSO) film casting solvent can be replaced by DMAC or DMF. Furthermore, the anion exchange membrane has a thickness of 80-110 μm.

[0010] Furthermore, in step (3), deionized water is poured in for elution 3 to 5 times to ensure that the residual solvent is completely washed away.

[0011] Compared with the prior art, the present invention has the following beneficial effects: The present invention relates to a method for preparing an anion exchange membrane for cross-chain transport. This method has many significant advantages based on existing materials and technologies, which are mainly reflected in the following aspects: (1) Efficient ion transport path By introducing the crown ether structure, the present invention provides a more direct and efficient ion transmission path. The cyclic supramolecular compound characteristics of the crown ether optimize its internal space and can effectively enhance the cross-chain ion transport capacity in the membrane. This design allows ions to be directly guided through supramolecular responsive channels, rather than the traditional transmission through the separation of the gaps in the polymer main chain, thereby achieving more efficient ion transmission.

[0012] (2) Improved chemical stability and ion selectivity The introduction of crown ethers not only improves the chemical stability of anion exchange membranes, allowing the membranes to work stably in a wider range of chemical environments, but also enhances ion selectivity. The cavity structure of crown ethers can specifically recognize and transport ions of specific size and charge, which has significant advantages for accurately removing or recovering specific ions in complex solutions.

[0013] (3) Flexible design and wide application By chemically modifying the crown ether structure, the properties of the ion channel can be further regulated and optimized, such as changing the size, shape or characteristics of the functional groups of the channel to meet specific ion screening requirements. This flexible design makes the membrane material suitable for a wide range of applications, including water treatment, resource recovery, and separation and purification of biopharmaceutical products.

[0014] (4) Significant technological progress The technical progress of the anion exchange membrane of the present invention is not only reflected in chemical stability and ion selectivity, but also has achieved remarkable results in the optimization of permeability and resistance. These characteristics enable the membrane material to show higher efficiency and reliability in various industrial applications. DETAILED DESCRIPTION

[0015] The technical solution of the present invention is further described below through specific embodiments, but the protection scope of the present invention is not limited thereto: Example 1 (1) First, take 4.2 g of biphenyl, 0.9 g of dibenzo-18-crown-6, and 4.1 mL of N-methylpiperidone and dissolve them in 10 mL of dichloromethane.

[0016] (2) In an ice bath, add 2 mL of trifluoroacetic acid (TFA) at a constant rate. Then add 25 mL of trifluoromethanesulfonic acid (TFSA). The reaction lasts for 4 hours.

[0017] (3) Pour the viscous mixture into deionized water for elution. Then place it in a vacuum drying oven and dry it at 80 °C for 24 h. A white polymer is obtained.

[0018] (4) Take 1 g of the above white polymer and dissolve it in 10 mL of dimethyl sulfoxide (DMSO), add 3 mmol of 1-bromobutane, and react at 80 °C for 12 h. Then elute with ether to obtain a quaternized polymer.

[0019] (5) Dissolve 1 g of the quaternized polymer in 15 mL of dimethyl sulfoxide (DMSO) to obtain a transparent solution.

[0020] (6) Pour the above transparent solution onto a glass plate and place it in a vacuum drying oven and dry it at 80 °C for 24 h. Finally, the anion exchange membrane AEM-1 was obtained.

[0021] Example 2 (1) First, take 4.05 g of biphenyl, 1.0 g of dibenzo-18-crown-6, and 4.1 mL of N-methylpiperidone and dissolve them in 10 mL of dichloromethane.

[0022] (2) In an ice bath, add 2 mL of trifluoroacetic acid (TFA) at a constant rate. Then add 25 mL of trifluoromethanesulfonic acid (TFSA). The reaction lasts for 4 hours.

[0023] (3) Pour the viscous mixture into deionized water for elution and then place it in a vacuum drying oven at 80 °C for 24 h.

[0024] A white polymer was obtained.

[0025] (4) Take 1 g of the above white polymer and dissolve it in 10 mL of dimethyl sulfoxide (DMSO), add 3 mmol of 1-bromobutane, and react at 80 °C for 12 h. Then elute with ether to obtain a quaternized polymer.

[0026] (5) Dissolve 1 g of the quaternized polymer in 15 mL of dimethyl sulfoxide (DMSO) to obtain a transparent solution.

[0027] (6) Pour the above transparent solution onto a glass plate and place it in a vacuum drying oven and dry it at 80 °C for 24 h. Finally, the anion exchange membrane AEM-2 was obtained.

[0028] Example 3 (1) First, take 3.85 g of biphenyl, 1.8 g of dibenzo-18-crown-6, and 4.1 mL of N-methylpiperidone and dissolve them in 10 mL of dichloromethane.

[0029] (2) In an ice bath, add 2 mL of trifluoroacetic acid (TFA) at a constant rate. Then add 25 mL of trifluoromethanesulfonic acid (TFSA). The reaction lasts for 4 hours.

[0030] (3) Pour the viscous mixture into deionized water for elution and then place it in a vacuum drying oven at 80 °C for 24 h.

[0031] A white polymer was obtained.

[0032] (4) Take 1 g of the above white polymer and dissolve it in 10 mL of dimethyl sulfoxide (DMSO), add 3 mmol of 1-bromobutane, and react at 80 °C for 12 h. Then elute with ether to obtain a quaternized polymer.

[0033] (5) Dissolve 1 g of the quaternized polymer in 15 mL of dimethyl sulfoxide (DMSO) to obtain a transparent solution.

[0034] (6) Pour the above transparent solution onto a glass plate and place it in a vacuum drying oven and dry it at 80 °C for 24 h. Finally, the anion exchange membrane AEM-3 was obtained.

[0035] The performance of the prepared anion exchange membrane with cross-chain transport function is tested below: Test 1: The prepared membrane was tested for resistance and compared with commercial quaternary ammonium type AMX and tertiary amine type ACM anion exchange membranes. See Table 1 for specific results.

[0036] Table 1: Surface resistance of the prepared membrane and two commercial membranes with different types of functional groups Test 2: The chemical stability of the prepared anion exchange membrane in sodium hydroxide solution was tested to investigate the chemical stability of the anion exchange membrane. The weight loss rate was used as an indicator and the weight difference was used as an indicator to evaluate its chemical stability. After being completely dried in a vacuum oven at 80°C for 24 hours, the weight of the sample was recorded. Then, the dried ion exchange membrane sample was soaked in a 2.0M sodium hydroxide solution at 80°C for 24 hours, 48 ​​hours, and 96 hours, and then the retained solution on the surface of the sample was carefully wiped, and the soaked membrane was washed with water until the water became neutral. Then, the ion exchange membrane sample was dried at 80°C under vacuum conditions for 24 hours, and then the membrane mass was re-weighed. The mass loss was used to characterize the alkali resistance stability. See Table 2 for specific results.

[0037] Table 2: Weight loss rate of membranes immersed in 2.0 mol / L sodium hydroxide solution at different time periods Test 3: Compare the water absorption rate of the prepared anion exchange membrane with that of AMX at different temperatures. After the tested membrane sample is completely dried in a vacuum drying oven at 80°C for 24 hours, the length of the membrane sample is recorded. Then, the dried ion exchange membrane sample is soaked in deionized water at 20°C, 30°C, and 40°C for 48 hours. Then, the retained solution on the surface of the sample is carefully wiped off, and the weight of the membrane sample is recorded. Calculate the weight change of the sample compared to the dry state. See Table 3 for specific results.

[0038] Table 3: Water absorption of samples and AMX at different temperatures Embodiments 1-3 are only preferred embodiments of the present invention, and are not intended to limit the present invention in any other form. Any person skilled in the art may use the above technical content as inspiration to change or modify the equivalent embodiments with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiments without departing from the technical essence of the claims of the present invention shall still fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing an anion exchange membrane for cross-chain transport, characterized in that: The preparation method comprises the following steps: (1) First, take 3-5 g of biphenyl, 0.5-1 g of dibenzo-18-crown-6, and 4-5 mL of N-methylpiperidone and dissolve them in 5-20 mL of dichloromethane; (2) In an ice bath, add 1-3 mL trifluoroacetic acid (TFA) at a constant rate, then add 10-33 mL TFSA (trifluoromethanesulfonic acid), and continue the reaction for 3-5 hours. (3) pouring the viscous mixture obtained in step (2) into deionized water for elution, and then placing it in a vacuum drying oven at 60-80° C. for 10-24 hours to obtain a white polymer; (4) Take 0.5-1 g of the above white polymer and dissolve it in 10-15 mL of dimethyl sulfoxide (DMSO), add 1-3 mmol of 1-bromobutane, react at 60-80 °C for 10-24 h, and then elute with ether to obtain a quaternized polymer; (5) Dissolve 0.5-1 g of the quaternized polymer in 10-15 mL of dimethyl sulfoxide (DMSO) to obtain a transparent solution; (6) Pour the above transparent solution onto a glass plate, place it in a vacuum drying oven, and dry it at 60-80 °C for 10-24 h to obtain an anion exchange membrane with cross-chain transport.

2. The method for preparing an anion exchange membrane for cross-chain transport according to claim 1, characterized in that: The dimethyl sulfoxide (DMSO) film casting solvent can be replaced by DMAC or DMF.

3. The method for preparing an anion exchange membrane for cross-chain transport according to claim 1, characterized in that: The thickness of the anion exchange membrane is 80-110 μm.

4. The method for preparing an anion exchange membrane for cross-chain transport according to claim 1, characterized in that: In the step (3), deionized water is poured in for 3 to 5 times to ensure that the residual solvent is completely washed away.

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