Polyamide acid ion exchange membrane, method for preparing the same, and use thereof

Abstract

The present application relates to polyamide acid ion exchange membrane, its preparation method and application. The weight average molecular weight of the polyamide acid ion exchange membrane of the present application is 2000-200000 g / mol, which contains the structure shown in formula I below, in formula I, X represents an aromatic ring or an aliphatic ring with 6-30 carbon atoms, Y represents an aromatic ring or an aliphatic ring with 6-30 carbon atoms; n represents an integer of 10-500. The polyamide acid ion exchange membrane of the present application has excellent mechanical properties, excellent power generation performance under salt concentration gradient, and can efficiently extract transition metal ions in seawater and wastewater.

Description

Technical Field

[0001] This invention relates to ion exchange membranes for reverse electrodialysis, and more specifically to ion exchange membranes for the extraction of transition metal ions from reverse electrodialysis, seawater, and wastewater, as well as their preparation methods and applications. Background Technology

[0002] To meet the ever-increasing energy demands, osmotic energy stored in salinity gradient solutions is considered a promising renewable energy source. Membrane-based reverse electrodialysis technology can be used to capture osmotic energy from seawater and river water, which can then be used to power large-scale capacitors and sodium-ion battery packs. Furthermore, significant technological breakthroughs have recently been achieved in direct seawater electrolysis for hydrogen production; the osmotic energy from seawater and river water can directly power seawater electrolysis, thus realizing a fully closed-loop green energy system. Meanwhile, seawater contains abundant transition metal ions, but their concentration is extremely low, making evaporation and crystallization extraction very difficult. Therefore, we can capture transition metal ions from seawater through other methods, and ion exchange membranes are a promising membrane material.

[0003] Currently, as the core component of reverse electrodialysis, traditional ion exchange membranes are limited in their ion transport capacity due to their high resistance, resulting in an output power density lower than that required for commercial use.

[0004] To achieve efficient permeation energy conversion, various types of membranes have been developed. For example, high-porosity hydrogels based on three-dimensional cross-linked networks, but their large pore size and tendency to swell severely weaken their ion selectivity, limiting their energy conversion properties.

[0005] In recent years, highly selective and efficient artificial nanochannel membranes that mimic biological ion channels, such as covalent organic frameworks (COF), metal-organic frameworks (MOF), MXenes, and graphene oxide, have been developed. However, ion-selective membranes prepared from these materials have at least one of the following problems: lack of self-support, difficulty in mass production, and low power density due to low charge density.

[0006] Therefore, how to develop ion exchange membranes that are self-supporting, can be mass-produced, are inexpensive, and have high salinity gradient power generation efficiency is an urgent problem to be solved in this field. Summary of the Invention

[0007] To address at least one of the aforementioned technical problems, the inventors conducted in-depth research and discovered that a self-supporting polyamic acid ion exchange membrane with in-situ carboxyl groups, containing two carboxyl groups in each amic acid structural unit, exhibits excellent ion selectivity and is particularly suitable for reverse electrodialysis applications. Furthermore, the negatively charged carboxyl groups on the polymer chains of the polyamic acid ion exchange membrane can attract transition metal ions, while the oxygen and nitrogen atoms on the polymer chains can coordinate with the transition metal ions, thereby immobilizing the transition metal ions onto the polymer chains. This enables low-cost and efficient extraction of transition metal ions from seawater and wastewater.

[0008] To achieve this objective, this application provides the following technical solution:

[0009] The first aspect of this application provides a polyamic acid ion exchange membrane with a weight-average molecular weight of 2000~200000 g / mol, which contains the structure shown in Formula I below.

[0010] I

[0011] In Formula I, X represents an aromatic or aliphatic ring with 6 to 30 carbon atoms, Y represents an aromatic or aliphatic ring with 6 to 30 carbon atoms, and n represents an integer from 10 to 500.

[0012] A second aspect of this application provides a method for preparing the aforementioned polyamic acid ion exchange membrane, comprising the following steps:

[0013] Polyamic acid solution preparation steps: Add dianhydride monomer and diamine monomer to an aprotic polar solvent to carry out a polymerization reaction to generate polyamic acid;

[0014] Membrane formation step: The polyamic acid solution obtained in the aforementioned polyamic acid solution preparation step is coated onto a glass plate to form a polyamic acid film, and then immersed in water to separate the polyamic acid film from the glass plate.

[0015] A third aspect of this application provides a reverse electrodialysis apparatus comprising the aforementioned polyamic acid ion exchange membrane.

[0016] A fourth aspect of this application provides an application of the aforementioned polyamic acid ion exchange membrane in reverse electrodialysis.

[0017] A fifth aspect of this application provides an application of the aforementioned polyamic acid ion exchange membrane for extracting transition metal ions from seawater and wastewater.

[0018] Compared to other membranes, the polyamic acid ion exchange membrane of this application contains a large number of charged carboxyl groups, resulting in high charge density, enabling it to select cations and repel anions. This polyamic acid ion exchange membrane exhibits excellent mechanical properties, is self-supporting, and demonstrates superior power generation performance under salinity gradients. Furthermore, the negatively charged carboxyl groups on the polymer chains of the polyamic acid ion exchange membrane can attract transition metal ions, while the oxygen and nitrogen atoms on the polymer chains can coordinate with these transition metal ions, thereby immobilizing them onto the polymer chains. This enables low-cost and high-efficiency extraction of transition metal ions from seawater and wastewater.

[0019] The preparation method of the amic acid ion exchange membrane of the present invention is simple, suitable for large-scale production, and low in cost. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a reverse electrodialysis device used in an embodiment of this application.

[0021] Figure 2 This is a power generation test graph of the polyamic acid ion exchange membrane prepared in Example 1 and the commercially available polymeric polyacrylonitrile (PAN) of Comparative Example 1 under a potassium chloride salinity gradient of 50 times.

[0022] Figure 3 The polyamic acid ion exchange membrane prepared in Example 1 adsorbs copper ions (Cu). 2+ After that, copper ions (Cu) were placed in water for different periods of time. 2+ Changes in content. Detailed Implementation

[0023] To better understand the present invention, the following detailed description is provided in conjunction with embodiments. However, the scope of protection of the present invention is not limited to the scope shown in the embodiments. Those skilled in the art should understand that the specific description below is illustrative rather than restrictive and should not be construed as limiting the scope of protection of this disclosure.

[0024] Unless otherwise specified, percentages in this manual refer to mass percentages, and temperatures are in degrees Celsius (°C).

[0025] [Polyamic acid ion exchange membrane]

[0026] The polyamic acid ion exchange membrane of the present invention has a weight-average molecular weight of 2000~200000 g / mol and contains the structure shown in Formula I below.

[0027] I

[0028] In Formula I, X represents an aromatic or aliphatic ring with 6 to 30 carbon atoms, Y represents an aromatic or aliphatic ring with 6 to 30 carbon atoms, and n represents an integer from 10 to 500.

[0029] The aforementioned polyamic acid ion exchange membranes with a weight-average molecular weight of 2000~200000 g / mol and containing the structure shown in Formula I possess self-supporting properties and exhibit excellent power generation performance under salinity gradients. Furthermore, due to the presence of charged groups in its structure, it can adsorb transition metal ions and form coordination structures with electron-donating elements in the membrane, thereby stably immobilizing transition metal ions on the membrane, which helps to achieve low-cost and efficient extraction of transition metal ions from seawater.

[0030] As for the aforementioned aromatic or aliphatic ring with 6 to 30 carbon atoms represented by X, examples include aromatic or aliphatic rings with 6, 7, 8, 9, 10, 11, 12, 13, 14 carbon atoms, etc., and more preferably aromatic or aliphatic rings with 6 to 12 carbon atoms.

[0031] As for the aforementioned aromatic or aliphatic ring with 6 to 30 carbon atoms represented by Y, examples include aromatic or aliphatic rings with 6, 7, 8, 9, 10, 11, 12, 13, 14 carbon atoms, etc., and more preferably aromatic or aliphatic rings with 6 to 12 carbon atoms.

[0032] The thickness of the polyamic acid ion exchange membrane can be adjusted according to requirements, and is preferably 3 μm or more from the perspective of better self-supporting performance. The thickness of the polyamic acid membrane is preferably less than 100 μm.

[0033] The aforementioned polyamic acid ion exchange membrane has a weight-average molecular weight of 2000~200000 g / mol, preferably 2000~50000, and more preferably 5000~20000. The aforementioned n represents an integer from 10 to 500, preferably 10~150, and more preferably 10~50.

[0034] Some embodiments of the polyamic acid ion exchange membrane are constructed from the structure shown in Formula I above.

[0035] I

[0036] In Formula I, X represents an aromatic or aliphatic ring with 6 to 30 carbon atoms, Y represents an aromatic or aliphatic ring with 6 to 30 carbon atoms, and n represents an integer from 10 to 500.

[0037] In some embodiments, the polyamic acid ion exchange membrane may optionally contain a structure of one or more compounds selected from polyimide, polyethylene glycol, polyvinyl alcohol, polyurethane, polyamide, polyacrylonitrile, polyether ether ketone, sulfonated polyether ether ketone, graphene oxide, graphene, MXene (Ti3C2Tx), MOF, and COF.

[0038] In some embodiments of the polyamic acid ion exchange membrane, it may optionally contain additives, such as polyvinyl alcohol, polyurethane, or polyamide, to improve the mechanical properties of the polyamic acid ion exchange membrane. Those skilled in the art can appropriately select the type and content of the aforementioned additives as needed, as long as they do not affect the self-support, ion selectivity, coordination ability, ion adsorption capacity, and other performance requirements of the polyamic acid ion exchange membrane for related applications.

[0039] Polyamic acid ion exchange membranes can be prepared by the method described below.

[0040] [Preparation method of polyamic acid ion exchange membrane]

[0041] The preparation method of polyamic acid ion exchange membrane includes the following steps:

[0042] Polyamic acid solution preparation steps: Add dianhydride monomer and diamine monomer to an aprotic polar solvent to carry out a polymerization reaction to generate polyamic acid;

[0043] Film formation step: The polyamic acid solution obtained in the aforementioned polyamic acid solution preparation step is coated onto the substrate to form a polyamic acid film, and then immersed in water to separate the polyamic acid film from the glass plate.

[0044] In the aforementioned method for preparing the polyamic acid ion exchange membrane, preferably, the aforementioned dianhydride is selected from 1,2,4,5-pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, trimellitic acid dianhydride, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid dianhydride, 3,3,4,4-benzophenone tetracarboxylic acid dianhydride, 3,3',4,4' One or more of the following groups: benzophenone tetracarboxylic dianhydride, 4,4'-oxobisphthalic anhydride, bis(3,4-dicarboxyphenyl)dimethylsilane dianhydride, 4,4-bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride, sulfonylphthalic anhydride, cyclobutane-1,2,3,4-tetracarboxylic dianhydride, 4,4'-(4,4'-isopropylidenediphenoxy)bis(phthalic anhydride), and 4,4'-(4,4'-isopropylidenediphenoxy)bis(phthalic anhydride). More preferably, the aforementioned dianhydride is selected from monomers shown in the following structural formulas:

[0045]

[0046] More preferably, it is one or more selected from the group consisting of 1,2,4,5-pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride and 4,4'-oxobisphthalic anhydride.

[0047] In the aforementioned method for preparing the polyamic acid ion exchange membrane, preferably, the diamine is selected from p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenyl ether, p-methylenediphenylamine, m-methylenediphenylamine, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, bis(trifluoromethyl)benzidine, 2,2'-bis[4(4-aminophenoxy)phenyl]hexafluoropropane, 2,2'-bis(3-aminophenyl)hexafluoropropane, 2,2'-bis( One or more of the group consisting of 4-aminophenyl)hexafluoropropane, bis(4-aminophenyl) sulfone, bis(3-aminophenyl) sulfone, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 2,2-bis[4-(4-aminophenoxy)-phenyl]propane, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, 4,4'-bis(3-aminophenoxy)diphenyl sulfone, 9,9-bis(4-aminophenyl)fluorene, and 9,9-bis(3-fluoro-4-aminophenyl)fluorene. More preferably, at least one or more selected from the group consisting of the following structures.

[0048]

[0049] More preferably, it is one or more selected from the group consisting of 4,4'-diaminodiphenyl ether, p-phenylenediamine and 1,3-bis(3-aminophenoxy)benzene.

[0050] The aprotic polar solvent used in the aforementioned polyamic acid solution preparation step is preferably one or more selected from the group consisting of dimethylacetamide, N-methylpyrrolidone, dimethylformamide, dimethyl sulfoxide, acetone, ethyl acetate, diethylformamide, diethylacetamide, propylene glycol monomethyl ether, m-methylphenol, tetrahydrofuran, and chloroform, and more preferably one or more selected from the group consisting of dimethylacetamide, N-methylpyrrolidone, and dimethylformamide.

[0051] In the aforementioned polyamic acid solution preparation step, polyamic acid is prepared by reacting dianhydride and diamine monomer in an aprotic polar solvent. The molar ratio of the diamine monomer to the dianhydride monomer is, for example, 0.9 to 1.1, preferably 1 to 1.05.

[0052] In the aforementioned polyamic acid solution preparation step, preferably, one or more compounds selected from polyimide, polyethylene glycol, polyvinyl alcohol, polyurethane, polyamide, polyacrylonitrile, polyetheretherketone, sulfonated polyetheretherketone, graphene oxide, graphene, MXene (Ti3C2Tx), MOF, and COF may be added to the aforementioned aprotic polar solvent. This allows for the creation of highly selective and efficient simulated biological ion channels, such as artificial nanochannel membranes, thereby improving the overall performance of the ion exchange membrane. When adding the above compounds, the amount of the added compounds is preferably 20 wt% or less relative to the total mass of the added dianhydride monomer and diamine monomer.

[0053] In the aforementioned polyamic acid solution preparation step, the reaction temperature of the aforementioned polymerization reaction is, for example, -10~40℃.

[0054] In one embodiment of the method for preparing a polyamic acid ion exchange membrane, the solid content of the polyamic acid obtained in the aforementioned polyamic acid solution preparation step is, for example, 5 to 30 wt%. Considering the self-supporting properties of the obtained polyamic acid ion exchange membrane, the solid content is preferably set to 5 wt% or more. On the other hand, considering the uniformity of the obtained polyamic acid ion exchange membrane, it is preferably set to 20 wt% or less.

[0055] In the aforementioned film formation step, the polyamic acid solution obtained in the aforementioned polyamic acid solution preparation step is coated onto a substrate to form a polyamic acid film, and then immersed in water to separate the polyamic acid film from the substrate. The aforementioned substrate is, for example, a glass plate. Preferably, the surface of the substrate in contact with the formed polyamic acid film is smooth, so that after immersion in water, the formed polyamic acid film will naturally separate from the substrate, thereby obtaining the polyamic acid film.

[0056] Furthermore, in the aforementioned film formation step, preferably, after the polyamic acid film is formed, the solvent is removed by heating at a temperature of, for example, 10~180°C, preferably 25~60°C.

[0057] The polyamic acid ion exchange membrane prepared by the above method exhibits excellent physicochemical stability and superior salinity gradient power generation performance under artificial river water and seawater concentration gradients. Furthermore, the polyamic acid ion exchange membrane of this application has low preparation cost, can be mass-produced, and is suitable for large-scale reverse electrodialysis salinity gradient power generation and the extraction of transition metal ions from seawater.

[0058] [Reverse Electrodialysis Device]

[0059] The reverse electrodialysis device includes the aforementioned polyamic acid ion exchange membrane, or includes a polyamic acid ion exchange membrane prepared by the aforementioned method for preparing polyamic acid ion exchange membranes.

[0060] In a reverse electrodialysis apparatus, in addition to the aforementioned polyamic acid ion exchange membrane used as the ion exchange membrane, components such as electrodes are also included. There are no particular limitations on the electrodes and other components; those skilled in the art can select them appropriately according to their needs.

[0061] Figure 1 A schematic diagram of a reverse electrodialysis device is shown. Figure 1 As shown, an ion-exchange membrane separates a high-concentration solution from a low-concentration solution. Silver / silver chloride electrodes are then inserted on both sides of the solution. Cations spontaneously transport from the high-concentration solution to the low-concentration solution, while anions in the high-concentration solution cannot pass through the ion-exchange membrane. Reverse electrodialysis can be used for salinity gradient power generation, extracting osmotic energy from seawater and river water to output electrical energy.

[0062] The aforementioned polyamic acid ion exchange membrane can be used in reverse electrodialysis applications.

[0063] Furthermore, the aforementioned polyamic acid ion exchange membrane can be used to extract transition metal ions from seawater and wastewater. These transition metal ions can be, for example, copper ions. In use, for instance, the polyamic acid ion exchange membrane is immersed in a 0.5M copper chloride solution for 12 hours, then removed and washed with water. The copper ion content in the polyamic acid ion exchange membrane is then tested. Finally, the membrane is placed in deionized water for different periods, and the copper ion content remains essentially unchanged, thus confirming that copper ions are enriched in the polyamic acid ion exchange membrane.

[0064] [Example]

[0065] To make the technical problems, technical solutions, and beneficial effects solved by this application clearer, the following will provide a more detailed description in conjunction with the embodiments and accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its applications. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0066] All materials used in the embodiments of this application are commercially available.

[0067] Example 1

[0068] 9.67 g of thoroughly dried 4,4'-diaminodiphenyl ether (ODA) was dissolved in 150 g of N,N-dimethylacetamide (DMAc). The solution was stirred at 10 °C until completely dissolved. Then, 10.76 g of 1,2,4,5-pyromellitic dianhydride was slowly added, and the mixture was stirred thoroughly for 24 hours to allow the reaction to proceed, yielding a polyamic acid solution with a solid content of 12%. The resulting polyamic acid solution was coated onto a glass plate, and then the glass plate was quickly (within 30 minutes) immersed in deionized water. The polyamic acid film 1 was naturally peeled off from the glass plate. The polyamic acid film 1 was then removed from the water and dried for later use.

[0069] Example 2

[0070] 11.86 g of fully dried 4,4'-diaminodiphenyl ether (ODA) was dissolved in 100 g of N,N-dimethylacetamide (DMAc) and stirred at 10 °C until completely dissolved. Then, 12.92 g of 1,2,4,5-pyromellitic dianhydride was slowly added and stirred thoroughly for 24 h to obtain a polyamic acid solution with a solid content of 20%. The obtained polyamic acid solution was coated onto a glass plate, which was then placed in an oven and dried at 45 °C for 6 h. The glass plate was then placed in water, and the polyamic acid film 2 was peeled off from the glass plate. The polyamic acid film 2 was removed from the water and dried for later use.

[0071] Example 3

[0072] 20g of thoroughly dried 2,2'-bis(4-aminophenyl)hexafluoropropane (6FBA) was dissolved in 150g of N,N-dimethylacetamide (DMAc). The solution was stirred at 10°C until completely dissolved. Then, 17.49g of 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) was slowly added and allowed to react completely. After stirring thoroughly for 24 hours, a polyamic acid solution with a solid content of 20% was obtained. The resulting polyamic acid solution was coated onto a glass plate, and then the glass plate was quickly (within 30 minutes) immersed in deionized water. The polyamic acid film 3 was peeled off from the glass plate and removed from the water to air dry for later use.

[0073] Example 4

[0074] 20g of thoroughly dried 2,2'-bis(4-aminophenyl)hexafluoropropane (6FBA) was dissolved in 150g of N,N-dimethylacetamide (DMAc). The solution was stirred at 10°C until completely dissolved. Then, 17.49g of 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) was slowly added and allowed to react completely. After stirring thoroughly for 24 hours, a polyamic acid solution with a solid content of 20% was obtained. The polyamic acid solution was coated onto a glass plate, which was then placed in an oven and dried at 45°C for 6 hours. The glass plate was then placed in water and allowed to detach naturally, yielding a polyamic acid film 4. The polyamic acid film 4 was removed from the water and dried for later use.

[0075] Example 5

[0076] 5.92 g of thoroughly dried p-phenylenediamine (PDA) was dissolved in 100 g of N,N-dimethylacetamide (DMAc). The solution was stirred at 10 °C until completely dissolved. Then, 11.71 g of 1,2,4,5-pyromellitic dianhydride was slowly added and allowed to react completely. After stirring thoroughly for 24 h, a polyamic acid solution with a solid content of 15% was obtained. The resulting polyamic acid solution was coated onto a glass plate, and then the glass plate was quickly (within 5 minutes) immersed in deionized water. The polyamic acid film 5 was peeled off the glass plate and removed from the water to air dry for later use.

[0077] Example 6

[0078] 5.92 g of fully dried p-phenylenediamine (PDA) was dissolved in 100 g of N,N-dimethylacetamide (DMAc) and stirred at 10 °C until completely dissolved. Then, 11.71 g of 1,2,4,5-pyromellitic dianhydride was slowly added and allowed to react completely. After stirring thoroughly for 24 h, a polyamic acid solution with a solid content of 15% was obtained. The obtained polyamic acid solution was coated onto a glass plate, which was then placed in an oven and dried at 40 °C for 6 h. The glass plate was then placed in water and allowed to detach naturally, yielding a polyamic acid film 6. The polyamic acid film 6 was removed from the water and dried for later use.

[0079] Example 7

[0080] 6.83 g of thoroughly dried 4,4'-diaminodiphenyl ether (ODA) was dissolved in 100 g of N,N-dimethylacetamide (DMAc). The solution was stirred at 10 °C until completely dissolved. Then, 10.81 g of 4,4'-oxydiphthalic anhydride (4,4'-ODPA) was slowly added and allowed to react completely. After stirring thoroughly for 24 h, a polyamic acid solution with a solid content of 15% was obtained. The resulting polyamic acid solution was coated onto a glass plate, and then the glass plate was quickly (within 5 minutes) immersed in deionized water. The polyamic acid film 7 was peeled off the glass plate and removed from the water to air dry for later use.

[0081] Example 8

[0082] 6.83 g of fully dried 4,4'-diaminodiphenyl ether (ODA) was dissolved in 100 g of N,N-dimethylacetamide (DMAc) and stirred at 10 °C until completely dissolved. Then, 10.81 g of 4,4'-oxydiphthalic anhydride (4,4'-ODPA) was slowly added and allowed to react completely. After stirring thoroughly for 24 h, a polyamic acid solution with a solid content of 15% was obtained. The obtained polyamic acid solution was coated onto a glass plate, which was then placed in an oven and dried at 40 °C for 6 h. The glass plate was then placed in water and allowed to detach naturally, yielding a polyamic acid film 8. The polyamic acid film 8 was removed from the water and dried for later use.

[0083] Example 9

[0084] 11.86 g of fully dried 4,4'-diaminodiphenyl ether (ODA) was dissolved in 100 g of N,N-dimethylacetamide (DMAc) and stirred at 10 °C. After complete dissolution, 12.92 g of 1,2,4,5-pyromellitic dianhydride was slowly added and stirred thoroughly for 24 h to obtain a polyamic acid solution with a solid content of 20%. PEG (molecular weight 4000) was dissolved in N,N-dimethylformamide (DMF) to prepare a 10% PEG solution. Then, 20 ml of the 20% polyamic acid solution and 10 ml of the 10% PEG solution were mixed and stirred. The resulting mixture was coated onto a glass plate, which was then placed in an oven and dried at 45 °C for 6 h. The glass plate was then placed in water, and the polyamic acid film 9 was peeled off. The polyamic acid film 9 was removed from the water and dried for later use.

[0085] Comparative Example 1

[0086] Commercially available polyacrylonitrile membranes (polyacrylonitrile membranes from Shenzhen Jiaquan Membrane Filtration Equipment Co., Ltd.) were used as Comparative Example 1.

[0087] Comparative test of salinity gradient power generation performance:

[0088] Using the polyamic acid membrane 1 prepared in Example 1 and the commercially available membrane of Comparative Example 1, their salinity gradient performance was tested using a Shanghai Chenhua electrochemical workstation (CHI660e) and a Shanghai Zhengyang Instruments ZX99 resistance box with different resistances. The test results are shown in [Figure / Table / Insert Table ... Figure 2 . Figure 2 In the diagram, the horizontal axis represents external resistance, and the vertical axis represents power density. From... Figure 2 It can be seen that the power density of the polyamic acid membrane in Example 1 is higher than that of the membrane in Comparative Example 1, indicating that the salinity gradient power generation performance of the polyamic acid membrane in Example 1 is stronger than that of Comparative Example 1.

[0089] Transition metal ion adsorption experiment:

[0090] The polyamic acid membrane 1 prepared in Example 1 was placed in a 0.5M copper chloride dihydrate (CuCl2·2H2O) solution for different times. The copper ion concentration (Cu) in the polyamic acid membrane 1 was then measured using a PerkinElmer NexION 300X inductively coupled plasma mass spectrometer. 2+ The content of ) is shown in Figure 3 From. Figure 3 It can be seen that copper ions can be well adsorbed on the polyamic acid membrane. When the membrane is placed in deionized water for different times, the copper ion concentration remains basically unchanged, indicating that copper ions can be stably adsorbed on the polyamic acid membrane.

[0091] Obviously, the above embodiments of this disclosure are merely examples for clearly illustrating this disclosure, and are not intended to limit the implementation of this disclosure. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all implementation methods here. Any obvious variations or modifications derived from the technical solutions of this disclosure are still within the protection scope of this disclosure.

Claims

1. An application of a polyamic acid ion exchange membrane in reverse electrodialysis, wherein, The polyamic acid ion exchange membrane has a weight-average molecular weight of 2000~200000 g / mol and contains the structure shown in Formula I below, formed by the reaction of dianhydride and diamine. I In Formula I, X represents an aromatic or aliphatic ring with 6 to 30 carbon atoms, Y represents an aromatic or aliphatic ring with 6 to 30 carbon atoms, and n represents an integer from 10 to 500.

2. The application according to claim 1, wherein, The polyamic acid ion exchange membrane further contains a structure derived from one or more compounds selected from polyimide, polyethylene glycol, polyvinyl alcohol, polyurethane, polyamide, polyacrylonitrile, polyether ether ketone, sulfonated polyether ether ketone, graphene oxide, graphene, MXene, MOF, and COF.

3. An application of a polyamic acid ion exchange membrane for extracting transition metal ions from seawater and wastewater, wherein, The polyamic acid ion exchange membrane has a weight-average molecular weight of 2000~200000 g / mol and contains the structure shown in Formula I below, formed by the reaction of dianhydride and diamine. I In Formula I, X represents an aromatic or aliphatic ring with 6 to 30 carbon atoms, Y represents an aromatic or aliphatic ring with 6 to 30 carbon atoms, and n represents an integer from 10 to 500.

4. The application according to claim 3, wherein, The polyamic acid ion exchange membrane further contains a structure derived from one or more compounds selected from polyimide, polyethylene glycol, polyvinyl alcohol, polyurethane, polyamide, polyacrylonitrile, polyether ether ketone, sulfonated polyether ether ketone, graphene oxide, graphene, MXene, MOF, and COF.

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