Bipolar membrane, electrodialysis device, preparation method and application

Abstract

The invention discloses a bipolar membrane, an electrodialysis device, a preparation method and application. The bipolar membrane comprises a cation exchange membrane, a middle layer and an anion exchange membrane which are sequentially stacked, and the middle layer comprises nitrogen-doped graphene oxide. The bipolar membrane provided by the invention has the advantages of high water dissociation efficiency, high acid and alkali production rate, low voltage required in the water dissociation process and low energy consumption.

Description

Technical Field

[0001] The present application belongs to the technical field of bipolar membranes, and specifically relates to a bipolar membrane, an electrodialysis device, a preparation method and an application. Background Art

[0002] Bipolar membrane is a new type of ion exchange composite membrane, which is usually composed of a cation exchange layer, an intermediate layer and an anion exchange layer. The intermediate layer is usually a few nanometers thick, electrically neutral and contains a catalyst. Under the action of a DC electric field, the intermediate layer of the bipolar membrane can dissociate water to produce H + and OH - Subsequently, the generated H + and OH - Driven by the potential difference between the cathode and anode, the bipolar membrane migrates to the cathode and anode respectively. At the same time, the water in the solution on both sides of the bipolar membrane enters the IL layer through the AEL and CEL to replenish the water consumption.

[0003] The bipolar membrane is the core component of the bipolar membrane electrodialysis device, and the performance of the bipolar membrane has a decisive influence on the bipolar membrane electrodialysis process. At present, the water dissociation efficiency of the bipolar membrane is low, and the water dissociation voltage and energy consumption are high. Summary of the invention

[0004] Aiming at the technical problems of low water dissociation efficiency, high water dissociation voltage and high energy consumption of existing bipolar membranes, a bipolar membrane, an electrodialysis device, a preparation method and application are provided.

[0005] In some embodiments, a bipolar membrane is provided, comprising a cation exchange membrane, an intermediate layer, and an anion exchange membrane stacked in sequence, wherein the intermediate layer comprises nitrogen-doped graphene oxide.

[0006] In some embodiments, the bipolar membrane satisfies one or more of the following characteristics:

[0007] The loading amount of nitrogen-doped graphene oxide contained in the intermediate layer is 0.2 mg / cm 2 ~1.0mg / cm 2 ;

[0008] The molar percentage of nitrogen in the nitrogen-doped graphene oxide contained in the intermediate layer is 4% to 5%;

[0009] The particle size of the nitrogen-doped graphene oxide contained in the intermediate layer is less than or equal to 0.054 mm.

[0010] In some embodiments, the bipolar membrane satisfies one or more of the following characteristics:

[0011] The cation exchange membrane comprises sulfonated polysulfone, and the sulfonation degree of the sulfonated polysulfone is 35% to 50%;

[0012] The anion exchange membrane comprises quaternized polysulfone, and the quaternization degree of the quaternized polysulfone is 40% to 50%.

[0013] In some embodiments, a method for preparing a bipolar membrane is provided, comprising the following steps:

[0014] The cation exchange membrane is prepared by forming a cation exchange membrane liquid on a substrate by a tape casting method;

[0015] Loading nitrogen-doped graphene oxide onto the cation exchange membrane to form an intermediate layer comprising the nitrogen-doped graphene oxide on the cation exchange membrane;

[0016] The anion exchange membrane liquid is cast onto the surface of the intermediate layer away from the cation exchange membrane, and dried to form an anion exchange membrane on the surface of the intermediate layer away from the cation exchange membrane, thereby preparing a bipolar membrane.

[0017] In some embodiments, in the method for preparing the bipolar membrane, the cation exchange membrane liquid comprises sulfonated polysulfone and a first organic solvent; the anion exchange membrane liquid comprises quaternized polysulfone and a second organic solvent;

[0018] In some embodiments, the method for preparing the bipolar membrane satisfies one or more of the following characteristics:

[0019] In the cation exchange membrane liquid, the ratio of the sulfonated polysulfone to the first organic solvent is 10 g: (50-75) mL, based on the feed amount;

[0020] In the anion exchange membrane solution, the ratio of the quaternized polysulfone to the second organic solvent is 10 g: (50-75) mL, based on the feed amount;

[0021] The first organic solvent and the second organic solvent each independently comprise one or more of dimethylformamide, dimethylacetamide and N-methylpyrrolidone;

[0022] The step of loading nitrogen-doped graphene oxide onto a cation exchange membrane comprises: mixing the nitrogen-doped graphene oxide with a third solvent to prepare an intermediate layer suspension, loading the intermediate layer suspension onto the cation exchange membrane, and performing a suction filtration process.

[0023] In some embodiments, in the method for preparing the bipolar membrane, the method for preparing the sulfonated polysulfone comprises the following steps:

[0024] In the presence of a fourth organic solvent, the first polysulfone is subjected to a sulfonation reaction with sulfuric acid, followed by alcohol precipitation and drying to prepare the sulfonated polysulfone;

[0025] Optionally, the method for preparing the sulfonated polysulfone satisfies one or more of the following characteristics:

[0026] According to the feed amount, the ratio of the first polysulfone to the sulfuric acid is 10 g: (2-10) mL;

[0027] According to the feeding amount, the ratio of the first polysulfone to the fourth organic solvent is 10g: (100-150)mL;

[0028] The weight average molecular weight of the first polysulfone is 30 kDa to 40 kDa, and the number average molecular weight of the first polysulfone is 20 kDa to 30 kDa;

[0029] The fourth organic solvent comprises one or more of ethylene dichloride, methylene dichloride and chloroform.

[0030] In some embodiments, in the method for preparing the bipolar membrane, the method for preparing the nitrogen-doped graphene oxide comprises the following steps:

[0031] Adding graphene oxide powder to ammonia water, stirring the obtained suspension, performing solid-liquid separation, washing, and drying to prepare nitrogen-doped graphene oxide with a particle size of less than or equal to 0.054 mm;

[0032] Optionally, the method for preparing nitrogen-doped graphene oxide satisfies one or more of the following characteristics:

[0033] Calculated by feeding amount, the volume mass ratio of the ammonia water to the graphene oxide is (0.8-2) mL / mg;

[0034] The concentration of the ammonia water is 0.2mol / L~0.3mol / L;

[0035] The obtained suspension is stirred at 30°C to 75°C;

[0036] The obtained suspension is subjected to a stirring step, wherein the stirring time is 4 h to 6 h;

[0037] The obtained suspension is subjected to a stirring step, and the stirring speed is 200 rpm-400 rpm.

[0038] In some embodiments, in the method for preparing the bipolar membrane, the method for preparing the quaternized polysulfone comprises the following steps:

[0039] In the presence of a fifth organic solvent, the second polysulfone is reacted with chloromethyl ethyl ether and anhydrous tin tetrachloride, followed by alcohol precipitation and drying to prepare chloromethylated polysulfone;

[0040] In the presence of a sixth organic solvent, reacting the chloromethylated polysulfone with triethylamine, performing alcohol precipitation, and drying to prepare the quaternized polysulfone;

[0041] Optionally, the preparation method of the quaternized polysulfone satisfies one or more of the following characteristics:

[0042] According to the feeding amount, the ratio of the second polysulfone to the fifth organic solvent is 10 g: (100-150) mL;

[0043] According to the feed amount, the ratio of the second polysulfone to the chloromethyl ether is 10 g: (5-10) mL;

[0044] According to the feed amount, the ratio of the second polysulfone to the anhydrous tin tetrachloride is 10 g: (1-2) mL;

[0045] According to the feeding amount, the ratio of the chloromethylated polysulfone to the sixth organic solvent is 5 g: (100-200) mL;

[0046] According to the feeding amount, the ratio of the chloromethylated polysulfone to the triethylamine solution is 5 g: (5-10) mL;

[0047] The weight average molecular weight of the second polysulfone is 30 kDa to 40 kDa, and the number average molecular weight of the second polysulfone is 20 kDa to 30 kDa;

[0048] The fifth organic solvent comprises one or more of ethylene dichloride, methylene dichloride and chloroform;

[0049] The sixth organic solvent includes one or more of N-methylpyrrolidone, N,N-dimethylformamide and N,N-dimethylacetamide.

[0050] In some embodiments, there is provided use of the bipolar membrane or the bipolar membrane prepared by the preparation method in water dissociation or in the preparation of an electrodialysis device.

[0051] In some embodiments, an electrodialysis device is provided, comprising the bipolar membrane described above or the bipolar membrane prepared by the preparation method described above.

[0052] The bipolar membrane provided above has high water dissociation efficiency, high acid and base production rate, low voltage required in the water dissociation process, and low energy consumption. The nitrogen-doped graphene oxide contained in the middle layer can increase the water dissociation rate and hydrophilicity of the middle layer, thereby reducing the transmembrane voltage. The preparation method of the bipolar membrane provided has a simple preparation process and can accurately control the content of the middle layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solutions in the implementation methods and examples of the present application and to more completely understand the present application and its beneficial effects, the following is a brief introduction to the drawings required for use in the description of the implementation methods or examples. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0054] Figure 1 is a schematic diagram of a process flow for preparing a bipolar membrane in one embodiment;

[0055] Figure 2 is a flow chart for preparing a bipolar membrane in one embodiment;

[0056] Figure 3 is a schematic diagram of a bipolar membrane in one embodiment;

[0057] Figure 4 is a graph showing the test results of the elemental types of nitrogen-doped graphene oxide prepared in Example 1 using an X-ray photoelectron spectroscopy (XPS), wherein Intensity is the relative intensity and Binding energy is the binding energy;

[0058] Figure 5 is a cross-sectional SEM schematic diagram of the bipolar membrane prepared in Example 1;

[0059] Figure 6 1 is a graph showing the test results of the bipolar membrane current-voltage performance of Example 1 and Comparative Example 1, wherein the blank sample is Comparative Example 1;

[0060] Figure 7 1 is a graph showing the bipolar membrane stability test results of Example 1 and Comparative Example 1, wherein the blank sample is Comparative Example 1;

[0061] Figure 8 It is a graph showing the test results of the acid-base generation performance of the bipolar membrane of Example 1 and Comparative Example 1, wherein the blank sample is Comparative Example 1. DETAILED DESCRIPTION

[0062] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0063] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0064] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0065] The terms "and / or", "or / and", and "and / or" used in this application include any one of two or more related listed items, and also include any and all combinations of related listed items, and the arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or", "or / and", and "and / or", it should be understood that in this application, the technical solution undoubtedly includes technical solutions that are all connected by "logical and", and undoubtedly includes technical solutions that are all connected by "logical or". For example, "A and / or B" includes three parallel solutions of A, B and "a combination of A and B".

[0066] In the present application, "plurality", "multiple", "multiple times", "multiples", etc., unless otherwise specified, refer to a number greater than 2 or equal to 2. For example, "one or more" means one or greater than or equal to two.

[0067] The terms "combination thereof", "any combination thereof", "any combination thereof" and the like used in this application include all suitable combinations of any two or more of the listed items.

[0068] In this application, the "suitable" mentioned in "suitable combination", "suitable method", "any suitable method", etc. is based on the ability to implement the technical solution of this application, solve the technical problems of this application, and achieve the expected technical effects of this application.

[0069] In the present application, "preferred", "better", "more preferred" and "suitable" are only used to describe implementation methods or examples with better effects. It should be understood that they do not constitute limitations on the scope of protection of the present application.

[0070] In the present application, "further", "further", "particularly" and the like are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of the present application.

[0071] In this application, "optionally", "optional", and "optional" mean optional or dispensable, that is, any one of the two parallel schemes of "yes" or "no". If multiple "options" appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent.

[0072] In the present invention, in the "first aspect", "second aspect", "third aspect", "fourth aspect", etc., the terms "first", "second", "third", "fourth", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0073] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0074] In the present application, when it comes to numerical intervals (i.e., numerical ranges), unless otherwise specified, the optional numerical distribution is considered continuous within the above numerical interval, and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical range, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to the integers within the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints. In this article, it is equivalent to directly listing each integer, such as t is an integer selected from 1 to 10, indicating that t is any integer selected from the group of integers consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10. In addition, when multiple ranges are provided to describe features or characteristics, these ranges can be combined. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all subranges included therein.

[0075] The temperature parameters in this application, unless otherwise specified, are allowed to be either constant temperature treatment or to vary within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuations within the range of ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are allowed.

[0076] In the present application, % (w / w) and wt% both represent weight percentage, % (v / v) refers to volume percentage, and % (w / v) refers to mass volume percentage.

[0077] The "room temperature" in this application generally refers to 5°C to 30°C, preferably 25±5°C.

[0078] The bipolar membrane is the core component of the bipolar membrane electrodialysis device, and the performance of the bipolar membrane has a decisive influence on the bipolar membrane electrodialysis process. The ideal bipolar membrane should have the characteristics of high selectivity, reduced voltage, low energy consumption, stable mechanical properties, and long service life.

[0079] The modification of bipolar membranes can be divided into modification of bipolar membrane materials and modification of the intermediate layer. Regardless of the modification method used, improving the water dissociation efficiency of the intermediate layer and reducing the water dissociation voltage and energy consumption of the bipolar membrane are the key to the current research and development of bipolar membranes.

[0080] In some embodiments, a bipolar membrane is provided, comprising a cation exchange membrane, an intermediate layer, and an anion exchange membrane stacked in sequence, wherein the intermediate layer comprises nitrogen-doped graphene oxide.

[0081] In some embodiments, the bipolar membrane provided has a nitrogen-doped graphene oxide loading of 0.2 mg / cm 2 ~1.0mg / cm 2 For example, the loading amount of nitrogen-doped graphene oxide is 0.2 mg / cm 2 , 0.3mg / cm 2 , 0.4mg / cm 2 , 0.5mg / cm 2 , 0.6mg / cm 2 , 0.7mg / cm 2 , 0.8mg / cm 2 , 0.9mg / cm 2 , 1.0mg / cm 2 Or selected from a range consisting of any two of the aforementioned ratios.

[0082] Too low a content of nitrogen-doped graphene oxide will result in a low content of hydrophilic groups in the bipolar membrane, which will lead to a slow water dissociation catalytic rate and poor bipolar membrane performance; while too much content will make the thickness of the intermediate layer thicker, resulting in a slow water dissociation catalytic rate and poor bipolar membrane performance.

[0083] In some embodiments, the molar percentage of nitrogen in the nitrogen-doped graphene oxide contained in the intermediate layer is 4% to 5%. For example, the molar percentage of nitrogen in the nitrogen-doped graphene oxide is 4%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, 5% or a range selected from any two of the foregoing ratios.

[0084] The nitrogen-doped graphene oxide used in the middle layer can not only increase the water dissociation rate and hydrophilicity of the middle layer, thereby reducing the transmembrane voltage, but also increase the acid and alkali production rate and reduce energy consumption.

[0085] In some embodiments, the particle size of the nitrogen-doped graphene oxide contained in the intermediate layer is less than or equal to 0.054 mm.

[0086] In some embodiments, a bipolar membrane is provided wherein the cation exchange membrane comprises sulfonated polysulfone.

[0087] In some embodiments, the sulfonated polysulfone contained in the cation exchange membrane has a sulfonation degree of 35% to 50%.

[0088] Without limitation, in some embodiments, the cation exchange membrane comprises a sulfonated polysulfone having a repeating unit as shown below: .

[0089] In some embodiments, a bipolar membrane is provided wherein the anion exchange membrane comprises a quaternized polysulfone.

[0090] In some embodiments, the quaternized polysulfone included in the anion exchange membrane has a quaternization degree of 40% to 50%.

[0091] Without limitation, in some embodiments, the anion exchange membrane comprises a quaternized polysulfone having a repeating unit as shown below:

[0092] .

[0093] In some embodiments, a method for preparing a bipolar membrane is provided, comprising the following steps:

[0094] The cation exchange membrane is prepared by forming a cation exchange membrane liquid on a substrate by a tape casting method;

[0095] loading nitrogen-doped graphene oxide onto a cation exchange membrane to form an intermediate layer comprising nitrogen-doped graphene oxide on the cation exchange membrane;

[0096] The anion exchange membrane liquid is cast onto the surface of the middle layer away from the cation exchange membrane, and dried to form an anion exchange membrane on the surface of the middle layer away from the cation exchange membrane, thereby preparing a bipolar membrane. Figure 1 .

[0097] Without limitation, the bipolar membrane preparation flow chart can be found in Figure 2 .

[0098] Figure 3 Schematic diagram of a bipolar membrane in one embodiment.

[0099] In some embodiments, the cation exchange membrane solution comprises sulfonated polysulfone and a first organic solvent.

[0100] In some embodiments, the anion exchange membrane solution comprises quaternized polysulfone and a second organic solvent.

[0101] In some embodiments, in the method for preparing a bipolar membrane provided, in the cation exchange membrane liquid, the ratio of sulfonated polysulfone to the first organic solvent is 10 g: (50~75) mL, for example, 10 g: 50 mL, 10 g: 55 mL, 10 g: 60 mL, 10 g: 65 mL, 10 g: 70 mL, 10 g: 75 mL or a range selected from any two of the foregoing ratios.

[0102] In some embodiments, in the method for preparing a bipolar membrane provided, in the anion exchange membrane liquid, the ratio of the quaternized polysulfone to the second organic solvent is 10:(50~75) in terms of feed amount, in g / mL, for example, 10g:50mL, 10g:55mL, 10g:60mL, 10g:65mL, 10g:70mL, 10g:75mL or a range selected from any two of the foregoing ratios.

[0103] In some embodiments, in the method for preparing a bipolar membrane provided, the first organic solvent and the second organic solvent each independently comprise one or more of dimethylformamide, dimethylacetamide and N-methylpyrrolidone.

[0104] In some embodiments, in the provided method for preparing a bipolar membrane, the step of loading nitrogen-doped graphene oxide onto a cation exchange membrane includes mixing the nitrogen-doped graphene oxide with a third solvent to prepare an intermediate layer suspension, loading the intermediate layer suspension onto the cation exchange membrane, and performing a suction filtration treatment.

[0105] In some embodiments, in the method for preparing a bipolar membrane provided, in the step of loading nitrogen-doped graphene oxide onto a cation exchange membrane, the third solvent comprises water.

[0106] In some embodiments, in the method for preparing a bipolar membrane provided, in the step of loading nitrogen-doped graphene oxide onto a cation exchange membrane, the ratio of nitrogen-doped graphene oxide to the third solvent is (2.5-12.5) mg:100 mL, based on the feed amount.

[0107] The middle layer is loaded onto the cation exchange membrane by filtration and is not easy to stratify. The added nitrogen-doped graphene oxide increases the active sites for water dissociation catalysis, accelerates the water dissociation process, greatly reduces the water dissociation voltage, and significantly improves the acid-base production performance.

[0108] In some embodiments, the volume ratio of the cation exchange membrane liquid to the anion exchange membrane liquid is 2:(1-3).

[0109] In some embodiments, in the method for preparing a bipolar membrane provided, the method for preparing sulfonated polysulfone comprises the following steps:

[0110] In the presence of a fourth organic solvent, the first polysulfone is subjected to a sulfonation reaction with sulfuric acid, followed by alcohol precipitation and drying to prepare a sulfonated polysulfone.

[0111] In some embodiments, the sulfonation reaction is carried out for 4 hours to 8 hours, for example, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours or a range selected from any two of the foregoing values. If the sulfonation reaction is carried out for too short a time, the polysulfone sulfonation degree will be too low, and the prepared bipolar membrane will have poor performance.

[0112] In some embodiments, in the preparation method of the bipolar membrane provided, in the preparation method of the sulfonated polysulfone, based on the feed amount, the ratio of the first polysulfone to the sulfuric acid is 10g: (2~10)mL, for example, 10g: 2mL, 10g: 3mL, 10g: 4mL, 10g: 5mL, 10g: 6mL, 10g: 7mL, 10g: 8mL, 10g: 9mL, 10g: 10mL or a range selected from any two of the foregoing ratios.

[0113] In some embodiments, in the preparation method of the bipolar membrane provided, in the preparation method of the sulfonated polysulfone, the ratio of the first polysulfone to the fourth organic solvent is 10g: (100~150)mL, for example, 10g: 100mL, 10g: 110mL, 10g: 120mL, 10g: 130mL, 10g: 140mL, 10g: 150mL or a range selected from any two of the foregoing ratios.

[0114] In some embodiments, in the method for preparing a bipolar membrane provided, in the method for preparing sulfonated polysulfone, the weight average molecular weight of the first polysulfone is 30 kDa-40 kDa, and the number average molecular weight of the first polysulfone is 20 kDa-30 kDa.

[0115] Without limitation, in some embodiments, the repeating unit of the first polysulfone is as follows: .

[0116] In some embodiments, in the method for preparing a bipolar membrane and the method for preparing a sulfonated polysulfone, the fourth organic solvent comprises one or more of dichloroethane, dichloromethane and chloroform.

[0117] In some embodiments, in the method for preparing a bipolar membrane provided, the method for preparing nitrogen-doped graphene oxide comprises the following steps:

[0118] The graphene oxide powder is added into ammonia water, and the obtained suspension is stirred, solid-liquid separated, washed, and dried to prepare nitrogen-doped graphene oxide with a particle size of less than or equal to 0.054 mm.

[0119] In a non-limiting manner, nitrogen-doped graphene oxide is prepared by a low temperature method. The above nitrogen-doped graphene oxide preparation method is simple, and the obtained nitrogen-doped graphene oxide has good stability and high water dissociation.

[0120] In some embodiments, in the preparation method of the provided bipolar membrane, in the preparation method of nitrogen-doped graphene oxide, the ratio of graphene oxide to ammonia water is (50~100) mg: (30~90) mL, calculated by the amount of feed, for example, 50 mg: 30 mL, 50 mg: 60 mL, 50 mg: 90 mL, 75 mg: 30 mL, 75 mg: 60 mL, 75 mg: 90 mL, 100 mg: 30 mL, 100 mg: 60 mL, 100 mg: 90 mL or a range selected from any two of the foregoing ratios.

[0121] In some embodiments, in the preparation method of the provided bipolar membrane, in the preparation method of nitrogen-doped graphene oxide, based on the feeding amount, the volume mass ratio of ammonia water to graphene oxide is (0.8~2.0) mL / mg, for example, 0.8 mL / mg, 0.9 mL / mg, 1.0 mL / mg, 1.1 mL / mg, 1.2 mL / mg, 1.3 mL / mg, 1.4 mL / mg, 1.5 mL / mg, 1.6 mL / mg, 1.7 mL / mg, 1.8 mL / mg, 1.9 mL / mg, 2.0 mL / mg or a range selected from any two of the foregoing values.

[0122] In some embodiments, in the provided bipolar membrane preparation method, in the nitrogen-doped graphene oxide preparation method, the concentration of ammonia water is 0.2 mol / L to 0.3 mol / L.

[0123] In some embodiments, in the provided bipolar membrane preparation method, in the nitrogen-doped graphene oxide preparation method, the obtained suspension is stirred at 30°C ~ 75°C in the stirring step, for example, at 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C or in a range selected from any two of the foregoing ratios.

[0124] In some embodiments, in the provided bipolar membrane preparation method, in the nitrogen-doped graphene oxide preparation method, the obtained suspension is stirred for a time of 4 h to 6 h, for example, the stirring time is 4 h, 5 h, 6 h or a range selected from any two of the foregoing ratios.

[0125] In some embodiments, in the provided bipolar membrane preparation method, in the nitrogen-doped graphene oxide preparation method, in the stirring step of the obtained suspension, the stirring speed is 200rpm-400rpm, for example, 200rpm, 250rpm, 300rpm, 350rpm, 400rpm or a range selected from any two of the foregoing ratios.

[0126] In some embodiments, in the method for preparing a bipolar membrane provided, the method for preparing quaternized polysulfone comprises the following steps:

[0127] In the presence of a fifth organic solvent, the second polysulfone is reacted with chloromethyl ethyl ether and anhydrous tin tetrachloride, followed by alcohol precipitation and drying to prepare chloromethylated polysulfone;

[0128] In the presence of a sixth organic solvent, the chloromethylated polysulfone is reacted with triethylamine, precipitated with alcohol, and dried to prepare the quaternary aminated polysulfone.

[0129] In some embodiments, the second polysulfone is reacted with chloromethyl ethyl ether and anhydrous tin tetrachloride for 2 hours to 4 hours, for example, 2 hours, 3 hours, or 4 hours.

[0130] In some embodiments, the reaction time of chloromethylated polysulfone and triethylamine is 20 hours to 30 hours, for example, 20 hours, 25 hours, 30 hours. When chloromethylated polysulfone is quaternized, too short a reaction time will result in a low degree of quaternization and poor performance of the prepared bipolar membrane.

[0131] In some embodiments, in the method for preparing a bipolar membrane provided, in the method for preparing a quaternized polysulfone, the ratio of the second polysulfone to the fifth organic solvent is 10 g: (100-150) mL, measured in g / mL, based on the feed amount, for example, 10 g: 100 mL, 10 g: 110 mL, 10 g: 120 mL, 10 g: 130 mL, 10 g: 140 mL, 10 g: 150 mL or a range selected from any two of the foregoing ratios.

[0132] In some embodiments, in the method for preparing a bipolar membrane provided, in the method for preparing a quaternized polysulfone, the ratio of the second polysulfone to chloromethyl ethyl ether is 10 g: (5-10) mL, calculated in g / mL, based on the feed amount, for example, 10 g: 5 mL, 10 g: 6 mL, 10 g: 7 mL, 10 g: 8 mL, 10 g: 9 mL, 10 g: 10 or a range selected from any two of the foregoing ratios.

[0133] In some embodiments, in the method for preparing a bipolar membrane provided, in the method for preparing a quaternized polysulfone, the ratio of the second polysulfone to anhydrous tin tetrachloride is 10 g: (1-2) mL, calculated in g / mL.

[0134] Without limitation, in some embodiments, in the method for preparing a bipolar membrane provided, in the method for preparing quaternized polysulfone, the repeating unit of the chloromethylated polysulfone is as follows: .

[0135] In some embodiments, in the method for preparing a bipolar membrane provided, in the method for preparing a quaternized polysulfone, based on the amount of feed, the ratio of chloromethylated polysulfone to the sixth organic solvent is 5 g: (100-200) mL, for example, 5 g: 100 mL, 5 g: 110 mL, 5 g: 120 mL, 5 g: 130 mL, 5 g: 140 mL, 5 g: 150 mL, 5 g: 160 mL, 5 g: 170 mL, 5 g: 180 mL, 5 g: 190 mL, 5 g: 200 mL or a range selected from any two of the foregoing ratios.

[0136] In some embodiments, in the method for preparing a bipolar membrane provided, in the method for preparing a quaternized polysulfone, the ratio of chloromethylated polysulfone to triethylamine solution is 5 g: (5-10) mL, for example, 5 g: 5 mL, 5 g: 6 mL, 5 g: 7 mL, 5 g: 8 mL, 5 g: 9 mL, 5 g: 10 mL, or a range selected from any two of the foregoing ratios.

[0137] In some embodiments, in the method for preparing a bipolar membrane provided, in the method for preparing quaternized polysulfone, the weight average molecular weight of the second polysulfone is 30 kDa-40 kDa, and the number average molecular weight of the second polysulfone is 20 kDa-30 kDa.

[0138] Without limitation, in some embodiments, the repeating unit of the second polysulfone is as follows: .

[0139] In some embodiments, in the method for preparing a bipolar membrane and the method for preparing a quaternized polysulfone, the fifth organic solvent comprises one or more of dichloroethane, dichloromethane and chloroform.

[0140] In some embodiments, in the method for preparing a bipolar membrane provided, in the method for preparing a quaternized polysulfone, the sixth organic solvent comprises one or more of N-methylpyrrolidone, N,N-dimethylformamide and N,N-dimethylacetamide.

[0141] The bipolar membrane prepared by the above method can increase the water dissociation rate and hydrophilicity of the middle layer, thereby reducing the transmembrane voltage and increasing the acid and alkali production rate; the bipolar membrane is prepared by the casting method, in which the casting amount of the middle layer can be precisely controlled, and the preparation process is simple. The nitrogen-doped graphene oxide used can not only increase the water dissociation rate and hydrophilicity of the middle layer, thereby reducing the transmembrane voltage, but also increase the acid and alkali production rate and reduce energy consumption.

[0142] In some embodiments, there is provided use of the aforementioned bipolar membrane or the bipolar membrane prepared by the aforementioned preparation method in water dissociation or in the preparation of an electrodialysis device.

[0143] In some embodiments, an electrodialysis device is provided, comprising the aforementioned bipolar membrane or the bipolar membrane prepared by the aforementioned preparation method.

[0144] The bipolar membrane or electrodialysis device provided above can be applied to high-salt water treatment to achieve a zero-discharge effect.

[0145] The present invention is further described below with reference to specific embodiments and comparative examples.

[0146] 1. Preparation of bipolar membrane

[0147] Example 1

[0148] (1) Preparation of sulfonated polysulfone: Take 10g of polysulfone, place it in a three-necked flask, add 100ml of dichloroethane, stir at 50℃ until dissolved, add 10ml of concentrated sulfuric acid, and react for 5h. After the reaction is completed, pour the reaction solution into ethanol to precipitate, and wash it repeatedly with pure water and ethanol, and dry it at 70℃ for 48h.

[0149] (2) Preparation of cation exchange membrane liquid: Take 2 g of dried sulfonated polysulfone powder, place it in a single-necked flask, add 10 ml of dimethylformamide solution, stir at 50°C until dissolved, and let it stand for 24 hours to degas.

[0150] (3) Preparation of nitrogen-doped graphene oxide: 50 mg of graphene oxide powder was added to 60 mL of 25% ammonia water, and the resulting suspension was magnetically stirred at 75°C until it became a muddy state. The precipitate was separated by high-speed centrifugation at 4200 r / min for 8 min, and was repeatedly washed three times with ethanol and distilled water to obtain a black solid, which was dried in a vacuum drying oven at 50°C. The dried product was ground into powder with an agate mortar and sieved with a standard test sieve (pore size d = 0.054 mm).

[0151] (4) Preparation of intermediate layer suspension: Take 5 mg of nitrogen-doped graphene oxide powder, place it in a beaker, add 100 ml of pure water, and stir vigorously to make it evenly dispersed.

[0152] (5) Preparation of chloromethylated polysulfone: Take 10g of polysulfone, place it in a three-necked flask, add 100ml of dichloroethane, stir at 50℃ until dissolved, add 5mL of chloromethyl ether and 1mL of anhydrous tin tetrachloride, and react for 2h. After the reaction is completed, pour the reaction solution into ethanol to precipitate, and wash it repeatedly with pure water and ethanol, and dry it at 70℃ for 48h.

[0153] (6) Preparation of quaternized polysulfone: Take 5g of chloromethylated polysulfone, place it in a three-necked flask, add 100mL of N-methylpyrrolidone, stir at 50℃ until dissolved, add 6mL of triethylamine solution, and react for 24h. After the reaction is completed, pour the reaction solution into ethanol to precipitate, and wash it repeatedly with pure water and ethanol, and dry it at 70℃ for 48h.

[0154] (7) Preparation of anion exchange membrane liquid: Take 2 g of dried quaternary ammonium polysulfone powder, place it in a single-necked flask, add 10 ml of dimethylformamide solution, stir at 50°C until dissolved, and let it stand for 24 hours to degas.

[0155] (8) Preparation of bipolar membrane: Take a clean glass plate, pour the cation exchange membrane liquid on the glass plate, scrape the membrane with a 200μm scraper, and heat it on a 70℃ heating plate for 3h. Immerse it in pure water and wait for the membrane to fall off naturally to obtain a cation exchange membrane. Take 50ml of the intermediate layer suspension and filter it onto the cation exchange membrane with a suction filter to obtain a cation exchange membrane containing an intermediate layer, where the effective area of ​​the intermediate layer is 12.56cm 2 The cation exchange membrane containing the intermediate layer was re-pasted onto the glass plate, and the anion exchange membrane liquid was cast thereon, which was then placed on a heating plate at 50° C. and heated for 3 h to obtain a bipolar membrane.

[0156] Example 2

[0157] The difference from Example 1 is that, in the preparation of the intermediate layer suspension, 2.5 mg of nitrogen-doped graphene oxide powder is taken and placed in a beaker, and 100 ml of pure water is added, and the mixture is stirred vigorously to make it evenly dispersed.

[0158] Example 3

[0159] The difference from Example 1 is that the intermediate layer suspension is prepared by taking 7.5 mg of nitrogen-doped graphene oxide powder, placing it in a beaker, adding 100 ml of pure water, and stirring vigorously to make it evenly dispersed.

[0160] Example 4

[0161] The difference from Example 1 is that the intermediate layer suspension is prepared by taking 10 mg of nitrogen-doped graphene oxide powder, placing it in a beaker, adding 100 ml of pure water, and stirring vigorously to make it evenly dispersed.

[0162] Example 5

[0163] The difference from Example 1 is that, in the preparation of the intermediate layer suspension, 12.5 mg of nitrogen-doped graphene oxide powder is taken and placed in a beaker, and 100 ml of pure water is added, and the mixture is stirred vigorously to make it evenly dispersed.

[0164] Example 6

[0165] The difference from Example 1 is that the preparation of sulfonated polysulfone is as follows: 10 g of polysulfone is placed in a three-necked flask, 100 ml of ethylene dichloride is added, and the mixture is stirred at 50°C until dissolved, 5 ml of concentrated sulfuric acid is added, and the mixture is reacted for 5 hours. After the reaction is completed, the reaction solution is poured into ethanol for precipitation, and the mixture is repeatedly washed with pure water and ethanol, and dried at 70°C for 48 hours.

[0166] Example 7

[0167] The difference from Example 1 is that the preparation of chloromethylated polysulfone is as follows: 10 g of polysulfone is placed in a three-necked flask, 100 ml of ethylene dichloride is added, and the mixture is stirred at 50°C until dissolved, 10 ml of chloroacetyl chloride and 2 ml of anhydrous tin tetrachloride are added, and the mixture is reacted for 2 hours. After the reaction is completed, the reaction solution is poured into ethanol for precipitation, and the mixture is repeatedly washed with pure water and ethanol, and dried at 70°C for 48 hours.

[0168] Example 8

[0169] The difference from Example 1 is that the preparation of quaternized polysulfone is as follows: 5 g of chloromethylated polysulfone is placed in a three-necked flask, 100 mL of N-methylpyrrolidone is added, and the mixture is stirred at 50° C. until dissolved, 3 mL of trimethylamine solution is added, and the mixture is reacted for 24 hours. After the reaction is completed, the reaction solution is poured into ethanol for precipitation, and the mixture is repeatedly washed with pure water and ethanol, and dried at 70° C. for 48 hours.

[0170] Comparative Example 1

[0171] The difference from Example 1 is that step (3) of preparing nitrogen-doped graphene oxide is not performed, and the preparation process of step (8) of bipolar membrane is as follows:

[0172] Take a clean glass plate, pour the cation exchange membrane liquid on the glass plate, scrape the membrane with a 200μm scraper, and heat it on a 70℃ heating plate for 3h, immerse it in pure water and wait for the membrane to fall off naturally, and the cation exchange membrane is obtained. Paste the cation exchange membrane to the glass plate, cast the anion exchange membrane liquid on it, and heat it on a 50℃ heating plate for 3h to obtain a bipolar membrane. That is, the prepared bipolar membrane does not contain an intermediate layer.

[0173] 2. Performance Test

[0174] (1) Qualitative test: An X-ray photoelectron spectrometer model NEXSA from Thermo Fisher, USA, was used to qualitatively detect the elemental composition of the material. In this test, the elements contained in the nitrogen-doped graphene oxide prepared in Example 1 were determined. The results are shown in Table 1. Figure 4 As shown. Figure 4 , it can be seen that nitrogen is successfully loaded onto graphene oxide.

[0175] (2) Quantitative test: An elemental analyzer model vario EI cube from Elimonta of Germany was used to analyze the content percentage of C, H, N, and S elements contained in the material. In this test, the CHNS mode was used to determine the molar content percentage of C, H, and N elements contained in the nitrogen-doped graphene oxide prepared in Example 1. The results are shown in Table 1.

[0176] Table 1 Molar content percentage of nitrogen-doped graphene oxide elements

[0177]

[0178] It can be seen from Table 1 that the N content of the nitrogen-doped graphene oxide prepared in Example 1 is 4.02%, the C content is 54.58%, and the H content is 3.44%.

[0179] (3) Appearance morphology test: The cross section of the bipolar membrane prepared in Example 1 was observed using a scanning electron microscope of the Gemini SEM500 model produced by Carl Zeiss, Germany. The specific operation was as follows: the bipolar membrane was taken out of the deionized water, dried, and a suitable amount of the membrane was cut and pasted on the conductive glue for gold spraying and observation. The results are shown in FIG. Figure 5 As shown by Figure 5 It can be seen that the prepared bipolar membrane has an obvious three-layer structure without stratification. The thickness of the cation exchange membrane layer is 80 μm, and the thickness of the anion exchange membrane layer is about 40 μm.

[0180] (4) Current-voltage curve test: The quadrupole system membrane stack (+ proton exchange membrane | bipolar membrane | proton exchange membrane | -) was connected to the electrochemical workstation, and the Linear Sweep Voltammetry Galvanostatic program was selected to test the bipolar membranes of Comparative Example 1 and Example 1. The electrode chamber and the acid-base chamber both used 1 mol / L sodium sulfate solution. During the test, the current increase rate was 2 mA / s, and the current test range was 0-0.2 A. The results are shown in Figure 1. Figure 6 As shown, the transmembrane voltage of the bipolar membranes of Comparative Example 1 and Example 1 gradually increases with the increase of current. 2 When the transmembrane voltage of comparative example 1 is 2.18 V, the transmembrane voltage of embodiment 1 is 0.98 V, which proves that using nitrogen-doped graphene oxide as the intermediate catalytic layer can effectively reduce the voltage required for water dissociation.

[0181] (5) Stability test: The quadrupole system membrane stack (+ proton exchange membrane | bipolar membrane | proton exchange membrane | -) was connected to the electrochemical workstation, and the Chrono Potentiometry program was selected to test the bipolar membranes of Comparative Example 1 and Example 1. The electrode chamber and the acid-base chamber both used 1 mol / L sodium sulfate solution. During the test, the current was set to 50 mA / cm 2 The test duration is 10 hours and the time interval is 20 seconds. Figure 7 As shown, during the test process lasting up to 10 hours, compared with Comparative Example 1, the voltage required for water dissociation of the bipolar membrane of Example 1 is more stable, indicating that the nitrogen-doped graphene oxide intermediate layer catalyst added in the present invention can effectively enhance the stability of the bipolar membrane, and the intermediate layer is tightly combined with the cation exchange membrane layer, avoiding the problem of increased water dissociation voltage caused by catalyst shedding.

[0182] (6) Acid-base performance test: The bipolar membranes of Comparative Example 1 and Example 1 were tested using a hexapolar chamber system membrane stack (+anion exchange membrane|cation exchange membrane|bipolar membrane|anion exchange membrane|cation exchange membrane|-). The electrode chamber, salt chamber, and acid-base chamber all used 1 mol / L sodium sulfate solution, and the current density was set to 50 mA / cm during the test. 2 The running time is 3 hours, and samples are taken every 30 minutes to determine the concentration of the acid-base chamber by acid-base titration. Figure 8 As shown, compared with Comparative Example 1, the acid-base chamber concentration of Example 1 is positively correlated with time, and is almost linear, that is, its acid-base production rate does not change significantly during the 3-hour operation. 2 At a current density of , after 3 hours, the acid and alkali concentration of Comparative Example 1 is about 0.08 mol / L, and the acid and alkali concentration of Example 1 can reach about 0.15 mol / L.

[0183] Combining all the above test results, it can be concluded that using nitrogen-doped graphene oxide as a catalyst in the middle layer of the bipolar membrane can significantly reduce the voltage required for water dissociation in the bipolar membrane, reduce energy consumption and improve acid and alkali production performance.

[0184] At the same current density (50mA / cm 2 ), the voltage required for water dissociation in comparative example 1 is 2.18V, and the acid and base concentration is 0.08mol / L; the voltage required for water dissociation in embodiment 1 is 0.98V, and the acid and base concentration is 0.15mol / L. And during the test process of up to 10h, compared with comparative example 1, the voltage required for water dissociation of the bipolar membrane of embodiment 1 can be stabilized between 0.98 and 1.10V.

[0185] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0186] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims, and the description and drawings may be used to interpret the content of the claims.

Claims

1. A bipolar membrane, characterized in that The invention comprises a cation exchange membrane, an intermediate layer and an anion exchange membrane which are stacked in sequence, wherein the intermediate layer comprises nitrogen-doped graphene oxide.

2. The bipolar membrane according to claim 1, characterized in that Meet one or more of the following characteristics: The loading amount of nitrogen-doped graphene oxide contained in the intermediate layer is 0.2 mg / cm 2 ~1.0mg / cm 2 ; The molar percentage of nitrogen in the nitrogen-doped graphene oxide contained in the intermediate layer is 4% to 5%; The particle size of the nitrogen-doped graphene oxide contained in the intermediate layer is less than or equal to 0.054 mm.

3. The bipolar membrane according to claim 1 or 2, characterized in that Meet one or more of the following characteristics: The cation exchange membrane comprises sulfonated polysulfone, and the sulfonation degree of the sulfonated polysulfone is 35% to 50%; The anion exchange membrane comprises quaternized polysulfone, and the quaternization degree of the quaternized polysulfone is 40% to 50%.

4. A method for preparing a bipolar membrane, characterized in that: The following steps are involved: The cation exchange membrane is prepared by forming a cation exchange membrane liquid on a substrate by a tape casting method; Loading nitrogen-doped graphene oxide onto the cation exchange membrane to form an intermediate layer comprising the nitrogen-doped graphene oxide on the cation exchange membrane; The anion exchange membrane liquid is cast onto the surface of the intermediate layer away from the cation exchange membrane, and dried to form an anion exchange membrane on the surface of the intermediate layer away from the cation exchange membrane, thereby preparing a bipolar membrane.

5. The preparation method according to claim 4, characterized in that: The cation exchange membrane liquid comprises sulfonated polysulfone and a first organic solvent; the anion exchange membrane liquid comprises quaternized polysulfone and a second organic solvent; The method for preparing the bipolar membrane satisfies one or more of the following characteristics: In the cation exchange membrane liquid, the ratio of the sulfonated polysulfone to the first organic solvent is 10 g: (50-75) mL, based on the feed amount; In the anion exchange membrane solution, the ratio of the quaternized polysulfone to the second organic solvent is 10 g: (50-75) mL, based on the feed amount; The first organic solvent and the second organic solvent each independently comprise one or more of dimethylformamide, dimethylacetamide and N-methylpyrrolidone; The step of loading nitrogen-doped graphene oxide onto a cation exchange membrane comprises: mixing the nitrogen-doped graphene oxide with a third solvent to prepare an intermediate layer suspension, loading the intermediate layer suspension onto the cation exchange membrane, and performing a suction filtration process.

6. The preparation method according to claim 4, characterized in that: The preparation method of the sulfonated polysulfone comprises the following steps: In the presence of a fourth organic solvent, the first polysulfone is subjected to a sulfonation reaction with sulfuric acid, followed by alcohol precipitation and drying to prepare the sulfonated polysulfone; Optionally, the method for preparing the sulfonated polysulfone satisfies one or more of the following characteristics: According to the feed amount, the ratio of the first polysulfone to the sulfuric acid is 10 g: (2-10) mL; According to the feeding amount, the ratio of the first polysulfone to the fourth organic solvent is 10g: (100-150)mL; The weight average molecular weight of the first polysulfone is 30 kDa to 40 kDa, and the number average molecular weight of the first polysulfone is 20 kDa to 30 kDa; The fourth organic solvent comprises one or more of ethylene dichloride, methylene dichloride and chloroform.

7. The preparation method according to any one of claims 4 to 6, characterized in that The preparation method of nitrogen-doped graphene oxide comprises the following steps: Adding graphene oxide powder to ammonia water, stirring the obtained suspension, performing solid-liquid separation, washing, and drying to prepare nitrogen-doped graphene oxide with a particle size of less than or equal to 0.054 mm; Optionally, the method for preparing nitrogen-doped graphene oxide satisfies one or more of the following characteristics: Calculated by feeding amount, the volume mass ratio of the ammonia water to the graphene oxide is (0.8-2.0) mL / mg; The concentration of the ammonia water is 0.2mol / L~0.3mol / L; The obtained suspension is stirred at 30°C to 75°C; The obtained suspension is subjected to a stirring step, wherein the stirring time is 4 h to 6 h; The obtained suspension is subjected to a stirring step, and the stirring speed is 200 rpm-400 rpm.

8. The preparation method according to any one of claims 4 to 7, characterized in that The preparation method of the quaternized polysulfone comprises the following steps: In the presence of a fifth organic solvent, the second polysulfone is reacted with chloromethyl ethyl ether and anhydrous tin tetrachloride, followed by alcohol precipitation and drying to prepare chloromethylated polysulfone; In the presence of a sixth organic solvent, reacting the chloromethylated polysulfone with triethylamine, performing alcohol precipitation, and drying to prepare the quaternized polysulfone; Optionally, the preparation method of the quaternized polysulfone satisfies one or more of the following characteristics: According to the feeding amount, the ratio of the second polysulfone to the fifth organic solvent is 10 g: (100-150) mL; According to the feed amount, the ratio of the second polysulfone to the chloromethyl ether is 10 g: (5-10) mL; According to the feed amount, the ratio of the second polysulfone to the anhydrous tin tetrachloride is 10 g: (1-2) mL; According to the feeding amount, the ratio of the chloromethylated polysulfone to the sixth organic solvent is 5 g: (100-200) mL; According to the feeding amount, the ratio of the chloromethylated polysulfone to the triethylamine solution is 5 g: (5-10) mL; The weight average molecular weight of the second polysulfone is 30 kDa to 40 kDa, and the number average molecular weight of the second polysulfone is 20 kDa to 30 kDa; The fifth organic solvent comprises one or more of ethylene dichloride, methylene dichloride and chloroform; The sixth organic solvent includes one or more of N-methylpyrrolidone, N,N-dimethylformamide and N,N-dimethylacetamide.

9. Use of the bipolar membrane according to any one of claims 1 to 3 or the bipolar membrane prepared by the preparation method according to any one of claims 4 to 8 in water dissociation or in the preparation of an electrodialysis device.

10. An electrodialysis device, characterized in that: The invention comprises the bipolar membrane according to any one of claims 1 to 3 or the bipolar membrane prepared by the preparation method according to any one of claims 4 to 8.

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