Ion exchange membrane, anti-pollution and scaling waste salt solution utilization device and application

Abstract

The present invention proposes an ion exchange membrane, a device for utilizing waste salt solution that is resistant to pollution and scaling, and its application, belonging to the technical field of waste salt resource processing. It comprises a bipolar membrane electrodialysis module disposed in an electrolytic cell, wherein the bipolar membrane electrodialysis module is provided with an anode plate and a cathode plate, and at least one bipolar membrane electrodialysis stack is provided between the anode plate and the cathode plate. The bipolar membrane electrodialysis stack comprises an anode-side mixed matrix bipolar membrane, a first screen, a composite anion exchange membrane, a second screen, a composite cation exchange membrane, a third screen, and a cathode-side mixed matrix bipolar membrane that are sequentially spaced. The device of the present invention treats waste salt solution to obtain purified acid and alkali, efficiently removing pollutants from the waste salt solution while converting salt into acid and alkali, thereby achieving high-value utilization of the waste salt solution. Furthermore, the mixed matrix bipolar membrane and the composite ion exchange membrane in the device have good anti-pollution performance, solving problems such as the difficulty in treating waste salt solution, low high-value utilization rate, and unstable device operation.

Description

Technical Field

[0001] The present invention relates to the technical field of waste salt resource treatment, and in particular to an ion exchange membrane, a waste salt solution utilization device resistant to pollution and scaling, and applications thereof. Background Art

[0002] The coal chemical and fine chemical industries generate a large amount of industrial waste salt each year. In addition to soluble salts, this waste salt also contains heavy metals, silicon compounds, and organic matter. Treating this waste salt as hazardous waste not only wastes salt resources but also incurs disposal costs. Therefore, recycling waste salt generated in industrial production, purifying and removing impurities before reuse in chemical production or manufacturing higher-value industrial products like soda ash and caustic soda, achieves waste salt recycling and has significant economic and social benefits.

[0003] At present, the main technologies used to treat waste salt or waste salt liquid are incineration, pyrolysis, ion exchange, high-temperature thermal oxidation, and evaporation crystallization. However, there are still problems such as immature technology, low and unstable impurity removal efficiency, poor product quality or low added value, and high treatment costs. The ever-increasing amount of industrial waste salt has become the biggest bottleneck for the development of related companies. In recent years, although membrane integration technology has been partially applied in high-salt wastewater resource projects, its large-scale application and promotion are limited by the stability of the treatment process under high-salt conditions, scaling and clogging of separation membranes, impurity enrichment problems, and pollution resistance of the equipment. Therefore, how to improve the efficiency of waste salt resource treatment and the high-value utilization rate of waste salt in an efficient and low-cost manner, enhance the pollution resistance of treatment equipment, reduce treatment costs, and improve product quality and equipment stability are key issues that need to be solved urgently. Summary of the Invention

[0004] (1) Technical issues to be resolved

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention proposes an ion exchange membrane, a waste salt liquid utilization device and its application that is resistant to pollution and scaling. The device has high efficiency in high-value treatment of waste salt liquid and good anti-pollution and scaling performance, and solves the problems of difficulty in waste salt liquid treatment and unstable operation of the device.

[0006] (2) Technical solution

[0007] In order to achieve the above objectives, the main technical solutions adopted by the present invention include:

[0008] In a first aspect, the present invention provides an ion exchange membrane, wherein the ion exchange membrane is a composite anion exchange membrane or a composite cation exchange membrane;

[0009] The composite anion exchange membrane comprises a mesh alloy electrode plate, one side of which is bonded with an anion exchange membrane layer by a scattered conductive adhesive; the anion exchange membrane layer is formed by an aminated polyphenylene ether membrane solution doped with carbon nanotubes; and the other side of the mesh alloy electrode plate is grafted with poly(3-sulfopropyl methacrylate) by in-situ free radical polymerization.

[0010] The composite cation exchange membrane includes a mesh steel electrode plate, one side of which is bonded with a cation exchange membrane layer by a scattered conductive adhesive, and the cation exchange membrane layer is formed by a sulfonated polyetheretherketone membrane liquid doped with carbon nanotubes; the other side of the mesh steel electrode plate is bonded with a polyamide layer by a scattered adhesive, and the polyamide layer is a polypiperazineamide polymer layer containing polyethyleneimine chelated calcium or polyethyleneimine, and poly(3-sulfonate propyl methacrylate) is grafted onto the polyamide layer by an in-situ free radical polymerization reaction.

[0011] In the composite anion exchange membrane of the present invention, poly(3-sulfonate propyl methacrylate) is grafted onto one side of the mesh alloy electrode, thereby effectively preventing the alloy electrode from being contaminated by impurities in the waste salt solution.

[0012] In the composite cation exchange membrane of the present invention, a polyamide layer is bonded to a mesh steel plate using an adhesive to prevent separation during use due to weak bonding between the steel plate and the polyamide layer. The positively charged polypiperazinamide polymer layer containing calcium chelate or polyethyleneimine effectively prevents multivalent cations from entering the alkaline solution chamber and causing scaling and clogging. Furthermore, the poly(3-sulfonate propyl methacrylate) effectively prevents organic pollutants from affecting the polypiperazinamide polymer layer and contaminating the steel plate.

[0013] Optionally, the mesh alloy electrode plate is a mesh aluminum-indium-magnesium alloy electrode plate; the mesh steel electrode plate is a mesh stainless steel electrode plate.

[0014] The aluminum-indium-magnesium alloy plate improves the electrochemical performance of the plate. Alloying can effectively promote the activation and dissolution of the passivation film on the electrode surface, thereby reducing system energy consumption and increasing the service life of the electrode. At the same time, the plate is mesh-shaped to ensure that ion transfer between compartments is not affected.

[0015] Optionally, the viscose is an imidazole cationic polyionic liquid having an alkoxy side chain; the anion of the polyionic liquid is one of tetrafluoroborate ion, hexafluorophosphate ion and bis(trifluoromethanesulfonyl imide) ion.

[0016] Optionally, the conductive adhesive is made of silver nanofiber material and imidazole cationic polyionic liquid with alkoxy side chains, and the silver nanofiber material accounts for 10wt%-30wt%. The anion of the polyionic liquid is one of tetrafluoroborate ion, hexafluorophosphate ion and bis(trifluoromethanesulfonyl imide) ion.

[0017] The conductive adhesive not only ensures that the ion exchange membrane layer does not peel off from the mesh plate during use, but also effectively improves the conductivity and avoids an increase in the energy consumption of the device.

[0018] Alternatively, the imidazolium cationic polyionic liquids with alkoxy side chains can be found in prior art such as CN110699020A. The introduction of alkoxy side chains not only significantly lowers the glass transition temperature of the polyionic liquid, but also allows the oxygen atoms themselves to act as hydrogen bond acceptors, generating strong hydrogen bonding within the ionic liquid. Combined with the unique electrostatic effects of the ionic liquid, these alkoxy polyionic liquids exhibit both high cohesive energy and interfacial adhesion. These adhesives exhibit strong adhesion to various substrates, such as stainless steel, aluminum alloys, and polymers.

[0019] Optionally, the carbon nanotube content in the carbon nanotube-doped aminated polyphenylene ether membrane liquid is 0.5wt%-10wt%; the carbon nanotube content in the carbon nanotube-doped sulfonated polyetheretherketone membrane liquid is 0.5wt%-10wt%. The anion exchange membrane layer is formed by spraying, brushing, or casting the carbon nanotube-doped aminated polyphenylene ether membrane liquid. The cation exchange membrane layer is formed by spraying, brushing, or casting the carbon nanotube-doped sulfonated polyetheretherketone membrane liquid. The incorporation of carbon nanotubes improves the internal network structure of the ion exchange membrane layer, increases conductivity, and effectively reduces surface resistance, thereby reducing operating energy consumption.

[0020] In a second aspect, the present invention provides a waste salt solution utilization device that is resistant to pollution and scaling, comprising a bipolar membrane electrodialysis module disposed in an electrolytic cell, wherein the bipolar membrane electrodialysis module is provided with an anode plate and a cathode plate, and at least one bipolar membrane electrodialysis membrane stack is provided between the anode plate and the cathode plate, wherein the bipolar membrane electrodialysis membrane stack comprises an anode-side mixed matrix bipolar membrane, a first spacer, the composite anion exchange membrane described in the first aspect, a second spacer, the composite cation exchange membrane described in the first aspect, a third spacer, and a cathode-side mixed matrix bipolar membrane, which are sequentially arranged at intervals; the anode-side mixed matrix bipolar membrane is disposed near the anode plate, and the cathode-side mixed matrix bipolar membrane is disposed near the cathode plate;

[0021] The anion exchange membrane layer in the composite anion exchange membrane is arranged close to the anode-side mixed matrix bipolar membrane, and the cation exchange membrane layer in the composite cation exchange membrane is arranged close to the cathode-side mixed matrix bipolar membrane.

[0022] Optionally, an acid solution chamber is located between the anode-side mixed matrix bipolar membrane and the composite anion exchange membrane, a salt solution chamber is located between the composite anion exchange membrane and the composite cation exchange membrane, and an alkaline solution chamber is located between the composite cation exchange membrane and the cathode-side mixed matrix bipolar membrane.

[0023] Optionally, the anode-side mixed matrix bipolar membrane and the cathode-side mixed matrix bipolar membrane both include a cation exchange layer and an anion exchange layer, the material of the cation exchange layer is sulfonated polyetheretherketone, and the material of the anion exchange layer is aminated polyphenylene ether; the cation exchange layer of the anode-side mixed matrix bipolar membrane and the anion exchange layer of the cathode-side mixed matrix bipolar membrane are both doped with activated carbon fibers, and the doping ratio of the activated carbon fibers is 0.1wt%-5wt%.

[0024] The anode-side mixed matrix bipolar membrane and the cathode-side mixed matrix bipolar membrane of the present invention are doped with activated carbon fibers, have excellent adsorption performance, and can further purify acid and alkali solutions.

[0025] In a third aspect, the present invention provides an application of a waste salt liquid utilization device that is resistant to pollution and scaling, which is used to treat industrial waste salt, wherein the sodium chloride content in the industrial waste salt is ≥90,000 mg / L, the silicon content is ≥75 mg / L, the heavy metal content is ≥56 mg / L, and the COD content is ≥180 mg / L.

[0026] (3) Beneficial effects

[0027] The beneficial effects of the present invention are:

[0028] 1. In the composite anion exchange membrane provided by the present invention, the aluminum-indium-magnesium alloy plate improves the electrochemical performance of the plate compared to aluminum plates, titanium alloy plates, stainless steel plates, etc., effectively promotes the activation and dissolution of the passivation film on the electrode surface, and at the same time, the plate is in a mesh shape to ensure that the ion transfer between compartments is not affected. The bonding layer of the meshed aluminum-indium-magnesium alloy plate can effectively prevent the ion exchange layer from peeling off from the alloy plate. The silver nanofiber material added to the bonding layer can further improve the conductivity of the bonding layer and avoid an increase in the energy consumption of the device operation. The present invention grafts poly (3-sulfonic acid propyl methacrylate) on the meshed alloy plate through atom transfer radical polymerization reaction, which can effectively prevent impurities in the waste salt solution from contaminating the alloy plate.

[0029] 2. In the composite cation exchange membrane provided by the present invention, the mesh stainless steel plate ensures that the ion transfer between compartments is not affected. The adhesive layer of the stainless steel plate prevents the ion exchange layer from peeling off from the plate. Adding silver nanofiber material to the adhesive on the side adjacent to the cation exchange membrane layer can further improve the conductivity of the adhesive layer and avoid an increase in the energy consumption of the device. The polyvinyl imine chelated calcium or polypiperazineamide polymer layer containing polyethyleneimine on the mesh stainless steel plate can effectively prevent multivalent cations from entering the alkaline solution chamber and causing scaling and clogging. Grafting poly (3-sulfonate propyl methacrylate) on the polyamide layer can effectively prevent impurities in the waste salt solution from contaminating the stainless steel plate.

[0030] 3. The anion exchange membrane layer and the cation exchange membrane layer of the present invention are doped with carbon nanotubes, which can improve the internal network structure of the ion exchange layer, effectively reduce the surface resistance, and thus reduce the energy consumption of the device operation.

[0031] 4. The pollution-resistant and scaling-resistant waste salt high-value utilization device provided by the present invention can efficiently remove pollutants in the waste salt solution while converting the salt into acids and bases with higher value, thereby realizing the high-value utilization of the waste salt solution. In addition, the mixed matrix bipolar membrane and the composite ion exchange membrane in the device have good pollution resistance, which solves the problems existing in the prior art such as the difficulty in treating the waste salt solution, the low high-value utilization rate and the unstable operation of the device.

[0032] 5. In the pollution-resistant and scaling-resistant waste salt high-value utilization device provided by the present invention, the activated carbon fiber doped in the mixed matrix bipolar membrane has excellent adsorption performance and can further purify acid and alkali solutions.

[0033] 6. The pollution-resistant and scaling-resistant waste salt high-value utilization device provided by the present invention has high treatment efficiency and high-value utilization rate for waste salt liquid. It can effectively remove pollutants while treating the waste salt liquid in a high-value manner, greatly improving product quality. In addition, the device has strong pollution-resistant and scaling-resistant performance, preventing the current efficiency of the device from being reduced due to impurity contamination in the waste salt liquid, thereby effectively reducing the processing energy consumption of the device and improving the processing stability of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic structural diagram of a waste salt solution utilization device that is resistant to pollution and scaling in an embodiment of the present invention.

[0035] Figure 2 for Figure 1 perspective drawing.

[0036] [Description of Reference Numerals]

[0037] 1: electrolytic cell; 2: anode plate; 3: cathode plate; 4: anode-side mixed matrix bipolar membrane; 5: first separator; 6: composite anion exchange membrane; 7: second separator; 8: composite cation exchange membrane; 9: third separator; 10: cathode-side mixed matrix bipolar membrane; 11: power supply. DETAILED DESCRIPTION

[0038] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific embodiments. Although exemplary embodiments of the present invention are shown below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0039] The following describes in detail the pollution-resistant and scaling-resistant waste salt high-value utilization device proposed in an embodiment of the present invention. The mixed matrix bipolar membrane (+) represents the mixed matrix bipolar membrane near the anode (i.e., the anode-side mixed matrix bipolar membrane), and the mixed matrix bipolar membrane (-) represents the mixed matrix bipolar membrane near the cathode (i.e., the cathode-side mixed matrix bipolar membrane).

[0040] The invention provides a device for high-value utilization of waste salt solution with an anti-fouling and scaling property, comprising a bipolar membrane electrodialysis module arranged in an electrolytic cell, wherein an anode plate and a cathode plate are provided in the bipolar membrane electrodialysis module, wherein a mixed matrix bipolar membrane (+), a first spacer, a composite anion exchange membrane, a second spacer, a composite cation exchange membrane, a third spacer, and a mixed matrix bipolar membrane (-) are sequentially arranged between the anode plate and the cathode plate from the side adjacent to the anode, an acid chamber is formed between the mixed matrix bipolar membrane (+) and the composite anion exchange membrane, a salt chamber is formed between the composite anion exchange membrane and the composite cation exchange membrane, and an alkaline chamber is formed between the composite cation exchange membrane and the mixed matrix bipolar membrane (-). The anode plate and the cathode plate are respectively externally connected to the positive and negative poles of a power supply.

[0041] The composite anion exchange membrane is prepared by spraying a conductive adhesive on the A surface of a mesh aluminum-indium-magnesium alloy plate (the indium content of the alloy plate is 0.05%-0.2%, and the magnesium content is 2.5%-6%) (conductive adhesive dots are provided at non-mesh locations, and the conductive adhesive dots occupy an area ratio of 1%-5% on the mesh aluminum-indium-magnesium alloy plate). The conductive adhesive comprises 10wt%-30wt% of a silver nanofiber material and 70wt%-90wt% of an imidazole cationic polyionic liquid with an alkoxy side chain. A mixture of carbon nanotubes and aminated polyphenylene ether is prepared by casting the membrane solution onto a conductive adhesive and drying the membrane to obtain an anion exchange membrane layer (thickness 0.1-0.2 mm; a thinner membrane layer is more likely to produce defects, while a thicker one increases membrane resistance, leading to increased power consumption during use). The membrane solution is a mixture of 0.5-10 wt% carbon nanotubes and 90-99.5 wt% aminated polyphenylene ether; poly(3-sulfopropyl methacrylate) is grafted onto the B surface of a meshed aluminum-indium-magnesium alloy electrode plate by atom transfer radical polymerization. The meshed aluminum-indium-magnesium alloy electrode plate has a side A adjacent to the anode and a side B adjacent to the anode.

[0042] The preparation method of the composite cation exchange membrane comprises the following steps: spraying a conductive glue on the surface A of a mesh stainless steel electrode plate (conductive glue dots are provided at non-mesh locations, and the conductive glue dots occupy an area ratio of 1% to 5% on the mesh stainless steel electrode plate); the conductive glue is a mixture of 10wt% to 30wt% of a silver nanofiber material and 70wt% to 90wt% of an imidazole cationic polyionic liquid with an alkoxy side chain; and then casting a membrane liquid onto the conductive glue. After drying, a cation exchange membrane layer is obtained (the thickness is 0.1 to 0.2 mm; if the thickness is too small, the membrane layer is prone to defects; if the thickness is too large, the membrane resistance will increase, resulting in increased power consumption during use). The membrane liquid is 0.5wt% to 10wt% of carbon nanotubes and 90wt% to 99.5wt% of a sulfonated poly A mixture of ether ether ketone; an imidazole-based cationic polyionic liquid with alkoxy side chains is randomly sprayed on the B surface of a mesh stainless steel electrode plate as a bonding layer (occupying 1%-5% of the electrode plate area), followed by a first interfacial polymerization reaction between trimesoyl chloride and piperazine. Polyethyleneimine is then added, and the polyethyleneimine undergoes a second interfacial polymerization reaction with the remaining acyl chloride groups from the first interfacial polymerization reaction to form a polyamide layer on the bonding layer (alternatively, a calcium salt and polyethyleneimine are complexed to form polyethyleneimine chelate calcium, followed by a polymerization reaction between trimesoyl chloride, piperazine, and polyethyleneimine chelate calcium to form a polyamide layer on the bonding layer). Poly(3-sulfopropyl methacrylate) is then grafted onto the polyamide layer via atom transfer radical polymerization. The side of the mesh stainless steel electrode plate closest to the cathode is designated as side A, and the other side is designated as side B.

[0043] Both the mixed matrix bipolar membrane (+) and the mixed matrix bipolar membrane (-) comprise a cation exchange layer and an anion exchange layer, wherein the cation exchange layer is made of sulfonated polyetheretherketone and the anion exchange layer is made of aminated polyphenylene ether. Furthermore, the present invention dopes 0.1 wt% to 5 wt% of activated carbon fiber into the cation exchange layer of the mixed matrix bipolar membrane (+) and the anion exchange layer of the mixed matrix bipolar membrane (-).

[0044] Waste salt solution with a sodium chloride content of 90,000 mg / L, a silicon content of 75 mg / L, a heavy metal content of 56 mg / L, and a COD content of 180 mg / L was injected into the above device for treatment at a current density of 10 mA / cm 2 The running time of the device pollution experiment is 12 h, and the current efficiency decay is expressed as the ratio of the difference between the initial current efficiency of the device and the instantaneous current efficiency to the initial current efficiency.

[0045] The following are application examples of the present invention.

[0046] The imidazole cationic polyionic liquid with alkoxy side chains in the following examples is polyvinyl imidazole bis(trifluoromethanesulfonyl imide) salt (PVImTFSI) with introduced alkoxy side chains. Specifically, PVImTFSI with alkoxy side chains is obtained by quaternization reaction of 2-ethoxyethyl chloride with polyvinyl imidazole (PVIm) and then anion exchange.

[0047]

[0048] Wherein, n=an integer of 100-300.

[0049] Example 1

[0050] In the present embodiment, the high-value utilization device of waste salt solution for resisting pollution and scaling comprises a bipolar membrane electrodialysis module arranged in an electrolyzer, wherein an anode and a cathode are provided in the bipolar membrane electrodialysis module, and a mixed matrix bipolar membrane (+), a screen, a composite anion exchange membrane, a screen, a composite cation exchange membrane, a screen, and a mixed matrix bipolar membrane (-) are sequentially provided between the anode and the cathode from one side adjacent to the anode, an acid chamber is formed between the mixed matrix bipolar membrane (+) and the composite anion exchange membrane, a salt chamber is formed between the composite anion exchange membrane and the composite cation exchange membrane, and an alkaline solution chamber is formed between the composite cation exchange membrane and the mixed matrix bipolar membrane (-). The anode plate and the cathode plate are respectively externally connected to the positive pole and the negative pole of the power supply.

[0051] The composite anion exchange membrane is prepared by randomly spraying a conductive adhesive on surface A of a meshed aluminum-indium-magnesium alloy electrode plate having an indium content of 0.05% and a magnesium content of 4% (conductive adhesive dots are provided in non-mesh areas, and the conductive adhesive dots occupy 1% of the area of the meshed aluminum-indium-magnesium alloy electrode plate). The conductive adhesive is a mixture of 30 wt% silver nanofiber material and 70 wt% imidazole cationic polyionic liquid with alkoxy side chains. A membrane liquid is then cast onto the conductive adhesive and dried to obtain an anion exchange membrane layer with a thickness of 0.1 mm. The membrane liquid is a mixture of 0.5 wt% carbon nanotubes and 99.5 wt% aminated polyphenylene ether. Poly(3-sulfopropyl methacrylate) is grafted onto surface B of the meshed aluminum-indium-magnesium alloy electrode plate by atom transfer radical polymerization. The side of the meshed aluminum-indium-magnesium alloy electrode plate closest to the anode is surface A, and the other side is surface B.

[0052] The preparation method of the composite cation exchange membrane comprises the following steps: spraying a conductive adhesive on the surface A of a mesh stainless steel electrode plate (conductive adhesive dots are provided at non-mesh locations, and the conductive adhesive dots occupy 1% of the area of the mesh stainless steel electrode plate). The conductive adhesive is a mixture of 30 wt% silver nanofiber material and 70 wt% imidazole cationic polyionic liquid with alkoxy side chains. The membrane liquid is then cast onto the conductive adhesive and dried to obtain a cation exchange membrane layer with a thickness of 0.1 mm. The membrane liquid is a mixture of 0.5 wt% carbon nanotubes and 99.5 wt% sulfonated polyionic liquid. A mixture of polyetheretherketone (PEEK) and imidazole-based cationic polyionic liquid with alkoxy side chains is randomly sprayed onto the mesh stainless steel electrode surface B as a bonding layer (occupying 1% of the electrode surface area). Trimesoyl chloride and piperazine undergo a first interfacial polymerization reaction. Polyethyleneimine is then added, and the polyethyleneimine undergoes a second interfacial polymerization reaction with the remaining acyl chloride groups from the first interfacial polymerization reaction to form a polyamide layer on the bonding layer. Poly(3-sulfopropyl methacrylate) is then grafted onto the polyamide layer via atom transfer radical polymerization. The mesh stainless steel electrode surface adjacent to the cathode is designated as surface A, and the other surface is designated as surface B.

[0053] The cation exchange layer of the mixed matrix bipolar membrane (+) and the anion exchange layer of the mixed matrix bipolar membrane (-) of this embodiment are both doped with 0.1 wt % of activated carbon fibers.

[0054] After the waste salt solution is treated by the above-mentioned anti-pollution and scaling waste salt high-value utilization device, the purity of the acid and alkali obtained is 98.7% and 98.3% respectively, the initial current efficiency is 87.6%, and the current efficiency decay is 10.5%.

[0055] Example 2

[0056] In the present embodiment, the high-value utilization device of waste salt solution for resisting pollution and scaling comprises a bipolar membrane electrodialysis module arranged in an electrolyzer, wherein an anode and a cathode are provided in the bipolar membrane electrodialysis module, and a mixed matrix bipolar membrane (+), a screen, a composite anion exchange membrane, a screen, a composite cation exchange membrane, a screen, and a mixed matrix bipolar membrane (-) are sequentially provided between the anode and the cathode from one side adjacent to the anode, an acid chamber is formed between the mixed matrix bipolar membrane (+) and the composite anion exchange membrane, a salt chamber is formed between the composite anion exchange membrane and the composite cation exchange membrane, and an alkaline solution chamber is formed between the composite cation exchange membrane and the mixed matrix bipolar membrane (-). The anode plate and the cathode plate are respectively externally connected to the positive pole and the negative pole of the power supply.

[0057] The composite anion exchange membrane is prepared by randomly spraying a conductive adhesive on the surface A of a meshed aluminum-indium-magnesium alloy electrode plate having an indium content of 0.2% and a magnesium content of 2.5% (conductive adhesive dots are provided in non-mesh areas, and the conductive adhesive dots occupy 5% of the area of the meshed aluminum-indium-magnesium alloy electrode plate). The conductive adhesive is a mixture of 10 wt% silver nanofiber material and 90 wt% imidazole cationic polyionic liquid with alkoxy side chains. A membrane liquid is then cast onto the conductive adhesive and dried to obtain an anion exchange membrane layer with a thickness of 0.2 mm. The membrane liquid is a mixture of 10 wt% carbon nanotubes and 90 wt% aminated polyphenylene ether. Poly(3-sulfopropyl methacrylate) is grafted onto the surface B of the meshed aluminum-indium-magnesium alloy electrode plate by atom transfer radical polymerization. The surface of the meshed aluminum-indium-magnesium alloy electrode plate adjacent to the anode is surface A, and the other surface is surface B.

[0058] The preparation method of the composite cation exchange membrane is as follows: a conductive glue is randomly sprayed on the surface A of the mesh stainless steel electrode plate (conductive glue dots are set at non-mesh areas, and the conductive glue dots occupy an area ratio of 5% on the mesh stainless steel electrode plate). The conductive glue is a mixture of 10wt% silver nanofiber material and 90wt% imidazole cationic polyionic liquid with alkoxy side chains. Then, a membrane liquid is cast on the conductive glue, and after drying, a cation exchange membrane layer with a thickness of 0.2mm is obtained. The membrane liquid is a mixture of 10wt% carbon nanotubes and 90wt% sulfonated polyionic liquid. A mixture of ether ether ketone; an imidazole-based cationic polyionic liquid with alkoxy side chains is randomly sprayed on the B surface of the mesh stainless steel electrode as a bonding layer (occupying 5% of the electrode area). Trimesoyl chloride and piperazine are subjected to a first interfacial polymerization reaction. Then, polyethyleneimine is added, and the polyethyleneimine undergoes a second interfacial polymerization reaction with the remaining acyl chloride groups from the first interfacial polymerization reaction to form a polyamide layer on the bonding layer. Poly(3-sulfopropyl methacrylate) is then grafted onto the polyamide layer via atom transfer radical polymerization. The side of the mesh stainless steel electrode closest to the cathode is designated as side A, and the other side is designated as side B.

[0059] The cation exchange layer of the mixed matrix bipolar membrane (+) and the anion exchange layer of the mixed matrix bipolar membrane (-) of this embodiment are both doped with 5 wt % of activated carbon fibers.

[0060] After the waste salt solution is treated by the above-mentioned anti-pollution and scaling waste salt high-value utilization device, the purity of the acid and alkali obtained is 97.6% and 98.5% respectively, the initial current efficiency is 86.9%, and the current efficiency decay is 11.4%.

[0061] Example 3

[0062] In the present embodiment, the high-value utilization device of waste salt solution for resisting pollution and scaling comprises a bipolar membrane electrodialysis module arranged in an electrolyzer, wherein an anode and a cathode are provided in the bipolar membrane electrodialysis module, and a mixed matrix bipolar membrane (+), a screen, a composite anion exchange membrane, a screen, a composite cation exchange membrane, a screen, and a mixed matrix bipolar membrane (-) are sequentially provided between the anode and the cathode from one side adjacent to the anode, an acid chamber is formed between the mixed matrix bipolar membrane (+) and the composite anion exchange membrane, a salt chamber is formed between the composite anion exchange membrane and the composite cation exchange membrane, and an alkaline solution chamber is formed between the composite cation exchange membrane and the mixed matrix bipolar membrane (-). The anode plate and the cathode plate are respectively externally connected to the positive pole and the negative pole of the power supply.

[0063] The composite anion exchange membrane is prepared by randomly spraying a conductive adhesive onto surface A of a meshed aluminum-indium-magnesium alloy electrode plate having an indium content of 0.08% and a magnesium content of 5% (conductive adhesive dots are provided at non-mesh locations, and the conductive adhesive dots occupy 3% of the area of the meshed aluminum-indium-magnesium alloy electrode plate). The conductive adhesive is a mixture of 15 wt% silver nanofiber material and 85 wt% imidazole cationic polyionic liquid with alkoxy side chains. A membrane solution is then cast onto the conductive adhesive and dried to obtain an anion exchange membrane layer with a thickness of 0.1 mm. The membrane solution is a mixture of 5 wt% carbon nanotubes and 95 wt% aminated polyphenylene ether. Poly(3-sulfopropyl methacrylate) is grafted onto surface B of the meshed aluminum-indium-magnesium alloy electrode plate by atom transfer radical polymerization. The side of the meshed aluminum-indium-magnesium alloy electrode plate closest to the anode is surface A, and the other side is surface B.

[0064] The preparation method of the composite cation exchange membrane is as follows: a conductive glue is randomly sprayed on the surface A of the mesh stainless steel electrode plate (conductive glue dots are set at non-mesh areas, and the conductive glue dots occupy an area ratio of 3% on the mesh stainless steel electrode plate). The conductive glue is a mixture of 25wt% silver nanofiber material and 75wt% imidazole cationic polyionic liquid with alkoxy side chains. Then, a membrane liquid is cast on the conductive glue and dried to obtain a cation exchange membrane layer with a thickness of 0.1mm. The membrane liquid is 5wt% carbon nanotubes and 95wt% sulfonated poly A mixture of ether ether ketone; an imidazole-based cationic polyionic liquid with alkoxy side chains is randomly sprayed on the B surface of the mesh stainless steel electrode as a bonding layer (occupying 3% of the electrode area). Trimesoyl chloride and piperazine are subjected to a first interfacial polymerization reaction. Polyethyleneimine is then added, and the polyethyleneimine undergoes a second interfacial polymerization reaction with the remaining acyl chloride groups from the first interfacial polymerization reaction to form a polyamide layer on the bonding layer. Poly(3-sulfopropyl methacrylate) is then grafted onto the polyamide layer via atom transfer radical polymerization. The side of the mesh stainless steel electrode closest to the cathode is designated as side A, and the other side is designated as side B.

[0065] The cation exchange layer of the mixed matrix bipolar membrane (+) and the anion exchange layer of the mixed matrix bipolar membrane (-) of this embodiment are doped with 2 wt % and 5 wt % of activated carbon fibers, respectively.

[0066] After the waste salt solution is treated by the above-mentioned anti-pollution and scaling waste salt high-value utilization device, the purity of the acid and alkali obtained is 98.1% and 98.6% respectively, the initial current efficiency is 88.3%, and the current efficiency decay is 9.9%.

[0067] Example 4

[0068] In the present embodiment, the high-value utilization device of waste salt solution for resisting pollution and scaling comprises a bipolar membrane electrodialysis module arranged in an electrolyzer, wherein an anode and a cathode are provided in the bipolar membrane electrodialysis module, and a mixed matrix bipolar membrane (+), a screen, a composite anion exchange membrane, a screen, a composite cation exchange membrane, a screen, and a mixed matrix bipolar membrane (-) are sequentially provided between the anode and the cathode from one side adjacent to the anode, an acid chamber is formed between the mixed matrix bipolar membrane (+) and the composite anion exchange membrane, a salt chamber is formed between the composite anion exchange membrane and the composite cation exchange membrane, and an alkaline solution chamber is formed between the composite cation exchange membrane and the mixed matrix bipolar membrane (-). The anode plate and the cathode plate are respectively externally connected to the positive pole and the negative pole of the power supply.

[0069] The composite anion exchange membrane is prepared by randomly spraying a conductive adhesive onto surface A of a meshed aluminum-indium-magnesium alloy electrode plate having an indium content of 0.1% and a magnesium content of 6% (conductive adhesive dots are provided at non-mesh locations, and the conductive adhesive dots occupy 1% of the area of the meshed aluminum-indium-magnesium alloy electrode plate). The conductive adhesive is a mixture of 25 wt% silver nanofiber material and 75 wt% imidazole cationic polyionic liquid with alkoxy side chains. A membrane solution is then cast onto the conductive adhesive and dried to obtain an anion exchange membrane layer with a thickness of 0.1 mm. The membrane solution is a mixture of 5 wt% carbon nanotubes and 95 wt% aminated polyphenylene ether. Poly(3-sulfopropyl methacrylate) is grafted onto surface B of the meshed aluminum-indium-magnesium alloy electrode plate by atom transfer radical polymerization. The side of the meshed aluminum-indium-magnesium alloy electrode plate closest to the anode is surface A, and the other side is surface B.

[0070] The composite cation exchange membrane is prepared by spraying a conductive adhesive on the surface A of a mesh stainless steel electrode plate (conductive adhesive dots are provided at non-mesh locations, and the conductive adhesive dots occupy 1% of the area of the mesh stainless steel electrode plate). The conductive adhesive is a mixture of 25 wt% silver nanofiber material and 75 wt% imidazole cationic polyionic liquid with alkoxy side chains. The membrane liquid is then cast onto the conductive adhesive and dried to obtain a cation exchange membrane layer with a thickness of 0.1 mm. The membrane liquid is 8 wt% carbon nanotubes and 92 wt% sulfonated polyether. A mixture of ether ketones; an imidazole-based cationic polyionic liquid with alkoxy side chains is randomly sprayed onto the B surface of the mesh stainless steel electrode as a bonding layer (occupying 1% of the electrode area). Trimesoyl chloride and piperazine are subjected to a first interfacial polymerization reaction. Polyethyleneimine is then added, and the polyethyleneimine undergoes a second interfacial polymerization reaction with the remaining acyl chloride groups from the first interfacial polymerization reaction to form a polyamide layer on the bonding layer. Poly(3-sulfopropyl methacrylate) is then grafted onto the polyamide layer via atom transfer radical polymerization. The side of the mesh stainless steel electrode closest to the cathode is designated as side A, and the other side is designated as side B.

[0071] The cation exchange layer of the mixed matrix bipolar membrane (+) and the anion exchange layer of the mixed matrix bipolar membrane (-) of this embodiment are both doped with 2 wt % of activated carbon fibers.

[0072] After the waste salt solution is treated by the above-mentioned anti-pollution and scaling waste salt high-value utilization device, the purity of the obtained acid and alkali are 97.9% and 97.6% respectively, the initial current efficiency is 87.4%, and the current efficiency decay is 12.2%.

[0073] Example 5

[0074] In the present embodiment, the high-value utilization device of waste salt solution for resisting pollution and scaling comprises a bipolar membrane electrodialysis module arranged in an electrolyzer, wherein an anode and a cathode are provided in the bipolar membrane electrodialysis module, and a mixed matrix bipolar membrane (+), a screen, a composite anion exchange membrane, a screen, a composite cation exchange membrane, a screen, and a mixed matrix bipolar membrane (-) are sequentially provided between the anode and the cathode from one side adjacent to the anode, an acid chamber is formed between the mixed matrix bipolar membrane (+) and the composite anion exchange membrane, a salt chamber is formed between the composite anion exchange membrane and the composite cation exchange membrane, and an alkaline solution chamber is formed between the composite cation exchange membrane and the mixed matrix bipolar membrane (-). The anode plate and the cathode plate are respectively externally connected to the positive pole and the negative pole of the power supply.

[0075] The composite anion exchange membrane is prepared by randomly spraying a conductive adhesive onto surface A of a meshed aluminum-indium-magnesium alloy electrode plate having an indium content of 0.15% and a magnesium content of 4.5% (conductive adhesive dots are provided at non-mesh locations, and the conductive adhesive dots occupy 1% of the area of the meshed aluminum-indium-magnesium alloy electrode plate). The conductive adhesive is a mixture of 20 wt% silver nanofiber material and 80 wt% imidazole cationic polyionic liquid with alkoxy side chains. A membrane solution is then cast onto the conductive adhesive and dried to obtain an anion exchange membrane layer with a thickness of 0.1 mm. The membrane solution is a mixture of 8 wt% carbon nanotubes and 92 wt% aminated polyphenylene ether. Poly(3-sulfopropyl methacrylate) is grafted onto surface B of the meshed aluminum-indium-magnesium alloy electrode plate by atom transfer radical polymerization. The side of the meshed aluminum-indium-magnesium alloy electrode plate closest to the anode is surface A, and the other side is surface B.

[0076] The preparation method of the composite cation exchange membrane is as follows: a conductive glue is randomly sprayed on the surface A of the mesh stainless steel electrode plate (conductive glue dots are set at non-mesh areas, and the conductive glue dots occupy an area ratio of 1% on the mesh stainless steel electrode plate). The conductive glue is a mixture of 20wt% silver nanofiber material and 80wt% imidazole cationic polyionic liquid with alkoxy side chains. Then, a membrane liquid is cast on the conductive glue and dried to obtain a cation exchange membrane layer with a thickness of 0.1mm. The membrane liquid is 8wt% carbon nanotubes and 92wt% sulfonated polyether ether. A mixture of ketones; an imidazole-based cationic polyionic liquid with alkoxy side chains is randomly sprayed on the B surface of the mesh stainless steel electrode as a bonding layer (occupying 1% of the electrode area), trimesoyl chloride and piperazine are subjected to a first interfacial polymerization reaction, and then polyethyleneimine is added. The polyethyleneimine undergoes a second interfacial polymerization reaction with the remaining acyl chloride groups from the first interfacial polymerization reaction to form a polyamide layer on the bonding layer. Poly(3-sulfopropyl methacrylate) is then grafted onto the polyamide layer via atom transfer radical polymerization. The side of the mesh stainless steel electrode closest to the cathode is designated as side A, and the other side is designated as side B.

[0077] The cation exchange layer of the mixed matrix bipolar membrane (+) and the anion exchange layer of the mixed matrix bipolar membrane (-) of this embodiment are both doped with 5 wt % of activated carbon fibers.

[0078] After the waste salt solution is treated by the above-mentioned anti-pollution and scaling waste salt high-value utilization device, the purity of the acid and alkali obtained is 98.5% and 98.8% respectively, the initial current efficiency is 89.1%, and the current efficiency decay is 9.6%.

[0079] Example 6

[0080] In the present embodiment, the high-value utilization device of waste salt solution for resisting pollution and scaling comprises a bipolar membrane electrodialysis module arranged in an electrolyzer, wherein an anode and a cathode are provided in the bipolar membrane electrodialysis module, and a mixed matrix bipolar membrane (+), a screen, a composite anion exchange membrane, a screen, a composite cation exchange membrane, a screen, and a mixed matrix bipolar membrane (-) are sequentially provided between the anode and the cathode from one side adjacent to the anode, an acid chamber is formed between the mixed matrix bipolar membrane (+) and the composite anion exchange membrane, a salt chamber is formed between the composite anion exchange membrane and the composite cation exchange membrane, and an alkaline solution chamber is formed between the composite cation exchange membrane and the mixed matrix bipolar membrane (-). The anode plate and the cathode plate are respectively externally connected to the positive pole and the negative pole of the power supply.

[0081] The composite anion exchange membrane is prepared by randomly spraying a conductive adhesive on surface A of a meshed aluminum-indium-magnesium alloy electrode plate having an indium content of 0.15% and a magnesium content of 4.5% (conductive adhesive dots are provided in non-mesh areas, and the conductive adhesive dots occupy 1% of the area of the meshed aluminum-indium-magnesium alloy electrode plate). The conductive adhesive is a mixture of 10 wt% silver nanofiber material and 90 wt% imidazole cationic polyionic liquid with alkoxy side chains. A membrane solution is then cast onto the conductive adhesive and dried to obtain an anion exchange membrane layer with a thickness of 0.1 mm. The membrane solution is a mixture of 10 wt% carbon nanotubes and 90 wt% aminated polyphenylene ether. Poly(3-sulfopropyl methacrylate) is grafted onto surface B of the meshed aluminum-indium-magnesium alloy electrode plate by atom transfer radical polymerization. The side of the meshed aluminum-indium-magnesium alloy electrode plate closest to the anode is surface A, and the other side is surface B.

[0082] The composite cation exchange membrane is prepared by spraying a conductive adhesive on the surface A of a mesh stainless steel electrode plate (conductive adhesive dots are provided at non-mesh locations, and the conductive adhesive dots occupy 1% of the area of the mesh stainless steel electrode plate). The conductive adhesive is a mixture of 30 wt% silver nanofiber material and 70 wt% imidazole cationic polyionic liquid with alkoxy side chains. The membrane liquid is then cast onto the conductive adhesive and dried to obtain a cation exchange membrane layer with a thickness of 0.1 mm. The membrane liquid is 5 wt% carbon nanotubes and 95 wt% sulfonated polyether. A mixture of ether ketones; an imidazole-based cationic polyionic liquid with alkoxy side chains is randomly sprayed onto the B surface of the mesh stainless steel electrode as a bonding layer (occupying 1% of the electrode area). Trimesoyl chloride and piperazine are subjected to a first interfacial polymerization reaction. Polyethyleneimine is then added, and the polyethyleneimine undergoes a second interfacial polymerization reaction with the remaining acyl chloride groups from the first interfacial polymerization reaction to form a polyamide layer on the bonding layer. Poly(3-sulfopropyl methacrylate) is then grafted onto the polyamide layer via atom transfer radical polymerization. The side of the mesh stainless steel electrode closest to the cathode is designated as side A, and the other side is designated as side B.

[0083] The cation exchange layer of the mixed matrix bipolar membrane (+) and the anion exchange layer of the mixed matrix bipolar membrane (-) of this embodiment are doped with 3 wt % and 1 wt % of activated carbon fibers, respectively.

[0084] After the waste salt solution is treated by the above-mentioned anti-pollution and scaling waste salt high-value utilization device, the purity of the acid and alkali obtained is 98.6% and 98.2% respectively, the initial current efficiency is 88.5%, and the current efficiency decay is 11.8%.

[0085] Comparative Example 1

[0086] In this comparative example, the waste salt solution high value utilization device of anti-pollution scaling, including the bipolar membrane electrodialysis group device arranged in the electrolyzer, the bipolar membrane electrodialysis group device is provided with anode and cathode, between anode and cathode, from adjacent anode side, mixed matrix type bipolar membrane (+), spacer, composite anion exchange membrane, spacer, composite cation exchange membrane, spacer, mixed matrix type bipolar membrane (-) are sequentially provided with, acid solution chamber is formed between mixed matrix type bipolar membrane (+) and composite anion exchange membrane, salt solution chamber is formed between composite anion exchange membrane and composite cation exchange membrane, alkali solution chamber is formed between composite cation exchange membrane and mixed matrix type bipolar membrane (-). Anode plate and cathode plate are externally connected to the positive pole and negative pole of power supply respectively.

[0087] The composite anion exchange membrane is prepared by randomly spraying a conductive adhesive onto surface A of a meshed aluminum-indium-magnesium alloy electrode plate having an indium content of 0.15% and a magnesium content of 4.5% (conductive adhesive dots are provided at non-mesh locations, and the conductive adhesive dots occupy 1% of the area of the meshed aluminum-indium-magnesium alloy electrode plate). The conductive adhesive is a mixture of 8 wt% silver nanofiber material and 92 wt% imidazole cationic polyionic liquid with alkoxy side chains. A membrane liquid is then cast onto the conductive adhesive and dried to obtain an anion exchange membrane layer with a thickness of 0.1 mm. The membrane liquid is a mixture of 0.4 wt% carbon nanotubes and 99.6 wt% aminated polyphenylene ether. Poly(3-sulfopropyl methacrylate) is grafted onto surface B of the meshed aluminum-indium-magnesium alloy electrode plate by atom transfer radical polymerization. The side of the meshed aluminum-indium-magnesium alloy electrode plate closest to the anode is surface A, and the other side is surface B.

[0088] The preparation method of the composite cation exchange membrane is as follows: a conductive glue is randomly sprayed on the surface A of the mesh stainless steel electrode plate (conductive glue dots are set at non-mesh areas, and the conductive glue dots occupy an area ratio of 1% on the mesh stainless steel electrode plate). The conductive glue is a mixture of 10wt% silver nanofiber material and 90wt% imidazole cationic polyionic liquid with alkoxy side chains. Then, a membrane liquid is cast on the conductive glue and dried to obtain a cation exchange membrane layer with a thickness of 0.1mm. The membrane liquid is 0.3wt% carbon nanotubes and 99.7wt% sulfonated A mixture of polyetheretherketone (PEEK) is used; an imidazole-based cationic polyionic liquid with alkoxy side chains is sprayed onto the mesh stainless steel electrode surface B as a bonding layer (occupying 1% of the electrode surface area). Trimesoyl chloride and piperazine are subjected to a first interfacial polymerization reaction. Polyethyleneimine is then added, and the polyethyleneimine undergoes a second interfacial polymerization reaction with the remaining acyl chloride groups from the first interfacial polymerization reaction to form a polyamide layer on the bonding layer. Poly(3-sulfopropyl methacrylate) is then grafted onto the polyamide layer via atom transfer radical polymerization. The mesh stainless steel electrode surface adjacent to the cathode is designated as surface A, and the other surface is designated as surface B.

[0089] The cation exchange layer of the mixed matrix bipolar membrane (+) and the anion exchange layer of the mixed matrix bipolar membrane (-) of this comparative example are both doped with 2 wt % of activated carbon fibers.

[0090] After the waste salt solution is treated by the above-mentioned anti-pollution and scaling waste salt high-value utilization device, the purity of the acid and alkali obtained is 96.1% and 95.6% respectively, the initial current efficiency is 76.3%, and the current efficiency decay is 25.1%.

[0091] Comparative Example 2

[0092] In this comparative example, the waste salt solution high value utilization device of anti-pollution scaling, including the bipolar membrane electrodialysis group device arranged in the electrolyzer, the bipolar membrane electrodialysis group device is provided with anode and cathode, between anode and cathode, from adjacent anode side, mixed matrix type bipolar membrane (+), spacer, composite anion exchange membrane, spacer, composite cation exchange membrane, spacer, mixed matrix type bipolar membrane (-) are sequentially provided with, acid solution chamber is formed between mixed matrix type bipolar membrane (+) and composite anion exchange membrane, salt solution chamber is formed between composite anion exchange membrane and composite cation exchange membrane, alkali solution chamber is formed between composite cation exchange membrane and mixed matrix type bipolar membrane (-). Anode plate and cathode plate are externally connected to the positive pole and negative pole of power supply respectively.

[0093] The composite anion exchange membrane is prepared by randomly spraying a conductive adhesive onto surface A of a meshed aluminum-indium-magnesium alloy electrode plate having an indium content of 0.15% and a magnesium content of 4.5% (conductive adhesive dots are provided at non-mesh locations, and the conductive adhesive dots occupy 1% of the area of the meshed aluminum-indium-magnesium alloy electrode plate). The conductive adhesive is a mixture of 35 wt% silver nanofiber material and 65 wt% imidazole cationic polyionic liquid with alkoxy side chains. A membrane solution is then cast onto the conductive adhesive and dried to obtain an anion exchange membrane layer with a thickness of 0.1 mm. The membrane solution is a mixture of 5 wt% carbon nanotubes and 95 wt% aminated polyphenylene ether. Poly(3-sulfopropyl methacrylate) is grafted onto surface B of the meshed aluminum-indium-magnesium alloy electrode plate by atom transfer radical polymerization. The side of the meshed aluminum-indium-magnesium alloy electrode plate closest to the anode is surface A, and the other side is surface B.

[0094] The composite cation exchange membrane is prepared by spraying a conductive adhesive on the surface A of a mesh stainless steel electrode plate (conductive adhesive dots are provided at non-mesh locations, and the conductive adhesive dots occupy 1% of the area of the mesh stainless steel electrode plate). The conductive adhesive is a mixture of 35 wt% silver nanofiber material and 65 wt% imidazole cationic polyionic liquid with alkoxy side chains. The membrane liquid is then cast onto the conductive adhesive and dried to obtain a cation exchange membrane layer with a thickness of 0.1 mm. The membrane liquid is 12 wt% carbon nanotubes and 88 wt% sulfonated polyether. A mixture of ether ketones; an imidazole-based cationic polyionic liquid with alkoxy side chains is randomly sprayed onto the B surface of the mesh stainless steel electrode as a bonding layer (occupying 1% of the electrode area). Trimesoyl chloride and piperazine are subjected to a first interfacial polymerization reaction. Polyethyleneimine is then added, and the polyethyleneimine undergoes a second interfacial polymerization reaction with the remaining acyl chloride groups from the first interfacial polymerization reaction to form a polyamide layer on the bonding layer. Poly(3-sulfopropyl methacrylate) is then grafted onto the polyamide layer via atom transfer radical polymerization. The side of the mesh stainless steel electrode closest to the cathode is designated as side A, and the other side is designated as side B.

[0095] The cation exchange layer of the mixed matrix bipolar membrane (+) and the anion exchange layer of the mixed matrix bipolar membrane (-) of this comparative example are both doped with 2 wt % of activated carbon fibers.

[0096] After the waste salt solution is treated by the above-mentioned anti-pollution and scaling waste salt high-value utilization device, the purity of the acid and alkali obtained is 94.7% and 95.3% respectively, the initial current efficiency is 78.1%, and the current efficiency decay is 19.6%.

[0097] Comparative Example 3

[0098] In this comparative example, the waste salt solution high value utilization device of anti-pollution scaling, including the bipolar membrane electrodialysis group device arranged in the electrolyzer, the bipolar membrane electrodialysis group device is provided with anode and cathode, between anode and cathode, from adjacent anode side, mixed matrix type bipolar membrane (+), spacer, composite anion exchange membrane, spacer, composite cation exchange membrane, spacer, mixed matrix type bipolar membrane (-) are sequentially provided with, acid solution chamber is formed between mixed matrix type bipolar membrane (+) and composite anion exchange membrane, salt solution chamber is formed between composite anion exchange membrane and composite cation exchange membrane, alkali solution chamber is formed between composite cation exchange membrane and mixed matrix type bipolar membrane (-). Anode plate and cathode plate are externally connected to the positive pole and negative pole of power supply respectively.

[0099] The composite anion exchange membrane is prepared by randomly spraying a conductive adhesive onto surface A of a meshed aluminum-indium-magnesium alloy electrode plate having an indium content of 0.08% and a magnesium content of 3.5% (conductive adhesive dots are provided at non-mesh locations, and the conductive adhesive dots occupy 1% of the area of the meshed aluminum-indium-magnesium alloy electrode plate). The conductive adhesive is a mixture of 15 wt% silver nanofiber material and 85 wt% imidazole cationic polyionic liquid with alkoxy side chains. A membrane solution is then cast onto the conductive adhesive and dried to obtain an anion exchange membrane layer with a thickness of 0.1 mm. The membrane solution is a mixture of 8 wt% carbon nanotubes and 92 wt% aminated polyphenylene ether. Poly(3-sulfopropyl methacrylate) is grafted onto surface B of the meshed aluminum-indium-magnesium alloy electrode plate by atom transfer radical polymerization. The side of the meshed aluminum-indium-magnesium alloy electrode plate closest to the anode is surface A, and the other side is surface B.

[0100] The composite cation exchange membrane is prepared by spraying a conductive adhesive on the surface A of a mesh stainless steel electrode plate (conductive adhesive dots are provided at non-mesh locations, and the conductive adhesive dots occupy 1% of the area of the mesh stainless steel electrode plate). The conductive adhesive is a mixture of 25 wt% silver nanofiber material and 85 wt% imidazole cationic polyionic liquid with alkoxy side chains. The membrane liquid is then cast onto the conductive adhesive and dried to obtain a cation exchange membrane layer with a thickness of 0.1 mm. The membrane liquid is 8 wt% carbon nanotubes and 92 wt% sulfonated polyether. A mixture of ether ketones; an imidazole-based cationic polyionic liquid with alkoxy side chains is randomly sprayed onto the B surface of the mesh stainless steel electrode as a bonding layer (occupying 1% of the electrode area). Trimesoyl chloride and piperazine are subjected to a first interfacial polymerization reaction. Polyethyleneimine is then added, and the polyethyleneimine undergoes a second interfacial polymerization reaction with the remaining acyl chloride groups from the first interfacial polymerization reaction to form a polyamide layer on the bonding layer. Poly(3-sulfopropyl methacrylate) is then grafted onto the polyamide layer via atom transfer radical polymerization. The side of the mesh stainless steel electrode closest to the cathode is designated as side A, and the other side is designated as side B.

[0101] The cation exchange layer of the mixed matrix bipolar membrane (+) and the anion exchange layer of the mixed matrix bipolar membrane (-) of this comparative example are both doped with 6 wt % of activated carbon fibers.

[0102] After the waste salt solution is treated by the above-mentioned anti-pollution and scaling waste salt high-value utilization device, the purity of the acid and alkali obtained is 89.4% and 88.6% respectively, the initial current efficiency is 82.5%, and the current efficiency decay is 28.4%.

[0103] Comparative Example 4

[0104] In this comparative example, the waste salt solution high value utilization device of anti-pollution scaling, including the bipolar membrane electrodialysis group device arranged in the electrolyzer, the bipolar membrane electrodialysis group device is provided with anode and cathode, between anode and cathode, from adjacent anode side, mixed matrix type bipolar membrane (+), spacer, composite anion exchange membrane, spacer, composite cation exchange membrane, spacer, mixed matrix type bipolar membrane (-) are sequentially provided with, acid solution chamber is formed between mixed matrix type bipolar membrane (+) and composite anion exchange membrane, salt solution chamber is formed between composite anion exchange membrane and composite cation exchange membrane, alkali solution chamber is formed between composite cation exchange membrane and mixed matrix type bipolar membrane (-). Anode plate and cathode plate are externally connected to the positive pole and negative pole of power supply respectively.

[0105] The composite anion exchange membrane is prepared by randomly spraying a conductive adhesive onto surface A of a meshed aluminum-indium-magnesium alloy electrode plate having an indium content of 0.08% and a magnesium content of 3.5% (conductive adhesive dots are provided at non-mesh locations, and the conductive adhesive dots occupy 1% of the area of the meshed aluminum-indium-magnesium alloy electrode plate). The conductive adhesive is a mixture of 25 wt% silver nanofiber material and 75 wt% imidazole cationic polyionic liquid with alkoxy side chains. A membrane solution is then cast onto the conductive adhesive and dried to obtain an anion exchange membrane layer with a thickness of 0.1 mm. The membrane solution is a mixture of 5 wt% carbon nanotubes and 95 wt% aminated polyphenylene ether. Poly(3-sulfopropyl methacrylate) is grafted onto surface B of the meshed aluminum-indium-magnesium alloy electrode plate by atom transfer radical polymerization. The side of the meshed aluminum-indium-magnesium alloy electrode plate closest to the anode is surface A, and the other side is surface B.

[0106] The composite cation exchange membrane is prepared by spraying a conductive adhesive on the surface A of a mesh stainless steel electrode plate (conductive adhesive dots are provided at non-mesh locations, and the conductive adhesive dots occupy 1% of the area of the mesh stainless steel electrode plate). The conductive adhesive is a mixture of 25wt% silver nanofiber material and 75wt% imidazole cationic polyionic liquid with alkoxy side chains. The membrane liquid is then cast onto the conductive adhesive and dried to obtain a cation exchange membrane layer with a thickness of 0.1mm. The membrane liquid is 5wt% carbon nanotubes and 95wt% sulfonated polyether. A mixture of ether ketones; an imidazole-based cationic polyionic liquid with alkoxy side chains is randomly sprayed onto the B surface of the mesh stainless steel electrode as a bonding layer (occupying 1% of the electrode area). Trimesoyl chloride and piperazine are subjected to a first interfacial polymerization reaction. Polyethyleneimine is then added, and the polyethyleneimine undergoes a second interfacial polymerization reaction with the remaining acyl chloride groups from the first interfacial polymerization reaction to form a polyamide layer on the bonding layer. Poly(3-sulfopropyl methacrylate) is then grafted onto the polyamide layer via atom transfer radical polymerization. The side of the mesh stainless steel electrode closest to the cathode is designated as side A, and the other side is designated as side B.

[0107] The cation exchange layer of the mixed matrix bipolar membrane (+) and the anion exchange layer of the mixed matrix bipolar membrane (-) of this comparative example were both doped with 0.05 wt % of activated carbon fibers.

[0108] After the waste salt solution is treated by the above-mentioned anti-pollution and scaling waste salt high-value utilization device, the purity of the obtained acid and alkali are 90.6% and 91.2% respectively, the initial current efficiency is 72.7%, and the current efficiency decay is 15.9%.

[0109] Comparative Example 5

[0110] Compared with Example 1, in the composite anion exchange membrane and composite cation exchange membrane of this comparative example, poly(3-sulfonate propyl methacrylate) was not grafted onto the aluminum-indium-magnesium alloy electrode plates.

[0111] After the waste salt solution is treated by the above-mentioned anti-pollution and scaling waste salt high-value utilization device, the purity of the acid and alkali obtained is 89.6% and 89.2% respectively, the initial current efficiency is 76.3%, and the current efficiency decay is 27.5%.

[0112] Comparative Example 6

[0113] Compared with Example 1, in the composite cation exchange membrane of this comparative example, no positively charged polyamide layer is provided on the stainless steel electrode plate, and the rest is the same as Example 1.

[0114] After the waste salt solution is treated by the above-mentioned anti-pollution and scaling waste salt high-value utilization device, the purity of the acid and alkali obtained is 87.9% and 88.3% respectively, the initial current efficiency is 82.1%, and the current efficiency decay is 29.7%.

[0115] Comparative Example 7

[0116] Compared with Example 1, the composite anion exchange membrane of this comparative example uses a mesh stainless steel plate as the electrode plate, and the rest is the same as Example 1.

[0117] After the waste salt solution is treated by the above-mentioned anti-pollution and scaling waste salt high-value utilization device, the purity of the acid and alkali obtained is 82.4% and 82.2% respectively, the initial current efficiency is 73.6%, and the current efficiency decay is 41.1%.

[0118] In summary, compared with the technical solution of the present invention, in Comparative Examples 1 and 2, the amount of silver nanofiber material added to the binder of the composite anion exchange membrane, and the amount of carbon nanotubes added to the anion exchange membrane layer and the cation exchange membrane layer will reduce the purity of the acid and alkali obtained after the waste salt solution is treated, reduce the initial current efficiency, and significantly reduce the current efficiency. Adding too little silver nanofiber material to the binder of the composite anion exchange membrane will increase the resistance and reduce the current efficiency. Under the same conditions, the impurity removal effect will also deteriorate, not only affecting the acid and alkali quality but also causing the current efficiency to decay. Adding too much will cause the bonding performance of the cation exchange membrane layer and the electrode plate to deteriorate or peel off, which will affect the treatment effect and current efficiency as it runs. Adding too little carbon nanotubes to the anion exchange membrane layer and the cation exchange membrane layer will not improve the conductivity of the membrane layer, and the current efficiency will therefore be reduced. Adding too much will cause membrane defects, resulting in reduced membrane ion permselectivity and impurity barrier performance, thereby significantly reducing the treatment effect and current efficiency.

[0119] In Comparative Examples 3 and 4, excessive or insufficient amounts of activated carbon fibers doped into the cation exchange layer of the mixed matrix bipolar membrane (+) and the anion exchange layer of the mixed matrix bipolar membrane (-) resulted in reduced acid and base purity, lower initial current efficiency, and significant current efficiency decay. Excessive doping of activated carbon fibers into the cation exchange layer of the mixed matrix bipolar membrane (+) and the anion exchange layer of the mixed matrix bipolar membrane (-) also resulted in membrane defects that severely impacted bipolar membrane performance, reducing acid and base purity and current efficiency. Excessive doping failed to reduce membrane resistance or enhance ion transport performance, resulting in reduced current efficiency.

[0120] In Comparative Example 5, the plates were not grafted with poly(3-sulfopropyl methacrylate), which could contaminate the plates with impurities from the waste brine. In Comparative Example 6, the plates were not coated with a positively charged polyamide layer, and the multivalent cations generated during the electrolysis process could enter the lye chamber, causing scaling and clogging. Both Comparative Examples 5 and 6 resulted in reduced purity of the resulting acid and base. Contamination of the plates or lye chamber also resulted in poor electrolysis performance and increased current efficiency.

[0121] The composite anion exchange membrane of Comparative Example 7 uses a mesh stainless steel plate as the electrode plate. Through data comparison, it can be seen that the mesh aluminum-indium-magnesium alloy electrode plate selected in this application can significantly improve the electrolysis efficiency.

[0122] It should be understood that the above description of the specific embodiments of the present invention is merely illustrative of the technical features of the present invention and is intended to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. However, the present invention is not limited to the above-described specific embodiments. Any changes or modifications made within the scope of the claims of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. An ion exchange membrane, characterized in that The ion exchange membrane is a composite anion exchange membrane or a composite cation exchange membrane; The composite anion exchange membrane comprises a mesh alloy electrode plate, one side of which is bonded with an anion exchange membrane layer by a scattered conductive adhesive; the anion exchange membrane layer is formed by an aminated polyphenylene ether membrane solution doped with carbon nanotubes; and the other side of the mesh alloy electrode plate is grafted with poly(3-sulfopropyl methacrylate) by in-situ free radical polymerization. The composite cation exchange membrane includes a mesh steel plate, one side of which is bonded with a cation exchange membrane layer by a scattered conductive adhesive, wherein the cation exchange membrane layer is formed by a sulfonated polyetheretherketone membrane solution doped with carbon nanotubes; the other side of which is bonded with a polyamide layer by a scattered adhesive, wherein the polyamide layer is a polypiperazineamide polymer layer containing polyethyleneimine chelated calcium or polyethyleneimine, and poly(3-sulfonatepropyl methacrylate) is grafted onto the polyamide layer by an in-situ free radical polymerization reaction; The mesh alloy plate is a mesh aluminum-indium-magnesium alloy plate; The viscose is made of an imidazole cationic polyionic liquid with an alkoxy side chain; The conductive adhesive is composed of silver nanofiber material and imidazole cationic polyionic liquid with alkoxy side chains, and the silver nanofiber material accounts for 10wt%-30wt%.

2. The ion exchange membrane according to claim 1, characterized in that The mesh steel pole plate is a mesh stainless steel pole plate.

3. The ion exchange membrane according to claim 1, characterized in that The anion of the polyionic liquid is one of tetrafluoroborate ion, hexafluorophosphate ion and bis(trifluoromethanesulfonyl imide) ion.

4. The ion exchange membrane according to claim 1, characterized in that The carbon nanotube content in the carbon nanotube-doped aminated polyphenylene ether membrane solution is 0.5 wt%-10 wt%; the carbon nanotube content in the carbon nanotube-doped sulfonated polyetheretherketone membrane solution is 0.5 wt%-10 wt%.

5. A waste salt solution utilization device that resists pollution and scaling, characterized in that: The invention comprises a bipolar membrane electrodialysis module arranged in an electrolytic cell, wherein the bipolar membrane electrodialysis module is provided with an anode plate and a cathode plate, and at least one bipolar membrane electrodialysis membrane stack is provided between the anode plate and the cathode plate, wherein the bipolar membrane electrodialysis membrane stack comprises an anode-side mixed matrix bipolar membrane, a first spacer, the composite anion exchange membrane according to claim 1, a second spacer, the composite cation exchange membrane according to claim 1, a third spacer, and a cathode-side mixed matrix bipolar membrane, which are arranged in sequence and spaced apart; the anode-side mixed matrix bipolar membrane is arranged close to the anode plate, and the cathode-side mixed matrix bipolar membrane is arranged close to the cathode plate; The anion exchange membrane layer in the composite anion exchange membrane is arranged close to the anode-side mixed matrix bipolar membrane, and the cation exchange membrane layer in the composite cation exchange membrane is arranged close to the cathode-side mixed matrix bipolar membrane.

6. The device for utilizing waste salt solution with resistance to pollution and scaling according to claim 5, characterized in that: An acid solution chamber is formed between the anode-side mixed matrix bipolar membrane and the composite anion exchange membrane, a salt solution chamber is formed between the composite anion exchange membrane and the composite cation exchange membrane, and an alkaline solution chamber is formed between the composite cation exchange membrane and the cathode-side mixed matrix bipolar membrane.

7. The device for utilizing waste salt solution with resistance to pollution and scaling according to claim 5, characterized in that: The anode-side mixed matrix bipolar membrane and the cathode-side mixed matrix bipolar membrane both include a cation exchange layer and an anion exchange layer, the cation exchange layer is made of sulfonated polyetheretherketone, and the anion exchange layer is made of aminated polyphenylene ether; the cation exchange layer of the anode-side mixed matrix bipolar membrane and the anion exchange layer of the cathode-side mixed matrix bipolar membrane are both doped with activated carbon fibers, and the doping ratio of the activated carbon fibers is 0.1wt%-5wt%.

8. Application of the anti-pollution and scaling waste salt solution utilization device according to any one of claims 5 to 7, characterized in that: It is used to treat industrial waste salt, wherein the sodium chloride content of the industrial waste salt is ≥90,000 mg / L, the silicon content is ≥75 mg / L, the heavy metal content is ≥56 mg / L, and the COD content is ≥180 mg / L.

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