Integrated electrode and method for manufacturing same, and electrodeposition and ion removal device

Abstract

The application relates to the field of electrochemistry and discloses an integrated electrode, a preparation method of the integrated electrode and an electric adsorption ion removal device. The integrated electrode comprises an electric adsorption electrode and an anion exchange functional layer coated on the surface of the electric adsorption electrode; the anion exchange functional layer comprises a plurality of polyphenyl ether molecular chains; the polyphenyl ether molecular chain has a structure shown in formula I; Q1, Q2, Q3 and Q4 are independently groups shown in formula II, groups shown in formula III, Br or H; at least two of Q1, Q2, Q3 and Q4 are groups shown in formula II and groups shown in formula III; and the at least two polyphenyl ether molecular chains are connected through Ar structures from a crosslinking agent. The integrated electrode can significantly improve the ion transmission rate and the saturated adsorption capacity of the electric adsorption electrode, and when the integrated electrode is used in the electric adsorption ion removal device, the desalination performance of the electric adsorption ion removal device can be significantly improved.

Description

Technical Field

[0001] This invention relates to the field of electrochemistry, specifically to an integrated electrode and its preparation method, and an electro-adsorption deionization device. Background Technology

[0002] Co-sorption and desorption (CDI) is an electrochemical water treatment technology for moderate desalination, offering advantages such as high efficiency, environmental friendliness, and renewability. By placing an ion exchange membrane on the electrode surface, the common ion effect during adsorption can be weakened, reducing adsorption resistance. Simultaneously, it prevents ions from being re-adsorbed by the opposite electrode during desorption, thus improving performance.

[0003] In actual operation, the desalination performance of CDI devices remains relatively low. On the one hand, existing ion exchange membranes have a low number of active ion exchange groups, resulting in high membrane surface resistance and limiting ion transport rates. On the other hand, the physical superposition of the ion exchange membrane and electrode generates high contact resistance and inhibits ion diffusion from the ion exchange membrane to the electrode surface. Under the combined effect of low ion transport rates and high contact resistance, existing electroadsorption devices generally suffer from low electrode adsorption capacity, low desalination efficiency, and high energy consumption, hindering the industrial application of electroadsorption technology.

[0004] CN109502708A proposes a method for preparing ion exchange membrane / carbon composite electrodes by spraying an ion exchange membrane slurry. The ion exchange membrane slurry is a mixture of pretreated ion exchange resin and a binder solution. The composite electrode prepared by this method has a heterogeneous structure, with the ion exchange resin and electrode bonded together by the binder. On the one hand, the ion exchange resin is a discontinuous phase with a low ion transport channel density; on the other hand, the binder has no ion exchange function, increasing the contact resistance between the electrode and the ion exchange resin, thus limiting its performance improvement effect on the conductive carbon electrode. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing electroadsorption electrodes, such as low capacity, low desalination efficiency, and high energy consumption, and to provide an integrated electrode. This integrated electrode includes an electroadsorption electrode and an anion exchange functional layer with a specific structure coated on the surface of the electroadsorption electrode. It can significantly improve the ion transport rate and the saturated adsorption capacity of the electroadsorption electrode. When this integrated electrode is used in an electroadsorption deionization device, it can significantly improve the desalination performance of the electroadsorption deionization device.

[0006] To achieve the above objectives, the first aspect of the present invention provides an integrated electrode, wherein the integrated electrode includes an electroadsorption electrode and an anion exchange functional layer coated on the surface of the electroadsorption electrode;

[0007] The anion exchange functional layer comprises multiple polyphenylene ether molecular chains; the polyphenylene ether molecular chains have the structure shown in Formula I;

[0008]

[0009] Q1, Q2, Q3, and Q4 are each independently a group represented by Formula II, a group represented by Formula III, Br, or H; and at least two of Q1, Q2, Q3, and Q4 are groups represented by Formula II and groups represented by Formula III.

[0010]

[0011] At least two polyphenylene ether molecular chains are connected by an Ar structure from the crosslinking agent;

[0012] Among them, R1, R2, R4, R5, R7, and R8 are each independently H, CH3, or CH2CH3, and R3 is C8-C. 25 R6 is a C2-C5 straight-chain or branched alkyl group; x is 0.3-0.8.

[0013] A second aspect of the present invention provides a method for preparing an integrated electrode, characterized in that the preparation method includes the following steps:

[0014] S1. Mix and react the compound A shown in Formula 1, the compound B shown in Formula 2, the brominated polyphenylene ether shown in Formula 3, and an organic solvent, and then add a crosslinking agent to obtain a precursor solution.

[0015] S2. After vacuum degassing the precursor liquid, it is coated onto the electroadsorption electrode to obtain an electroadsorption electrode with a liquid coating.

[0016] S3. The electroadsorption electrode with liquid coating is cured to obtain the integrated electrode;

[0017]

[0018] Among them, R1', R2', R4', R5', R7', and R8' are each independently H, CH3, or CH2CH3, and R3' is C8-C. 25 R6' is a C2-C5 straight-chain or branched alkylene; X1 and X2 are each independently H or Br, and at least one of X1 and X2 is Br; x is 0.3-0.8.

[0019] A third aspect of the present invention provides an integrated electrode prepared by the above-described preparation method.

[0020] A fourth aspect of the present invention provides an electro-adsorption deionization device, wherein the electro-adsorption deionization device includes the aforementioned integrated electrode.

[0021] Through the above technical solutions, the integrated electrode, its preparation method, and the electroadsorption deionization device provided by the present invention achieve the following beneficial effects:

[0022] In this invention, the integrated electrode comprises an electroadsorption electrode and an anion exchange functional layer with a specific structure coated on the surface of the electroadsorption electrode. This anion exchange membrane has a double-side-chain structure, which can greatly increase the number of active ion exchange groups, thereby increasing the ion transport rate on the surface of the electroadsorption electrode containing the anion exchange functional layer and improving the exchange capacity of the electroadsorption electrode. In particular, when this integrated electrode is used in an electroadsorption deionization device, it can significantly improve the desalination performance of the adsorption deionization device and reduce energy consumption.

[0023] In this invention, the integrated electrode is prepared by forming an anion exchange functional layer on the surface of the electroadsorption electrode through in-situ polymerization. This significantly enhances the bonding between the anion exchange functional layer and the electroadsorption electrode, thereby reducing contact resistance, increasing the ion transport rate on the electrode surface, and improving the exchange capacity of the electroadsorption electrode. Specifically, when this integrated electrode is used in an electroadsorption deionization device, it can significantly improve the desalination performance of the device and reduce energy consumption.

[0024] The integrated electrode prepared by this invention has a high adsorption capacity for anions (e.g., chloride ions), and the electro-adsorption deionization device containing this integrated electrode has a high desalination rate. Furthermore, the adsorption rate of the opposite electrode is low during desorption. Specifically, the integrated electrode has an adsorption capacity of 14-25 mg / g for anions, the desalination rate of the electro-adsorption deionization device is 72-86%, and the adsorption rate of the opposite electrode during desorption is less than or equal to 10%, preferably 2-9%. The adsorption time can be shortened to 85% of the original time, which greatly improves the desalination performance of the electro-adsorption deionization device. Attached Figure Description

[0025] Figure 1 This is a process flow diagram of the method for preparing an integrated electrode according to the present invention. Detailed Implementation

[0026] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0027] Unless otherwise defined, all terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. While any methods and materials similar to or equivalent to those described herein may also be used in the practice or testing of this invention, preferred methods and materials are now described.

[0028] In this invention, the range of dosage concentration, temperature or other physical or chemical properties or characteristics, unless otherwise specified, covers or includes the upper and lower limits of that range.

[0029] The first aspect of the present invention provides an integrated electrode, characterized in that the integrated electrode includes an electroadsorption electrode and an anion exchange functional layer coated on the surface of the electroadsorption electrode;

[0030] The anion exchange functional layer comprises multiple polyphenylene ether molecular chains; the polyphenylene ether molecular chains have the structure shown in Formula I;

[0031]

[0032] Q1, Q2, Q3, and Q4 are each independently a group represented by Formula II, a group represented by Formula III, Br, or H; and at least two of Q1, Q2, Q3, and Q4 are groups represented by Formula II and groups represented by Formula III.

[0033]

[0034] At least two polyphenylene ether molecular chains are connected by an Ar structure from the crosslinking agent;

[0035] Among them, R1, R2, R4, R5, R7, and R8 are each independently H, CH3, or CH2CH3, and R3 is C8-C. 25 R6 is a C2-C5 straight-chain or branched alkyl group; x is 0.3-0.8.

[0036] In this invention, the integrated electrode comprises an electroadsorption electrode and an anion exchange functional layer with a specific structure coated on the surface of the electroadsorption electrode. This anion exchange functional layer has a double-side-chain structure, which can greatly increase the number of active ion exchange groups, thereby increasing the ion transport rate on the surface of the electroadsorption electrode containing the anion exchange membrane and improving the saturated adsorption capacity of the electroadsorption electrode. In particular, when this integrated membrane electrode is used in an electroadsorption deionization device, it can significantly improve the desalination performance of the adsorption deionization device and reduce energy consumption.

[0037] Specifically, the anion exchange functional layer uses polyphenylene ether as a backbone, and introduces two kinds of long-chain hydrophobic alkyl side chains on the molecular chain of the polyphenylene ether backbone. Compared with the traditional short side chains, the long-chain hydrophobic alkyl side chains have stronger mobility and can promote the formation of hydrophilic and hydrophobic micro-phase separation aggregate structure in the membrane. At the same time, the introduction of the two kinds of long-chain hydrophobic alkyl side chains significantly increases the number of active ion exchange groups in the ion exchange membrane. The two work together to significantly improve the ion exchange performance of the anion exchange functional layer.

[0038] Furthermore, R1, R2, R4, R5, R7, and R8 are each independently CH2CH3 or CH3; R3 is C. 10 -C 20 R6 is a C2-C3 straight-chain or branched alkyl group; x is 0.4-0.6.

[0039] In one specific embodiment of the present invention, R1 and R2 are CH3, and R3 is C. 18 Straight-chain alkyl groups.

[0040] In one specific embodiment of the present invention, R1 and R2 are CH3, and R3 is C. 10 Straight-chain alkyl groups.

[0041] In one specific embodiment of the present invention, R4, R5, R7, and R8 are each independently CH3, and R6 is ethylene.

[0042] In one specific embodiment of the present invention, R4, R5, R7, and R8 are each independently CH3, and R6 is methylene.

[0043] According to the present invention, the Ar structure from the crosslinking agent is selected from at least one of the following:

[0044]

[0045] Among them, R9 and R 10 Each can be independently H, OH, or CH3; R 11 and R 12 Each is independently H, CH3, or CH2CH3; n and m are each independently an integer from 1 to 3; p and q are each independently an integer from 1 to 3.

[0046] In this invention, at least two polyphenylene ether molecular chains are connected by the specific Ar structure described above to form a stable network structure, which provides active sites for ion migration without reducing the ion exchange capacity of the membrane.

[0047] Furthermore, R9, R 10 R 11 and R 12Each is H, and n, m, p and q are all 1.

[0048] According to the present invention, based on the total molar amount of the anion exchange membrane, the molar content of the group represented by Formula II is 10-40%, the molar content of the group represented by Formula III is 20-60%, the molar content of Br is 0-5%, and the molar content of Ar structure is 5-15%.

[0049] In this invention, when the content of each structural unit in the anion exchange functional layer meets the above-mentioned range, the crosslinking agent and the main linking branch can form a cationic imidazole group, which provides an active site for ion migration and can improve the saturated adsorption capacity of the electroadsorption electrode containing the anion exchange functional layer.

[0050] In this invention, when the anion exchange functional layer is prepared on the electroadsorption electrode, compounds A and B are essentially left without residue, indicating that compounds A and B can completely react with brominated polyphenylene ether during the preparation of the anion exchange functional layer. Therefore, the content of each structural unit in the anion exchange functional layer can be determined by the amount of material fed.

[0051] Furthermore, based on the total amount of the anion exchange functional layer, the content of the structural unit shown in Formula I is 10-30%, the content of the structural unit shown in Formula II is 30-50%, the content of Br is 0.2-2%, and the content of Ar structure is 6-9%.

[0052] According to the present invention, the thickness of the anion exchange functional layer is 100-200 μm.

[0053] In this invention, when the thickness of the anion exchange functional layer is controlled to meet the above-mentioned range, the water absorption of the ion exchange groups can be suppressed and the establishment of ion migration channels can be facilitated, thereby further improving the ion exchange capacity of the anion exchange functional layer.

[0054] Furthermore, the thickness of the anion exchange functional layer is 100-150 μm.

[0055] According to the present invention, the electroadsorption electrode is selected from at least one of porous foam carbon electrode, activated carbon electrode, graphene electrode and metal modified electrode.

[0056] According to the present invention, the chloride ion adsorption capacity of the integrated electrode is 14-25 mg / g, preferably 21-25 mg / g.

[0057] A second aspect of the present invention provides a method for preparing an integrated electrode, wherein the preparation method includes:

[0058] S1. Mix and react the compound A shown in Formula 1, the compound B shown in Formula 2, the brominated polyphenylene ether shown in Formula 3, and an organic solvent, and then add a crosslinking agent to obtain a precursor solution.

[0059] S2. After vacuum degassing the precursor liquid, it is coated onto the electroadsorption electrode to obtain an electroadsorption electrode with a liquid coating.

[0060] S3. The electroadsorption electrode with liquid coating is cured to obtain the integrated electrode;

[0061] in,

[0062] Among them, R1', R2', R4', R5', R7', and R8' are each independently H, CH3, or CH2CH3, and R3' is C8-C. 25 R6' is a C2-C5 straight-chain or branched alkylene group; X1 and X2 are each independently H or Br, and at least one of X1 and X2 is Br; x is 0.3-0.8. In this invention, in the preparation method of the integrated electrode, an anion exchange functional layer is formed on the surface of the electroadsorption electrode by in-situ polymerization, which can significantly enhance the binding ability between the anion exchange functional layer and the electroadsorption electrode, thereby reducing contact resistance, providing the ion transport rate on the electrode surface, and improving the exchange capacity of the electroadsorption electrode. In particular, when this integrated electrode is used in an electroadsorption deionization device, it can significantly improve the desalination performance of the adsorption deionization device and reduce energy consumption.

[0063] Furthermore, R1', R2', R4', R5', R7', and R8' are each independently CH2CH3 or CH3, and R3' is C. 10 -C 20 R6' is a C2-C3 straight-chain or branched alkylene; X1 and X2 are each independently H or Br, and at least one of X1 and X2 is Br; x is 0.4-0.6.

[0064] In one specific embodiment of the present invention, compound A represented by Formula 1 is octadecyl dimethyl tertiary amine, i.e., R1' and R2' are CH3, and R3' is C. 18 Straight-chain alkyl groups.

[0065] In another specific embodiment of the present invention, compound A shown in Formula 1 is a decaalkyldimethyl tertiary amine, that is, R1' and R2' are CH3, and R3' is C. 10 Straight-chain alkyl groups.

[0066] In one specific embodiment of the present invention, compound B shown in Formula 2 is N,N,N,N-tetramethylethylenediamine, that is, R4', R5', R7', and R8' are each independently CH3, and R6' is ethylene.

[0067] In another specific embodiment of the present invention, compound B shown in Formula 2 is N,N,N,N-tetramethylethylenediamine, that is, R4', R5', R7', and R8' are each independently CH3, and R6' is methylene.

[0068] In this invention, there is no particular limitation on the type of organic solvent, as long as it can fully dissolve the brominated polyphenylene ether. For example, the organic solvent is selected from at least one of N-methylpyrrolidone, tetrahydrofuran, and N,N-dimethylformamide.

[0069] In this invention, the weight-average molecular weight of the brominated polyphenylene ether is 70,000-90,000 g / mol.

[0070] In this invention, there is no particular limitation on the source of the polyphenylene ether; it can be commercially available or prepared in-house.

[0071] In one specific embodiment of the present invention, the brominated polyphenylene ether is prepared according to the following steps:

[0072] S1. In the presence of a solvent and a protective gas, poly(2,6-dimethyl-1,4-phenylene ether) (PPO), a brominating agent and an initiator are mixed and subjected to a bromination reaction.

[0073] S2. After cooling the product obtained in step S1, an alcohol solution is added dropwise, followed by filtration, washing, purification, and drying to obtain the brominated polyphenylene ether.

[0074] In this invention, the molar ratio of poly(2,6-dimethyl-1,4-phenyl ether) (PPO) to the brominated reagent is 1:0.5-3, preferably 1:1-2.

[0075] In this invention, the weight-average molecular weight M of the poly(2,6-dimethyl-1,4-phenyl ether) is... w 40000-50000g / mol.

[0076] In this invention, the molar ratio of poly(2,6-dimethyl-1,4-phenyl ether) (PPO) to the initiator is 1:0.05-0.08, preferably 1:0.06-0.07.

[0077] In this invention, the brominating agent can be a conventional type of brominating agent in the art, such as N-bromosuccinimide (NBS) and / or 1,3-dibromo-5,5-dimethylhydantoin (DBH).

[0078] In this invention, the initiator can be a conventional type of initiator in the art, such as azobisisobutyronitrile (AIBN) and / or azobisisoheptanenitrile (ABVN).

[0079] In this invention, the organic solvent can be a conventional organic solvent in the art, such as chlorobenzene. There is no particular limitation on the amount of organic solvent used, as long as it can fully dissolve poly(2,6-dimethyl-1,4-phenylene ether) (PPO).

[0080] In this invention, there is no particular limitation on the type of protective gas; conventional protective gases in the art, such as nitrogen, can be used.

[0081] In this invention, the conditions for the bromination reaction include: a reaction temperature of 110-140℃ and a reaction time of 2-4h.

[0082] In this invention, there is no particular limitation on the type of alcohol solution; conventional alcohol solutions in the art, such as methanol solutions, can be used. There is also no particular limitation on the amount of alcohol solution used, as long as it is sufficient to ensure complete precipitation of the brominated polyphenylene ether. To further ensure complete precipitation of the brominated polyphenylene ether, preferably, the alcohol solution is added dropwise; more preferably, it is added dropwise to the product obtained in step S1 at a rate of 20-50 mL / min.

[0083] In this invention, methanol is used to wash the filtered product.

[0084] In this invention, the purification step includes: redissolving the washed product in a first organic solvent and washing it with a second organic solvent.

[0085] In this invention, the first organic solvent is selected from at least one of chloroform, dichloromethane, and tetrahydrofuran. In this invention, the amount of the first organic solvent used is 1000-2000 mL relative to 100 g of the washed product.

[0086] In this invention, the second organic solvent is selected from acetone and / or butanone.

[0087] In this invention, the amount of the second organic solvent used is 1000-2000 mL relative to 100 g of the washed product.

[0088] According to the present invention, the crosslinking agent is selected from at least one of compounds having the following structures;

[0089]

[0090] Among them, R9' and R 10 Each can be independently H, OH, or CH3; R 11 'and R12 Each is independently H, CH3, or CH2CH3; X is Br or Cl; n and m are each independently an integer from 1 to 3; p and q are each independently an integer from 1 to 3.

[0091] In this invention, the use of the above-mentioned specific crosslinking agent enables the connection of at least two polyphenylene ether molecular chains to form a stable network structure, which provides active sites for ion migration without reducing the ion exchange capacity of the anion exchange functional layer.

[0092] Furthermore, R9', R 10 '、R 11 'and R 12 Each is H, and n, m, p and q are all 1.

[0093] In one specific embodiment of the present invention, the crosslinking agent is selected from at least one of 4,4'-dibromomethylbiphenyl, 1,4-di(bromomethyl)benzene, 4,4'-dibromobiphenyl, 4,4'-3,3'-dimethyldibromobiphenyl, 4,4'-dibromo-2,2'-dimethylbiphenyl, 1,4-di(chloromethyl)benzene, 4,4'-dichlorobiphenyl, and 2,2'-dihydroxy-4,4'-dichlorobiphenyl.

[0094] Preferably, the crosslinking agent is selected from at least one of 4,4'-dibromomethylbiphenyl, 1,4-di(bromomethyl)benzene and 4,4'-dibromobiphenyl.

[0095] According to the present invention, the molar ratio of bromomethyl group of brominated polyphenylene ether to compound A in the precursor solution is 1:4-10, the molar ratio of bromomethyl group of brominated polyphenylene ether to compound B in the precursor solution is 1:2-6, and the molar ratio of brominated polyphenylene ether to crosslinking agent in the precursor solution is 1:1-5.

[0096] In this invention, when the molar ratio of brominated polyphenylene ether, compound A, compound B and crosslinking agent in the precursor solution is controlled to meet the above range, the crosslinking agent and the main linking branch can form cationic imidazole groups, which provide active sites for ion migration and can improve the saturated adsorption capacity of the electroadsorption electrode containing the anion exchange functional layer.

[0097] Furthermore, the molar ratio of bromomethyl group of brominated polyphenylene ether to compound A in the precursor solution is 1:4-6, the molar ratio of bromomethyl group of brominated polyphenylene ether to compound B in the precursor solution is 1:4-6, and the molar ratio of brominated polyphenylene ether to crosslinking agent in the precursor solution is 1:2-4.

[0098] According to the present invention, there are no special requirements for the amount of organic solvent in the precursor solution, as long as the components are fully mixed and dispersed evenly. For example, the amount of organic solvent is 20-40 times that of brominated polyphenylene ether.

[0099] In a preferred embodiment of the present invention, brominated polyphenylene ether of Formula 3 and an organic solvent are mixed to obtain a mixture, and compound A of Formula 1 and compound B of Formula 2 are added to the mixture to react and obtain the precursor solution.

[0100] In this invention, the brominated polyphenylene ether is mixed with an organic solvent in advance, which ensures that the brominated polyphenylene ether is fully dissolved and dispersed in the organic solvent, improves the dispersibility of the brominated polyphenylene ether in the mixture, and thus allows compound A and compound B to fully contact and react with the brominated polyphenylene ether.

[0101] In this invention, in order to control the dispersibility of brominated polyphenylene ether, preferably, the concentration of brominated polyphenylene ether in the mixture is 5wt%-20wt%, more preferably 5wt%-10wt%.

[0102] According to the present invention, in step S1, the mixing temperature is 20-30°C and the mixing time is 40-50 hours.

[0103] According to the present invention, in step S2, the conditions for vacuum degassing include: a relative vacuum of -80 kPa to -90 kPa, preferably -82 kPa to -88 kPa.

[0104] In this invention, the vacuum degassing method includes static degassing and / or vacuum degassing.

[0105] According to the present invention, the thickness of the liquid coating is 100-200 μm, preferably 100-150 μm.

[0106] According to the present invention, the curing conditions include: a curing temperature of 80-120°C and a curing time of 8-20 hours.

[0107] In this invention, curing under the above conditions can ensure that the liquid coating is completely cured while preventing the anion exchange functional layer from deforming due to heat.

[0108] Furthermore, the curing conditions include: a curing temperature of 90-110℃ and a curing time of 12-16h.

[0109] According to the present invention, the preparation method further includes washing the cured product.

[0110] In this invention, deionized water is used to wash the cured product. Preferably, the cured product is immersed in deionized water for washing.

[0111] A third aspect of the present invention provides an integrated electrode prepared by the above-described preparation method.

[0112] A fourth aspect of the present invention provides an electro-adsorption deionization device, characterized in that the electro-adsorption deionization device includes the aforementioned integrated electrode.

[0113] In this invention, the electro-adsorption deionization device includes the aforementioned integrated electrode, which can significantly improve the desalination performance of the adsorption deionization device and significantly reduce energy consumption.

[0114] In this invention, the desalination rate of the integrated electrode electro-adsorption deionization device can reach 72-86%, and the adsorption rate of the opposite electrode during desorption is less than or equal to 10%, preferably 2-9%, and the adsorption time can be shortened to 85% of the original, which greatly improves the desalination performance of the electro-adsorption deionization device.

[0115] The present invention will be described in detail below through embodiments. In the following embodiments,

[0116] All raw materials used in the examples and comparative examples were commercially available products from McLean Corporation, including poly(2,6-dimethyl-1,4-phenylene ether M... w It is 45000 g / mol.

[0117] The content of each structure in the anion functional exchange layer is calculated based on the amount of raw materials fed.

[0118] The thickness of the anion functional exchange layer in the integrated electrode was measured using a film thickness gauge.

[0119] The chloride ion adsorption capacity of the integrated electrode and the desalination rate of the electroadsorption device were tested using the methods described in the test examples.

[0120] Preparation Example 1

[0121] 9 g of poly(2,6-dimethyl-1,4-phenylene ether) (PPO) was dissolved in 100 mL of chlorobenzene. 9.34 g of N-bromosuccinimide and 0.57 g of azobisisobutyronitrile were added, and the mixture was stirred in an oil bath at 135 °C for 3 h under a nitrogen atmosphere. After cooling, the reactants were added dropwise to 1000 mL of methanol to obtain a crude polymer. The polymer was filtered and washed several times with methanol. The crude product was then dissolved in 50 mL of chloroform and washed with 200 mL of acetone. The resulting light yellow powder was filtered and dried under vacuum to obtain BPPO-1.

[0122] The brominated polyphenylene ether has a bromination rate (x) of 0.57 and a weight-average molecular weight of 77751 g / mol.

[0123] Preparation Example 2

[0124] 9 g of poly(2,6-dimethyl-1,4-phenylene ether) (PPO) was dissolved in 100 mL of chlorobenzene. 11.45 g of N-bromosuccinimide (NBS) and 0.60 g of azobisisobutyronitrile (AIBN) were added, and the mixture was stirred in an oil bath at 135 °C for 3 h under a nitrogen atmosphere. After cooling, the reactants were added dropwise to 1000 mL of methanol to obtain a crude polymer. The polymer was filtered and washed several times with methanol. The crude product was then dissolved in 50 mL of chloroform and washed with 200 mL of acetone. The resulting light yellow powder was filtered and dried under vacuum to obtain BPPO-2.

[0125] The brominated polyphenylene ether has a bromination rate (x) of 0.75 and a weight-average molecular weight of 87652 g / mol.

[0126] Example 1

[0127] S1: Preparation of the precursor solution. 1 g of BPPO-1 was dissolved in 15 g of N-methylpyrrolidone, and octadecyl dimethyl tertiary amine and N,N,N,N-tetramethylethylenediamine were added sequentially. The mixture was stirred and reacted at room temperature for 40 h. Then, the crosslinking agent 4,4'-dibromomethylbiphenyl was added to obtain the precursor solution. The amounts of octadecyl dimethyl dimethyl tertiary amine, N,N,N,N-tetramethylethylenediamine, and 4,4'-dibromomethylbiphenyl were such that the molar ratio of bromomethyl to octadecyl dimethyl tertiary amine in the brominated polyphenylene ether was 1:6, the molar ratio of bromomethyl to N,N,N,N-tetramethylethylenediamine in the brominated polyphenylene ether was 1:4.25, and the molar ratio of brominated polyphenylene ether to the crosslinking agent was 1:4.

[0128] S2: Coating. The precursor liquid prepared in step 1 is degassed under vacuum at a vacuum degree of -80 kPa; the degassed precursor liquid is then coated onto the activated carbon electroadsorption electrode with a scraper thickness of 150 μm to obtain an electroadsorption electrode with a liquid coating.

[0129] S3: Polymerization and curing. The electroadsorption electrode with the liquid coating is placed in an oven and cured at 110°C for 8 hours.

[0130] S4: Cleaning. Immerse the polymerized and cured monolithic electrode in deionized water to obtain monolithic electrode A1.

[0131] Example 2

[0132] The integrated electrode was prepared according to the method of Example 1, except that:

[0133] Step S1: Preparation of the precursor solution. 1 g of BPPO-1 was dissolved in 15 g of N-methylpyrrolidone, and octadecyl dimethyl tertiary amine and N,N,N,N-tetramethylethylenediamine were added sequentially. The mixture was stirred at room temperature for 40 h, followed by the addition of 4,4'-dibromomethylbiphenyl. The amounts of octadecyl dimethyl dimethyl tertiary amine, N,N,N,N-tetramethylethylenediamine, and 4,4'-dibromomethylbiphenyl were such that the molar ratio of bromomethyl to octadecyl dimethyl tertiary amine in the brominated polyphenylene ether was 1:5, the molar ratio of bromomethyl to N,N,N,N-tetramethylethylenediamine in the brominated polyphenylene ether was 1:4.25, and the molar ratio of brominated polyphenylene ether to the crosslinking agent was 1:4. The integrated electrode A2 was thus obtained.

[0134] Example 3

[0135] The integrated electrode was prepared according to the method of Example 1, except that:

[0136] Step S1: Dissolve 1g of BPPO-1 in 15g of N-methylpyrrolidone, then add octadecyl dimethyl tertiary amine and N,N,N,N-tetramethylethylenediamine sequentially. Stir the reaction at room temperature for 40h, followed by the addition of 4,4'-dibromomethylbiphenyl. The amounts of octadecyl dimethyl dimethyl tertiary amine, N,N,N,N-tetramethylethylenediamine, and 4,4'-dibromomethylbiphenyl are such that the molar ratio of bromomethyl to octadecyl dimethyl tertiary amine in the brominated polyphenylene ether is 1:6, the molar ratio of bromomethyl to N,N,N,N-tetramethylethylenediamine in the brominated polyphenylene ether is 1:4.25, and the molar ratio of brominated polyphenylene ether to crosslinking agent is 1:3. An integrated membrane electrode A3 is thus obtained.

[0137] Example 4

[0138] The integrated electrode was prepared according to the method of Example 1, except that:

[0139] Step S1: Dissolve 1g of BPPO-2 in 15g of N-methylpyrrolidone, then add octadecyl dimethyl tertiary amine and N,N,N,N-tetramethylethylenediamine sequentially. Stir the reaction at room temperature for 40 hours, followed by the addition of 4,4'-dibromomethylbiphenyl. The amounts of octadecyl dimethyl dimethyl tertiary amine, N,N,N,N-tetramethylethylenediamine, and 4,4'-dibromomethylbiphenyl are such that the molar ratio of bromomethyl to octadecyl dimethyl tertiary amine in the brominated polyphenylene ether is 1:6, the molar ratio of bromomethyl to N,N,N,N-tetramethylethylenediamine in the brominated polyphenylene ether is 1:4.25, and the molar ratio of brominated polyphenylene ether to crosslinking agent is 1:4. The integrated electrode A4 is thus obtained.

[0140] Example 5

[0141] The integrated electrode was prepared according to the method of Example 1, except that:

[0142] Step S1: Dissolve 1g of BPPO-1 in 15g of N-methylpyrrolidone, then add decaalkyldimethyl tertiary amine and N,N,N,N-tetramethylethylenediamine sequentially. Stir the reaction mixture at room temperature for 40 hours, followed by the addition of 4,4'-dibromomethylbiphenyl. The amounts of decaalkyldimethyldimethyl tertiary amine, N,N,N,N-tetramethylethylenediamine, and 4,4'-dibromomethylbiphenyl are such that the molar ratio of bromomethyl to decaalkyldimethyl tertiary amine in the brominated polyphenylene ether is 1:6, the molar ratio of bromomethyl to N,N,N,N-tetramethylethylenediamine in the brominated polyphenylene ether is 1:4.25, and the molar ratio of brominated polyphenylene ether to crosslinking agent is 1:4. The integrated electrode A5 is thus obtained.

[0143] Example 6

[0144] The integrated electrode was prepared according to the method of Example 1, except that:

[0145] Step S1: Dissolve 1g of BPPO-1 in 15g of N-methylpyrrolidone, then add octadecyl dimethyl dimethylamine and N,N,N,N-tetramethylmethyldiamine sequentially. Stir the reaction mixture at room temperature for 40 hours, followed by the addition of 4,4'-dibromomethylbiphenyl. The amounts of octadecyl dimethyl dimethyl tertiary amine, N,N,N,N-tetramethylmethyldiamine, and 4,4'-dibromomethylbiphenyl are such that the molar ratio of bromomethyl to octadecyl dimethyl tertiary amine in the brominated polyphenylene ether is 1:6, the molar ratio of bromomethyl to N,N,N,N-tetramethylmethyldiamine in the brominated polyphenylene ether is 1:4.25, and the molar ratio of brominated polyphenylene ether to crosslinking agent is 1:4. This yields an integrated electrode A6.

[0146] Example 7

[0147] The integrated electrode was prepared according to the method of Example 1, except that:

[0148] Step S1: Dissolve 1g of BPPO-1 in 15g of N-methylpyrrolidone, then add octadecyl dimethyl tertiary amine and N,N,N,N-tetramethylethylenediamine sequentially. Stir the reaction at room temperature for 40 hours, followed by the addition of 4,4'-dibromomethylbiphenyl. The amounts of octadecyl dimethyl dimethyl tertiary amine, N,N,N,N-tetramethylethylenediamine, and 4,4'-dibromomethylbiphenyl are such that the molar ratio of bromomethyl to octadecyl dimethyl tertiary amine in the brominated polyphenylene ether is 1:2, the molar ratio of bromomethyl to N,N,N,N-tetramethylethylenediamine in the brominated polyphenylene ether is 1:4.25, and the molar ratio of brominated polyphenylene ether to crosslinking agent is 1:4. This produces an integrated electrode A7.

[0149] Example 8

[0150] The integrated electrode was prepared according to the method of Example 1, except that:

[0151] Step S1: Dissolve 1g of BPPO-1 in 15g of N-methylpyrrolidone, then add octadecyl dimethyl tertiary amine and N,N,N,N-tetramethylethylenediamine sequentially. Stir the reaction mixture at room temperature for 40 hours, followed by the addition of 4,4'-dibromomethylbiphenyl. The amounts of octadecyl dimethyl dimethyl tertiary amine, N,N,N,N-tetramethylethylenediamine, and 4,4'-dibromomethylbiphenyl are such that the molar ratio of bromomethyl to octadecyl dimethyl tertiary amine in the brominated polyphenylene ether is 1:8, the molar ratio of bromomethyl to N,N,N,N-tetramethylethylenediamine in the brominated polyphenylene ether is 1:4.25, and the molar ratio of brominated polyphenylene ether to crosslinking agent is 1:4. This yields an integrated electrode A8.

[0152] Example 9

[0153] The integrated electrode was prepared according to the method of Example 1, except that:

[0154] Step S1: Dissolve 1g of BPPO-1 in 15g of N-methylpyrrolidone, then add octadecyl dimethyl tertiary amine and N,N,N,N-tetramethylethylenediamine sequentially. Stir the reaction mixture at room temperature for 40 hours, followed by the addition of 4,4'-dibromomethylbiphenyl. The amounts of octadecyl dimethyl dimethyl tertiary amine, N,N,N,N-tetramethylethylenediamine, and 4,4'-dibromomethylbiphenyl are such that the molar ratio of bromomethyl to octadecyl dimethyl tertiary amine in the brominated polyphenylene ether is 1:3, the molar ratio of bromomethyl to N,N,N,N-tetramethylethylenediamine in the brominated polyphenylene ether is 1:0.5, and the molar ratio of brominated polyphenylene ether to crosslinking agent is 1:0.4. This yields the integrated electrode A9.

[0155] Comparative Example 1

[0156] The integrated electrode was prepared according to the method of Example 1, except that:

[0157] S1: 1 g of BPPO-1 was dissolved in 15 g of N-methylpyrrolidone, and tert-amylamine and N,N,N,N-tetramethylmethyldiamine were added sequentially. The mixture was stirred at room temperature for 40 h, followed by the addition of 4,4'-dibromomethylbiphenyl. The amounts of tert-amylamine, N,N,N,N-tetramethylmethyldiamine, and 4,4'-dibromomethylbiphenyl were such that the molar ratio of bromomethyl to tert-amylamine in the brominated polyphenylene ether was 1:6, the molar ratio of bromomethyl to N,N,N,N-tetramethylmethyldiamine in the brominated polyphenylene ether was 1:4.25, and the molar ratio of brominated polyphenylene ether to crosslinking agent was 1:4. An integrated electrode D1 was thus prepared.

[0158] Comparative Example 2

[0159] S1: Preparation of the precursor solution. 1 g of BPPO-1 was dissolved in 15 g of N-methylpyrrolidone, and octadecyl dimethyl tertiary amine and N,N,N,N-tetramethylethylenediamine were added sequentially. The mixture was stirred and reacted at room temperature for 40 h. Then, the crosslinking agent 4,4'-dibromomethylbiphenyl was added to obtain the precursor solution. The amounts of octadecyl dimethyl dimethyl tertiary amine, N,N,N,N-tetramethylethylenediamine, and 4,4'-dibromomethylbiphenyl were such that the molar ratio of bromomethyl to octadecyl dimethyl tertiary amine in the brominated polyphenylene ether was 1:6, the molar ratio of bromomethyl to N,N,N,N-tetramethylethylenediamine in the brominated polyphenylene ether was 1:4.25, and the molar ratio of brominated polyphenylene ether to the crosslinking agent was 1:4.

[0160] S2: Membrane preparation. The precursor liquid prepared in step 1 is degassed under vacuum at a vacuum degree of -80 kPa. The degassed precursor liquid is then coated onto a glass plate with a scraper thickness of 150 μm to obtain a liquid membrane layer. The membrane is then cured in a vacuum oven at 110 °C for 8 hours and peeled off from the glass plate to obtain an anion exchange membrane with a thickness of 123 μm.

[0161] The above-mentioned anion exchange membrane was assembled with an activated carbon electroadsorption electrode to obtain electrode D2.

[0162] Comparative Example 3

[0163] Electrode D3 was obtained by assembling a commercially available anion exchange membrane (AMVN) with a commercially available activated carbon electrode.

[0164] The content of each group and the thickness of the anion exchange functional layer in the integrated electrodes of the embodiments and comparative examples were tested, and the results are shown in Table 1.

[0165] Table 1

[0166]

[0167]

[0168] Test case

[0169] Electrodes prepared in the examples and comparative examples, as well as a commercially available activated carbon electrode (reference example), were used as anodes and a commercially available activated carbon electrode as cathodes to assemble an electro-adsorption deionization device to test its desalination performance for salt solutions.

[0170] The activated carbon electrode measures 5cm x 10cm.

[0171] The test conditions were as follows: the water sample used in the test was a 500 mL sodium chloride solution with an initial conductivity of 1500 μS·cm. -1 The test voltage is 1.2V.

[0172] The test process is as follows: (1) Weigh the mass of the anode electrode and record it as M; (2) Use a peristaltic pump to circulate the sodium chloride solution in the electro-adsorption deionization device, turn on the voltage, and start the adsorption process; (3) After the adsorption has been carried out for a period of time, test the conductivity of the sodium chloride solution and record it as the product water conductivity C1, and record the time as the operation time t1; (4) Disconnect the power supply, short-circuit the device or apply a reverse voltage to carry out the desorption operation; (5) After the desorption has been carried out for a period of time, test the conductivity of the sodium chloride solution and record it as the concentrate water conductivity C2.

[0173] According to the formula The electrode adsorption capacity Q (mg / g) was calculated, and the results are shown in Table 2.

[0174] According to the formula The desalination rate α1 was calculated, and the results are shown in Table 2.

[0175] According to the formula The adsorption rate of the opposite electrode during desorption was calculated, and the results are shown in Table 2.

[0176] Table 2

[0177]

[0178]

[0179] As can be seen from Table 2, the integrated electrode prepared by the present invention includes anion exchange functional layer with a specific structure, which makes the electrode have a higher adsorption capacity for anions (e.g., chloride ions).

[0180] Furthermore, the electro-adsorption deionization device incorporating the integrated electrode of the present invention reaches saturation adsorption in a shorter time under the same operation, which is more conducive to improving the ion transport rate and improving the desalination performance of the electro-adsorption deionization device.

[0181] The integrated electrode prepared by this invention has an adsorption capacity for anions (e.g., chloride ions), and the electro-adsorption deionization device containing the integrated electrode has a high desalination rate and a low adsorption rate of the opposite electrode during desorption. Specifically, the integrated electrode has an adsorption capacity for anions of 14-25 mg / g, the electro-adsorption deionization device has a desalination rate of 72-86%, and the adsorption rate of the opposite electrode during desorption is less than or equal to 10%, preferably 2-9%.

[0182] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. An integrated electrode, characterized in that, The integrated electrode includes an electroadsorption electrode and an anion exchange functional layer coated on the surface of the electroadsorption electrode. The anion exchange functional layer comprises multiple polyphenylene ether molecular chains; the polyphenylene ether molecular chains have the structure shown in Formula I; Equation I Q1, Q2, Q3, and Q4 are each independently a group represented by Formula II, a group represented by Formula III, Br, or H; and at least two of Q1, Q2, Q3, and Q4 are groups represented by Formula II and groups represented by Formula III. Formula II; Formula III; At least two polyphenylene ether molecular chains are connected by an Ar structure from the crosslinking agent; Among them, R1, R2, R4, R5, R7, and R8 are each independently H, CH3, or CH2CH3, and R3 is C8-C. 25 R6 is a C2-C5 straight-chain or branched alkyl group; x is 0.3-0.

8.

2. The integrated electrode according to claim 1, wherein, R1, R2, R4, R5, R7, and R8 are each independently CH2CH3 or CH3; R3 is C. 10 -C 20 R6 is a C2-C3 straight-chain or branched alkyl group; x is 0.4-0.

6.

3. The integrated electrode according to claim 1 or 2, wherein, The Ar structure is selected from at least one of the following: ； ； ； Among them, R9 and R 10 Each can be independently H, OH, or CH3; R 11 and R 12 Each is independently H, CH3, or CH2CH3; n and m are each independently an integer from 1 to 3; p and q are each independently an integer from 1 to 3.

4. The integrated electrode according to claim 3, wherein, R9, R 10 R 11 and R 12 Each is H, and n, m, p and q are all 1.

5. The integrated electrode according to claim 1, wherein, Based on the total molar amount of the anion exchange functional layer, the molar content of the group shown in Formula II is 10-40%, the molar content of the group shown in Formula III is 20-60%, the molar content of Br is 0-5%, and the molar content of Ar structure is 5-15%.

6. The integrated electrode according to claim 5, wherein, Based on the total molar amount of the anion exchange functional layer, the molar content of the group shown in Formula II is 10-30%, the molar content of the group shown in Formula III is 30-50%, the molar content of Br is 0.2-2%, and the molar content of Ar structure is 6-9%.

7. The integrated electrode according to claim 1, wherein, The thickness of the anion exchange functional layer is 100-200 μm.

8. The integrated electrode according to claim 1, wherein, The electroadsorption electrode is selected from at least one of porous foam carbon electrode, activated carbon electrode, graphene electrode and metal modified electrode.

9. The integrated electrode according to claim 1, wherein, The chloride ion adsorption capacity of the electrode is 14-25 mg / g.

10. A method for preparing an integrated electrode, characterized in that, The preparation method includes the following steps: S1. Mix and react the compound A shown in Formula 1, the compound B shown in Formula 2, the brominated polyphenylene ether shown in Formula 3, and an organic solvent, and then add a crosslinking agent to obtain a precursor solution. S2. After vacuum degassing the precursor liquid, it is coated onto the electroadsorption electrode to obtain an electroadsorption electrode with a liquid coating. S3. The electroadsorption electrode with liquid coating is cured to obtain the integrated electrode; Formula 1; Formula 2; Formula 3; Among them, R1', R2', R4', R5', R7', and R8' are each independently H, CH3, or CH2CH3, and R3' is C8-C. 25 R6' is a C2-C5 straight-chain or branched alkylene; X1 and X2 are each independently H or Br, and at least one of X1 and X2 is Br; x is 0.3-0.

8.

11. The preparation method according to claim 10, wherein, The crosslinking agent is selected from at least one of compounds having the following structures; ； ； ； Among them, R9' and R 10 Each can be independently H, OH, or CH3; R 11 'and R 12 Each is independently H, CH3, or CH2CH3; X is Br or Cl; n and m are each independently an integer from 1 to 3; p and q are each independently an integer from 1 to 3.

12. The preparation method according to claim 11, wherein, R9'、R 10 '、R 11 'and R 12 Each is H, and n, m, p and q are all 1.

13. The preparation method according to claim 10, wherein, The molar ratio of the bromomethyl group of the brominated polyphenylene ether to compound A in the precursor solution is 1:4-10.

14. The preparation method according to claim 10, wherein, The molar ratio of bromomethyl groups of brominated polyphenylene ether to compound B in the precursor solution is 1:2-6.

15. The preparation method according to claim 10, wherein, The molar ratio of brominated polyphenylene ether to crosslinking agent in the precursor solution is 1:1-5.

16. The preparation method according to claim 10, wherein, In step S1, the mixing temperature is 20-30℃ and the mixing time is 40-50h.

17. The preparation method according to claim 10, wherein, The conditions for vacuum degassing include a relative vacuum of -80 to -90 kPa.

18. The preparation method according to claim 10, wherein, The thickness of the liquid coating is 100-200 μm.

19. The preparation method according to claim 10, wherein, The curing conditions include: heating from room temperature to 80-120°C at a rate of 1-10°C / min and holding at that temperature for 8-20 hours.

20. The preparation method according to claim 10, wherein, The preparation method further includes washing the cured product.

21. An integrated electrode prepared by any one of claims 10-20.

22. An electro-adsorption deionization device, characterized in that, The electro-adsorption deionization device includes the integrated electrode as described in any one of claims 1-9 and 21.

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