Integrated electrode, preparation method thereof and electro-adsorption deionization device

Abstract

The invention relates to the field of electrochemistry, and discloses an integrated electrode, a preparation method thereof and an electro-adsorption deionization device. The integrated electrode comprises an electro-adsorption electrode and an anion exchange functional layer coated on the surface of the electro-adsorption electrode; wherein the anion exchange functional layer comprises a plurality of polyphenyl ether molecular chains; the polyphenyl ether molecular chain has a structure as shown in a formula I; # imgabs0 # Q1, Q2, Q3 and Q4 are each independently a group represented by formula II, a group represented by formula III, Br or H; at least two of Q1, Q2, Q3 and Q4 are a group as shown in a formula II and a group as shown in a formula III; at least two polyphenyl ether molecular chains of the # imgabs 1 # are connected through an Ar structure from a cross-linking agent. According to the integrated electrode, the ion transmission rate can be remarkably improved, the saturated adsorption capacity of the electro-adsorption electrode is improved, and when the integrated electrode is used for the electro-adsorption deionization device, the desalting performance of the electro-adsorption deionization device can be remarkably improved.

Description

Technical Field

[0001] The present invention relates to the field of electrochemistry, and in particular to an integrated electrode and a preparation method thereof, and an electric adsorption deionization device. Background Art

[0002] Electrodesorption (CDI) is an electrochemical water treatment technology for moderate desalination, which has the advantages of high efficiency, environmental protection, and renewability. By placing an ion exchange membrane on the electrode surface, the common ion effect in the adsorption process can be weakened, the adsorption resistance can be reduced, and the secondary adsorption of ions by the opposite electrode during the desorption process of CDI can be avoided, thereby improving performance.

[0003] In actual operation, the desalination performance of CDI devices is still relatively low. On the one hand, the number of active ion exchange groups in existing ion exchange membranes is low, the membrane surface resistance is high and the ion transfer rate is limited; on the other hand, the ion exchange membrane and the electrode are combined in the form of physical superposition, which produces a high contact resistance and inhibits the diffusion of ions from the ion exchange membrane to the electrode surface. Under the combined effect of low ion transfer rate and high contact resistance, existing electrosorption devices generally have the disadvantages of low electrode adsorption capacity, low desalination efficiency and high energy consumption, which affects the industrial application of electrosorption technology.

[0004] CN109502708A proposes to prepare an ion exchange membrane / carbon composite electrode by spraying an ion exchange membrane slurry, wherein the ion exchange membrane slurry is a mixture of pretreated ion exchange resin and a binder solution. The composite electrode prepared by this method is a heterogeneous structure, and the ion exchange resin and the electrode are combined by a binder. On the one hand, the ion exchange resin is a discontinuous phase, and the density of the ion transmission channel is low; on the other hand, the binder has no ion exchange function, which increases the contact resistance between the electrode and the ion exchange resin, and has limited effect on improving the performance of the conductive carbon electrode. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art, such as low capacity, low desalination efficiency and high energy consumption of the electrosorption electrode, and to provide an integrated electrode, which includes an electrosorption electrode and an anion exchange functional layer with a specific structure coated on the surface of the electrosorption electrode, and can significantly improve the ion transfer rate and the saturated adsorption capacity of the electrosorption electrode. When the integrated electrode is used in an electrosorption deionization device, the desalination performance of the electrosorption deionization device can be significantly improved.

[0006] In order to achieve the above object, the first aspect of the present invention provides an integrated electrode, wherein the integrated electrode comprises an electrosorption electrode and an anion exchange functional layer coated on the surface of the electrosorption electrode;

[0007] Wherein, the anion exchange functional layer comprises a plurality of polyphenylene ether molecular chains; the polyphenylene ether molecular chains have a structure as 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 a group represented by formula II and a group represented by formula III;

[0010]

[0011] At least two polyphenylene ether molecular chains are connected via an Ar structure from a cross-linking agent;

[0012] Among them, R 1 , R 2 , R 4 , R 5 , R 7 , R 8 Each independently is H, CH 3 or CH 2 CH 3 , R 3 C 8 -C 25 A straight chain or branched alkyl group; R 6 C 2 -C 5 A straight chain alkylene group or a branched chain alkylene 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 comprises the following steps:

[0014] S1, mixing and reacting the compound A represented by Formula 1, the compound B represented by Formula 2, the brominated polyphenylene ether represented by Formula 3 and an organic solvent, and then adding a cross-linking agent to obtain a precursor solution;

[0015] S2, after vacuum degassing the precursor liquid, coating it on the electrosorption electrode to obtain the electrosorption electrode with a liquid coating;

[0016] S3, curing the electrosorption electrode with the liquid coating to obtain the integrated electrode;

[0017]

[0018] Among them, R 1 '、R 2 '、R 4 '、R 5 '、R 7 '、R8 ' are independently H, CH 3 or CH 2 CH 3 , R 3 ' is C 8 -C 25 A straight chain or branched alkyl group; R 6 ' is C 2 -C 5 A straight chain alkylene or branched chain alkylene, X 1 and X 2 are each independently H or Br, and X 1 and X 2 At least one of them is Br; and x is 0.3-0.8.

[0019] The third aspect of the present invention provides an integrated electrode produced by the above-mentioned preparation method.

[0020] A fourth aspect of the present invention provides an electrosorption deionization device, wherein the electrosorption deionization device comprises the above-mentioned integrated electrode.

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

[0022] In the present invention, the integrated electrode includes an electrosorption electrode and an anion exchange functional layer with a specific structure coated on the surface of the electrosorption electrode. The anion exchange membrane has a double side chain structure, which can greatly increase the number of active ion exchange groups, thereby increasing the ion transmission rate on the surface of the electrosorption electrode containing the anion exchange functional layer, and increasing the exchange capacity of the electrosorption electrode. In particular, when the integrated electrode is used in an electrosorption deionization device, the desalination performance of the adsorption deionization device can be significantly improved, and energy consumption can be reduced.

[0023] In the present invention, in the preparation method of the integrated electrode, an anion exchange functional layer is formed on the surface of the electrosorption electrode by in-situ polymerization, which can significantly enhance the binding ability between the anion exchange functional layer and the electrosorption electrode, thereby reducing the contact resistance, increasing the ion transmission rate on the electrode surface, and improving the exchange capacity of the electrosorption electrode. In particular, when the integrated electrode is used in an electrosorption deionization device, the desalination performance of the adsorption deionization device can be significantly improved and the energy consumption can be reduced.

[0024] The integrated electrode prepared by the present invention has an adsorption capacity for anions (such as chloride ions), and the electric adsorption deionization device including the integrated electrode has a high desalination rate, and the adsorption rate of the opposite electrode during desorption is low. Specifically, the adsorption capacity of the integrated electrode for anions is 14-25 mg / g, the desalination rate of the electric adsorption deionization device is 72-86%, 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 time, thereby greatly improving the desalination performance of the electric adsorption deionization device. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The present invention is a process flow chart for preparing an integrated electrode by the method of the present invention. DETAILED DESCRIPTION

[0026] The endpoints and any values ​​of the ranges disclosed in this article 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 each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

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

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

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

[0030] Wherein, the anion exchange functional layer comprises a plurality of polyphenylene ether molecular chains; the polyphenylene ether molecular chains have a structure as 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 a group represented by formula II and a group represented by formula III;

[0033]

[0034] At least two polyphenylene ether molecular chains are connected via an Ar structure from a cross-linking agent;

[0035] Among them, R 1 , R 2 , R 4 , R 5 , R 7 , R 8 Each independently is H, CH 3 or CH 2 CH 3 , R 3 C 8 -C 25 A straight chain or branched alkyl group; R 6 C 2 -C 5 A straight chain alkylene group or a branched chain alkylene group; x is 0.3-0.8.

[0036] In the present invention, the integrated electrode includes an electrosorption electrode and an anion exchange functional layer with a specific structure coated on the surface of the electrosorption electrode. The 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 transmission rate on the surface of the electrosorption electrode containing the anion exchange membrane, and increasing the saturated adsorption capacity of the electrosorption electrode. In particular, when the integrated membrane electrode is used in an electrosorption deionization device, the desalination performance of the adsorption deionization device can be significantly improved, and energy consumption can be reduced.

[0037] Specifically, the anion exchange functional layer uses polyphenylene ether as a skeleton, and introduces two long-chain hydrophobic alkyl side chains on the molecular chain of the polyphenylene ether skeleton. Compared with traditional short side chains, long-chain hydrophobic alkyl side chains have stronger activity and can promote the formation of a hydrophilic-hydrophobic microphase-separated aggregation structure in the membrane. At the same time, the introduction of the two 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, R 1 , R 2 , R 4 , R 5 , R 7 , R 8 Each independently is CH 2 CH 3 or CH 3 ; R 3 C 10 -C 20 A straight chain or branched alkyl group; R 6 C 2 -C3 A straight chain alkylene group or a branched chain alkylene group; x is 0.4-0.6.

[0039] In a specific embodiment of the present invention, R 1 , R 2 CH 3 , R 3 C 18 of a straight chain alkyl group.

[0040] In a specific embodiment of the present invention, R 1 , R 2 CH 3 , R 3 C 10 of a straight chain alkyl group.

[0041] In a specific embodiment of the present invention, R 4 , R 5 , R 7 , R 8 Each independently is CH 3 , R 6 For ethylene.

[0042] In a specific embodiment of the present invention, R 4 , R 5 , R 7 , R 8 Each independently is CH 3 , R 6 For methylene.

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

[0044]

[0045] Among them, R 9 and R 10 Each independently is H, OH or CH 3 ; R 11 and R 12 Each independently is H, CH 3 or CH 2 CH 3 ; n and m are each independently an integer of 1-3; p and q are each independently an integer of 1-3.

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

[0047] Furthermore, R 9 , R10 , R 11 and R 12 Each 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 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 the Ar structure is 5-15%.

[0049] In the present invention, when the content of each structural unit in the anion exchange functional layer meets the above range, the crosslinking agent and the main chain graft can form a cationic group imidazole group, which provides an active site for ion migration and can increase the saturated adsorption capacity of the electrosorption electrode containing the anion exchange functional layer.

[0050] In the present invention, when the anion exchange functional layer is prepared on the electrosorption electrode, compound A and compound B are substantially free of residue, indicating that in the present invention, when the anion exchange functional layer is prepared, compound A and compound B can all react with the brominated polyphenylene ether. Therefore, the content of each structural unit in the anion exchange functional layer can be determined by the feed amount.

[0051] Furthermore, based on the total amount of the anion exchange functional layer, the content of the structural unit represented by formula I is 10-30%, the content of the structural unit represented by 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 the present invention, when the thickness of the anion exchange functional layer is controlled to meet the above range, the water absorption of the ion exchange group can be suppressed and the ion migration channel can be established, which can further increase 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 electro-adsorption electrode is selected from at least one of a porous foam carbon electrode, an activated carbon electrode, a graphene electrode and a 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 comprises:

[0058] S1, mixing and reacting the compound A represented by Formula 1, the compound B represented by Formula 2, the brominated polyphenylene ether represented by Formula 3 and an organic solvent, and then adding a cross-linking agent to obtain a precursor solution;

[0059] S2, after vacuum degassing the precursor liquid, coating it on the electrosorption electrode to obtain the electrosorption electrode with a liquid coating;

[0060] S3, curing the electrosorption electrode with the liquid coating to obtain the integrated electrode;

[0061] in,

[0062] Among them, R 1 '、R 2 '、R 4 '、R 5 '、R 7 '、R 8 ' are independently H, CH 3 or CH 2 CH 3 , R 3 ' is C 8 -C 25 A straight chain or branched alkyl group; R 6 ' is C 2 -C 5 A straight chain alkylene or branched chain alkylene, X 1 and X 2 are each independently H or Br, and X 1 and X 2 At least one of them is Br; x is 0.3-0.8. In the present invention, in the preparation method of the integrated electrode, an anion exchange functional layer is formed on the surface of the electrosorption electrode by in-situ polymerization, which can significantly enhance the binding ability between the anion exchange functional layer and the electrosorption electrode, thereby reducing the contact resistance, providing an ion transmission rate on the electrode surface, and improving the exchange capacity of the electrosorption electrode. In particular, when the integrated electrode is used in an electrosorption deionization device, it can significantly improve the desalination performance of the adsorption deionization device and reduce energy consumption.

[0063] Furthermore, R 1 '、R 2 '、R 4 '、R 5 '、R 7 '、R 8 'Each independently is CH 2 CH 3 or CH 3 , R 3 ' is C 10 -C 20A straight chain or branched alkyl group; R 6 ' is C 2 -C 3 A straight chain alkylene or branched chain alkylene, X 1 and X 2 are each independently H or Br, and X 1 and X 2 At least one of them is Br; and x is 0.4-0.6.

[0064] In one embodiment of the present invention, the compound A shown in Formula 1 is octadecyl dimethyl tertiary amine, that is, R 1 '、R 2 'For CH 3 , R 3 ' is C 18 of a straight chain alkyl group.

[0065] In another specific embodiment of the present invention, the compound A shown in Formula 1 is a dodecyl dimethyl tertiary amine, that is, R 1 '、R 2 'For CH 3 , R 3 ' is C 10 of a straight chain alkyl group.

[0066] In one embodiment of the present invention, the compound B shown in Formula 2 is N,N,N,N-tetramethylethylenediamine, that is, R 4 '、R 5 '、R 7 '、R 8 'Each independently is CH 3 , R 6 ' is ethylene.

[0067] In another specific embodiment of the present invention, the compound B shown in Formula 2 is N,N,N,N-tetramethylethylenediamine, that is, R 4 '、R 5 '、R 7 '、R 8 'Each independently is CH 3 , R 6 ' is a methylene group.

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

[0069] In the present invention, the weight average molecular weight of the brominated polyphenylene ether is 70000-90000 g / mol.

[0070] In the present invention, there is no particular limitation on the source of the polyphenylene ether, which can be purchased from the market 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 to carry out a bromination reaction;

[0073] S2, cooling the product obtained in step S1, adding alcohol solution dropwise, filtering, washing, purifying and drying to obtain the brominated polyphenylene ether.

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

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

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

[0077] In the present invention, the bromination reagent may be a conventional bromination reagent in the art, such as N-bromosuccinimide (NBS) and / or 1,3-dibromo-5,5-dimethylhydantoin (DBH).

[0078] In the present invention, the initiator may be a conventional initiator in the art, for example, azobisisobutyronitrile (AIBN) and / or azobisisoheptanenitrile (ABVN).

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

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

[0081] In the present invention, the conditions of the bromination reaction include: reaction temperature of 110-140° C., and reaction time of 2-4 h.

[0082] In the present invention, there is no particular limitation on the type of alcohol solution, and conventional alcohol solutions in the art, such as methanol solutions, can be used. There is no particular limitation on the amount of the alcohol solution, as long as the brominated polyphenylene ether can be completely precipitated. In order to further ensure that the brominated polyphenylene ether can be completely precipitated, preferably, the alcohol solution is added dropwise, more preferably, added dropwise to the product obtained in step S1 at a rate of 20-50 mL / min.

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

[0084] In the present invention, the purification step comprises: re-dissolving the washed product in a first organic solvent, and washing with a second organic solvent.

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

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

[0087] In the present 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 cross-linking agent is selected from at least one of the compounds having the structures shown below;

[0089]

[0090] Among them, R 9 ' and R 10 ' are each independently H, OH or CH 3 ; R 11 ' and R 12 ' are independently H, CH 3 or CH 2 CH 3 ; X is Br or Cl, n and m are each independently an integer of 1-3; p and q are each independently an integer of 1-3.

[0091] In the present invention, the use of the above specific cross-linking agent can realize the connection of at least two polyphenylene ether molecular chains to form a stable network structure, which will not reduce the ion exchange capacity of the anion exchange functional layer while providing active sites for ion migration.

[0092] Furthermore, R 9 '、R 10 '、R 11 ' and R 12' are all H, and n, m, p and q are all 1.

[0093] In a specific embodiment of the present invention, the cross-linking 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 cross-linking 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 the bromomethyl group of the brominated polyphenylene ether to compound A in the precursor solution is 1:4-10, the molar ratio of the bromomethyl group of the brominated polyphenylene ether to compound B in the precursor solution is 1:2-6, and the molar ratio of the brominated polyphenylene ether to the crosslinking agent in the precursor solution is 1:1-5.

[0096] In the present invention, when the molar ratio of brominated polyphenylene ether, compound A, compound B and cross-linking agent in the precursor solution is controlled to meet the above range, the cross-linking agent and the main chain can be grafted to form a cationic group imidazole group, which provides an active site for ion migration and can increase the saturated adsorption capacity of the electrosorption electrode containing the anion exchange functional layer.

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

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

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

[0100] In the present invention, the brominated polyphenylene ether is mixed with the organic solvent in advance, which can ensure that the brominated polyphenylene ether is fully dissolved and dispersed in the organic solvent, improve the dispersibility of the brominated polyphenylene ether in the mixed solution, and then allow compound A and compound B to fully contact and react with the brominated polyphenylene ether.

[0101] In the present invention, in order to control the dispersibility of the brominated polyphenylene ether, preferably, the concentration of the brominated polyphenylene ether in the mixed solution 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 h.

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

[0104] In the present 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 the present invention, the curing under the above conditions can achieve complete curing of the liquid coating while ensuring that the anion exchange functional layer is not deformed due to heat.

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

[0109] According to the present invention, the preparation method further comprises: washing the solidified product.

[0110] In the present invention, the solidified product is washed with deionized water. Preferably, the solidified product is immersed in deionized water for washing.

[0111] The third aspect of the present invention provides an integrated electrode produced by the above-mentioned preparation method.

[0112] A fourth aspect of the present invention provides an electrosorption deionization device, characterized in that the electrosorption deionization device comprises the above-mentioned integrated electrode.

[0113] In the present invention, the electric adsorption deionization device includes the above-mentioned integrated electrode, which can significantly improve the desalination performance of the adsorption deionization device and significantly reduce energy consumption.

[0114] In the present invention, the desalination rate of the electric adsorption deionization device with integrated electrodes described in the present invention 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, greatly improving the desalination performance of the electric adsorption deionization device.

[0115] The present invention will be described in detail below by way of examples. In the following examples,

[0116] All raw materials in the examples and comparative examples are commercially available products from MacLean, among which poly (2,6-dimethyl-1,4-phenylene ether) M w It is 45000g / mol.

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

[0118] The thickness of the anion functional exchange layer in the integrated electrode was tested using a membrane thickness measuring instrument.

[0119] The chloride ion adsorption capacity of the integrated electrode and the desalination rate of the electric adsorption device were tested using the method described in the test example.

[0120] Preparation Example 1

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

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

[0123] Preparation Example 2

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

[0125] The bromination rate x of the brominated polyphenylene ether was 0.75, and the weight average molecular weight was 87652 g / mol.

[0126] Example 1

[0127] S1: Preparation of precursor solution. Dissolve 1g BPPO-1 in 15g N-methylpyrrolidone, add octadecyl dimethyl tertiary amine and N,N,N,N-tetramethylethylenediamine in turn, stir and react at room temperature for 40h, then add crosslinker 4,4'-dibromomethylbiphenyl to obtain a precursor solution. 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 brominated polyphenylene ether is 1:6, the molar ratio of bromomethyl to N,N,N,N-tetramethylethylenediamine in brominated polyphenylene ether is 1:4.25, and the molar ratio of brominated polyphenylene ether to crosslinker is 1:4.

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

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

[0130] S4: Cleaning: Soak the polymerized and solidified integrated electrode in deionized water to obtain an integrated 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 precursor solution. Dissolve 1g BPPO-1 in 15g N-methylpyrrolidone, add octadecyl dimethyl tertiary amine and N,N,N,N-tetramethylethylenediamine in turn, stir the reaction at room temperature for 40h, and then add 4,4'-dibromomethylbiphenyl. Among them, the amount of octadecyl dimethyl dimethyl tertiary amine, N,N,N,N-tetramethylethylenediamine and 4,4'-dibromomethylbiphenyl is such that the molar ratio of bromomethyl to octadecyl dimethyl tertiary amine in brominated polyphenylene ether is 1:5, the molar ratio of bromomethyl to N,N,N,N-tetramethylethylenediamine in brominated polyphenylene ether is 1:4.25, and the molar ratio of brominated polyphenylene ether to crosslinking agent is 1:4. . An integrated electrode A2 is 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, add octadecyl dimethyl tertiary amine and N,N,N,N-tetramethylethylenediamine in turn, stir the reaction at room temperature for 40h, and then add 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 brominated polyphenylene ether is 1:6, the molar ratio of bromomethyl to N,N,N,N-tetramethylethylenediamine in brominated polyphenylene ether is 1:4.25, and the molar ratio of brominated polyphenylene ether to crosslinking agent is 1:3. The integrated membrane electrode A3 is 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, add octadecyl dimethyl tertiary amine and N,N,N,N-tetramethylethylenediamine in turn, stir the reaction at room temperature for 40h, and then add 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 brominated polyphenylene ether is 1:6, the molar ratio of bromomethyl to N,N,N,N-tetramethylethylenediamine in 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 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, add dodecyl dimethyl tertiary amine and N,N,N,N-tetramethylethylenediamine in turn, stir the reaction at room temperature for 40h, and then add 4,4'-dibromomethylbiphenyl. The amounts of dodecyl dimethyl dimethyl tertiary amine, N,N,N,N-tetramethylethylenediamine and 4,4'-dibromomethylbiphenyl are such that the molar ratio of bromomethyl to dodecyl dimethyl tertiary amine in brominated polyphenylene ether is 1:6, the molar ratio of bromomethyl to N,N,N,N-tetramethylethylenediamine in 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 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, add octadecyl dimethyl tertiary amine and N,N,N,N-tetramethyl methanediamine in turn, stir the reaction at room temperature for 40h, and then add 4,4'-dibromomethyl biphenyl. The amounts of octadecyl dimethyl dimethyl tertiary amine, N,N,N,N-tetramethyl methanediamine and 4,4'-dibromomethyl biphenyl are such that the molar ratio of bromomethyl to octadecyl dimethyl tertiary amine in brominated polyphenylene ether is 1:6, the molar ratio of bromomethyl to N,N,N,N-tetramethyl methanediamine in brominated polyphenylene ether is 1:4.25, and the molar ratio of brominated polyphenylene ether to crosslinking agent is 1:4. The integrated electrode A6 is obtained.

[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, add octadecyl dimethyl tertiary amine and N,N,N,N-tetramethylethylenediamine in turn, stir the reaction at room temperature for 40h, and then add 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 brominated polyphenylene ether is 1:2, the molar ratio of bromomethyl to N,N,N,N-tetramethylethylenediamine in brominated polyphenylene ether is 1:4.25, and the molar ratio of brominated polyphenylene ether to crosslinking agent is 1:4. The prepared 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, add octadecyl dimethyl tertiary amine and N,N,N,N-tetramethylethylenediamine in turn, stir the reaction at room temperature for 40h, and then add 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 brominated polyphenylene ether is 1:8, the molar ratio of bromomethyl to N,N,N,N-tetramethylethylenediamine in brominated polyphenylene ether is 1:4.25, and the molar ratio of brominated polyphenylene ether to crosslinking agent is 1:4. The integrated electrode A8 is obtained.

[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, add octadecyl dimethyl tertiary amine and N,N,N,N-tetramethylethylenediamine in turn, stir the reaction at room temperature for 40h, and then add 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 brominated polyphenylene ether is 1:3, the molar ratio of bromomethyl to N,N,N,N-tetramethylethylenediamine in brominated polyphenylene ether is 1:0.5, and the molar ratio of brominated polyphenylene ether to crosslinking agent is 1:0.4. The integrated electrode A9 is obtained.

[0155] Comparative Example 1

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

[0157] S1: Dissolve 1g of BPPO-1 in 15g of N-methylpyrrolidone, add tert-amylamine and N,N,N,N-tetramethylmethanediamine in turn, stir the reaction at room temperature for 40h, and then add 4,4'-dibromomethylbiphenyl. The amounts of tert-amylamine, N,N,N,N-tetramethylmethanediamine and 4,4'-dibromomethylbiphenyl are such that the molar ratio of bromomethyl to tert-amylamine in brominated polyphenylene ether is 1:6, the molar ratio of bromomethyl to N,N,N,N-tetramethylmethanediamine in brominated polyphenylene ether is 1:4.25, and the molar ratio of brominated polyphenylene ether to crosslinking agent is 1:4. The integrated electrode D1 is obtained.

[0158] Comparative Example 2

[0159] S1: Preparation of precursor solution. Dissolve 1g BPPO-1 in 15g N-methylpyrrolidone, add octadecyl dimethyl tertiary amine and N,N,N,N-tetramethylethylenediamine in turn, stir and react at room temperature for 40h, then add crosslinker 4,4'-dibromomethylbiphenyl to obtain a precursor solution. 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 brominated polyphenylene ether is 1:6, the molar ratio of bromomethyl to N,N,N,N-tetramethylethylenediamine in brominated polyphenylene ether is 1:4.25, and the molar ratio of brominated polyphenylene ether to crosslinker is 1:4.

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

[0161] The anion exchange membrane and the activated carbon electrosorption electrode are assembled to obtain electrode D2.

[0162] Comparative Example 3

[0163] A commercially available anion exchange membrane (AMVN) was assembled with a commercially available activated carbon electrode to obtain electrode D3.

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

[0165] Table 1

[0166]

[0167]

[0168] Test Case

[0169] The electrodes prepared in the examples and comparative examples and a commercially available activated carbon electrode (reference example) were respectively used as anodes, and the commercially available activated carbon electrode was used as cathodes to assemble an electric adsorption deionization device to test its desalination performance for saline solutions.

[0170] Among them, the size of the activated carbon electrode is 5cm*10cm.

[0171] The test conditions are as follows: the water sample used in the test is 500mL of sodium chloride solution, and the initial conductivity is 1500μs·cm -1 , the test voltage is 1.2V.

[0172] The test process is as follows: (1) weigh the mass of the anode electrode, denoted as M; (2) use a peristaltic pump to circulate the sodium chloride solution in the electric adsorption deionization device, turn on the voltage, and start the adsorption process; (3) after a period of adsorption, test the conductivity of the sodium chloride solution, denoted as the conductivity of the produced water C. 1 , the time is recorded as the operation time t 1 ; (3) Disconnect the power supply, short-circuit the device or apply reverse voltage to perform desorption operation; (4) After desorption for a period of time, test the conductivity of the sodium chloride solution and record it as the concentrated water conductivity C 2 .

[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 Calculate the salt rejection rate α 1 , 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] It can be seen from Table 2 that the integrated electrode prepared in the present invention includes an anion exchange functional layer with a specific structure, so that the adsorption capacity of the electrode for anions (such as chloride ions) is higher.

[0180] In addition, the electric adsorption deionization device including the integrated electrode of the present invention takes a shorter time to reach saturated adsorption under the same operation, is more conducive to improving the ion transfer rate, and improves the desalination performance of the electric adsorption deionization device.

[0181] The integrated electrode prepared by the present invention has an adsorption capacity for anions (such as chloride ions), and the electrosorption deionization device including the integrated electrode has a high desalination rate, and the adsorption rate of the opposite electrode during desorption is low. Specifically, the adsorption capacity of the integrated electrode for anions is 14-25 mg / g, the desalination rate of the electrosorption 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%.

[0182] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. An integrated electrode, It is characterized in that The integrated electrode comprises an electrosorption electrode and an anion exchange functional layer coated on the surface of the electrosorption electrode; Wherein, the anion exchange functional layer comprises a plurality of polyphenylene ether molecular chains; the polyphenylene ether molecular chains have a structure as shown in Formula 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 a group represented by formula II and a group represented by formula III; At least two polyphenylene ether molecular chains are connected via an Ar structure from a cross-linking agent; Among them, R 1 , R 2 , R 4 , R 5 , R 7 , R 8 Each independently is H, CH 3 or CH 2 CH 3 , R 3 C 8 -C 25 A straight chain or branched alkyl group; R 6 C 2 -C 5 A straight chain alkylene group or a branched chain alkylene group; x is 0.3-0.

8.

2. The integrated membrane electrode according to claim 1, in, R 1 , R 2 , R 4 , R 5 , R 7 , R 8 Each independently is CH 2 CH 3 or CH 3 ; R 3 C 10 -C 20 A straight chain or branched alkyl group; R 6 C 2 -C 3 A straight chain alkylene group or a branched chain alkylene group; x is 0.4-0.

6.

3. The integrated electrode according to claim 1 or 2, in, The Ar structure is selected from at least one of the following: Among them, R 9 and R 10 Each independently is H, OH or CH 3 ; R 11 and R 12 Each independently is H, CH 3 or CH 2 CH 3 ; n and m are each independently an integer of 1-3; p and q are each independently an integer of 1-3; Preferably, R 9 , R 10 , R 11 and R 12 Each is H, and n, m, p and q are all 1.

4. The integrated electrode according to any one of claims 1 to 3, in, Based on the total molar amount of the anion exchange functional layer, 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 the Ar structure is 5-15%; Preferably, based on the total molar amount of the anion exchange functional layer, the molar content of the group represented by formula II is 10-30%, the molar content of the group represented by formula III is 30-50%, the molar content of Br is 0.2-2%, and the molar content of the Ar structure is 6-9%.

5. The integrated electrode according to any one of claims 1 to 4, in, The thickness of the anion exchange functional layer is 100-200 μm.

6. The integrated electrode according to any one of claims 1 to 5, in, The electro-adsorption electrode is selected from at least one of a porous foam carbon electrode, an activated carbon electrode, a graphene electrode and a metal modified electrode.

7. The integrated electrode according to any one of claims 1 to 6, in, The chloride ion adsorption capacity of the electrode is 14-25 mg / g.

8. A method for preparing an integrated electrode, It is characterized in that The preparation method comprises the following steps: S1, mixing and reacting the compound A represented by Formula 1, the compound B represented by Formula 2, the brominated polyphenylene ether represented by Formula 3 and an organic solvent, and then adding a cross-linking agent to obtain a precursor solution; S2, after vacuum degassing the precursor liquid, coating it on the electrosorption electrode to obtain the electrosorption electrode with a liquid coating; S3, curing the electrosorption electrode with the liquid coating to obtain the integrated electrode; Among them, R 1 '、R 2 '、R 4 '、R 5 '、R 7 '、R 8 ' are independently H, CH 3 or CH 2 CH 3 , R 3 ' is C 8 -C 25 A straight chain or branched alkyl group; R 6 ' is C 2 -C 5 A straight chain alkylene or branched chain alkylene, X 1 and X 2 are each independently H or Br, and X 1 and X 2 At least one of them is Br; and x is 0.3-0.

8.

9. The preparation method according to claim 8, in, The cross-linking agent is selected from at least one of the compounds having the structures shown below; Among them, R 9 ' and R 10 ' are each independently H, OH or CH 3 ; R 11 ' and R 12 ' are independently H, CH 3 or CH 2 CH 3 ; X is Br or Cl, n and m are each independently an integer of 1-3; p and q are each independently an integer of 1-3; Preferably, R 9 '、R 10 '、R 11 ' and R 12 ' are all H, and n, m, p and q are all 1.

10. The preparation method according to claim 8 or 9, in, The molar ratio of the bromomethyl group of the brominated polyphenylene ether to the compound A in the precursor solution is 1:4-10; Preferably, the molar ratio of the bromomethyl group of the brominated polyphenylene ether to the compound B in the precursor solution is 1:2-6; Preferably, the molar ratio of brominated polyphenylene ether to cross-linking agent in the precursor solution is 1:1-5; Preferably, in step S1, the mixing temperature is 20-30°C, and the mixing time is 40-50h.

11. The preparation method according to any one of claims 8 to 10, in, The vacuum degassing conditions include: relative vacuum degree of -80 to -90 kPa; Preferably, the thickness of the liquid coating is 100-200 μm.

12. The preparation method according to any one of claims 8 to 11, in, The curing conditions include: heating from room temperature to 80-120°C at a rate of 1-10°C / min, and keeping the temperature for 8-20h; Preferably, the preparation method further comprises: washing the solidified product.

13. An integrated electrode prepared by the preparation method according to any one of claims 7 to 12.

14. An electrosorption deionization device, It is characterized in that The electrosorption deionization device comprises the integrated electrode as described in any one of claims 1-6 and 13.

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