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CN-122011459-A - Modified sulfonated polyether sulfone membrane and preparation method and application thereof

CN122011459ACN 122011459 ACN122011459 ACN 122011459ACN-122011459-A

Abstract

The invention discloses a modified sulfonated polyether sulfone membrane and a preparation method and application thereof, wherein the preparation method of the membrane is that after a sulfonated polyether sulfone solution is prepared into the membrane by adopting a tape casting method, and (3) immersing the film into acrylic acid solution after drying, initiating grafting reaction by ultraviolet light, and then washing and drying. The carboxyl is grafted on the surface of the membrane through ultraviolet initiation, so that the physical and chemical properties of the membrane, such as hydrophilicity, hydroxyl conductivity and the like, are obviously improved, and the efficient trans-membrane transport of carriers is realized.

Inventors

  • XU ZHI
  • HUANG KANG
  • WANG HANGYUAN
  • DING JINGYI
  • WANG YIXING

Assignees

  • 南京工业大学

Dates

Publication Date
20260512
Application Date
20260109

Claims (10)

  1. 1. The modified sulfonated polyether sulfone membrane is characterized by comprising a sulfonated polyether sulfone matrix membrane and a carboxyl-containing functional layer positioned on at least one side surface of the sulfonated polyether sulfone matrix membrane, wherein the carboxyl-containing functional layer is in covalent grafting connection with the surface of the matrix membrane, so that the membrane has both sulfonic acid groups and carboxyl anionic functional groups.
  2. 2. The modified sulfonated polyether sulfone membrane according to claim 1, wherein said carboxyl group-containing functional layer is a graft copolymer layer formed by graft polymerization of a vinyl unsaturated carboxylic acid monomer under ultraviolet action, said vinyl unsaturated carboxylic acid monomer is selected from at least one of acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid and combinations of any two or more thereof, and carboxyl groups in said carboxyl group-containing functional layer are present in the form of-COOH and/or-COO - , and said carboxyl group-containing functional layer is located on at least one of both side surfaces of said base film, preferably on both side surfaces.
  3. 3. The modified sulfonated polyethersulfone membrane according to claim 1 or 2, characterized in that the sulfonated polyethersulfone matrix membrane is obtained by introducing sulfonic acid groups from polyethersulfone through sulfonation reaction in a sulfonation system comprising chlorosulfonic acid and/or sulfuric acid, the membrane is an ion-conducting membrane suitable for alkaline systems, preferably a hydroxide ion-conducting membrane, and the carboxyl-containing functional layer makes the membrane surface exhibit electronegativity to generate electrostatic repulsion to negatively charged ions in alkaline systems, thereby inhibiting the formation tendency of metallic zinc deposition dendrites.
  4. 4. A modified sulfonated polyethersulfone membrane according to any one of claims 1-3, characterized in that said membrane is a membrane prepared by the method of any one of claims 5-9.
  5. 5. A method for preparing the modified sulfonated polyether sulfone membrane according to claim 1 is characterized by comprising the following steps of (1) preparing sulfonated polyether sulfone casting solution and forming a membrane to obtain a sulfonated polyether sulfone matrix membrane, (2) contacting the matrix membrane with grafting solution containing vinyl unsaturated carboxylic acid monomers to infiltrate the monomers on the surface of the matrix membrane, (3) carrying out ultraviolet irradiation on the infiltrated matrix membrane to initiate grafting reaction to form a carboxyl-containing functional layer on the surface of the matrix membrane, and (4) washing and drying the grafted membrane to obtain the modified sulfonated polyether sulfone membrane.
  6. 6. The method according to claim 5, wherein the sulfonated polyethersulfone in step (1) is obtained by sulfonation of polyethersulfone in a sulfonation system comprising chlorosulfonic acid and/or sulfuric acid, the ratio of the amount of polyethersulfone to chlorosulfonic acid and sulfuric acid being 1 g (1-3) mL (5-20) mL, the sulfonation temperature being 40-80 ℃, preferably 40-60 ℃, and the reaction time being 3-10 h, preferably about 6 h.
  7. 7. The method according to claim 5 or 6, wherein the solvent of the casting solution in step (1) is at least one of an amide-based polar aprotic solvent and a sulfoxide-based solvent, preferably N, N-dimethylacetamide and/or dimethylsulfoxide, the concentration of sulfonated polyethersulfone in the casting solution is 0.15-0.35 g/mL, preferably 0.18-0.30 g/mL, more preferably 0.20-0.25 g/mL, and the casting solution is subjected to a dispersion treatment prior to film formation, the dispersion treatment comprising ultrasonic treatment of 0.5-3 h and/or ball milling of 24-96 h, preferably not less than 48 h.
  8. 8. The method according to any one of claims 5 to 7, wherein the film is formed in step (1) by casting with a doctor blade gap of 50 to 500 μm, preferably 100 to 300 μm, more preferably about 200 μm, and drying after the film forming comprises pre-drying at 50 to 90 ℃ for 2 to 12h setting and drying at 100 to 150 ℃ under vacuum to remove residual solvent.
  9. 9. The method according to any one of claims 5 to 8, wherein the grafting liquid is a solution of ethylenically unsaturated carboxylic acid-based monomers in a polar solvent, preferably comprising water, the volume fraction of ethylenically unsaturated carboxylic acid-based monomers in the grafting liquid is 5-40%, preferably 10-30%, more preferably 15-25%, the wavelength of the uv irradiation in step (3) is 300-400 nm, preferably about 365-nm, the uv irradiation time is 5-120 min, preferably 10-90 min, more preferably 30-60 min, and the uv irradiation is performed under the protection of an inert gas selected from nitrogen and/or argon, the washing liquid is water-washed in step (4) until the pH of the washing liquid is neutral or near neutral, the drying temperature is 50-90 ℃, preferably 60-80 ℃, the drying time is 6-24-h, preferably about 12-h, wherein the ethylenically unsaturated carboxylic acid-based monomers are preferably acrylic acid, and the grafting liquid is preferably a mixed solution of acrylic acid and water.
  10. 10. The use of a modified sulfonated polyethersulfone membrane as defined in any one of claims 1-4 in alkaline zinc-iron flow batteries, characterized in that said modified sulfonated polyethersulfone membrane is used as ion conducting separator/separator between positive and negative electrodes, preferably for improving battery voltage efficiency and energy efficiency and improving cycle stability under operating conditions with a current density of 40-200 mA cm "2; preferably, the application is as a separator in an alkaline zinc-iron flow battery; The modified sulfonated polyethersulfone membrane is used for conducting hydroxyl ions and inhibiting zinc dendrite growth.

Description

Modified sulfonated polyether sulfone membrane and preparation method and application thereof Technical Field The invention relates to a modified sulfonated polyether sulfone membrane and a preparation method and application thereof, and belongs to the technical field of alkaline zinc-iron redox flow batteries. Background With the development of green energy, the demand for large-scale energy storage technology is becoming urgent, and in recent years, flow batteries have received extensive attention from researchers. The flow battery has the advantages of long service life, high safety, power capacity separation design and the like, and has great application prospect in the field of large-scale energy storage. The core device is composed of a galvanic pile, an electrolyte storage tank, a circulating system and the like, wherein the core component of the galvanic pile comprises a diaphragm, an electrode, a bipolar plate and the like. A diaphragm is arranged between the positive electrode and the negative electrode of the flow battery, can selectively allow ions to pass through to form a complete battery passage, and can isolate positive and negative electrolyte, so that cross contamination of the electrolyte is prevented and short circuit of the battery is avoided. In an alkaline zinc-iron flow battery, an ideal diaphragm should have the following conditions of stability under ① alkaline conditions, no corrosion by alkali, ② high ionic conductivity and selectivity, ③ high mechanical strength, resistance to dendrite penetration and support long-term stable operation. The most commonly used diaphragm in the field of flow batteries at present is a perfluorosulfonic acid ion exchange membrane (Nafion TM) produced by DuPont company in U.S., but factors such as high cost, complex process, poor ion selectivity and poor long-term stability are likely to cause to restrict the large-scale popularization and application of the Nafion TM membrane in the field of flow batteries. From an economic standpoint, sulfonated Polyethersulfone (SPES) prepared with cheaper Polyethersulfone (PES) materials has good development prospects in zinc-iron flow batteries. The polyether sulfone has excellent thermal stability and excellent chemical stability in a stronger corrosion environment, and most importantly, the excellent mechanical property of the polyether sulfone film can effectively resist the penetration of zinc dendrites to the diaphragm, so that the stability of long-term operation of the battery is improved. Although the polyethersulfone material has excellent physicochemical properties, the defect of no ion exchange group also limits the application of the polyethersulfone material in the field of flow batteries. Sulfonation is a common polymer modification method, and the materials are provided with ion exchange groups, and meanwhile, the membrane performance such as hydrophilicity, water flux, ion permeability, ion conductivity and the like can be greatly improved, so that researchers usually use sulfonated polyethersulfone as a base membrane preparation material. However, the SPES film still has the defects of low conductivity and the like, so that the SPES film is further modified to improve the performance of the SPES film in the alkaline zinc-iron flow battery has important significance. Disclosure of Invention The invention aims to provide a modified sulfonated polyether sulfone membrane, a preparation method and application thereof, wherein carboxyl groups are grafted on the surface of the membrane through ultraviolet initiation, so that the physical and chemical properties of the membrane, such as hydrophilicity, hydroxyl conductivity and the like, are obviously improved, and efficient transmembrane transport of carriers is realized. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: A modified sulfonated polyether sulfone membrane comprises a sulfonated polyether sulfone matrix membrane and a carboxyl-containing functional layer positioned on at least one side surface of the sulfonated polyether sulfone matrix membrane, wherein the carboxyl-containing functional layer is in covalent grafting connection with the surface of the matrix membrane, so that the membrane has two anionic functional groups, namely a sulfonic group and a carboxyl group. The carboxyl-containing functional layer is a graft copolymer layer formed by graft polymerization of vinyl unsaturated carboxylic acid monomers under the action of ultraviolet. The vinyl unsaturated carboxylic acid monomer is at least one selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid and a combination of any two or more thereof. The carboxyl group in the carboxyl-containing functional layer exists in the form of-COOH and/or-COO -. The carboxyl-containing functional layer is located on at least one of the two side surfaces of the base film, prefera