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CN-121972022-A - Composite cation exchange membrane and preparation method and application thereof

CN121972022ACN 121972022 ACN121972022 ACN 121972022ACN-121972022-A

Abstract

The application belongs to the technical field of ion exchange membranes, and particularly relates to a composite cation exchange membrane, and a preparation method and application thereof. The composite cation exchange membrane comprises the following preparation raw materials of 45-55 parts of sulfonated polyether-ether-ketone, 30-40 parts of polyetherimide, 2-8 parts of zirconium phosphate with surface amino modified by functionalization and 2-5 parts of cross-linking agent. The composite cation exchange membrane disclosed by the application has the beneficial effects that through the chemical copolymerization of sulfonated polyether ether ketone (SPEEK) and Polyetherimide (PEI), a compact interpenetrating network is constructed by utilizing the crosslinking reaction of sulfonic acid groups (-SO 3 H) and amino groups (-NH 2 ), and the inorganic layered support of zirconium phosphate (KH-a-ZrP) with the surface modified by amino functionalization is matched, SO that not only is the rich ion exchange site of the SPEEK reserved, but also the swelling of the membrane is inhibited by the physical barrier between a rigid chain segment of PEI and KH-a-ZrP, SO that the composite cation exchange membrane has higher conduction efficiency and structural stability.

Inventors

  • YANG WENQIANG
  • GAO JIAMIN
  • SU YAN
  • JIANG QI
  • WU HUOQIANG
  • LIU FANG
  • JIA JIWU
  • LI ZHIQIANG
  • ZHANG PENG

Assignees

  • 西安西热水务环保有限公司
  • 华能嘉祥发电有限公司

Dates

Publication Date
20260505
Application Date
20260109

Claims (10)

  1. 1. A composite cation exchange membrane is characterized by comprising the following preparation raw materials of 45-55 parts of sulfonated polyether-ether-ketone, 30-40 parts of polyetherimide, 2-8 parts of zirconium phosphate with surface amino modified by functionalization and 2-5 parts of cross-linking agent.
  2. 2. The composite cation exchange membrane according to claim 1, which comprises 45-55 parts of sulfonated polyether ether ketone, 30-40 parts of polyetherimide, 4-6 parts of zirconium phosphate modified by surface amino functionalization and 3 parts of cross-linking agent.
  3. 3. The composite cation exchange membrane of claim 1, wherein the sulfonated polyetheretherketone has a degree of sulfonation of 65% to 78%; and/or the crosslinking agent comprises one or more of sulfonyl chloride, phosphorus oxychloride, p-toluenesulfonyl chloride and thionyl chloride.
  4. 4. A method for preparing a composite cation exchange membrane according to any one of claims 1 to 3, comprising the steps of: (1) Mixing sulfonated polyether-ether-ketone, polyetherimide, zirconium phosphate with surface amino functional modification, a cross-linking agent and an organic solvent for reaction to obtain a reaction solution; (2) Mixing the reaction solution with a defoaming agent, and performing defoaming treatment to obtain a composite membrane solution; (3) And (3) forming a film from the composite membrane solution, and contacting the film with acid liquor for activation treatment to obtain the composite cation exchange membrane.
  5. 5. The method for producing a composite cation exchange membrane according to claim 4, wherein in the step (1), the organic solvent comprises one or more of N-methylpyrrolidone, N-dimethylformamide and N, N-dimethylacetamide; and/or the mass ratio of the sulfonated polyether-ether-ketone to the organic solvent is 1 (2-3); And/or in the step (1), the temperature of the mixing reaction is 50-60 ℃, and the time of the mixing reaction is 8-12h.
  6. 6. The method for producing a composite cation exchange membrane according to claim 4, wherein in the step (2), the antifoaming agent comprises one or more of polyether-modified silicone oil, silicone antifoaming agent, polyether antifoaming agent and mineral oil antifoaming agent; and/or, the adding amount of the defoaming agent is 0.3-0.7% of the mass of the reaction liquid; And/or, in the step (2), the temperature of the mixing is 25-35 ℃, and the mixing time is 20-40min; And/or in the step (2), the vacuum degree of the defoaming treatment is-0.08 to-0.1 MPa, the temperature is 25-35 ℃ and the time is 1-2h.
  7. 7. The method for preparing a composite cation exchange membrane according to claim 4, wherein in the step (3), the acid solution comprises one or more of sulfuric acid solution, hydrochloric acid solution, phosphoric acid solution and nitric acid solution, and the concentration of the acid solution is 0.3-0.7mol/L; And/or the temperature of the activation treatment is 20-30 ℃ and the time is 8-12h.
  8. 8. The method for preparing a composite cation exchange membrane according to claim 4, further comprising the step of preparing a zirconium phosphate with a functionalized modified surface amino group; the preparation method of the zirconium phosphate with the functionalized and modified surface amino group comprises the following steps: a. mixing zirconium oxychloride with a phosphoric acid solution for reaction to obtain layered zirconium phosphate; b. and mixing the layered zirconium phosphate, gamma-aminopropyl triethoxysilane and a solvent to obtain the zirconium phosphate with the surface amino group functionally modified.
  9. 9. The method for preparing a composite cation exchange membrane according to claim 8, wherein in the step a, the concentration of the phosphoric acid solution is 7-9mol/L; And/or the mass ratio of zirconium oxychloride to phosphoric acid is (40-90): 1; And/or in the step a, the temperature of the mixing reaction is 110-130 ℃ and the time is 20-28h; And/or in the step b, the mass ratio of the layered zirconium phosphate to the gamma-aminopropyl triethoxysilane is (3-8): 1; and/or, in step b, the solvent comprises N-methylpyrrolidone; And/or in step b, the temperature of the mixing is 65-75 ℃ and the time is 4-8h.
  10. 10. Use of a composite cation exchange membrane according to any one of claims 1 to 3 or a composite cation exchange membrane obtained by a method of preparation according to any one of claims 4 to 9 in separation; The separation includes electrolysis of water or desalination of sea water.

Description

Composite cation exchange membrane and preparation method and application thereof Technical Field The application belongs to the technical field of ion exchange membranes, and particularly relates to a composite cation exchange membrane, and a preparation method and application thereof. Background The ion exchange membrane is used as a core functional material of desalination technologies such as electrodialysis, membrane Capacitance Deionization (MCDI) and the like, the performance of the ion exchange membrane directly determines desalination efficiency, energy consumption and system stability, and the ion exchange membrane has irreplaceable functions in the fields of sea water desalination, industrial wastewater treatment, pure water preparation and the like. The ideal ion exchange membrane needs to have high ion exchange capacity, low surface resistance, low swelling rate and excellent mechanical heat stability, however, the prior art still has a plurality of bottlenecks, and the cooperative optimization of multiple performances is difficult to realize. Traditional ion exchange membranes are largely divided into two types, single organic membranes and simple inorganic-organic blend membranes. The single organic membrane (such as sulfonated polysulfone and sulfonated polyether ether ketone) depends on sulfonic acid groups on polymer chains to provide ion exchange sites, but has poor structural stability, is easy to distort an ion transmission channel in aqueous solution due to hydrophilic expansion of chain segments, has high surface resistance and is easy to swell and crack after long-term use, and meanwhile, the ion adsorption selectivity of the single organic group is limited, and common ion permeation is easy to accompany in the desalting process, so that the desalting efficiency and the charge efficiency are reduced. In order to improve structural stability, chemical crosslinking modification (such as adding crosslinking agents such as formaldehyde, epichlorohydrin and the like) is mostly adopted in the prior art, but the crosslinking reaction needs high-temperature (80-120 ℃) and long-time (6-12 hours) conditions, so that not only is energy consumption high, but also sulfonic acid groups can be decomposed, and the ion exchange capacity is reduced, and in addition, the toxic residual risk exists in part of the crosslinking agents, so that the environment-friendly application of the membrane is limited. Simple inorganic-organic blend membranes attempt to inhibit membrane swelling by physical support of the inorganic phase by physically mixing inorganic fillers (e.g., silica, montmorillonite) with the organic polymer. However, because the interfacial compatibility of the inorganic filler and the organic polymer is poor, agglomeration is easy to occur, defects are formed in the film, the ion transmission resistance is increased, and stable chemical combination cannot be formed by physical blending, after long-term soaking or recycling, the inorganic filler is easy to fall off from the film matrix, so that the film performance is fast attenuated. For example, the ion exchange capacity of existing SPEEK/inorganic particle blend membranes is typically less than 1.6mmol/g, with an area resistance exceeding 5 ΩCm 2, the swelling rate is higher than 18%, and the requirements of electrodialysis desalination on high efficiency and long acting are difficult to meet. In addition, the existing ion exchange membrane preparation process has the problems of insufficient economy and environmental protection, that part of the process relies on expensive functional monomers or toxic solvents (such as fluorine-containing solvents), that the solvent recovery rate is low, and that byproducts generated in the chemical crosslinking process are easy to cause environmental pollution. Therefore, the development of the ion exchange membrane preparation technology with mild process, stable structure and high ion transmission efficiency becomes a key for breaking through the bottleneck of the existing desalination technology, and has important significance for promoting the industrialized development of sea water desalination and wastewater resource utilization. Disclosure of Invention The application provides a composite cation exchange membrane, a preparation method and application thereof, and aims to solve the problems of harsh reaction conditions, insufficient ion selectivity and limited desalting performance caused by chemical crosslinking in the preparation of the existing cation exchange membrane. The first aspect of the application provides a composite cation exchange membrane, which comprises the following preparation raw materials of 45-55 parts of sulfonated polyether-ether-ketone, 30-40 parts of polyetherimide, 2-8 parts of zirconium phosphate with surface amino functional modification and 2-5 parts of cross-linking agent. Some embodiments of the composite cation exchange membrane according to the application comprise