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Preparation method of carbon nitride doped anion exchange membrane

An anion exchange membrane and carbon nitride technology, applied in the field of anion exchange membrane preparation, can solve the problems of low overall performance, decreased ionic conductivity and dimensional change rate, large dimensional change rate, etc., and achieves simple synthesis process and uniform membrane material. dense effect

Active Publication Date: 2020-09-18
NANJING UNIV OF SCI & TECH
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Problems solved by technology

For example, document 2 (Yang et al. Journal of Power Sources, 2012, 199, 37-45.) prepared an anion exchange membrane by doping quaternized silicon dioxide and quaternized polyvinyl alcohol, which improved the strength of the membrane to a certain extent. The IEC and ionic conductivity of the membrane have improved the dimensional stability of the membrane, but the overall performance of the membrane is still at a low level. The IEC of the best performance membrane QPVA / 20wt% Q-SiO2 is 0.66mmol / g, and the conductivity at 70°C rate is only 6.4mS / cm, but the size change rate reaches 81.9%; Document 3 (Liu et al.RSC Adv., 2015, 5, 43381.) combined quaternized mesoporous silica Anion-exchange membranes were prepared by doping polysulfone polymers, which improved the ionic conductivity and rigidity of the membranes, but the elongation at break of the membranes was small, up to 6.8%, and the dimensional change rate at room temperature was large, and the thickness and The lowest plane direction reaches 6.5% and 7.2% respectively; Document 4 (Luo et al.RSC Adv., 2016, 6, 13618.) modified graphene oxide with dopamine and doped it with quaternized polysulfone polymer Prepared as an anion exchange membrane, the doped membrane has better thermal stability, mechanical stability and alkali resistance stability, but the ionic conductivity and dimensional change rate are significantly reduced, and the conductivity of the QPSF / 0.5% DGO membrane at 60 ° C is only 10.7mS / cm, the dimensional change rate reaches 13.5%

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  • Preparation method of carbon nitride doped anion exchange membrane
  • Preparation method of carbon nitride doped anion exchange membrane
  • Preparation method of carbon nitride doped anion exchange membrane

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preparation example Construction

[0026] The preparation method of the doped polyaryl ether ketone anion exchange membrane of the present invention utilizes DFBP, BHPF and HFBPA monomer to synthesize polyaryl ether ketone polymer (PAEK) according to certain dosing ratio through nucleophilic polycondensation reaction; The amount of gram reaction catalyst, reaction temperature and time are used to control the degree of chloromethyl substitution of the polymer to obtain a chloromethylated polyaryletherketone polymer (CMPAEK) similar to IEC; Obtain small-sized carbon nitride powder; finally, blend and cast carbon nitride powder and CMPAEK to form a film, and prepare an anion exchange membrane through quaternization reaction and alkaline ion exchange. The steps are as follows:

[0027] Step 1, preparation of polyaryletherketone polymer: 4,4'-difluorobenzophenone (DFBP), bisphenol fluorene (BHPF) and hexafluorobisphenol A (HFBPA) were dissolved in N,N-difluoro Methylacetamide (DMAc), adding potassium carbonate 1.1-1...

Embodiment 1

[0036] The preparation of embodiment 1 PAEK polymer

[0037] In a completely dry three-neck flask equipped with nitrogen inlet and outlet devices and an oil-water separator, under nitrogen protection, add 1.1674g DFBP (5.35mmol), 1.1248g BHPF (3.21mmol), 0.7195g of HFBPA (2.14mmol), 15mL of DMAc, stir to dissolve completely, then add 0.8503g of potassium carbonate (6.15mmol) and 15mL of toluene. The temperature was slowly raised to 140° C. for 4 hours, and the moisture generated in the reaction was removed in the form of toluene / water azeotrope. Then the temperature was slowly raised to 165°C, and the temperature was kept constant for 6h. After the reaction was over, the heating was stopped and cooled to 60°C. The product was slowly poured into 500 mL of deionized water, and a white fibrous polymer product was precipitated. The product was fully washed with deionized water and then dried in a vacuum oven at 105°C for 24 hours to obtain the polymer PAEK.

Embodiment 2

[0038] The preparation of embodiment 2 CMPAEK polymer

[0039] Add 1.2g of PAEK polymer and 18mL of tetrachloroethane into a completely dry three-neck flask equipped with nitrogen inlet and outlet devices and an oil-water separator, stir and heat to dissolve; at the same time, add 6.7mL of Chloromethyl ether and 0.2186g of anhydrous tin tetrachloride were dissolved in 6mL of tetrachloroethane; after the polymer was completely dissolved, nitrogen was slowly passed through to maintain the nitrogen atmosphere, and the three-necked flask was placed in an ice bath, and then the dropwise The catalyst solution in the liquid funnel was slowly dropped into the three-necked flask, and after the dropping, the temperature was returned to room temperature, and then the temperature was raised to 30° C. for constant temperature reaction for 12 hours. After the reaction, the reaction product was poured into excess ethanol to precipitate a white flocculent polymer product, fully soaked and was...

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Abstract

The invention discloses a preparation method of a carbon-nitride doping type anion-exchange membrane. The preparation method comprises the following steps of: firstly synthesizing chloromethylated polyaryletherketone polymer by nucleophilic polycondensation reaction and Friedel-Crafts reaction, preparing graphite-phase carbon nitride by a direct pyrolysis method, peeling the graphite-phase carbonnitride into small-size carbon nitride powder, then uniformly mixing the chloromethylated polyaryletherketone polymer and the carbon nitride powder according to the proportion, carrying out quaternization, finally carrying out membrane casting and alkalization by a solution casting method to obtain the carbon-nitride doping type anion-exchange membrane. The preparation method of the carbon-nitridedoping type anion-exchange membrane disclosed by the invention has the beneficial effects that the synthesis process is simple, the ion exchange capacity is controllable, and the prepared anion-exchange membrane has the advantages of uniform density, higher ionic conductivity and good stability and the like; a carbon-nitride material with excellent stability is adopted as a doping substance to prepare the anion-exchange membrane with uniform density; under the similar IEC (Ion-Exchange Chromatography) level, the prepared doping type anion-exchange membrane has the advantages of uniform density, higher ionic conductivity and good stability and the like.

Description

technical field [0001] The invention belongs to the technical field of anion exchange membrane preparation, and in particular relates to a preparation method of carbon nitride doped anion exchange membrane. Background technique [0002] Anion exchange membranes have been widely used in various industrial fields, such as the application of electrodialysis in water treatment to treat bitter brine, in the recovery of industrial waste acids, anion membranes are used for diffusion dialysis, as anion selective electrodes, in the chlor-alkali industry As the diaphragm of the electrolyte, as the diaphragm in the battery, etc. [0003] As a key component in anion exchange membrane fuel cell (AEMFC), anion exchange membrane plays an important role in the development of AEMFC. Among them, the anion exchange membrane needs to meet the following conditions (1) It has excellent mechanical stability, thermal stability and dimensional stability for production and operation; (2) The activit...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08J5/22C08G65/48C08G65/40C08K3/28
CPCC08G65/4025C08G65/48C08J5/2262C08J2371/08C08K3/28C08K2201/003
Inventor 陈守文潘雪婷胡朝霞
Owner NANJING UNIV OF SCI & TECH