Optimizing functional layer of cation exchange membrane by three-dimensional cross-linking quaternization for enhancing monovalent selectivity  

作　　者：Jiefeng Pan Lei Zhao Xiaohong Yu Jiajing Dong Lingling Liu Xueting Zhao Lifen Liu 

机构地区：[1]College of Chemical Engineering,Zhejiang University of Technology,Hangzhou 310014,China

出　　处：《Chinese Chemical Letters》2022年第5期2757-2762,共6页中国化学快报（英文版）

基　　金：supported by the Public Welfare Project of the Science and Technology Committee of Zhejiang Province(No.LGF20B060002);the China Postdoctoral Science Foundation funded project(No.2016M601964);Provincial Key R&D Program of Zhe-jiang Province(No.2019C03094);the National Natural Science Foundation of China(Nos.22075246 and 21776253).

摘　　要：Monovalent cation perm-selective membrane(MCPMs)allow fast and selective transport of monovalent cations,and they are promisingly required for extraction of special ions,such as lithium extraction,acid recovery and sea salt production.Herein,we report a novel strategy to design the critical functional layers of MCPMs with both space charge repulsion and cross-linked dense screenability.The in-situ depo-sition polymerization of pyrrole was carried out on the surface of sulfonated polyphenyl sulfone(SPPSU)substrate membrane followed by cross-linking quaternization of the polypyrrole(PPy)layer with diiodi-nated functional molecules,thus,the membrane obtained more excellent selective permeability and sta-ble transport properties of monovalent cations.It confirms that the designed PPy layers with charged sur-face and cross-linking structure improved the hydrophilicity,facilitated cation transport and increased ion flux.Meanwhile,for the dense PPy layer,the charged cross-linked structure endowed the functional layer with the synergistic characteristics of Donnan exclusion and pore size sieving for positively charged ions,which improved the monovalent cation perm-selectivity of the membranes.At a constant current density of 5.1 mA/cm^(2),the optimal membrane exhibited superior perm-selectivity(P^(Na)_(Mg)=2.07)and monovalent cation flux(J_(Na+)=2.80×10^(−8)mol cm^(−2)s^(−1))during electrodialysis.

关 键 词：Cation exchange membrane Monovalent ion selectivity ELECTRODIALYSIS POLYPYRROLE Cross-linking 

分 类 号：TQ051.893[化学工程]