摘要
纳滤膜目前多采用界面聚合的方法制备.层层自组装是近年来发展的一种新型制膜方法,但层层自组装所制备的纳滤膜大多需要5个以上双层,制备过程繁琐,同时,以静电力结合的阴阳离子聚电解质在水中存在一定程度的解离和溶胀,结构不稳定.本文提出用静电组装与化学交联相结合的方法制备纳滤膜,增强膜的稳定性.以改性的聚丙烯腈(PAN)为基膜,以聚丙烯酸(PAA)和聚乙烯亚胺(PEI)分别为阴阳离子聚电解质,以戊二醛(GA)为交联剂,制备了共价层层自组装纳滤膜(PEI/PAA/GA)n,研究了双层数、交联剂浓度、交联时间等因素对膜性能的影响.结果表明,当制备两个双层时,(PEI/PAA/GA)2纳滤膜对2000 mg/L Na 2SO 4溶液中的Na 2SO 4的截留率就能达到98.1%,水通量为12.6 L/(m^2·h·MPa);对2000 mg/L NaCl溶液中的NaCl的截留率达到82.9%,水通量为16.8 L/(m^2·h·MPa).交联后的纳滤膜有良好的耐溶胀性和长期运行稳定性.
Nanofiltration(NF)membranes are currently prepared by interfacial polymerization.layer-by-layer(LBL)self-assembly is a new type of method developed in recent years.However,most of the NF membranes prepared by LBL self-assembly require more than 5 double layers.The preparation process is cumbersome.Meanwhile,as the anionic and cationic polyelectrolytes combined by electrostatic force,they would dissociate to a certain degree and swell in the water,and thus the self-assembled membrane is unstable.In this work,a combination of electrostatic assembly and chemical crosslinking is adopted to prepare NF membrane with enhanced stability.Using modified polyacrylonitrile(PAN)membrane as substrate,polyacrylic acid(PAA)and polyethyleneimine(PEI)as the anion-cation polyelectrolyte,and glutaraldehyde(GA)as the cross-linking agent,a kind of covalent LBL self-assembled NF membrane(PEI/PAA/GA)n was prepared.The effects of fabrication factors such as number of double layer,concentration of crosslinker and crosslinking time on the separation performance of the prepared LBL membranes were investigated.The results show that the only two bilayers’LBL membrane,(PEI/PAA/GA)2,can achieve a rejection of 98.1%for divalent ions and a flux of 12.6 L/(m^2·h·MPa).The crosslinked LBL NF membrane has good swelling resistance and long-term running stability.
作者
张金苗
贾瑞
李树轩
苏保卫
ZHANG Jinmiao;JIA Rui;LI Shuxuan;SU Baowei(Key Laboratory of Marine Chemistry Theory and Technology(Ocean University of China),Ministry of Education/College of Chemistry&Chemical Engineering,Ocean University of China,Qingda O266100,China)
出处
《膜科学与技术》
CAS
CSCD
北大核心
2020年第1期139-147,共9页
Membrane Science and Technology
基金
国家自然科学基金项目(20976170)。
关键词
纳滤膜
层层自组装
共价交联
nanofiltration
layer-by-layer self-assembly
covalent cross-linking
