PA/PMIA复合纳滤膜的制备及性能研究

Preparation and performance study of PA/PMIA composite nanofiltration membrane

以聚间苯二甲酰间苯二胺(PMIA)为膜材料,LiCl和水为添加剂,N,N-二甲基乙酰胺(DMAc)为溶剂,通过相转化法制备PMIA超滤基膜.以哌嗪(PIP)为水相单体,均苯三甲酰氯(TMC)为油相单体,通过界面聚合法制备PA/PMIA复合纳滤膜.考察了单体浓度对复合纳滤膜渗透分离性能的影响,结果表明,当单体浓度增加时,复合纳滤膜的水通量下降,Na_(2)SO_(4)的截留率增大;水相单体PIP质量分数为0.5%,油相单体TMC质量分数为0.07%,反应时间为30 s,后处理温度为70℃,后处理时间为3 min时,所制备的PA/PMIA复合纳滤膜的水通量为508.9 L/(m^(2)·h·MPa),Na_(2)SO_(4)截留率为98.24%,酰胺(PA)层厚度为40 nm,接触角为44°;PA/PMIA复合纳滤膜在有机溶剂和酸碱中浸泡30 d后,仍保持稳定的Na_(2)SO_(4)截留率.

PMIA ultrafiltration basement membrane was prepared by phase conversion using polyisophthaloyl-m-phenylenediamine(PMIA)as membrane material,LiCl and H_(2)O as non-solvent additives,and N,N-dimethylacetamide(DMAc)as solvent.PA/PMIA composite nanofiltration membrane was prepared by interfacial polymerization with piperazine(PIP)as aqueous monomer and benzenetricarbonyl chloride(TMC)as oil-phase monomer.The effect of monomer concentration on the permeation and separation performance of composite nanofiltration membrane was investigated.It was shown that when the monomer concentration increased,the water flux of the membrane decreased and the interception rate of Na_(2)SO_(4)increased.When the mass fraction of aqueous monomer PIP was O.5%,the mass fraction of TMC of oil-phase monomer was 0.07%,the reaction time was 30 s,the post-treatment temperature was 70℃,and the post-treatment time was 3 min,the water flux of the prepared PA/PMIA composite nanofiltration membrane was 508.9 L/(m^(2)·h·MPa),the retention rate of Na_(2)SO_(4)was 98.24%,the thickness of amide(PA)layer was 40 nm,and the contact angle was 44.The PA/PMIA composite nanofiltration membrane had stable Na2 SO4 retention after 30 days immersion in organic solvents and acids and bases.