动态LBL组装聚离子膜对乙醇/水体系的渗透汽化性能

Pervaporation separation of water-ethanol by dynamic polyion composite membrane

采用动态层-层吸附成膜法(动态LBL),以聚醚砜超滤膜为基膜,以聚丙烯酸(PAA)、聚乙烯亚胺(PEI)为聚离子制备了聚离子复合膜.考察了动态成膜与静态吸附成膜的膜性能比较,研究了动态过滤时间、聚离子浓度、进料浓度、温度等因素对该复合膜渗透汽化性能的影响;并对复合膜表面和截面做了扫描电镜分析.在40℃时,该复合膜对乙醇/水体系的分离因子可达1300,渗透通量约150 g/(m2.h),体现了较好的渗透汽化分离性能.

The dynamic polyion composite membranes were prepared by depositing polyacrylic acid（PAA） and polyethyleneimine （PEI） alternatively on the ultrafiltration support membrane under a certain pressure. The polyion composite membranes were used to separate of water- ethanol mixture in a pervaporation apparatus. The performance of dynamic LBL polyion membrane was compared with that of the static LBL membrane. The findings suggested that the high separation factor could be obtained with only 4 composite layers in dynamic LBL polyion membrane. The filtrating time, temperature and weight ratio of water in the feed, and the polyion concentration were investigated. The surface and cross- section of polyion composite membranes were observed by SEM. The dynamic polyion composite membranes showed good pervaporation performance for the separation of water- ethanol mixture. Under the temperature of 40 ℃, the separation factor and the permeate flux were about 1300 and 150 g/（m^2·h）, respectively.