界面聚合工艺条件对反渗透复合膜性能的影响

Effect of process conditions of interfacial polymerization on performance of reverse osmosis composite membrane

以聚砜超滤膜为支撑膜,间苯二胺(MPD)为水相功能单体,均苯三甲酰氯(TMC)为油相功能单体,通过界面聚合法制备了反渗透复合膜。研究了功能单体浓度、界面聚合反应时间、界面聚合成膜后热处理时间和温度等条件对复合膜分离性能的影响;并对在水相中添加相转移催化剂对复合膜分离性能的影响和相转移催化机理进行了初步探讨。首先在单因素实验条件下确定工艺条件的优化范围,然后经过正交实验得到最佳工艺条件,实验结果表明,油相中TMC浓度为3g.L-1、水相中MPD浓度为20g.L-1、界面聚合反应时间为30s、界面聚合成膜后热处理温度为90℃、后处理时间15min时,所制备的反渗透复合膜表现出良好的分离性能,通量达14.91L.m-2.h-1,截留率为0.951(测试条件:压力1.6MPa,温度25℃,NaCl浓度20000mg.L-1);当水相中MPD浓度较低时,加入适量的相转移催化剂,能有效地改善膜的分离性能。

Reverse osmosis composite membrane was prepared by interfacial polymerization（IP）of metaphenylene diamine（MPD）with trimesoyl chloride（TMC）on the surface of polysulfone（PS）support.The effects of monomers concentration,reaction time of IP,time and temperature of heat treatment on the separation performance of composite membranes were investigated.The influences of phase-transfer catalyst（PTC）on the separation performance of composite membrane were also studied,and the mechanism of reaction process was discussed.From the orthogonal experiment results,the optimum conditions were the concentration of TMC and PMD 3 g·L^-1,20 g·L^-1 respectively,and the temperature and time of heat treatment 90 ℃ and 15 min,and the flux of 14.91 L·m^-2·h^-1 as well as rejection of 0.951（pressure 1.6 MPa,temperature 25℃,concentration of NaCl 20000 mg·L^-1）were obtained under these conditions.In addition,it was found that at a low concentration of MPD,the separation performance of composite membrane could be remarkably improved by adding PTC into the water phase.