PDMS对PEI/TMC复合纳滤膜结构和性能的影响

Effect of PDMS on structure and performance of PEI/TMC composite nanofiltration membranes

以亲水改性后的聚四氟乙烯(PTFE)平板膜作基膜,正己烷为油相溶剂,聚乙烯亚胺(PEI)和均苯三甲酰氯(TMC)分别作为水相单体和油相单体,聚二甲基硅氧烷(PDMS)作油相的添加剂,采用界面聚合方法制得PEI/TMC复合纳滤膜。通过优化制备条件,制得高通量、性能良好的PEI/TMC复合纳滤膜。结果表明:随着油相添加剂PDMS的加入,PEI/TMC复合纳滤膜表面变得光滑且疏松,使得PEI/TMC复合纳滤膜的通量大幅度增加。当PDMS的浓度为0.4 wt%时,PEI/TMC复合纳滤膜同时具有较高的水通量和截留率;当PEI的浓度为1.0 wt%,TMC浓度为0.6 wt%,PDMS的浓度为0.4 wt%,热处理温度为70℃,热处理时间为10 min时,PEI/TMC复合纳滤膜对MgSO4溶液的截留率达到了86.6%,水通量为12.8 L/(m2·h),对不同的盐溶液按截留率从大到小依次为MgSO4(86.6%)、MgCl2(83.6%)、Na2SO4(77.7%)、NaCl(48.8%)。

PEI/TMC composite nanofiltration membranes were prepared by interfacial polymerization with polyethyleneimine(PEI)and trimesoyl chloride(TMC)on the hydrophilic polytetrafluoroethylene(PTFE)flat sheet membranes,in which polydimethylsiloxane(PDMS)was introduced in the oil phase,and PEI/TMC composite nanofiltration membranes of high flux and good performance were obtained by optimizing the fabrication processing conditions.The results show the surface of the PEI/TMC composite nanofiltration membranes became smooth and loose with the addition of PDMS,which resulted in a significant increase of the flux.When the concentration of PDMS was 0.4 wt%,the PEI/TMC composite nanofiltration membranes achieved higher water flux and rejection values.When the concentration of PEI was 1.0 wt%,the concentration of TMC was 0.6 wt%,the concentration of PDMS was 0.4 wt%,the heat treatment temperature was 70℃and the heat treatment time was 10 minutes,the rejection value of(MgSO4)solution by the membranes reached 86.6%,and the water flux was 12.8 L/(m^2·h).The values of the rejection for different salt solutions from high to low were MgSO4(86.6%),MgCl2(83.6%),Na2SO4(77.7%),and NaCl(48.8%).