High mono/divalent selectivity thin film composite membrane prepared at 1,2-propanediol/hexane organic-organic interface

Abstract

A new organic-organic phase interface was constructed for the interfacial polymerization to control the formation of polyamide. 1,2-propanediol was introduced to dissolve reactive amines to extend optional amines and reduce the hydrolysis of acyl chloride. The properties of the 1,2-propanediol/hexane interface such as interfacial intension, partition coefficient, and interface thickness were investigated and compared with the water/hexane system. The thin film composite (TFC) membranes prepared at different phase interfaces via interfacial polymerization were systematically characterized and explored. Compared to the conventional TFC membrane, a smoother and thinner polyamide skin layer with more hydrophilicity was fabricated. The optimum 1,2-propanediol based membrane displayed a high Na2SO4 rejection of 99.1% and mono/divalent ion selectivity of 98. This organic-organic interfacial polymerization not only provided a simple strategy to fabricate smooth polyamide nanofilms but also offered a feasible way for preparing polyamide membranes with good ion sieving performance that was in demand in nanofiltration.