Surfactant-induced intervention in interfacial polymerization to develop highly-selective thin-film composite membrane for forward osmosis process

Thin-film composite (TFC) membrane capable of superior permeability contributes to the industrial implementation of forward osmosis (FO) technology, but it is plagued with some bottlenecks including the unsatisfactory selectivity. Herein, the surfactant-induced intervention in interfacial polymerization was performed by incorporating hexadecyltrimethylammonium toluene-p-sulphonate (CTAT) into the amine aqueous solution for developing the highly-permeable TFC membrane with exceptional selectivity. The effect of CTAT incorporation on the physicochemical properties of polyamide (PA) layer was systemically investigated by conventional characterizations, so as to unravel the mechanism for the improved performance of resultant TFC-FO membrane. Besides, three typical surfactants of Tween 80, sodium dodecyl sulfate (SDS) and hexadecyltrimethylammonium chloride (CTAC) were also introduced and studied contrastively for comparison. Amongst the fabricated membranes, the optimized TFC-CTAT membrane achieves the improved water fluxes (JV) of 31.8 and 21.7 L.m-2.h−1 accompanied with the reduced specific reverse salt fluxes (JS/JV) of 0.05 and 0.04 g·L−1 in active layer facing the draw solution (AL-DS) and active layer facing the feed solution (AL-FS) orientations respectively, using 1 M NaCl solution and deionized water as draw and feed solutions. Therefore, this work provides a new perspective for constructing TFC-FO membrane with high perm-selectivity by employing suitable surfactant at the relatively low concentrations.