Development of high-performance thin-film composite FO membrane by tailoring co-deposition of dopamine and m-phenylenediamine for the Caspian seawater desalination

Rational manipulation of the thin film composite (TFC) membranes properties and their surface structures are important to optimize forward osmosis (FO) performance. In this study, a facile approach is proposed for fabricating a hydrophilic and high-flux TFC membrane. Through this strategy, dopamine (DA) was mixed into m-phenylenediamine (MPD) as an aqueous solution followed by interfacial polymerization (IP) reaction with trimesoyl chloride (TMC) on a fabricated polyvinyl chloride (PVC) substrate. For the first time, the simultaneous effects of the DA concentration and the co-deposition time on the membrane morphology and FO properties were systematically investigated to explore the optimum condition. After evaluating the as-prepared membranes, the membranes with the DA concentration of 0.1 g/L and 120 min co-deposition time of PDA and MPD showed high water flux (24.40 L/m2.h) and acceptable reverse salt flux (RSF) compared with the control membrane without DA incorporation (15.95 L/m2.h) using deionized (DI) water as the feed solution (FS) and 1 M NaCl as the draw solution (DS) in the FO mode. Moreover, the optimum membranes exhibited excellent performance in the seawater desalination test. This study demonstrated that incorporation of DA during the IP reaction can be an effective and facile strategy for tailoring the membrane structure and obtaining high-performance FO membranes with outstanding performance for desalination purposes.