Developing thin-film-composite forward osmosis membranes on the PES/SPSf substrate through interfacial polymerization



A new scheme has been developed to fabricate high-performance forward osmosis (FO) membranes through the interfacial polymerization reaction on porous polymeric supports. p-Phenylenediamine and 1,3,5-trimesoylchloride were adopted as the monomers for the in-situ polycondensation reaction to form a thin aromatic polyamide selective layer of 150 nm in thickness on the substrate surface, a lab-made polyethersulfone (PES)/sulfonated polysulfone (SPSf)-alloyed porous membrane with enhanced hydrophilicity. Under FO tests, the FO membrane achieved a higher water flux of 69.8 LMH when against deionized water and 25.2 LMH when against a model 3.5 wt % NaCl solution under 5.0 M NaCl as the draw solution in the pressure-retarded osmosis mode. The PES/SPSf thin-film-composite (TFC)-FO membrane has a smaller structural parameter S of 238 μm than those reported data. The morphology and topology of substrates and TFC-FO membranes have been studied by means of atomic force microscopy and scanning electronic microscopy. © 2011 American Institute of Chemical Engineers AIChE J, 2012