(278f) High Performance Thin Film Composite Membranes with Well-Aligned Nanofiber Substrates for Forward Osmosis Applications

Forward osmosis (FO) membranes with ultrahigh water flux and low reverse salt flux is of urgently demand in FO process. However, the severe internal concentration polarization (ICP) effect in FO is one of the important problems to be overcome in order to maintain a high FO performance of thin film composite (TFC) membranes. In this work, a highly aligned nanofiber-based thin film composite membrane was reported for the first time to develop the high-performance TFC-FO membrane. By adjusting the rotating speed of the collector via the electrospinning process, the prepared aligned nanofiber substrates possess higher pore size and better pore interconnectivity than the random ones. Polyamide selective layer were successfully formed via interfacial polymerization on aligned and random nanofiber substrates. The surface structure, water permeability, salt rejection and forward osmosis performance of resultant thin film composite TFC membranes were systemically studied. The ICP effect is significantly eliminated, which may be due to the higher pore size and better pore interconnectivity of the aligned nanofiber substrate. Consequently, the prepared aligned nanofiber based TFC membrane exhibits a high water flux (J_w) of 50.7 LMH and a low reverse salt flux (J_s) of 6.8 gMH in FO mode, as well as J_w of 62.9 LMH with J_S of 8.7 gMH in PRO mode, using deionized (DI) water and 1 M NaCl aqueous solution as the feed and draw solutions respectively. This work may provide a new orientation in developing high-performance TFC membranes with high selectivity.