Thin film nanocomposite forward osmosis membrane prepared by graphene oxide embedded PSf substrate

Abstract

One of the limiting factors in good performance of forward osmosis (FO) membranes is the internal concentration polarization (ICP). To reduce ICP, thin film nanocomposite forward osmosis (TFN-FO) membranes were fabricated by adding different amounts of graphene oxide (GO) nanoplates (0-1 wt. %) to polymer matrix of polysulfone (PSf) substrate. The prepared nanocomposite membranes exhibited both hydrophilicity and porosity higher than that of neat PSf counterpart. An optimum amount of 0.5 wt% was obtained for GO addition into the membranes. The corresponding fabricated thin film nanocomposite (TFN) membrane (TFNG0.5) revealed a water permeability of 2.44 L/m2hbar which is 66% higher compared to an in-house made composite membrane. The FO performance of TFN was assessed by DI water as feed solution and 1 M NaCl as draw solution in AL-DS orientation. The water flux of the synthesized FO membranes increased upon adding of GO nanoplates and reached to a maximum water flux of 37.74 (L/m2h) for TFNG0.5 membrane. This flux is about 3 times higher than TFC membranes without significant changes in their salt rejection. The higher water flux of the TFN membranes can be attributed to ICP decrease originating from reduction of structural parameter of the membranes.