Electrospun nanofiber based forward osmosis membrane using graphene oxide as substrate modifier for enhanced water flux and rejection performance

Electrospun nanofiber (ENs) membranes with advantages of high porosity and low tortuosity have been considered as the ideal forward osmosis (FO) substrates for the effective mitigation of internal concentration polarization (ICP). However, the rough surface and large surface pores of ENs substrates may have adverse effects on the properties of the polyamide (PA) active layer. In this study, graphene oxide (GO) nanosheet was chosen as the modifier to adjust the characteristics of polyacrylonitrile (PAN) ENs substrate. The structure and properties (e.g., osmotic flux and specific salt flux) of the PA active layer was found be effectively tailored by the GO loading density. The appropriate loading of GO nanosheets might retard the penetration of polyamide into the substrate surface pores and meanwhile enhance the cross-linking degree of the PA active layer, resulting in the improvement of water flux and salt rejection. The optimized FO membrane (TFC-GO2) could achieve a higher water flux (32.7 g/m2·h) and lower specific salt flux (0.26 g/L) than the control membrane (TFC-0) in the FO mode. The appropriate loading of GO nanosheets on ENs substrates was proven to be a competitive strategy for developing high-performance ENs based FO membranes.