High performance thin-film nanocomposite forward osmosis membrane based on PVDF/bentonite nanofiber support

Abstract

In this study, PVDF electrospun nanofibers impregnated with bentonite nanoclay based highly hydrophilic thin-film nanocomposite (TFN) membranes were synthesized by interfacial polymerization of a polyamide selective layer for forward osmosis (FO) applications. It was revealed that the bentonite nanoclay can tune the properties of the PVDF nanofiber supported TFN membranes, including the key parameters, such as hydrophilicity, the β-phase fraction (polar phase), and its mechanical properties. The PVDF/bentonite nanoclay mixture resulted in a significant improvement in FO performance. X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray (EDX) analysis confirmed the successful integration of bentonite nanoclay into the electrospun nanofiber. The prepared TFN membranes showed higher hydrophilicity, mechanical strength and water permeability compared to the pristine PVDF electrospun nanofiber TFN membrane due to an increase in the β-phase fraction (hydrophilicity) by the synergetic effect of electrospinning and addition of bentonite nanoclay. A TFN membrane with the highest nanoclay content (2.0wt%) showed an exceptionally high FO water flux of 40.64L/m2 h at 1M NaCl draw solution, without a considerable increase in reverse solute flux (RSF).