Investigation of antifouling performance a novel nanofibrous S-PVDF/PVDF and S-PVDF/PVDF/GO membranes against negatively charged oily foulants

Novel electrospun nanofibrous microfiltration membranes (ENMs) are fabricated by using sulfonated polyvinylidene fluoride (S-PVDF)/PVDF and S-PVDF/PVDF/graphene oxide (GO) with negative charge which was prepared by electrospinning technique. The GO with different weight percentages (0, 0.1, 0.5 and 1.0 wt%) was used as additive in membrane and its effect on hydrophilicity, pure water flux, mean fiber and pore diameter was studied. The results showed that the most appropriate amount of GO is 0.5 wt% (low contact angle (77.08°) with high pure water flux (1222 L/m² h) was obtained). Therefore, in the fabrication of the rest of the membranes 0.5 wt% GO was utilized as optimal amount of GO. In addition, the effects of sulfonation on morphology, oil removal, and fouling parameters were investigated. Finally, data analysis indicated that among the novel prepared ENMs, M₈ (S-PVDF/PVDF/GO-50/50=volume ratio) displayed the lower irreversible fouling (41%), the highest flux recovery ratio (59%), and the superior antifouling properties. This higher antifouling performance of the M₈ compared with other novel ENMs was attributed to hydrophilicity and enhanced strong electrostatic repulsion force between the membrane matrix and the oily foulant. The low degree of total fouling (70%) for the intact PVDF nanofibrous compared with novel ENMs (91–97%) was interpreted by the bigger pore diameter (300 nm) of the intact PVDF nanofibrous.