A superwetting rough structured nanofibrous membrane with enhancing anti-fouling performance for oil-water separation

Oily wastewater generated from many industries has become a tremendous potential threat to ecological balance and human health. However, severely hindered by interfacial wettability, the present oil/water separation membranes are subjected to a serious oil fouling problem during long-term oily wastewater separation. Herein, we construct superwetting rough structured nanofibrous membrane (SRSNM) composed of superhydrophilic PVA/SA bead-on-string nanofibrous functional layer and PVA nanofibrous substrate by two step electrospinning together with chemical crosslinking. Benefitting from the inherent hydrophilic properties of SA and PVA combined with the rough structure endowed by the bead-on-string nanofibers, the SRSNMs exhibited fascinating superhydrophilicity and underwater superoleophobicity. Meanwhile, thanks to the submicron pores and high porosity, the SRSNM could separate submicron oil-in-water emulsions with robust permeation flux of 1319 L m(-2)h(-1) and high separation efficiency of 99.9 % under the gravity driving (similar to 1 kPa). More importantly, this SRSNM showed excellent anti-oil-fouling performance with high flux recovery of 99 %, negligible irreversible oil fouling rate of 1 %, and intriguing reusability for the long-term separation. The design of such superwetting rough structured nanofibrous membrane may provide an efficacious strategy for synthesizing high-performance separation membranes.