Preparation and characterization of electrospun PVDF/PVP/SiO2 nanofiber membrane for oil-water separation

For oily wastewater purification, polyvinylidene fluoride (PVDF) nanofiber membranes have been widely noticed for their excellent mechanical strength and corrosion resistance. However, it is prone to serious oil fouling problems during use, resulting in reduced flux and inability to be used repeatedly. It has become a hot research topic to develop simple methods to realize its hydrophilic modification for oily wastewater treatment to address this problem. Herein, a novel separation membrane was prepared by doping polyvinylpyrrolidone (PVP) and hydrophilic silica nanoparticles (SiO2 NPs) into PVDF using a facile one-step electrospinning method. The modified membrane shows hydrophilicity, water contact angle (WCA) is 0°, oleophobicity in water, and oil contact angle (OCA) is more than 145° and has good separation efficiency and flux for both oil-water mixtures and emulsions. After 30 times of mixture and emulsion separation tests, the separation efficiency is above 99.5 % and 97 %, respectively, showing good separation and reusability. Besides, compared with hydrophilic modification methods such as surface coating and grafting, the proposed modification method is simpler and has great potential in treating oily wastewater.