Silica-Modified Electrospun Membrane with Underwater Superoleophobicity for Effective Gravity-driven Oil/Water Separation

Superhydrophilic and underwater superoleophobic membrane materials have been widely studied owing to their excellent separation efficiency. However, the oil-fouling problem is a major drawback limiting their practical oil/water separation applications. Herein, a silica-enhanced functionalized poly(styrene-alt-maleic anhydride)/fluorocarbon surfactant nanofibrous composite membrane (f-PSMA/FS/SiO2) with underwater superoleophobicity was fabricated by the electrospinning method. The uniformly dispersed silica nanoparticles not only increased the roughness of the as-prepared composite membrane but also substantially improved the underwater superoleophobicity. Therefore, the as-prepared composite membrane showed excellent underwater anti-oil-fouling performance, thus preventing the decrease in the separation efficiency and flux caused by membrane fouling during oil/water separation. Throughout 60 separation cycles solely driven by gravity, the separation efficiencies were above 99.27 %, and the flux remained higher than 3743 L m−2 h−1. More importantly, the as-prepared composite membrane maintained exceptional underwater superoleophobicity in a harsh environment (30 wt% NaCl for 12 h, pH 1 (HCl) for 12 h, oven temperature at 90 °C for 2 h). Thus, because of its robust thermal stability and chemical durability, the antifouling f-PSMA/FS/SiO2 composite membrane has tremendous potential for future practical applications in the treatment of oily wastewater.