Superwettable Membrane with Hierarchical Porosity for Simultaneous Separation of Emulsions and Removal of Nanoparticles

Abstract The burgeoning severity of water pollution calls for new developments in membrane design, particularly those that can separate oil from water while simultaneously removing nanoparticulates. In this study, a poly(vinyl alcohol-co-ethylene) nanofiber membrane possessing a hierarchically porous structure was fabricated. Subsequent modification with ethylenediamine tetraacetic acid disodium salt induced special properties, such as superamphiphilicity in air, superoleophobicity in water and superhydrophobicity in oil. This superwetting property endows the membrane with high oil/water emulsion separation efficiency ( > 96%) while its porous nature also makes it ideal for pigment microfiltration, achieving > 99.8% separation efficiency. This membrane also displays a stable underoil hydrophobicity, and underwater oleophobicity over a wide pH range. The stable surface property and simultaneous removal efficiency of oil (96%) and nanoparticles (99.5%) from water indicate that this novel membrane possesses great potential in water purifying applications.