Asymmetric superwetting stainless steel meshes for on-demand and highly effective oil-water emulsion separation

Oil-water separation, especially emulsion separation, has become a global challenge due to frequent oil spills and the increase in industrial oily wastewater. It is of great significance to develop a feasible and effective separation membrane to purify highly stable emulsified oily wastewater. Here, a Janus membrane that can be used to realize the on-demand separation of oil-water emulsion is prepared by spraying silicon dioxide nanoparticles modified by hexadecyltrimethoxysilane onto the stainless steel meshes. The on-demand separation of surface-stabilized emulsions whether water-in-oil or oil-in-water emulsions can be achieved by using the Janus membrane. In addition, the prepared membrane still maintains outstanding performance after 10 oil-water separation cycles and 50 sandpaper abrasion cycles. The membrane can keep hydrophobicity whether under acidic or alkaline conditions, so it can cope with various harsh environments.