Structure-controllable superhydrophobic Cu meshes for effective separation of oils with different viscosities and aqueous pollutant purification

Abstract

Micropothole-based oxidized (MPO) Cu meshes with various surface morphologies, such as needle-like (NL), hair-like (HL), arch-like (AL), and pine needle-like (PNL) structures, were prepared by controlling the pH and temperature of the oxidation reaction solution. The separation efficiencies of 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFTOS)-coated MPO-Cu meshes were found to be 96–99% for oil/water separation, and the meshes maintained this performance over 20 separation cycles without deterioration. The HL mesh with long and flexible structures was outstanding for the separation of low viscosity oils, while the NL mesh with short and rigid structures was optimal for the separation of highly viscous oils. Double-layered meshes consisting of photocatalytic and superhydrophobic meshes exhibited high catalytic performance after the oil/water separation, demonstrating purification of an aqueous pollutant separated from the oil/water mixture.