Superhydrophilic–underwater superoleophobic ZnO-based coated mesh for highly efficient oil and water separation

Abstract Synergistic superhydrophilic–underwater superoleophobic meshes were fabricated by spraying ZnO nanoparticles and polyurethane mixtures on stainless steel mesh substrates. The coated meshes were then used to study gravity-driven oil/water separation for a series of oil/water mixtures, where only the water permeate through the mesh while the oil is repelled on the mesh. Separation efficiency up to 99.0% could be achieved through the coated mesh for the kerosene–water mixture. Moreover, the as-prepared coated mesh still maintained high separation efficiency and stable recyclability after 50 separation cycles with the separation efficiency for the kerosene–water mixture always above 97.3%. The fabrication approach presented here can be applied for coating large surface areas and to develop a large-scale oil/water separation facility for oil-field applications and petroleum industries.