2D→3D conversion of superwetting mesh: A simple but powerful strategy for effective and efficient oil/water separation

•The importance of 2D → 3D conversion of superwetting mesh is demonstrated.•A simple, versatile and universal oil/water separation system has been developed.•External pumping operation was introduced for the removal of non-wetting phase.•The use of single SOPhi-SHPho mesh can separate oil/water mixtures effectively.•A mechanism of synergistic capillary-driven and gravity-driven separation is proposed.