Facile preparation of superhydrophilic and underwater superoleophobic stainless steel mesh for oil–water separation

Effective oil–water separation is necessary to cope with frequent oil spill accidents, which pose huge risks to the marine ecosystem. Among existing oil–water separation methods, gravitational filtration is the most efficient. When super-wetting materials are used for gravitational filtration, they have the merit of high efficiency but they still have the disadvantages of high price, low eco-friendliness, and complex procedures. To overcome those problems, we fabricated a stainless steel mesh by a one-step method via an annealing process. The annealed mesh achieved both superhydrophilicity and superoleophilicity. For oil–water separation, the annealed mesh, which was pre-wetted by water, demonstrated underwater superoleophobicity. Thus, this study confirmed that the proposed system can separate various oily mixtures with high efficiency (>99 %) and it exhibits underwater anti-oil-fouling.