Facile Preparation of Ag-Coated Superhydrophobic/Superoleophilic Mesh for Efficient Oil/Water Separation with Excellent Corrosion Resistance.

We present the facile preparation of a superhydrophobic-oleophilic stainless steel mesh with excellent oil/water separation efficiency and resistance to corrosion through hydrofluoric (HF) acid etching, Ag nanoparticle coating, and stearic acid modification, to construct a superhydrophobic micro/nanohierarchical structure. The surface of the treated mesh exhibits superhydrophobicity, with a water contact angle of 152°, and superoleophilicity, with an oil contact angle of 0°. The effects of variation in the HF etching time and Ag nanoparticle coating on surface wettability were explored. The treated mesh demonstrated a very high separation efficiency, as high as 98% for the optimal preparation, on a series of oil/water mixtures. The durability of the treated mesh was tested by repeated separation of kerosene/water mixtures, with the separation efficiency remaining higher than 97% after 40 cycles. In addition, the mesh exhibited an excellent chemical resistance to both acidic and alkaline conditions, with good wearing in hot water. The improved superhydrophobic-oleophilic mesh represents a feasible and realistic oil/water separation methodology even under harsh conditions, and it could have wide application in industrial processes.