Environmentally-friendly fabrication of a recyclable oil-water separation material using copper mesh for immiscible oil/water mixtures

Abstract Oily wastewater created by industrial disposal and oil spill disasters enormously affects human health and ecological systems. Environmentally-friendly methods for oil–water separation are highly desirable. We propose an environmentally-friendly approach for fabricating superwettable surfaces with recyclability to separate oil-water mixtures efficiently. A superwettable surface with a dendrite-like hierarchical structure for separating various oil–water mixtures was fabricated using copper mesh via modification by non-toxic stearic acid. The prepared surface was confirmed to be superhydrophobic and superoleophilic, in which the water contact angle, water slide angle and oil contact angle are 158°, 3° and 1°, respectively. These properties resulted in the surface achieving oil–water separation driven by gravity, and exhibiting efficient separation (> 98%) and high recyclability (throughout 22 consecutive cycles) of various oil–water mixtures. Moreover, the prepared surface also exhibited self-cleaning performance and stability to long-term water jet exposure. This efficient and environmentally-friendly method provides a green strategy for separating various oils from water.