Laser-Heat Surface Treatment of Superwetting Copper Foam for Efficient Oil–Water Separation

Oil pollution in the ocean has been a great threaten to human health and the ecological environment, which has raised global concern. Therefore, it is of vital importance to develop simple and efficient techniques for oil–water separation. In this work, a facile and low-cost laser-heat surface treatment method was employed to fabricate superwetting copper (Cu) foam. Nanosecond laser surface texturing was first utilized to generate micro/nanostructures on the skeleton of Cu foam, which would exhibit superhydrophilicity/superoleophilicity. Subsequently, a post-process heat treatment would reduce the surface energy, thus altering the surface chemistry and the surface wettability would be converted to superhydrophobicity/superoleophilicity. With the opposite extreme wetting scenarios in terms of water and oil, the laser-heat treated Cu foam can be applied for oil–water separation and showed high separation efficiency and repeatability. This method can provide a simple and convenient avenue for oil–water separation.