Fabrication of super-wetting copper foam based on laser ablation for selective and efficient oil-water separation

Abstract

Oil pollution has caused damage to the ecological environment and human health, which cannot be ignored in industrial production and marine economic. It is very vital to explore a simpler and easier to manufacture oil-water separation method. In this work, the super-wetting copper foam with superhydrophobicity or superhydrophilicity on was fabricated based on low-cost nanosecond laser ablation combined chemical modification. The surface of copper foam was covered with fluffy microstructures and smaller nanoparticles after laser ablation, which greatly enhances the hydrophobicity, with a maximum contact angle of 156°. The droplet could rebound many times after being compressed in a cake shape on the superhydrophobic surface but spread rapidly on the superhydrophilic surface. Analysis of chemical composition verified the fluorine-containing long-chain greatly reduces surface energy, while the oxygen group of graphene oxide is the opposite. Based on the oil permeability of the superhydrophobic copper foam and the water permeability of the superhydrophilic copper foam, the separation of heavy oil and light oil can be selectively achieved. The separation efficiency of different oil-water mixtures could be higher than 99%, and the recyclability was better after multiple separations. It provides a convenient and selective way for oil-water separation.