Study on oil-water separation via stainless steel mesh fabricated by waterjet-assisted laser ablation

The materials with extreme wettability have attracted abundant attention all over the world, which can be used for solving the increasingly serious problem of Oily wastewater. Here, a novel technology named waterjet-assisted laser ablation (WJAL) is developed to fabricate microstructures on 304 stainless steel mesh (SSM) for oil-water separation. It is discovered that the obtained rough oxide coating on SSM having approximate 0° contact angle (CA) values of water/oil in the air and more than 150° CA of water in oil/oil in water environment, showing the extreme wettability of superhydrophilicity/ superoleophilicity in air and underwater superoleophobicity/ underoil superhydrophobicity. Based on the special wettability, the separation process of both light and heavy oil-water mixtures are completed utilizing machined SSM with higher separation efficiency and water flux. More importantly, the functional surface maintained the ability of oil-water separation after 30 cycle tests. Therefore, this research presents an advanced method for the one-step process of durable separation material.