Opposite Superwetting Nickel Meshes for On-Demand and Continuous Oil/Water Separation

Oil/water separation is widely studied because of the growing discharge of industrial and domestic oily water, as well as frequent petroleum spills; however, on-demand and continuous oil/water separation has seldom been reported. For this purpose, we prepared opposite wetting nickel meshes by creating FeNiO_<i>x</i>(OH)_<i>y</i> micro-/nanostructures on the surface and further modification. The surface morphology, chemical composition, and the wetting property were investigated by SEM, EDS, XRD, Raman spectrum, XPS, and contact angle measurement. The as-prepared superhydrophilic/underwater superoleophobic and superhydrophobic/superoleophilic meshes could be used for reusable on-demand oil/water separation with high efficiency. Additionally, continuous oil/water separation was realized by integrating the opposite meshes. The current work will be beneficial for the design and development of materials with special wettabilities and the practical application of oil/water separation