Abstract: In order to study the oil-water separation ability of meshes with special wettability, two copper-based superhydrophilic/underwater-superoleophobic meshes with micro-nano structures of Ag and Cu(OH)₂ were prepared by in situ displacement and oxidative modification methods. The effects of microstructure, surface wettability, permeation pressure, and the pH value on the separation performance of meshes were experimentally studied. The results show that the efficiencies of the two meshes for separating oil-water mixtures with single oil (e.g., diesel or gasoline) and multi-oil (e.g., the mixture of diesel and gasoline) both reached more than 99%. Owning to the difference in microstructures, the separation efficiency of the mesh with Ag micro-nano structure was slightly higher than that of the Cu(OH)₂ mesh. However, the mesh with Cu(OH)₂ micro-nano structure withstood a higher permeation pressure and had a greater liquid flux. Moreover, both the meshes were excellent in acid and alkali resistance. They can be reused for more than 10 times after washing without significant efficiency reducing, and there was no obvious degeneration arising after long-term placement. In short, these two types of meshes showed distinct advantages in separation efficiency, medium adaptability, repeatability, and durability for oil-water separation, and they would have broad application prospects.

Key words: superhydrophilic, superoleophobic, selective wettability, multi-component, separation efficiency