A Novel and Facile Preparation of Superhydrophilic/Superoleophobic Mg(Oh)2/Zno Coated Mesh for Fast and Efficient Oil/Water Separation

Abstract

A novel superhydrophilic/underwater superhydrophobic Mg(OH)2/ZnO coated mesh with a high underwater oil contact angle of 168.54° was swiftly prepared by one-step electrodeposition. The electrodeposition process involved the deposition of ZnO nanoparticles on the cathode due to the presence of Mg2+ in the electroplating solution, while Mg(OH)2 was simultaneously formed on the surface of the cathode copper mesh. The cathode surface, where hydrogen is generated, leads to the formation of micropores and nanosheets on the Mg(OH)2/ZnO coated mesh structure. This structural feature traps more water molecules, further enhancing the superhydrophilicity of the coated mesh. The oil/water separation efficiencies for p-xylene, kerosene, paraffin liquid, and mineral oil were 99.8%, 99.3%, 99.5%, and 99.4%, respectively. The separation efficiency remained higher than 99.4% even after conducting 350 p-xylene/water separation experiments. Additionally, the coated mesh displayed a strong oil/water separation ability after being immersed in alkali and salt solutions (pH=7, 9) for 10 hours. The coated mesh exhibited an enhanced water flux of (3±0.03)×105 L·m-2·h-1, along with a heightened invasion pressure (>2.8 kPa) and excellent oil-resistance performance. The Mg(OH)2/ZnO coated mesh developed in this study shows promising potential as a membrane for fast and efficient oil/water separation.

Keywords: Mg(OH)2/ZnO coated mesh, Electrodeposition, oil/water separation, Water flux, Oil resistance