ZnO/WO < inf > 3 < /inf > .H < inf > 2 < /inf > O micro-nanostructures coated mesh for efficient separation of oil-water mixture

Abstract

In this work, we report the fabrication of superhydrophilic-underwater superoleophobic ZnO/WO3.H2O coated stainless steel mesh for the effective oil-water separation. X-ray diffraction studies confirm the occurrence of hexagonal wurtzite and orthorhombic phase of ZnO and WO3.H2O respectively in the ZnO/WO3.H2O coated mesh. The superhydrophilic-underwater superoleophobic nature of ZnO/WO3.H2O covered mesh is attributed to the innate hydrophilicity and surface roughness of WO3.H2O, which is again enhanced by the inclusion of ZnO. The oil-water separation efficiency of ZnO/WO3.H2O covered stainless steel mesh was over 98% for various oil-water mixtures. The coated mesh maintains high efficiency of separation even after 10 cycles of operation. Moreover, the as-deposited meshes demonstrated good separation ability for the emulsified oil droplets larger than its pore size. The excellent abrasion-resistant ability of ZnO/WO3.H2O coated mesh indicate its excellent mechanical stability. In addition, the high intrusion pressure of ZnO/WO3.H2O coated mesh favors the separation of oil-water mixture in large volumes. Furthermore, the photocatalytic activity of the coated mesh could degrade the organic pollutants present in the oil-water mixture. The proposed novel strategy in designing a multifunctional surface paves the way for the treatment of oleaginous water for environmental remediation.