Fluorine-free superhydrophobic steel mesh prepared by ZnO electrodeposition and MTES modification for effective oil-water separation

Abstract

The development of environmentally friendly superhydrophobic materials for oil-water separation remains a significant challenge. In this study, a fluorine-free superhydrophobic/superoleophilic stainless steel mesh was fabricated by ZnO electrodeposition followed by methyltriethoxysilane (MTES) modification. The hierarchical ZnO micro/nanostructures combined with the low-surface-energy MTES layer produced water contact angles above 150°. The modified mesh enabled gravity-driven separation of condensate oil/water mixtures, achieving a mean separation efficiency of 95.7±2.5% (n=10) and a representative permeation flux of 7.82×10³ L·m⁻²·h⁻¹. The mesh remained functional over ten consecutive reuse cycles and retained its superhydrophobic/superoleophilic characteristics after six months of ambient storage, indicating good short-term reusability and storage stability. These results demonstrate that ZnO electrodeposition combined with fluorine-free MTES modification provides a simple and effective strategy for fabricating superhydrophobic stainless steel meshes for gravity-driven separation of immiscible oil/water mixtures.