Biomimetic Hierarchical TiO₂@CuO Nanowire Arrays-Coated Copper Meshes with Superwetting and Self-Cleaning Properties for Efficient Oil/Water Separation

Creating a practical and energy-efficient method with high efficiency to separate oil–water mixtures and emulsions is essential for sustainable aquatic ecosystem and waste oil recycling. Herein, we reported a completely inorganic hierarchical TiO2@CuO nanowire array-coated copper mesh membrane fabricated using chemical oxidation and hydrothermal recrystallization. The biomimetic hierarchical nano/micro-structure can form a lotus-leaf-like interface with fine surface roughness and hydration ability, thus endows the membrane superhydrophilic and underwater superoleophobic nature. Thus, the as-synthesized TiO2@CuO nanowire array-coated copper mesh membrane demonstrates promising water flux of 87.6 kL h–1 m–2 and ultrahigh separation efficiency with oil residue of only 12.4 mg L–1 in the permeate. Moreover, the uniformly immobilized TiO2 nanoparticles exhibit UV-irradiated photocatalytic ability, which can be effectively regenerate the contaminated membrane after exposure to UV irradiations for 60 min. Therefore, this highly-efficient, reusable, and easy-scalable membrane fabrication strategy may possess practical potential for next-generation oil/water separation application.