Nanostructured TiO2/CuO dual-coated copper meshes with superhydrophilic, underwater superoleophobic and self-cleaning properties for highly efficient oil/water separation

Oil-contaminated water caused by either oil spill disasters or industrial disposal has posed a global risk to environmental sustainability and human health. To address the ever-growing need for highly efficient separation of oil/water mixtures, nanostructured TiO 2 /CuO dual coatings were fabricated on the copper mesh by a combination of electrochemical anodization and layer-by-layer self-assembly deposition to render its surface with superhydrophilic, underwater superoleophobic and self-cleaning functionality. Cu(OH) 2 nanoneedle arrays (NNA) were vertically grown from the copper mesh surfaces by electrochemical anodization processes, followed by the deposition of TiO 2 multilayer on the Cu(OH) 2 NNA via layer-by-layer assembly prior to being calcinated to form TiO 2 /CuO dual coatings. The nanostructured TiO 2 /CuO NNA dual-coated copper meshes were demonstrated to exhibit a high separation efficiency (oil residue content less than 20   ppm), excellent water flux (more than 80   kL·h −1 ·m −2 ), and desirable self-cleaning ability under ultraviolet (UV) illumination. The photo-catalytic ability of the deposited TiO 2 layers enabled the facile and rapid removal of the oil contaminants on the mesh surface under UV illumination to recover oil/water separation ability of the as-fabricated mesh for recycle use. With the adherent features of superhydrophilicity, underwater superoleophobicity and self-cleaning ability, the proposed TiO 2 /CuO NNA dual-coated meshes are potentially useful in practical oil/water separation applications.