Fabrication of TiO2/WO3 heterostructure mesh with hierarchical structures, a tool for oily wastewater treatment

To address water pollution caused by the water-soluble organic contaminants and oily wastewater, a multifunctional TiO2/WO3 heterostructure mesh exhibiting superhydrophilic/underwater superoleophobic behavior has been developed by a combination of hydrothermal and solvothermal methods followed by an annealing process. The formation of TiO2/WO3 heterostructure was established by the XPS and HR-TEM analysis. Exhibiting exceptional water affinity and underwater oil-rejection behavior, the TiO2/WO3 mesh separates different mixtures of water with oil of varying densities achieving efficiency of ~98% for lighter oils and 97% for heavier oils respectively. Moreover, the TiO2/WO3 mesh separates emulsified oil from water with an efficiency of ~95% following the size-sieving effect. The corresponding separation flux was found to be ~31560 L.m-2.hr-1, 15759 L.m-2.hr-1 and 523 L.m-2.hr-1 for lighter oil-water, heavier oil-water and emulsions respectively. In addition to this, the TiO2/WO3 mesh demonstrated outstanding self-cleaning behavior and exceptional abrasion resistance ability. Furthermore, the filtrate's organic contaminants were effectively degraded by the Z-scheme TiO2/WO3 heterostructure mesh with exceptional efficiency (~92%). Owing to the outstanding ability to separate light oil-water, heavy oil-water and emulsions along with powerful photocatalytic degradation capabilities, the TiO2/WO3 heterostructure mesh stands out as an innovative material in the practical field oily wastewater remediation.