Fabrication of meshes with inverse wettability based on the TiO2 nanowires for continuous oil/water separation

With the purpose of avoiding the limitation of oil/water density relationship, as well as achieving the continuous separation, two types of filtering materials with inverse wettability have attracted extensive attention. In our work, a superhydrophilic mesh was fabricated via a series of procedures, including the deposition of TiO2 seed layer on the surface, the growth of TiO2 nanowires by a hydrothermal method and calcination process. As expected, the as-prepared superhydrophilic mesh turned to be superhydrophobic after the decoration by low surface energy reagent. The formation mechanism of grass-like TiO2 nanowires was proposed and surface morphological optimization conditions were studied. As for the oil/water application, the T-shaped bidirectional device combining the meshes with inverse wettability was adopted for achieving continuous oil/water separation. Meanwhile, the separation test showed that the separation efficiency of greater than 99% and high flux were obtained for various oil/water mixtures. Furthermore, according to the results simulating the realistic industrial application, the as-prepared meshes exhibited excellent reuse durability and stability in corrosive environment. The extension of TiO2 nanowires on mesh, cooperating the multiple wettability behaviors could be regarded as a prospective candidate for large-scale oil/water separation.