A mechanically robust copper mesh with switchable wettability and antibacterial activity for selective oil-water separation

With the continuous improvement in living standards, the discharge of oily sewage in daily life and industry has gradually increased, causing considerable damage to the environment and also great inconvenience to people. Traditional treatment methods cannot meet the increasing demand for sewage treatment, so more efficient treatment methods need to be studied. Research on oil-water separation materials is gradually becoming intelligent, but most of these intelligent materials cannot solve the problem of bacterial growth on the surface, new antibacterial and hydrophobic materials need to be studied. Here, an inexpensive and simple method is presented to prepare an antibacterial copper mesh with pH-responsive wettability between hydrophilic and hydrophobic. First, a copper mesh with a rough surface was prepared by an oxidation method, and then the oxidized copper mesh was immersed in the prepared coating solution of stearate (SA)-TiO2 to obtain a superhydrophobic copper mesh. Scanning electron microscopy analysis showed that the modified copper mesh changed from the original smooth surface to a rough surface covered with needle-like nano-oxide wires. The SA-TiO2-coated copper mesh (STCM) has good separation efficiency (about 97%) and separation flux (about 1.1 x 10(5) L center dot m(-2)center dot h(-1)) for the immiscible oil-water mixture, the separation efficiency remained basically unchanged (about 97%) after 15 separation cycles, and the wettability of this can be changed by soaking in an alkaline solution at a specific pH (from 12 to 14). In addition, the prepared STCM showed good antibacterial properties against Staphylococcus aureus and Escherichia coli. This preparation strategy of STCM provides a low-cost and facile method for wastewater treatment in practical applications.