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

Abstract

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 × 105 L·m−2·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.

Photoresponsive Electrospun Fiber Meshes with Switchable Wettability for Effective Fog Water Harvesting in Variable Humidity Conditions

“…In this study, a novel manufacturing approach of electrospinning and electrospraying was conducted to control the amount of titanium dioxide (TiO 2 ) incorporated within polyvinylidene fluoride (PVDF) fibers. TiO 2 has been widely studied due to its interaction with UV light making it an efficient photocatalyst, antibacterial, antifouling, and photoinduced wettability surface . TiO 2 has low reactivity, is chemically inert, and is widely used in outdoor applications such as paints, coatings, and pigments .…”

Preparation of pH-responsive reversible wettable surfaces and application for oil-water separation

“…Cheng et al [28] performed anodic oxidation on copper mesh substrates to generate Cu(OH) 2 nanostructures, and nanostructured copper mesh films modified by mixed thiols (containing alkyl and carboxylic acid groups) to prepare pH-responsive controllable water-permeable copper mesh films. Hou et al [29] prepared copper mesh with rough surface by oxidation method and then immersed the oxidized copper mesh into the prepared stearate (SA)-TiO 2 coating solution to obtain superhydrophobic copper mesh with switchable wettability. Wang et al [30] prepared micro-nano structures on the surface of copper mesh by electrochemical deposition and surface modified them with thiol mixture to prepare superhydrophobic copper mesh with pH-responsive properties.…”