Micro-dissolved fabrication of robust Superhydrophilic and Underwater Superoleophobic membranes based on cotton fabrics for oil/water separation

Abstract

The superhydrophilic and underwater superoleophobic membranes based on textile possessed excellent separation efficiency and anti-oil fouling property, but the poor stability caused by nanoparticles (NPs) shedding had severely limited the practical application in oily wastewater treatment. In this paper, a feasible method to prepare the robust membranes based on cotton fabric (CF) decorated with TiO 2 NPs and citric acid (CA) using micro-dissolution method was reported. The CF were slightly dissolved in a NaOH/urea solution at low temperature, allowing the incorporation of the TiO 2 NPs into the superficial layers of the fabrics. Then, the vacuum filtration process facilitated the TiO 2 NPs uniformly deposition on the CF surface. In the subsequent coagulation process, the TiO 2 NPs were firmly anchored on the fabric surface. Then, the esterification reaction between CA and cotton was carried out to impart the fabric with superior hydrophilic properties. The prepared membranes were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermogravimetric analysis (TG). Additionally, the separation efficiency and stability of membranes were systematically evaluated. The results of SEM indicated that the TiO 2 NPs were uniformly anchored on the membrane surface. The prepared membranes could not only separate traditional oil/water mixture but also treat complicated oil-in-water (O/W) emulsion with excellent separation efficiency. What’s more, the membranes could withstand various harsh condition and repeated use. Therefore, the prepared TiO 2 /CA decorated membranes have the potential to be used in the practical oily wastewater treatment.