Synthesis and performance of antifouling and self-cleaning polyethersulfone/graphene oxide composite membrane functionalized with photoactive semiconductor catalyst Nadir Dizge, Hakan Gonuldas, Yasin Ozay, Hasan Ates, Kasim Ocakoglu, Ersan Harputlu, Saadet Yildirimcan and Ali Unyayar ABSTRACT This study was performed to synthesize membranes of polyethersulfone (PES) blended with graphene oxide (GO) and PES blended with GO functionalized with photoactive semiconductor catalyst (TiO 2 and ZnO). The antifouling and self-cleaning properties of composite membranes were also investigated. The GO was prepared from natural graphite powder by oxidation method at low temperature. TiO 2 and ZnO nanopowders were synthesized by anhydrous solgel method. The surface of TiO 2 and ZnO nanopowders was modied by a surfactant (myristic acid) to obtain a homogeneously dispersed mixture in a solvent, and then GO was functionalized by loading with these metal oxide nanopowders. The PES membranes blended with GO and functionalized GO into the casting solution were prepared via phase inversion method and tested for their antifouling as well as self-cleaning properties. The composite membranes were synthesized as 14%wt. of PES polymer with three different concentrations (0.5, 1.0, and 2.0%wt.) of GO, GO-TiO 2 , and GO-ZnO. The functionalization of membranes improved hydrophilicity property of membranes as compared to neat PES membrane. However, the lowest ux was obtained by functionalized membranes with GO- TiO 2 . The results showed that functionalized membranes demonstrated better self-cleaning property than neat PES membrane. Moreover, the ux recovery rate of functionalized membranes over ve cycles was higher than that of neat membrane. Nadir Dizge (corresponding author) Hakan Gonuldas Yasin Ozay Hasan Ates Ali Unyayar Department of Environmental Engineering, Mersin University, Yenisehir, Mersin 33343, Turkey E-mail: nadirdizge@gmail.com Kasim Ocakoglu Ersan Harputlu Saadet Yildirimcan Advanced Technology, Research and Application Center, Mersin University, Mersin 33343, Turkey Kasim Ocakoglu Department of Energy Systems Engineering, Faculty of Technology, Mersin University, Mersin 33480, Turkey Saadet Yildirimcan Faculty of Engineering, Department of Electrical- Electronics Engineering, Toros University, Mersin 33140, Turkey Key words | antifouling, composite membrane, functionalized surface, graphene oxide, self-cleaning surface INTRODUCTION Textile processing industry is one of the common sectors in developing countries. The sector uses excessive amounts of water and produces wastewater resulting in pollution loading being too much. The wastewater contains high amount of sus- pended and dissolved solids, non-reacted dyestuffs (color) and other chemicals that are used in the different stages of dyeing and other processing. The presence of even small amounts of dye in water (e.g. 1020 mg/L) is highly visible and affects the water transparency (Rajkumar & Kim ). So far, many wastewater treatment technologies have been developed for color removal, including physical, chemical and biological processes. All of them have some advantages and drawbacks (Alver & Metin ; Kurt et al. ; De Jager et al. ; Hayat et al. ; Dehghani et al. ). The conventional chemical coagulation process gener- ates a large volume of hazardous sludge and has a problem of sludge disposal. However, the biological treatment of tex- tile wastewater shows low degradation efciency due to presence of biologically inert high molecular weight dye- stuffs (Rajkumar et al. ). Additionally, a combination of two or more treatment methods for the further treatment was investigated by different researchers in order to satisfy the legal requirements (Doumic et al. ; Jung et al. ; Punzi et al. ). 670 © IWA Publishing 2017 Water Science & Technology | 75.3 | 2017 doi: 10.2166/wst.2016.543 Downloaded from https://iwaponline.com/wst/article-pdf/75/3/670/455828/wst075030670.pdf by guest on 10 November 2018