Preparation of reduced graphene oxide/titanium dioxide composite materials and its application in the treatment of oily wastewater

In current study, a reduced graphene oxide/titanium dioxide (RGO/TiO2) with good demulsification performance was prepared. The structure and morphology of RGO/TiO2 was characterized by Fourier transform infrared spectroscopy (FT-IR), UV–vis absorption spectra (UV), X-ray diffraction spectra (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectrometer (EDS). The bottle test showed that the light transmittance was up to 79.1 % when the concentration of RGO/TiO2 was 500 mg/L and the settling time was 30 min at ambient temperature. Furthermore, it had high salt tolerance under acidic and neutral conditions. The wettability, interfacial activity, dynamic interfacial tension (IFT), zeta potential, self-assemble of the interfacial film and microscopic analysis were further studied to explore the demulsification mechanism. The possible demulsification mechanism exhibited that RGO/TiO2 could be rapidly migrated to the oil-water interface and then to destroy the stability of oil droplets by adsorbing or replacing asphaltenes through π-π interaction. The finding in this work can bring a better understanding on the demulsification mechanism and provide a promising demulsifier to treat the oily wastewater.