Preparation of photocatalytic self-cleaning graphene oxide/titanium dioxide composite films for oil–water emulsion separation

Abstract

This study took graphene oxide (GO) as the basic material and modified it by grafting with polydopamine (PDA) and 3-aminopropyltriethoxysilane (APTES). Nano-titanium dioxide (TiO₂) was introduced, and a new type of superhydrophilic/underwater superoleophobic composite membrane (GPAT membrane) for photocatalytic degradation of pollutants was prepared by a vacuum filtration self-assembly method. Its structure and performance were deeply studied by means of FTIR, XRD, SEM, PL and other methods. The experimental results show that the water contact angle of the modified GPAT membrane reaches 0° within 0.5 seconds, which is in a superhydrophilic state. The maximum flux of oil–water emulsion can reach more than 793.8 L m⁻² h⁻¹, and it demonstrates excellent emulsion separation ability. The separation efficiency of oil–water emulsion for different oil phases can all reach more than 98.82%. After 20 service cycles, the separation efficiency can still reach over 97.98%. The addition of titanium dioxide endows the membrane with photocatalytic self-cleaning ability. Under ultraviolet irradiation, it can degrade pollutants on the membrane surface, which is conducive to the recovery of membrane performance and thus beneficial to the long-term stable operation of the membrane. The modified GPAT membrane also has certain self-cleaning properties. After being exposed to ultraviolet light, it can degrade pollutants and restore certain performance, highlighting its good potential for practical applications.