MoS2/RGO composites for photocatalytic degradation of ranitidine and elimination of NDMA formation potential under visible light

Ranitidine (RAN) is a primary precursor of NDMA (N-nitrosodimethylamine), which is a carcinogenic disinfection by-product that poses a serious threat to human health and environmental safety. Photocatalysis is a useful and effective technology for degrading RAN and eliminating its NDMA formation potential. In our work, MoS2/RGO (reduced graphene oxide) composites with various mass ratios were fabricated using a hydrothermal method and characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Xray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectrometer. In terms of the photocatalytic degradation of RAN, the MoS2-RGO-3 composite (with 23.2 wt% RGO) achieved the best performance with 74% RAN photodegraded in 60 min under visible light. Furthermore, this composite obtained the highest RAN mineralization efficiency (50%) and had the lowest NDMA formation potential (6.76%). Additionally, the generated hydroxyl radicals ((OH)-O-center dot), superoxide radicals (O-center dot(2)-) and holes (h(+)) were involved in the RAN photocatalytic degradation process, where %OH was the most important active ingredient. This work may provide a new basis for the preparation of better photocatalysts under visible light for micro-pollutant degradation in water treatment.