Disinfection effects induced by graphene-based photocatalytic composites under solar light illumination

ZnO/graphene and ZnO/stellerite composite photocatalysts were prepared through a facile hydrothermal-calcination processing with zinc acetate , urea , natural stellerite and graphene.The composition , morphology , specific surface area ,pore size distribution and light absorption properties of prepared composites were characterized by scanning electron microscopy(SEM), X-ray diffraction (XRD ) ,nitrogen adsorption/desorption and UV-visible diffused reflectance spectroscopy (UV-vis DRS ). It was found that the prepared photocatalysts ZnO/stellerite and ZnO/ graphene had wurtzite ZnO phase morphology with ZnO paticle sizes of 22.42 nm and 15.72 nm.SHEr of composites were 16.54 m'/g and 35.55 m'/g respectively.3D structure between ZnO and graphene resulted in the response to visible light region , reduced recombination of free charges , and enhanced interface charge transfer.'The disinfection action towards Staphylococcus aureus ( S.aureus)under solar light showed that the optimal amount of ZnO/graphene was 100 mg/L.ZnO/graphene exhibited significantly enhanced photocatalytic
disinfection efficiency than ZnO/stellerite powders , and disinfection rate up to 1.17 h'is 1.31 times that of ZnO/stellerite composite.