Solar light induced photocatalytic degradation of sulfamethoxazole by ZnWO₄/CNNs nanocomposites

The preparation of ZnWO₄/CNNs nanocomposites was achieved through a simple method at room temperature. In order to investigate the optimum loading of carbon nitride nanosheets (CNNs) for the formation of the nanocomposites, a series of ZnWO₄/CNNs compositions were prepared and studied through a variety of characterization techniques, such as powder X-ray diffractrometry (pXRD), Scanning Electron Microscopy (SEM) and UV–vis optical measurements. The photocatalytic activity of the nanocomposites was investigated by using sulfamethoxazole (SMX) as a model pollutant. It was found that the material with 30 wt% ZnWO₄/CNNs exhibited the higher photocatalytic activity. The photocatalytic mechanism was further investigated using appropriate scavengers (t-ButOH, Kl) or under Argon atmosphere to examine the contribution of the different reactive species in the observed photocatalytic activity. The photogenerated holes and the superoxides produced following the promotion of electrons to the conduction band were the main responsible for pollutant's degradation. The photocatalytic efficiency after five sequential experiments showed only a slightly decreased implied high stability of the synthesized material.