Electrochemical monitoring of the photocatalytic degradation of the insecticide emamectin benzoate using TiO2 and ZnO materials

Photocatalysis is a rapidly expanding technology where a diverse range of toxic chemicals can be completely degraded in water. In this study, an efficient photocatalytic method for the degradation of the aquatic pollutant, emamectin benzoate, coupled with a novel electrochemical monitoring method is reported for the first time. Photocatalytic reactions were performed in a slurry-based reactor containing either a ZnO or TiO2 photocatalyst irradiated with 365 nm UV-LEDs. Electrochemical monitoring was accomplished using Square Wave Voltammetry using a cathodically pre-treated boron doped diamond indicator electrode. Parameters such as initial pollutant concentration, solution pH and photocatalyst dosage, were investigated to optimise the process. While ZnO provided a higher initial rate of degradation than TiO2 at all concentrations investigated, the overall degradation profiles were similar. This novel technique allowed a large range of parameters to be rapidly and effectively scrutinised using electrochemical monitoring of the degradation.

Automated summary

Photocatalysis is a rapidly growing technology for the complete degradation of toxic chemicals in water. This study introduces an efficient photocatalytic method, combined with a novel electrochemical monitoring technique, for the degradation of the aquatic pollutant emamectin benzoate. The photocatalytic reactions were conducted using ZnO or TiO2 photocatalysts irradiated with 365 nm UV-LEDs, while electrochemical monitoring was achieved through Square Wave Voltammetry with a boron doped diamond indicator electrode. Various parameters were investigated to optimize the process, and the overall degradation profiles of ZnO and TiO2 were similar.