Visible-light-driven photocatalytic degradation of fenpyroximate in rotating packed bed reactor using Fe3O4@PbS@Ni2P magnetic nanocomposite photocatalyst: Response surface modelling and optimization

摘要

A highly efficient rotating packed bed photocatalytic reactor based on Fe3O4@PbS@Ni2P composite for the degradation of fenpyroximate (FP) as an acaricide in agriculture is described. The visible-light-driven photocatalyst was characterized using various techniques. The interaction of operational parameters consisting of rotational speed (400-1200rpm), photocatalyst dosage (0.20-0.40gl(-1)), solution flow rate (0.10-0.50lmin(-1)), aeration rate (15-35lmin(-1)), FP initial concentration (5-45mgl(-1)), pH (2-10) and irradiation time (20-100min) for FP degradation was examined via central composite design under response surface methodology. Accordingly, under the suggested optimum conditions, namely rotational speed of 950rpm, Fe3O4@PbS@Ni2P dosage of 0.30gl(-1), solution flow rate of 0.30lmin(-1), aeration rate of 25lmin(-1), pH of 6.0 and irradiation time of 85min, more than 99% of 45mgl(-1) FP was degraded. The Langmuir-Hinshelwood kinetic model was the best equation for the description of the experimental data. According to the rate constant, the contribution of photocatalytic degradation, adsorption and photolysis to the reduction of FP concentration and, subsequently, the efficiency of water treatment were studied.