Parametric study on degradation of fungicide carbendazim in dilute aqueous solutions using nano TiO2

Abstract

The carbendazim is a widely used benzimidazole fungicide. It is of major concern due to its suspected hormone disrupting effects. The degradation of carbendazim considered as a “priority hazard substance” by the Water Framework Directive of the European Commission was investigated by UV/solar photocatalytic process using P25 TiO2 and LR grade TiO2. A batch-type photoreactor was employed and the influence of catalyst loading, initial concentration, area/volume ratio, pH of the solution and light conditions were studied. Aeroxide P25 shows better degradation efficiency than LR grade TiO2 in both UV and sunlight conditions for optimized parameters. Degradation of fungicide was negligible with TiO2 under UV without catalyst. However, no adsorption took place with catalyst in dark. Also, the addition of oxidant (H2O2) had no appreciable increase in the rate of degradation for both the catalysts. Under UV light with TiO2 carbendazim has shown substantial degradation at different time of irradiation. The optimized parameters under UV for the degradation of carbendazim are catalyst loading 1 g L−1, area/volume ratio 0.919 cm2 ml−1, intensity 30W m−2, pH 6.5 and around 85% mineralization of carbendazim was achieved.