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 cm²ml⁻¹, intensity 30 W m⁻², pH 6.5 and around 85% mineralization of carbendazim was achieved.

Keywords:

• Photocatalytic degradation
• Carbendazim (technical)
• TiO₂
• TiO₂ LR
• Slurry reactor
• H₂O₂ and UV