Degradation of chlorantraniliprole by photocatalysis of supported titanium dioxide: Effect of operating parameters

The rinsing of sprayers after the phytosanitary treatment of agricultural plots generates waste water, which is discharged without prior treatment into aquatic environments. The aim of this study was to evaluate the efficiency of a supported photocatalytic process for the degradation of chlorantraniliprole in an aqueous medium. Clay balls were made in the laboratory from 40 mL of ultrapure water added to 100 g of clay powder to obtain a homogeneous paste. Beads were made and dried at 105°C for 24 h and then baked at 550°C in the oven to make them water-resistant. They were soaked in a 10 g/L ethanol solution of TiO2 for 24 h, then calcined at 400°C. The photocatalysis experiments were carried out with 50 ml reactors containing 40 g of beads under sunlight in a humid tropical zone for 300 min. The results showed a decrease in the concentration of chlorantraniliprole 500 µg/L under theses experimental conditions. The degradation of this insecticide is significantly improved by increasing the clay mass at pH = 6 for a concentration of 500 µg/L. In addition, the application of this photocatalytic process on environmental matrices showed that this process was effective for the depollution of drinking water and river water. The beads were reused for all experiments by recycling them by calcination at 400°C.   Key words: Chlorantraniliprole, supported titanium dioxide, clay beads, aqueous medium.