Modeling of Chlorpyrifos degradation by TiO2 photo catalysis under visible light using response surface methodology

Chlorpyrifos has been classified by the Stockholm Convention as priority pesticide under consideration because of its toxicological profile that succinctly characterizes the toxicological and adverse effects on health. TiO 2 photo catalysis of aqueous chlorpyrifos (CPF) solution using a raceway pond, containing total nitrogen and total phosphorus, has been modeled using response surface methodology (RSM). The RSM was used to improve the optimum condition of CPF degradation using R software. The ANOVA, p-value of lack of fit > 0.05 indicated that the equation was well-fitted. 71.09 ± 1.9% of removal was obtained for CPF (2.84 ppm), time (55.15 min) and dosage of TiO 2 (17.07 mg L –1 ) under TiO 2 visible photo catalysis compared to the 25.6 ± 0.25% by visible photolysis under similar experimental conditions. Nitrogen and phosphorus showed negligible interference on CPF degradation.