Heterogeneous photocatalytic degradation of isoproturon in aqueous solution: Experimental design and intermediate products analysis

The photocatalytic degradation of the herbicide isoproturon (3-(4-isopropylphenyl)-1,1-dimethylurea) in aqueous solution has been investigated. The influence of pH, TiO2 loading and isoproturon concentration on the efficiency of the reaction has been studied by statistical design of experiments. Under optimal conditions (1.95 g L−1 TiO2 loading, pH 3.8 and 5 mg L−1 of isoproturon), 95% of the herbicide was removed within 20 min of irradiation. HPLC/MS/MS was used to identify and elucidate structural information of the main products formed during the photocatalytic reaction. According to the results obtained, a plausible mechanism for the formation of the different by-products has been proposed.