Heterogeneous photocatalyzed degradation of a pesticide derivative, 3-chloro-4-methoxyaniline, in aqueous suspensions of titania

The photocatalyzed degradation of a pesticide derivative, 3-chloro-4- methoxyaniline (1), has been investigated in aqueous suspensions of titanium dioxide (TiO ₂) and air as a function of irradiation time under a variety of conditions using UV- Vis spectroscopic andHPLC analysis techniques. The degradation kinetics were studied under different conditions such as types of TiO ₂ powders, reaction pH, catalyst loading, substrate, and H ₂O ₂ concentrations. The photocatalyst Degussa P25 showed better photocatalytic activity for the degradation of the compound 1. Addition of hydrogen peroxide as an electron acceptor in addition to oxygen greatly enhanced the degradation rate of the compound 1. Higher degradation rates were observed at lower and higher pH values, i.e., 3.15 and 9.15, respectively. The optimal substrate concentration and catalyst loading for the degradationwas found to be 0.6 mM with 1.5 g L ^-1.Aprobable pathway for the decomposition of compound 1 is proposed.