Kinetics of ferric ion promoted photodecomposition of 2-chlorophenol

Abstract

The photodecomposition of 2-chlorophenol in ferric solutions at pH:3.0 was investigated using monochromatic light(313 nm). The concentrations of 2-chlorophenol were in the range of 5.0×10 −6 to 1.5×10 −4 mol·l −1. Above 5.0×10 −5 mol·l −1 of 2-chlorophenol concentration, it decreased linearly with irradiation time and the rates of photodecomposition were independent of the initial concentrations. Below 3.0×10 −5 mol·l −1 of 2-chlorophenol concentration, the initial rates of photodecomposition decreased with lowering the initial concentration of 2-chlorophenol. The results were in good agreement with the kinetic model that assumed the steady-state concentration of hydroxyl radical formed by photo-dissociation of Fe(III)-hydroxy complex. The rates of ferrous ion formation in the presence of 2-chlorophenol were larger than that in the absence of 2-chlorophenol.