Kinetic modelling of Fe(III)/H2O2 oxidation reactions in dilute aqueous solution using atrazine as a model organic compound

In this paper, experimental data are presented to test and to validate a ki netic model for the oxidation of organic compound in dilute aqueous solutio n by the Fe(III)/H2O2 process in a batch reactor (NaClO4/HClO4 solutions, I onic strength: I = 0.1 M, pH less than or equal to 3.0, 25.0 degrees C). At razine was used as a model compound. Under the conditions employed in this study ([Atrazine](o) < 1 mu M), the OH radical was the unique species respo nsible for the oxidation of atrazine. Propagation and termination reactions involving organic radicals were assumed to be of little importance and wer e not incorporated in the model. The data showed that the effects of pH (pH range: 1-3) and of the concentrations of reactants ([H2O2](o) and [Fe(III) ](o)) on the rates of oxidation of atrazine and of decomposition of hydroge n peroxide were in good agreement with model predictions. The concentration -time profiles for transient species (Fe(II), HO2./O-2(.-); and OH. radical s) obtained by computer calculations were also useful to explain the lag pe riod and the pseudo-first order decay which were observed on the experiment al kinetic curves of degradation of atrazine (C) 2000 Elsevier Science Ltd. All rights reserved.