A Kinetic Model for Advanced Oxidation Processes of Aromatic Hydrocarbons in Water:  Application to Phenanthrene and Nitrobenzene

Abstract

A kinetic model for the advanced oxidation (ozonation alone, UV radiation alone, ozone plus hydrogen peroxide, ozone plus UV radiation, and UV radiation plus hydrogen peroxide) of aromatic hydrocarbons in water is proposed and tested with experimental results of the oxidation of nitrobenzene and phenanthrene, two aromatic hydrocarbons of different reactivity with ozone. The kinetic model leads to good results in the case that the compound treated reacts exclusively with ozone, that is, without the contribution of hydroxyl radical oxidation as in the case of phenanthrene oxidation. In this case, it is not necessary to account for intermediate reactions to have good predictions of experimental remaining concentrations of ozonation processes. On the contrary, when the aromatic hydrocarbon is mainly removed by hydroxyl radicals (case of nitrobenzene), mole balance equations of intermediates have to be included for the experimental concentrations to be reproduced. For so doing, the kinetic parameters, such as rate constants of reactions between ozone and hydroxyl radical with intermediates and their corresponding quantum yields at 254 nm, were also determined. The kinetic model, however, is unable to reproduce, with accuracy, the experimental results of the ozone−UV radiation oxidation system.