Modeling of the radicalary state in the H2O2/UV oxidation system to predict the degradation kinetics of phenolic mixture solutions



The characterization of radical oxidation in the degradation of phenolic compounds with H2O2/UV has been studied. A kinetic model was developed to estimate the concentration of different radical species. Radical concentration defines a determined oxidative level whose changes are analyzed for different oxidizing conditions involving pH and hydrogen peroxide dosage. This study has been developed to extend a previous radical model, only for simple phenolic solutions, to phenolic mixtures consisting of phenol and different cresols. In a mixture, the effects of composition and total amount of phenolics have a great influence on the degradation of each compound markedly modifying the behavior found in a simple solution.

The application of a new extended radicalary model requires the characterization of the phenolic mixture solution through two fundamental parameters. The first one is the equivalent phenol in the mixture or phenol concentration, which gives the same oxidative level as that of the mixture case. Besides, additional information must be considered to characterize the deviation of the radical level between each compound and the mixture through the corresponding coefficient of radicalary activity. The model has been applied and verified to estimate the degradation of the different phenolics of a mixture, whatever the composition of phenolics, with good fitting to the experimental data. © 2010 American Institute of Chemical Engineers Environ Prog, 2011