Degradation of a mixture of pollutants in water using UV/H2O2 process.

CRISTINA S. ZALAZAR; MELISA MARIANI; MARISOL D. LABAS; RODOLFO J. BRANDI; ALBERTO E. CASSANO

Berlin

Conferencia; 5th International Conference Oxidation Technologies for Water and Wastewater Treatment; 2009

The degradation reaction of a simple mixture of pollutants (Dichloroacetic acid + Formic acid) employing H2O2 and UVC radiation (253.7 nm) has been studied in a well-mixed reactor operating inside a recycling system. The final objective of this work is to develop, starting from a rather manageable system, a systematic methodology for treating degradation of mixtures of pollutants, progressing onwards to aggregates that are more complex. In this contribution, the effects of different variables such as hydrogen peroxide/pollutant mixture initial concentration ratio, pH and incident radiation at the reactor wall were studied. The results show that the best degradable conditions are: pH = 3.5 and hydrogen peroxide concentrations of 3.9 to 11.8 mM (134-400 mg/L), for initial concentrations of 1.10 mM and 0.39 mM for Formic acid and Dichoroacetic acid respectively (50 mg/L for both pollutants). The influence of the incident radiation at the reactor wall on the degradation rates of the mixture is markedly significant. In addition, it has been shown that in an aqueous solution no stable reaction intermediates are formed. On this basis, a complete reaction scheme for the mixture is proposed that is apt for a reaction kinetics mathematical modeling of the mixture and ulterior scaling-up.