Kinetics of the degradation of 2-chlorophenol by ozonation at pH 3.

Prediction of byproduct distribution during ozonation is of importance to the design of treatment process. In this study, degradation products in direct ozonation of 2-chlorophenol in aqueous solution were identified by employing the chemical derivatization technique, specifically, silylation. Transient distribution of degradation products, in a semi-batch reactor under three ozone dosages were identified and determined by HPLC analysis. An empirical degradation pathway was proposed to describe the ozonation reaction. A mathematical protocol consisting of 11 equations and 12 rate constants was developed to solve and optimize the kinetic parameters. Modeling results revealed that the empirical pathway was capable of predicting the ozonation reaction at the beginning phase under a higher ozone dosage (e.g., greater than 6mg/L(g)). The degree of agreement between predicted and experimental data decreased as the ozone dosage decreased to 1.2mg/L(g). Results suggested that there was a dosage-dependent pathway in the direct ozonation of 2-chlorophenol.