Kinetics of Microcystin-LR Oxidation by Ozone

Abstract

Abstract The oxidation kinetics of the reaction between dissolved ozone and microcystin-LR, in acidic and neutral buffer solutions over the temperature range of 10 to 30 °C was investigated. Also, the effect of natural organic matter (NOM) on the oxidation of microcystin-LR by ozone was evaluated. The reaction is very rapid and the overall kinetics can be modeled as a second order, with first order in each concentration of ozone and pure microcystin-LR. At 20 °C, the overall rate constant ranged from 3.4×l04 to l.0 v×105 M−1s−1 as the solution pH changed from 7 to 2. As the temperature increased from 10 to 30 °C, the average overall rate constant increased from 5.8×l04 to 1.6×l03 M−1s−1 at pH value of 2. A distinct lag before the oxidation of microcystin-LR, in the presence of NOM, was observed as DOC increased from 1 to 5 mg/L. Key words: OzoneCyanobacteriaKineticsMicrocystin-LROzonation RateReaction OrderToxinsDrinking Water Treatment