Kinetics and mass transfer of atrazine ozonation

Abstract

The kinetics of the atrazine oxidation in aqueous solution by ozone was studied under different initial pH conditions and in the presence of a hydroxyl radical scavenger at pH 2.8. It was verified that the process took place mainly through radical reaction, even in acid medium. Therefore, a relatively high value of 26.4 L/(mol.s) for the rate constant of the direct reaction between molecular ozone and atrazine was found. After 10 minutes of oxidation, the degradation of the herbicide was more effective for pH 10.30 than for pHs 6.25 and 2.80. The mass transfer of ozone from the gas phase to the liquid phase was strongly affected by the oxygen flowrate and to a lesser extent by the stirring speed.