Study of the degradation of trizines by O3/H2 and O3 kinetic and oxidation by-products.

The degradation of s-triazines (atrazine, simazine, propazine) in water by O3 and O3/H2O2 has been investigated. Experiments were carried out in phosphate-buffered water (pH=7.5 or in drinking water spiked with s-triazines. Competitive kinetic experiments showed that simazine is more rapidly oxidized than atrazine and propazine and that the second order rate constants for the reaction between OH radical and triazines are in the range of 1 109 - 3 109 1 mol-1S-1 at 20°C. High Performance Liquid Chromatography, Gas Chromatography and Mass Spectrometry analyses showed that the degradation of atrazine by O3 and O3 and O3/H2O2 leads to similar oxidation by-products.