| Abstract
| - The present study investigates the degradation of atrazine(2-chloro-4-(ethylamino)-6-isopropylamino-s-triazine) byozone and OH radicals during ozonation and advancedoxidation processes, with the identification of the maindegradation products. Besides the dealkylated and amidedegradation products (6-amino-2-chloro-4-isopropylamino-s-triazine, 6-amino-2-chloro-4-(ethylamino)-s-triazine,4-acetamido-2-chloro-6-isopropylamino-s-triazine, 4-acetamido-6-amino-2-chloro-s-triazine, and chlorodiamino-s-triazine), two new degradation products with an imine groupwere identified (2-chloro-4-ethylimino-6-isopropylamino-s-triazine and 6-amino-2-chloro-4-ethylimino-s-triazine).The contribution of the different pathways (direct ozoneand OH radical reaction) to the overall degradation processhas been quantified, and the rate constants of thereactions of atrazine and its main degradation productswith both oxidants have been measured. The ethyl groupis more reactive than the isopropyl group (i.e. 19 times duringozonation and four times during OH radical attack). Theethyl group reacts in higher proportion through oxidationto acetamide or imine derivates than to dealkylation. Incontrast, the isopropyl group reacts mainly throughdealkylation to the free amino group. Acetamido andimino groups are found to be resistant to chemical oxidation.These reactivities were corroborated by the measuredvalues of the rate constants with both oxidants. A combinationof product distribution and the kinetic parameters togetherwith ozone and OH radical concentrations allowed usto calculate the evolution of the concentration of thedegradation products for a given ozonation process.
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