DEGRADATION PATHWAYS OF ATRAZINE UNDER SOLAR LIGHT AND IN THE PRESENCE OF TIO2 COLLOIDAL PARTICLES

The transformation of atrazine under simulated solar light in the presence of particulates of titanium dioxide has been shown to occur through different routes: (i) hydrolysis of the 2-chloro substituent; (ii) alkyl chain oxidation; (iii) dealkylation of the side chain and final displacement of the amino with hydroxy groups. A series of degradation intermediates have been identified by means of chromatographic and mass spectrometric techniques. Cyanuric acid (e.g. 2,4,6-trihydroxy-1,3,5-triazine) is found not to be susceptible of further fast decomposition and can be considered as the final product of photodegradation. Comparison with other photolytic processes (e.g. direct, sensitized, in the adsorbed phase on alumina, in the presence of humic materials) is presented.