Evaluation of the main active species involved in the TiO2 photocatalytic degradation of ametryn herbicide and its by-products

In this study, we investigated the effectiveness of photocatalysis using TiO2 as catalyst on removal ametryn. The evaluation photocatalytic activity under simulated sunlight was discussed evidence by numerous controlled trials and several operational parameters such ametryn concentration, total organic carbon, chemical oxygen demand, specific UV absorbance, biochemical toxicity formed intermediates. Moreover, roles reactive species involved in degradation were examined different scavengers. Ametryn removed 0.4 g L?1 100% within 60 min, while only 30% achieved photolysis at same time. Biodegradability index improved from 0.3 (raw solution) up to 0.8 acute measured inhibition percentage bioluminescence Vibro fischeri indicates that treatment promotes 97% reduction. scavenger study shows percentages degradation, which allowed conclude HO•, valence-band holes O2•? could intervene ametryn, with predominance HO•. Thirty-eight intermediates identified comparison generation those without addition scavengers showed by-products are generated depending active species. For example, presence azide resulted condensation reactions. Based intermediates, reaction pathways a mechanism proposed, including HO• radicals, O2•?, holes, 1O2.