Photolysis of fluometuron in the presence of natural water constituents

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• 作者：Sabrina Halladja ; Amina Amine-Khodja ; Alex ; ra ter Halle ; Abdelaziz Boulkamh ; Claire Richard
• 关键词：Phenylurea herbicide ; Photosensitization ; Nitrate ions ; Fulvic acids ; Hydroxyl radicals
• 刊名：Chemosphere
• 出版年：2007
• 出版时间：November 2007
• 年：2007
• 卷：69
• 期：10
• 页码：1647-1654
• 全文大小：195 K

文摘

Phototransformation of the herbicide fluometuron (1 μM) in natural sunlight was investigated in neutral Milli-Q water and in synthetic waters containing either fulvic acids, nitrate ions or both in order to mimic reactions taking place in aquatic environments. Fluometuron degradation followed a pseudo-first order kinetics. The reaction was faster in synthetic than in Milli-Q water. Fulvic acids (10 mg l⁻¹) increased the rate of fluometuron photolysis by a factor 2.5 and nitrates (25 mg l⁻¹) by a factor 15. Identification of major photoproducts was conducted under laboratory conditions using LC–ESI–MS. Numerous photoproducts were detected and tentatively characterized. In the presence of nitrates, hydroxylation of the aromatic ring with or without hydrolysis of CF₃ into CO₂H and oxidation of the urea chain leading to demethylation were observed. In the presence of fulvic acids, hydroxylation of the aromatic ring was the major reaction route.