Kinetic studies of endosulfan photochemical degradations by ultraviolet light irradiation in aqueous medium |
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Authors: | Manuel H Barcelo-Quintal Maria C Cebada-Ricalde Angel R Trejo-Irigoyen Reyna B Rendon-Osorio Jose A Manzanilla-Cano |
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Institution: | 1. Department of Analytical Chemistry , University of Yucatan , Yucatan , Mexico;2. Department of Chemistry , University of Yucatan , Yucatan , Mexico |
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Abstract: | Kinetic studies of endosulfan photochemical degradation in controlled aqueous systems were carried out by ultraviolet light irradiation at λ = 254 nm. The photolysis of (α + β: 2 + 1) endosulfan, α-endosulfan and β-endosulfan were first-order kinetics. The observed rate constants obtained from linear least-squares analysis of the data were 1 × 10?4 s?1; 1 × 10?4 s?1; and 2 × 10?5 s?1, respectively, and the calculated quantum yields (φ) were 1, 1 and 1.6, respectively. Preliminary differential pulse polarographic (DPP) analysis allowed to observe the possible endosulfan photochemical degradation pathway. This degradation route involves the formation of the endosulfan diol, its transformation to endosulfan ether and finally the ether's complete degradation by observing the potential shifts. |
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Keywords: | Endosulfan organochloride pesticide degradation photolysis UV-Vis spectrophotometry differential pulse polarography quantum yield |
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