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Article Dans Une Revue Environmental Chemistry Letters Année : 2010

Phototransformation of oxamyl in aqueous solution

Résumé

The photolysis of the N methyl carbamate pesticide oxamyl (Z isomer) has been studied in aqueous solution. Continuous irradiation at mainly lambda = 254 and lambda > 290 nm has been performed to characterise the pesticide photochemical behaviour in water at pH = 6.0. Upon monochromatic irradiation, the phototransformation quantum yield was evaluated to be roughly constant, with a value of 0.54 +/- 0.08. Upon polychromatic irradiation, a photochemical efficiency has been estimated to be 0.5 +/- 0.1 by using phenol as a reference compound. Two main degradation products were identified: the isomer (E) of oxamyl and the nitrile derivative (N,N-dimethyl-2-nitrilo-acetamide). The photolysis of the oximino derivative, an hydrolysis product of oxamyl, was also studied. Upon irradiation at 254 nm, the quantum yield of phototransformation was found to be 0.28. A unique photoproduct was detected: it corresponds to the (E) isomer of the oximino derivative. For prolonged irradiations, a photostationary state was reached between the oximino and its (E) isomer. From kinetics data, the removal of oxamyl and of the oximino derivative during a UV disinfection step used in drinking water production was calculated to be 45 and 13%, respectively.

Dates et versions

hal-00512252 , version 1 (29-08-2010)

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Patrick Mazellier, C. Zamy, Mohamed Sarakha. Phototransformation of oxamyl in aqueous solution. Environmental Chemistry Letters, 2010, 8 (1), pp.19-24. ⟨10.1007/s10311-008-0184-8⟩. ⟨hal-00512252⟩
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