A Density Functional Theory and Laser Flash Photolysis Investigation of Carbofuran Photodegradation in Aqueous Medium

Density functional theory (DFT) approach was used to study the photodegradation of Carbofuran in aqueous medium. This computational method enables us to assign the electronic transitions and interpret the dissociative behavior upon irradiation based on a thermodynamical analysis of the bond dissociation energies (BDE) of Carbofuran. According to these calculations, phenoxy C---O bond appears weaker than the C---N bonds. Hence, it was predicted that the photodegradation of Carbofuran should occur with an initial homolytic dissociation of the C---O bond of the carbamate moiety. Laser Flash Photolysis (LFP) results clearly indicate the formation of the phenoxyl radical, which support the outcome of this theoretical approach

Laser flash photolysis spectroscopy for the elucidation of the degradation mechanism of the pesticides in aqueous solution

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Effect of polycarbonate photoageing on its permeability.

International audienc

The association between polycarbonate photoageing and oxygen permeability.

International audienc

Decatungstate, W10O324-, as a photocatalyst for the simultaneous oxidation of organic pollutants and reduction of Fe3+ and/or H2O2.

International audienc

Sequential photooxidation of polycarbonate: consequences on its oxygen permeability.

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Photocatalytic degradation of cholesterol-lowering statin drugs by TiO2-based catalyst. Kinetics, analytical studies and toxicity evaluation

International audienceThe photocatalytic degradation of simvastatin, lovastatin, and pravastatin, cholesterol-lowering statin drugs, by TiO2-based catalyst in aqueous solutions has been studied. In all cases the degradation was found to be efficient and was clearly owing to the formation of hydroxyl radicals. When present in their open forms, the life times were evaluated, in aerated conditions, to 8.1 +/- 1.2, 10.4 +/- 1.3 and 19.2 +/- 2.1 min for simvastatin, lovastatin and pravastatin respectively. In their lactone forms, in non-aerated conditions, the life times were found to be higher: 12.4 +/- 1.1 and 15.6 +/- 2.0 min for simvastatin and lovastatin. Several primary and secondary photoproducts were elucidated by means of LC-MS technique. They were obtained as a result of the addition of the hydroxyl radical to the double bonds leading to the formation of different hydroxy derivatives. Under prolonged irradiation, efficient mineralization of statin solutions was observed by means of total organic carbon (TOC) evolution. A detailed mechanism for the degradation of statins and the formation of photo-products is proposed and discussed, together with toxicity evaluation. It is stressed that photocatalysis appears to be an alternative to other chemical or biological methods for statins removal in aqueous solutions