Resumo

SAMET, Youssef; HMANI, Emna  e  ABDELHEDI, Ridha. Fenton and solar photo-Fenton processes for the removal of chlorpyrifos insecticide in wastewater. Water SA [online]. 2012, vol.38, n.4, pp.537-542. ISSN 1816-7950.

The degradation of chlorpyrifos in water by Fenton (H₂O₂/Fe²⁺) and solar photo-Fenton (H₂O₂/Fe²⁺/solar light) processes was investigated. A laboratory-scale reactor was designed to evaluate and select the optimal oxidation condition. The degradation rate is strongly dependent on pH, temperature, H₂O₂ dosing rate, and initial concentrations of the insecticide and Fe²+. The kinetics of organic matter decay was evaluated by means of chemical oxygen demand (COD) measurement. Overall kinetics can be described by a pseudo-second-order rate equation with respect to COD. The optimum conditions were obtained at pH 3, H₂O₂ dosing rate 120 mg-min^-1, [Fe²+]₀ 5.0 mM, initial COD 1 330 mg-£^-1 and 35°C for the Fenton process. However, in the solar photo-Fenton process, the degradation rate increased significantly. To achieve 90% of COD removal, the solar photo-Fenton process needs 50% less time than that used in the Fenton process which translates to a 50% gain of H₂O₂.

Palavras-chave : chlorpyrifos; degradation kinetic; Fenton; solar photo-Fenton; COD removal.

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