New Photochemical and Electrochemical Methods for the Degradation of Pesticides in Aqueous media. Environmental Applications


Abstract: The development of new electrochemical and photochemical methods for the decontamination of natural water containing significant concentrations of aromatic pesticides is described. The electrochemical method is based on the electro-Fenton process, i.e. the simultaneous reduction of O_{2} and Fe^{3+} ions. Hydroxyl (OH^{.}) radicals are electrosynthesized in aqueous solutions, followed by complete mineralization of the initial pollutants. The photochemical methods involve either a direct photodegradation reaction of pesticides by UV light, or indirect photodegradation processes including H_{2}O_{2} photolysis or photo-Fenton reagents (H_{2}O_{2}/ Fe^{3+} ). Examples of the application of these methods to chlorophenoxy acid herbicides and four aromatic pesticides (bendiocarb, pirimiphos-methyl, coumatetralyl, chlorophacinon) in aqueous media are given. Environmental applications are also presented. The performances of electrochemical and photochemical methods are compared.

Keywords: electro-Fenton method; photo-Fenton method; pesticides; water treatment.

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