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Etude cinétique de la dégradation électrochimique de composés organiques sur l'anode de diamant dope au bore : Application à la dépollution d'effluents aqueux.

Abstract : The aim of this work was to study the mineralization by electrochemical oxidation of organic compounds contained in aqueous effluents. Compounds chosen as models were phenol and carboxylic acids stemming from the oxidation (maleic, oxalic and formic acids). The performance of the boron doped diamond anode (BDD) was compared with that of a commercial PbO2 electrode, under the same hydrodynamic conditions. The oxidation of phenol in aqueous solution shows that BDD anode possesses better kinetic and energetic properties. Kinetic studies conducted on solutions of maleic acid in the presence of oxalic and/or formic acids, showed that oxalic acid is directly oxidized by electron transfer whereas maleic and formic acids react with electrogenerated hydroxyl radicals. On the other hand, the supporting electrolyte can play a role on the oxidation efficiency: the main effect was observed in the presence of the perchlorate anion; the oxygen transfer on maleic acid is much more important than that of a pure faradaic process. This result is explained assuming a direct anodic oxidation of the anion into a perchlorate radical. The electrochemical process was applied to the treatment of representative emulsions of effluents produced by the metallurgy industry. Oxidation on a BBD electrode gives rise to a full mineralization of the surfactant (sodium dodecylbenzenesulfonate) and of the organic phase (lauryl alcohol, lauric or oleic acids) without demixtion. The numeric resolution of a physico-chemical model demonstrated that the oxidation of the organic molecules by the hydroxyl radicals occurs in a reaction layer, the thickness of which is about 1000 times as fine as the diffusion layer.
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Contributor : Elsa Weiss <>
Submitted on : Sunday, May 6, 2007 - 5:09:11 PM
Last modification on : Friday, February 5, 2021 - 12:30:02 PM
Long-term archiving on: : Wednesday, April 7, 2010 - 1:19:37 AM

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  • HAL Id : tel-00144880, version 1

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Elsa Weiss-Hortala. Etude cinétique de la dégradation électrochimique de composés organiques sur l'anode de diamant dope au bore : Application à la dépollution d'effluents aqueux.. Génie des procédés. Université Paul Sabatier - Toulouse III, 2006. Français. ⟨tel-00144880⟩

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