Catalytic behavior of the Fe3+/Fe2+ system in the electro-Fenton degradation of the antimicrobial chlorophene

Abstract : The catalytic behavior of the Fe3+/Fe2+ System in the electro-Fenton degradation of the antimicrobial drug chlorophene has been studied considering four undivided electrolytic cells, where a Pt or boron-doped diamond (BDD) anode and a carbon felt or O-2-diffusion cathode have been used. Chlorophene electrolyses have been carried out at pH 3.0 under current control, with 0.05 M Na2SO4 as supporting electrolyte and Fe3+ as catalyst. In these processes the drug is oxidized with hydroxyl radical ((OH)-O-center dot) formed both at the anode from water oxidation and in the medium from electrochemically generated Fenton's reagent (Fe2+ + H2O2, both of them generated at the cathode). The catalytic behavior of the Fe3+/Fe2+ system mainly depends on the cathode tested. In the cells with an O-2-diffusion cathode, H2O2 is largely accumulated and the Fe3+ content remains practically unchanged. Under these conditions, the chlorophene decay is enhanced by increasing the initial Fe3+ concentration, because this leads to a higher quantity of Fe2+ regenerated at the cathode and, subsequently, to a greater (OH)-O-center dot production from Fenton's reaction. In contrast, when the carbon felt cathode is used, H2O2 is electrogenerated in small extent, whereas Fe2+ is largely accumulated because the regeneration of this ion from Fe3+ reduction at the cathode is much faster than its oxidation to Fe3+ at the anode. In this case, an Fe3+ concentration as low as 0.2 mM is required to obtain the maximum (OH)-O-center dot generation rate, yielding the quickest chlorophene removal. Chlorophene is poorly mineralized in the Pt/O-2 diffusion cell because the final Fe3+-oxalate complexes are difficult to oxidize with (OH)-O-center dot. These complexes are completely destroyed using a BDD anode at high current thanks to the great amount of (OH)-O-center dot generated on its surface. Total mineralization is also achieved in the Pt/carbon felt and BDD/carbon felt cells with 0.2 mM Fe3+, because oxalic acid and its Fe2+ complexes are directly oxidized with (OH)-O-center dot in the medium. Comparing the four cells, the highest oxidizing power regarding total mineralization is attained for the BDD/carbon felt cell at high current due to the simultaneous destruction of oxalic acid at the BDD surface and in the bulk solution. (c) 2006 Elsevier B.V. All rights reserved.
Document type :
Journal articles
Complete list of metadatas

https://hal-upec-upem.archives-ouvertes.fr/hal-00693652
Contributor : Admin Lge <>
Submitted on : Wednesday, May 2, 2012 - 9:55:33 PM
Last modification on : Monday, July 2, 2018 - 3:36:03 PM

Identifiers

Collections

Citation

Ignasi Sires, Jose Antonio Garrido, Rosa Maria Rodriguez, Enric Brillas, Nihal Oturan, et al.. Catalytic behavior of the Fe3+/Fe2+ system in the electro-Fenton degradation of the antimicrobial chlorophene. Applied Catalysis B: Environmental, Elsevier, 2007, 72 (3-4), pp.382--394. ⟨10.1016/j.apcatb.2006.11.016⟩. ⟨hal-00693652⟩

Share

Metrics

Record views

392