Environmental Chemistry Letters

, Volume 1, Issue 1, pp 38–44 | Cite as

Degradation of azo dyes in water by Electro-Fenton process

  • Elodie Guivarch
  • Stephane Trevin
  • Claude Lahitte
  • Mehmet A. OturanEmail author
Original Paper


The degradation of the azo dyes azobenzene, p-methyl red and methyl orange in aqueous solution at room temperature has been studied by an advanced electrochemical oxidation process (AEOPs) under potential-controlled electrolysis conditions, using a Pt anode and a carbon felt cathode. The electrochemical production of Fenton's reagent (H2O2, Fe2+) allows a controlled in situ generation of hydroxyl radicals (·OH) by simultaneous reduction of dioxygen and ferrous ions on the carbon felt electrode. In turn, hydroxyl radicals react with azo dyes, thus leading to their mineralization into CO2 and H2O. The chemical composition of the azo dyes and their degradation products during electrolysis were monitored by high performance liquid chromatography (HPLC). The following degradation products were identified: hydroquinone, 1,4-benzoquinone, pyrocatechol, 4-nitrocatechol, 1,3,5-trihydroxynitrobenzene and p-nitrophenol. Degradation of the initial azo dyes was assessed by the measurement of the chemical oxygen demand (COD). Kinetic analysis of these data showed a pseudo-first order degradation reaction for all azo dyes. A pathway of degradation of azo dyes is proposed. Specifically, the degradation of dyes and intermediates proceeds by oxidation of azo bonds and aromatic ring by hydroxyl radicals. The results display the efficiency of the Electro-Fenton process to degrade organic matter.


Azo dye Fenton's reagent Electro-Fenton process Hydroxyl radicals Water treatment Mineralization COD 



This work was supported in part by EDF (Electricité de France).


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Copyright information

© Springer-Verlag 2003

Authors and Affiliations

  • Elodie Guivarch
    • 1
  • Stephane Trevin
    • 2
  • Claude Lahitte
    • 2
  • Mehmet A. Oturan
    • 1
    Email author
  1. 1.Laboratoire des Geomateriaux, CNRS FRE 2455Université de Marne La ValléeMarne la Vallée Cedex 2France
  2. 2.EDF, Division Recherche et DéveloppementSite des Renardières Moret sur Loing CedexFrance

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