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  2. Direct and indirect electrochemical reduction prior to a biological treatment for dimetridazole removal

Direct and indirect electrochemical reduction prior to a biological treatment for dimetridazole removal

  • J Hazard Mater. 2017 Aug 5;335:10-17. doi: 10.1016/j.jhazmat.2017.04.028.
Melika Zaghdoudi 1 Florence Fourcade 2 Isabelle Soutrel 2 Didier Floner 3 Abdeltif Amrane 4 Hager Maghraoui-Meherzi 5 Florence Geneste 6
Affiliations

Affiliations

  • 1 Institut des Sciences Chimiques de Rennes, Université de Rennes 1, UMR-CNRS 6226, Equipe MaCSE, Campus de Beaulieu, 35042 Rennes Cedex, France; Institut des Sciences Chimiques de Rennes, Université de Rennes 1, Ecole Nationale Supérieure de Chimie de Rennes, UMR-CNRS 6226, 11 allée de Beaulieu, CS 50837, 3570 Renne Cedex 7, France; Université de Tunis El Manar, Faculté des Sciences de Tunis, LR99ES15 Laboratoire de Chimie Analytique et d'Electrochimie, 2092, Tunis, Tunisia.
  • 2 Institut des Sciences Chimiques de Rennes, Université de Rennes 1, Ecole Nationale Supérieure de Chimie de Rennes, UMR-CNRS 6226, 11 allée de Beaulieu, CS 50837, 3570 Renne Cedex 7, France.
  • 3 Institut des Sciences Chimiques de Rennes, Université de Rennes 1, UMR-CNRS 6226, Equipe MaCSE, Campus de Beaulieu, 35042 Rennes Cedex, France.
  • 4 Institut des Sciences Chimiques de Rennes, Université de Rennes 1, Ecole Nationale Supérieure de Chimie de Rennes, UMR-CNRS 6226, 11 allée de Beaulieu, CS 50837, 3570 Renne Cedex 7, France. Electronic address: abdeltif.amrane@univ-rennes1.fr.
  • 5 Université de Tunis El Manar, Faculté des Sciences de Tunis, LR99ES15 Laboratoire de Chimie Analytique et d'Electrochimie, 2092, Tunis, Tunisia.
  • 6 Institut des Sciences Chimiques de Rennes, Université de Rennes 1, UMR-CNRS 6226, Equipe MaCSE, Campus de Beaulieu, 35042 Rennes Cedex, France. Electronic address: florence.geneste@univ-rennes1.fr.
Abstract

Two different electrochemical reduction processes for the removal of dimetridazole, a nitroimidazole-based Antibiotic, were examined in this work. A direct electrochemical reduction was first carried out in a home-made flow cell in acidic medium at potentials chosen to minimize the formation of amino derivatives and then the formation of azo dimer. Analysis of the electrolyzed solution showed a total degradation of dimetridazole and the BOD5/COD ratio increased from 0.13 to 0.24. An indirect electrochemical reduction in the presence of titanocene dichloride ((C5H5)2TiCl2), which is used to reduce selectively nitro compounds, was then investigated to favour the formation of amino compounds over hydroxylamines and then to prevent the formation of azo and azoxy dimers. UPLC-MS/MS analyses showed a higher selectivity towards the formation of the amino compound for indirect electrolyses performed at pH 2. To confirm the effectiveness of the electrochemical reduction, a biological treatment involving activated sludge was then carried out after direct and indirect electrolyses at different pH. The enhancement of the biodegradability was clearly shown since mineralization yields of all electrolyzed solutions increased significantly.

Keywords

Biological treatment; Coupling process; Dimetridazole; Electrochemical reduction; Titanium complex.

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