Journal of Applied Electrochemistry

, Volume 37, Issue 5, pp 583–592

Electrochemical oxidation of an acid dye by active chlorine generated using Ti/Sn(1−x)IrxO2 electrodes

  • Flavio H. Oliveira
  • Marly E. Osugi
  • Fabiana M. M. Paschoal
  • Demetrius Profeti
  • Paulo Olivi
  • Maria Valnice Boldrin Zanoni
Original Paper

Abstract

The generation of active chlorine on Ti/Sn(1−x)IrxO2 anodes, with different compositions of Ir (x = 0.01, 0.05, 0.10 and 0.30 ), was investigated by controlled current density electrolysis. Using a low concentration of chloride ions (0.05 mol L−1) and a low current density (5 mA cm−2) it was possible to produce up to 60 mg L−1 of active chlorine on a Ti/Sn0.99Ir0.01O2 anode. The feasibility of the discoloration of a textile acid azo dye, acid red 29 dye (C.I. 16570), was also investigated with in situ electrogenerated active chlorine on Ti/Sn(1−x)IrxO2 anodes. The best conditions for 100% discoloration and maximum degradation (70% TOC reduction) were found to be: NaCl pH 4, 25 mA cm−2 and 6 h of electrolysis. It is suggested that active chlorine generation and/or powerful oxidants such as chlorine radicals and hydroxyl radicals are responsible for promoting faster dye degradation. Rate constants calculated from color decay versus time reveal a zero order reaction at dye concentrations up to 1.0 × 10−4 mol L−1. Effects of other electrolytes, dye concentration and applied density currents also have been investigated and are discussed.

Keywords

Ti/Sn(1−x)IrxO2 anodes Degradation of azo dye Dye oxidation Chlorine generation 

Copyright information

© Springer Science+Business Media, Inc. 2007

Authors and Affiliations

  • Flavio H. Oliveira
    • 1
  • Marly E. Osugi
    • 1
  • Fabiana M. M. Paschoal
    • 1
  • Demetrius Profeti
    • 2
  • Paulo Olivi
    • 2
  • Maria Valnice Boldrin Zanoni
    • 1
  1. 1.Departamento de Química Analítica, Instituto de QuímicaUniversidade Estadual PaulistaAraraquaraBrazil
  2. 2.Departamento de QuímicaFaculdade de Filosofia Ciências e Letras de Ribeirão Preto – USPRibeirão PretoBrazil

Personalised recommendations