Removal of Acid Orange 7 from water by electrochemically generated Fenton's reagent

Oezcan A., Oturan M. A., Oturan N., ŞAHİN Y.

JOURNAL OF HAZARDOUS MATERIALS, vol.163, no.2-3, pp.1213-1220, 2009 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 163 Issue: 2-3
  • Publication Date: 2009
  • Doi Number: 10.1016/j.jhazmat.2008.07.088
  • Journal Name: JOURNAL OF HAZARDOUS MATERIALS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.1213-1220
  • Keywords: Advanced oxidation process, Electro-Fenton, Hydroxyl radicals, Acid Orange 7, Degradation, Mineralization pathway, ELECTRO-FENTON, ANODIC-OXIDATION, HYDROXYL RADICALS, AQUEOUS-MEDIUM, AZO DYES, DEGRADATION, MINERALIZATION, DECOLORIZATION, DESTRUCTION, POLYHYDROXYLATION
  • Anadolu University Affiliated: Yes

Abstract

The removal of azo dye Acid Orange 7 (AO7) from water was investigated by the electro-Fenton technology using electrogenerated hydroxyl radicals ((OH)-O-center dot) which leads to the oxidative degradation of AO7 LIP to its complete mineralization. H2O2 and Fe (II) ions are electrogenerated in a catalytic way at the carbon-felt cathode. AO7 decay kinetics and evolution of its oxidation intermediates were monitored by high-performance liquid chromatography. The absolute rate constant of AO7 hydroxylation reaction has been determined as (1.20 +/- 0.17) x 10(10) M-1 s(-1). The optimal Current value for the degradation of AO7 was found as 300 mA. AO7 degradation rate was found to decrease by increase in Fe3+ concentration beyond 0.1 mM. Mineralization of AO7 aqueous solutions was followed by total organic carbon (TOC) measurements and found to be 92%. Based on TOC evolution and identification of aromatic intermediates, short-chain carboxylic acids and inorganic ions released during treatment, a plausible mineralization pathway was proposed. (C) 2008 Elsevier B.V. All rights reserved.