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Effect of electro‐Fenton application on azo dyes biodegradability
Author(s) -
Elias B.,
Guihard L.,
Nicolas S.,
Fourcade F.,
Amrane A.
Publication year - 2011
Publication title -
environmental progress and sustainable energy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.495
H-Index - 66
eISSN - 1944-7450
pISSN - 1944-7442
DOI - 10.1002/ep.10457
Subject(s) - mineralization (soil science) , chemistry , electrolysis , ferric , effluent , aqueous solution , anode , cathode , saturated calomel electrode , nuclear chemistry , biodegradation , catalysis , inorganic chemistry , electrochemistry , electrode , waste management , organic chemistry , reference electrode , nitrogen , engineering , electrolyte
The aim of this study was to examine the feasibility of combining an electro‐Fenton pre‐treatment and a biological treatment to remove azo dyes from aqueous effluents. The electro‐Fenton reaction was performed in a two‐compartment system involving a reference (saturated calomel electrode), a platinum anode and a graphite felt cathode. For the three considered dyes, high discoloration (in the range 77.1–97.8%) and low mineralization (in the range 7.7–18.8%) after 4‐h reaction were in favor of the hybrid process, which was confirmed during subsequent experiments with methyl red sodium salt (MRSS) as a model dye. When potential‐controlled electrolysis at −0.5 V/SCE was performed with a carbon‐felt cathode surface of 378 cm 2 and a catalytic amount of ferric iron of 1 mmol L −1 , less than 1‐h reaction was needed for an almost total discoloration (90.5%); while mineralization and oxidation remained low even after 48‐h reaction, 11.1 and 57.2%, respectively. High discoloration level concomitantly to low mineralization and oxidation for MRSS removal which were in favor of a hybrid process, confirmed by the decrease of the COD on DOC ratio (45.1%) and the increase of the average oxidation state AOS (2.1). Final BOD 5 on COD ratio of 0.24 and an absence of toxicity of the treated solution (EC 50 = 165%) also showed the positive impact of an electro‐Fenton pretreatment. © 2010 American Institute of Chemical Engineers Environ Prog, 2011