Skip to content
Home
About Us
Resources
Profiles Metrics
Authors Directory
Institutions Directory
Top Authors
Top Institutions
Top Sponsors
AI Digest
Contact Us
Menu
Home
About Us
Resources
Profiles Metrics
Authors Directory
Institutions Directory
Top Authors
Top Institutions
Top Sponsors
AI Digest
Contact Us
Home
About Us
Resources
Profiles Metrics
Authors Directory
Institutions Directory
Top Authors
Top Institutions
Top Sponsors
AI Digest
Contact Us
Menu
Home
About Us
Resources
Profiles Metrics
Authors Directory
Institutions Directory
Top Authors
Top Institutions
Top Sponsors
AI Digest
Contact Us
Publication Details
AFRICAN RESEARCH NEXUS
SHINING A SPOTLIGHT ON AFRICAN RESEARCH
chemistry
Oxidative decolorization of acid azo dyes by a mn oxide containing waste
Environmental Science and Technology, Volume 44, No. 3, Year 2010
Notification
URL copied to clipboard!
Description
A Mn oxide containing mine tailings, generated in the Kalahari Mn fields, has been shown to oxidatively breakdown acid azo dyes acid orange (AO) 7, acid red 88, acid red 151 and acid yellow 36 but not acid yellow 9. The total reducible Mn content of the tailings is 33%, of which 3% is hydroquinone extractable and thus easily reducible. The net oxidation state of the Mn within the tailings is 3+. Decolorization of AO 7 by the Mn tailings increases with decreasing pH. The decolorization mechanism is initiated on the hydroxyl group of AO7 and proceeds via successive electron transfers from the dye molecule to the oxide surface resulting in the asymmetric cleavage of the azo bond. The reaction products have been identified as 1,2-naphthoquinone, 4-hydroxybenzenesulfonate, and coupling products involving 1,2-naphthoquinone and benzenesulfonate radicals. The AO 7: Mn(III) reaction stoichiometry has been tentatively calculated to be 1:3. The reaction shows longevity with 95% decolorization still observed after 60 days of dye replenishment. Further breakdown of 1,2-naphthoquinone and 4-hydroxybenzenesulfonate was not observed, thus these compounds are considered to be the terminal reaction products of the AO 7- Mn tailings reaction. © 2010 American Chemical Society.
Authors & Co-Authors
Clarke, Catherine Elaine
South Africa, Stellenbosch
Stellenbosch University
Kielar, Filip
Italy, Vercelli
Università Degli Studi Del Piemonte Orientale Amedeo Avogadro
Talbot, Helen M.
United Kingdom, Newcastle
Newcastle University
Johnson, Karen L.
United Kingdom, Durham
Durham University
Statistics
Citations: 70
Authors: 4
Affiliations: 4
Identifiers
Doi:
10.1021/es902305e
ISSN:
0013936X
e-ISSN:
15205851