title: The oxidation of acid azo dye AY 36 by a manganese oxide containing mine waste.
abstract: The oxidative breakdown of acid azo dye acid yellow 36 (AY 36) by a Mn oxide containing mine tailings is demonstrated. The oxidation reaction is pH dependent with the rate of decolorization increasing with decreasing pH. The oxidation reaction mechanism is initiated at the amino moiety and proceeds via successive, one electron transfers from the dye to the Mn oxide minerals. The reaction pathway involves the formation of a number of colorless intermediate products, some of which hydrolyze in a Mn oxide-independent step. Decolorization of the dye is rapid and is observed before the cleavage of the azo-bond, which is a slower process. The terminal oxidation products were observed to be p-benzoquinone and 3-hydroxybenzenesulfonate. The reaction order of the initial decolorization was determined to be pseudo fractional order with respect to pH and pseudo first order with respect to dye concentration and Mn tailings' surface area.
authors: Department of Soil Science, Stellenbosch University, P/Bag X1, Matieland 7602, South Africa. cdowding@sun.ac.za
authors: Catherine E
authors: CE
authors: Clarke
authors: Filip
authors: F
authors: Kielar
authors: Karen L
authors: KL
authors: Johnson
mesh_terms: D001391:Azo Compounds / Q000737:chemistry*; D004785:Environmental Pollutants / Q000737:chemistry; D007220:Industrial Waste; D017895:Manganese Compounds / Q000737:chemistry*; D008906:Mining; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*
chemical_list: D001391:Azo Compounds; D004785:Environmental Pollutants; D007220:Industrial Waste; D017895:Manganese Compounds; D010087:Oxides; C027424:manganese oxide; C005108:metanil yellow