Degradation and decolorization of a biodegradable-resistant polymeric dye by chelator-mediated Fenton reactions.
Chelator-mediated Fenton reactions (CMFRs) were used to decolorize a biodegradable-resistant polymeric dye (Poly R-478). Screening of different iron chelators was performed on Fe(3+)-reduction activity. All chelators showed Fe(3+)-reduction activity over a wide range of pH (2-7) and each mol of catecholate chelators (3,4-dihydroxiphenilacetic acid--DOPAC and 2,3-dihydroxibenzoic acid--DHBA) reduced about 5-6 moles of Fe(3+) whereas hydroxamate chelators (acetohydroxamic acid-AHA and desferrioxamine B-DFB) reduced Fe(3+) stoichiometrically. The most effective decolorization of Poly R-478 was achieved by CMFR using catecholate chelators. In addition, a 2(4) factorial design was performed with the aim of evaluating the effects of the variables considered in this study (pH, [DOPAC], [Fe(3+)] and [H(2)O(2)]) and optimizing the dye decolorization, using response surface methodology. Statistical analysis of results showed that, in the range studied, except for Fe(3+), all variables have a significant effect on dye decolorization. A second-order model is proposed to represent the Poly R-478 decolorization. At optimum conditions, complete decolorization of the dye (degradation of the chromophoric group) and also complete chemical degradation of the dye was observed.
Arantes
Valdeir
V
Department of Biotechnology, Faculdade de Engenharia Química de Lorena-FAENQUIL, Brazil.
Baldocchi
Carolina
C
Milagres
Adriane Maria Ferreira
AM
D015102:3,4-Dihydroxyphenylacetic Acid / Q000737:chemistry; D000880:Anthraquinones / Q000737:chemistry*; D002614:Chelating Agents / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007220:Industrial Waste; D007501:Iron / Q000737:chemistry*; D016877:Oxidants / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical; D018508:Water Purification / Q000379:methods*
D000880:Anthraquinones; D002614:Chelating Agents; D004396:Coloring Agents; D007220:Industrial Waste; D016877:Oxidants; D011108:Polymers; D014874:Water Pollutants, Chemical; D015102:3,4-Dihydroxyphenylacetic Acid; C017971:poly R-478; D006861:Hydrogen Peroxide; D007501:Iron