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Degradation of Acid Blue 161 by Fenton and photo-Fenton processes
Trovó, A. G.; Hassan, A. K.; Sillanpää, M. & Tang, W. Z.
Abstract
Degradation kinetics of azo dye, Acid Blue 161
(AB161), by Fenton and photo-Fenton processes in aqueous
solution was investigated. At pH 3.5, the effects of
H2O2, Fe2+, and H2O2/Fe2+ molar ratios, on the AB161
decolorization kinetic rates, were evaluated. Experimental
results confirmed that the optimal H2O2/Fe2+ molar ratio of
12 is close to the theoretical value of 11 as predicted by
previously developed model. The influence of azo bond
loading (Lazo bond), from 0.25 to 1.0, and pH values from
2.5 to 4.0 were evaluated on AB161 decolorization kinetic
rates. A correlation between the natural logarithm of the
decolorization rates and Lazo bond was established at the
different pH values. The decolorization rate increased linearly
with decreasing Lazo bond, in the order of pH:
3.5>3.0>2.5>4.0. UV radiation of Fenton processes
increases degradation of AB161 more than 40 % due to the
regeneration of Fe2+ through photo-catalytic reactions.
This phenomenon was confirmed by measuring H2O2
concentration during the photo-Fenton processes. The
results suggest that Fenton processes can effectively
decolorize or degrade wastewater containing azo dye,
AB161. Photo-Fenton processes may further increase the
degradation efficiency of AB161 by 40 %.
Keywords
H2O2/Fe2+; Photo-Fenton; Oxidation; Kinetics; Azo bond; Chemical oxygen demand
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