Abstract
The kinetics of oxidative decolorization of brilliant cresyl blue dye (BCB)(+) by persulfate in the presence of cobalt(II) as a catalyst were investigated in aqueous acidic medium. The effects of different parameters like [H+], [BCB+], [S2O82-], [Co(II)], [organic ligands], [micelles], and temperatures were stud ied. The reaction between [BCB](+) and persulfate was studied under pseudo-first-order kinetics by using a large excess of [S2O82-] over [BCB+]. The effect of cobalt(II) as catalyst on the rate of reaction at different temperatures was investigated. A plausible mechanism for the cobalt(II) enhanced decolorization of [BCB](+) by persulfate is suggested. The surfactant sodium dodecyl sulfate was found to inhibate the reaction rate, whereas Triton X-100 had no effect. The effect of organic ligands like malonic acid, 1,10-phenanthroline, oxalic acid and EDTA was investigated and it was found that these compounds enhanced the reaction rate. An outer-sphere electron transfer process is the proposed mechanism for this reaction.