Kinetic and Mechanistic Study of the Oxidation of Orange-II by Hexacyanoferrate (III) Ions Catalyzed by Iridium Nanoclusters

Author(s): Anjali Goel, Ranjana Bhatt and Rajni Lasyal

Since aromatic azo-dyes-widely used for dyeing textiles – are toxic and potential carcinogens. It is essential to develop methods for their degradation in textile industry wastewater for letting this water out. In the present study, results of the degradation of orange-II, an azo-dye, through oxidation by potassium hexacyanoferrate i ons catalyzed by Iridium-na noclusters are presented. The kinetics of the reaction has been studied spectrophotometrically at 484 nm, the λ max of the dye. The kinetics obeys the rate law: R obs = k 3 [HCF][dye] [catalyst][OH − ] where R obs is the initial rate, k 3 is the rate constant and [H CF], [dye], [catalyst] and [OH − ] represent the concentrations of reagents in parenthesis. The energy of the activation was found to be 9.6 Kcal mol − 1 . A reaction mechanism, which assumes the formati on of a transient complex between Ir-nano and anionic form of the dye has been sugges ted. The products have also been analyzed.

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