Photooxidation of Toluidine Blue using Sulphate Radical Ion and Hydroxyl Radical Generated by Peroxydisulphate and Ferrous Ion

Author(s): Jyoti Soni, Anil Kumar and Kumud Intodia

This paper is focused on optimising the use of additional oxidants in the photooxidation of toluidine blue. Photochemical oxidation of toluidine blue was investigated using sulphate radical ion (SO 4 −• ) and hydroxyl radical (HO • ) which was generated by Fe 2+ and peroxydisulphate ions at normal temperature and pressure. The effect of operating variables like the concentr ation of ferrous ions, concentration of toluidine blue, pH, concentration of pe roxydisulphate ion and light intensity on the rate of reaction was also observed. The progress of the reaction was monitored spectrophotometrically. The photooxidation of dye follows pseudo first order kinetics. The toluidine blue was completely oxidized into CO 2 and H 2 O and maximum decolorization was achieved at the optimum conditions of the reaction time 30 min. A tentative mechanism for photooxidation of toluidine blue has been proposed.

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