ANJALI GOEL AND POOJA
Abstract
The present study deals with the degradation of mono azo dye, methyl red (MR), by hexacyanoferrate (III) ions in aqueous alkaline medium. The rate of degradation was determined by kinetic spectrophotometric method at 425 nm, λ max of the reaction mixture, at constant temperature and pH of the solution. The influences of experimental parameters such as concentration of dye, oxidant and solution pH on rate of degradation of MR dye have been studied. The results reveal that the reaction follows first order kinetics with respect to [HCF(III)] (oxidant) and [dye] at optimum pH of 8.0. Thermodynamic parameters have been calculated by studying the reaction rate at four different temperatures; 400 to 550C. The low value of energy of activation suggests high rate of degradation. Based on the experimental results a reaction mechanism through complex formation has been proposed which is confirmed by the product formation and rate law. The formation of simpler and less hazardous products as n- heptyl, p- nitro carbinilic acid, 2,5-dinitro, benzoic acid, 1-phenyl, 2- butanone, propanedioic acid and benzoic acid has been confirmed by UV-Vis and LCMS methods of analysis.