A KINETIC STUDY ABOUT THE INFLUENCE OF PHENOLIC MEDIATORS IN THE DECOLORIZATION OF DIFFERENT DYES BY FENTON SYSTEMS

The present work evaluated the influence of phenolic mediators (five dihydroxybenzenes and gallic acid) on the decolorization kinetics of phenol red, chromotrope 2R, and methylene blue by Fenton systems. The reactions were performed with H2O2, iron salts as catalysts, and the absence or presence of phenolic mediators. Based on the decolorization data from previous study of our group, the 1st and 2nd order kinetic models were analyzed, as well as the alternative BMG model. It was found that the mediators accelerated the reactions, based in 1st and 2nd order kinetic models. Reactions containing Fe2+ fitted better to the BMG model, while reactions containing Fe3+ fitted better to the 2nd order kinetic model, independent of mediators. Based on the three evaluated kinetic models, pro-oxidant properties were observed for the mediators in Fenton systems.