A Review of Gallic Acid-Mediated Fenton Processes for Degrading Emerging Pollutants and Dyes.

Diverse reducing mediators have often been used to increase the degradation of emerging pollutants (EPs) and dyes through the Fenton reaction (Fe + HO → Fe + HO + HO). Adding reductants can minimize the accumulation of Fe in a solution, leading to accelerated Fe regeneration and the enhanced generation of reactive oxygen species, such as the HO radical. The present study consisted in reviewing the effects of gallic acid (GA), a plant-extracted reductant, on the Fenton-based oxidation of several EPs and dyes.

Gallic acid influence on azo dyes oxidation by Fenton processes.

The present work consisted in evaluating the effect of a natural plant reducer, gallic acid (GA), on the discolouration/oxidation of two azo dyes by Fenton processes (Fe/HO and Fe/HO). A kinetic study was performed to better interpret the discolouration data at different temperatures. The 1st-order kinetic model presented the best fit for the experimental data of methyl orange discolouration, while the 2nd-order was better for chromotrope 2R.