Insights into the generation of hydroxyl radicals from H2O2 decomposition by the combination of Fe2+ and chloranilic acid

Ahmad, M. I.; Bensalah, N.

Insights into the generation of hydroxyl radicals from H2O2 decomposition by the combination of Fe2+ and chloranilic acid

2022

Ahmad, M. I. | Bensalah, N.

In this work, the degradation of chloranilic acid (CAA) by chemical oxidation with H₂O₂ alone and in the presence of ferrous iron Fe²⁺ catalyst was investigated in order to improve our understanding on the novel metal-independent approach. The interesting and efficient metal-independent hydroxyl radicals (OH) production by using halogenated quinones and H₂O₂ has been currently demonstrated. The results clearly confirmed the formation of OH radicals from the reaction of CAA with H₂O₂. CAA was slowly decayed by chemical oxidation with H₂O₂ and followed a pseudo-first kinetics. H₂O₂ doses ≥ 1000 mM were required to achieve complete CAA decay from 1 mM CAA. However, low total organic carbon (TOC) removal was measured with the accumulation of carboxylic acids. The addition of Fe²⁺ enhanced the kinetics of CAA degradation and reduced the required dose of H₂O₂. High TOC removal was obtained, almost complete release of chloride ions, without accumulation of carboxylic acids. The decolorization of methylene blue (MB) aqueous solutions was performed using H₂O₂, H₂O₂/CAA, H₂O₂/Fe²⁺, and H₂O₂/CAA/Fe²⁺. H₂O₂/CAA/Fe²⁺ was the most effective method in decolorizing MB solutions due to the accelerated Fe²⁺ regeneration. Coupling Fenton reagent with CAA seems to be promising alternative to physical activation in water and soil treatment.

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