Fenton-type process using peracetic acid: Efficiency, reaction elucidations and ecotoxicity

Abstract

Recent studies on Fenton-type processes involving peracetic acid (PAA) stimulated further development of advanced oxidative processes (AOPs). The objective of this work was to provide new information about such processes, elucidate their reaction mechanisms both experimentally and theoretically, and verify their possible uses. The Fenton-type reaction of PAA with Fe³⁺ exhibited a greater dye degradation efficiency than the Fenton process, while the efficiency of the PAA reaction with Fe²⁺ was very close of Fenton process. Moreover, the processes photocatalyzed by solar radiation demonstrated comparable efficiencies due to the photoreduction of Fe³⁺ to Fe²⁺. By conducting theoretical calculations, it was found that the formation of oxidizing radicals during the reaction of PAA with Fe²⁺ was not thermodynamically favorable and, therefore, unsuitable for practical use. In contrast, the processes occurred in the PAA/Fe³⁺ system included thermodynamically spontaneous reactions that generated peroxyl (CH₃C(O)OO•), alkoxyl (CH₃C(O)•), and hydroperoxyl (HO₂•) radicals. The ecotoxicological tests demonstrated that the toxicity of the PAA to the organism Dugesia tigrina can be attributed to the presence of H₂O₂.

Keywords: Advanced oxidative process; Alkoxy radical; Ecotoxicology; PAA / Fe(2+); PAA / Fe(3+).