The peroxyacid oxidant peracetic acid (CH3C(=O)OOH, PAA) is an emerging disinfectant for water treatment and food processing owing to its high biocidal effect, limited harmful byproduct formation, and easy retrofit. Moreover, activated PAA is a novel advanced oxidation process (AOP) that is drawing great interests for water decontamination and disinfection. Owing to the synthesis procedures, PAA and H2O2 typically co-exist in a mixture, and work concurrently or in tandem in the AOP depending on the activation methods. PAA/H2O2 may be activated by light irradiation or metal catalysts to generate reactive species including hydroxyl radical and organic radicals for advanced oxidation reactions. This presentation will highlight our recent research efforts in the AOPs of PAA/H2O2 for enhanced water decontamination and disinfection. Specifically, the discussion will focus on the generation of key reactive species from the activated PAA/H2O2 and the roles of the reactive species in promoting micropollutant degradation and microbial inactivation. For example, when the activation method is UV irradiation, photolysis of both PAA and H2O2 occurs to generate acetyloxyl (CH3C(=O)O●) and hydroxyl (●OH) radicals. Subsequent reactions of PAA and H2O2 with ●OH produce acetylperoxyl (CH3C(=O)OO●) and superoxide (HO2●) radicals. When the activation method is transition metals, PAA reacts with Fe(II) and Co(II) much faster than H2O2 and plays a predominant role in the generation of reactive species. Oxidation by the reactive species of activated PAA/H2O2 primarily leads to transformation products of hydroxylation and oxygenation. A range of complementary experimental, computational, and kinetic modeling approaches help elucidate the involved reaction mechanisms. The new findings and kinetic model are useful for further development and optimization of PAA-based processes for water treatment applications.

Advanced oxidation process with peracetic acid: Mechanism, modeling and application

ACS Fall 2021

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