Modeling the Kinetics of UV/Peracetic Acid Advanced Oxidation Process

Abstract

Peracetic acid combined with UV (i.e., UV/PAA) has emerged as a novel advanced oxidation process (AOP) for water disinfection and micropollutant degradation, but kinetic modeling for this AOP was lacking. In this study, a comprehensive model was developed to elucidate the reaction mechanisms and simulate reaction kinetics of UV/PAA process. By combining radical scavenging experiments and kinetic modeling, accurate quantum yield of PAA under UV254 (Φ = 0.88 ± 0.04 mol-Einstein–1) was determined via simultaneously quenching •OH and CH3C­(O)­O• with 2,4-hexadiene. The comparison between experimental observations and model predictions over a wide range of conditions allowed estimation of the rate constants of PAA with •OH (k •OH/PAA = 1.3 ± 0.2 × 109 M–1 s–1) and HO2 • (k HO2 •/PAA ≤ 5 × 102 M–1 s–1) with good accuracy. With derived Φ, k •OH/PAA and k HO2 •/PAA, the kinetic model accurately predicts PAA decay under UV254 photolysis across varying PAA and H2O2 concentrations and water pH (5.8–7.2). Meanwhile, the model reveals that UV/PAA generates a lower •OH concentration than UV/H2O2 at equivalent oxidant concentrations, with CH3C­(O)­OO• as the most abundant carbon-centered radical. This study significantly improves the knowledge of reactive species generation and reaction kinetics and mechanisms under UV/PAA, and provides a useful kinetic model for this AOP in water treatment.

Peracetic Acid–Ruthenium(III) Oxidation Process for the Degradation of Micropollutants in Water

“…The applications of PAA as an oxidant in synthesizing organic compounds have been studied for a long time. − However, there are a limited number of studies on the use of PAA in oxidizing organic contaminants in water; examples include oxidation of phenols and β-lactams by PAA. , Recently, activating PAA using ultraviolet (UV) light and transition-metal ions to oxidize micropollutants has been emphasized. In the UV activation of PAA, the • OH, CH 3 C­(O)­O • , and CH 3 C­(O)­OO • have been largely causing the oxidation of micropollutants. , In the case of the transition-metal ion Co­(II), detailed investigations have shown the involvement of CH 3 C­(O)­O • and CH 3 C­(O)­OO • with the latter to be the most important species for the degradation of micropollutants. , In the PAA–Fe­(II) system, the high-valent iron (Fe IV ) was also shown as an additional oxidant to CH 3 C­(O)­O • with CH 3 C­(O)­OO • contributing to the oxidation of micropollutants . Significantly, the degradations of the target pollutants were dependent on pH.…”

One-Step Synthesis of Hierarchical Flower-like SnO2/BiOCOOH Microspheres with Enhanced Light Response for the Removal of Pollutants

“…Meanwhile, the h + also had an ability to oxidize H 2 O to form ·OH ( E 0 (H 2 O/·OH) = 2.40 eV V NHE ) . On the other hand, ·OH could also be generated from H 2 O 2 under UV light irradiation, and ·O 2 – was formed through the reaction of H 2 O 2 and ·OH. , Although ·OH and ·O 2 – had the ability to oxidize pollutants, they could also be quenched (eqs –). Consequently, the contributions of ·OH and ·O 2 – to the decomposition of RhB were limited, which was in alignment with the trapping experiments results above (·O 2 – and ·OH had a slight effect on the degradation of pollutants).…”

Evaluation of Fe2+/Peracetic Acid to Degrade Three Typical Refractory Pollutants of Textile Wastewater

“…That said, the proportion of PAA and H 2 O 2 would affect the distribution of organic radicals and •OH in the Fe 2+ /PAA/H 2 O 2 process. In previous research [30][31][32][33], PAA-based AOP has exhibited structural selectivity in the removal performance of target pollutants and shown comparable or even superior performance compared to H 2 O 2 -based AOP.…”