UV/Peracetic Acid for Degradation of Pharmaceuticals and Reactive Species Evaluation

Peracetic acid (PAA) is a widely used disinfectant, and combined UV light with PAA (i.e., UV/PAA) can be a novel advanced oxidation process for elimination of water contaminants. This study is among the first to,evaluate the photolysis of PAA. under UV irradiation (254 nm) and degradation of pharmaceuticals by UV/PAA. PAA exhibited high quantum yields (Phi(254) (nm) = 1.20 and 2.09 mol-Einstein(-1) for the neutral (PAA(0)) and anionic (PAA(-)) species, respectively) and also showed scavenging effects on hydroxyl radicals (k.(0)(OH/PAA) = (9.33 +/- 0.3) X 10(8) M-1.s(-1) and k.(-)(OH/pAA) = (9.97 +/- 2.3) x 10(9) M-1.s(-1)). The pharmaceuticals were persistent with FAA alone but degraded rapidly by UV/PAA. The contributions of direct photolysis, hydroxyl radicals, and other radicals to pharmaceutical degradation under UV/PAA were systematically evaluated. Results revealed that center dot OH was the primary radical responsible for the degradation of carbamazepine and ibuprofen by UV/PAA., whereas CH3C(=-O)O-center dot and/or CH3C(=O)O-2 center dot contributed significantly to the degradation of naproxen and 2-naphthoxyacetic acid by LTV/PAA. in addition to (OH)-O-center dot. The carbon-centered radicals generated from UV/PAA showed strong reactivity to oxidize certain naphthyl compounds. The new knowledge Obtained in this study will facilitate further research and development of UV/PAA as a new degradation strategy for water contaminants.