Kinetic removal of acetaminophen and phenacetin during LED-UV365 photolysis of persulfate system: Reactive oxygen species generation.

Chaoqun Tan, Xinchi Jian, Lianghu Su, Xu Lu, Juan Huang, Jing Deng, Wenhai Chu

Chemosphere 2021 Apr

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Acetaminophen (ACT) and phenacetin (PNT) removal during light-emitting diode (LED)-UV photolysis of persulfate (PS) was evaluated with a typical wavelength of 365 nm. Decay of PNT and ACT in pH ranges of 5.5-8.5 followed pseudo-first order kinetics. Maximum pseudo-first order rate constants (kobs) of ACT and PNT decomposition of 1.8 × 10-1 and 1.2 × 10-1 min-1, respectively, were obtained at pH 8.5. Hydroxyl radicals (·OH), sulfate radicals (SO4·-), superoxide radicals (O2-·), and singlet oxygen (1O2) were determined in-situ electron paramagnetic resonance (EPR) and alcohol scavenging tests. The average contributions of ·OH and SO4·- were 23.5% and 53.0% for PNT removal, and 15.9% and 53.0% for ACT removal at pH ranges of 5.5-8.5. In samples subjected to chlorination after LED-UV365/PS pre-oxidation, a relatively small total concentration of five halogenated disinfection by-products (DBPs) was obtained of 90.9 μg L-1 (pH 5.5) and 126.7 μg L-1 (pH 7.0), which is 58.5% and 30.2% lower than that in system without LED-UV365/PS pre-oxidation. Meanwhile, a higher maximum value of total DBP concentration was obtained at pH 8.5 (445.6 μg L-1) following LED-UV365/PS pre-oxidation. The results of economy evaluation showed that UV365 was more cost-effective in application for organic contaminant removal compared with UV254. Copyright © 2020 Elsevier Ltd. All rights reserved.

Citation

Chaoqun Tan, Xinchi Jian, Lianghu Su, Xu Lu, Juan Huang, Jing Deng, Wenhai Chu. Kinetic removal of acetaminophen and phenacetin during LED-UV365 photolysis of persulfate system: Reactive oxygen species generation. Chemosphere. 2021 Apr;269:129337