Mechanistic insight into the degradation of ibuprofen in UV/H 2 O 2 process via a combined experimental and DFT study

The study investigated the degradation kinetic and transformation mechanism of ibuprofen (IBP) in UV/H O process from both experimental and theoretical aspects. Impacts of H O dosage, solution pH, quenching agent, and concentration of nitrite (NO ) on IBP degradation in UV/H O process were evaluated...

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Bibliographic Details
Published in:Chemosphere (Oxford) 2021-03, Vol.267, p.128883
Main Authors: Wang, Pin, Bu, Lingjun, Wu, Yangtao, Ma, Wangchi, Zhu, Shumin, Zhou, Shiqing
Format: Article
Language:English
Subjects:
Hydrogen Peroxide
Ibuprofen
Kinetics
Oxidation-Reduction
Ultraviolet Rays
Water Pollutants, Chemical - analysis
Water Purification
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Summary:The study investigated the degradation kinetic and transformation mechanism of ibuprofen (IBP) in UV/H O process from both experimental and theoretical aspects. Impacts of H O dosage, solution pH, quenching agent, and concentration of nitrite (NO ) on IBP degradation in UV/H O process were evaluated. Both experimental results and theoretical calculations indicated that OH played an important role in the degradation of IBP and its transformation products. The second-order rate constants of OH and NO with IBP were calculated as 3.93 × 10  M  s and 5.59 × 10  M  s , based on the transition state theory, which explained the phenomenon that addition of NO inhibited IBP degradation. Further, according to the results of ultra-high-resolution mass and density functional theory calculations, mechanisms of a detailed degradation pathway for IBP were clarified. Namely, the detailed mechanistic formation pathways for hydroxylated and keto-based products were proposed. Then, possible active sites of the keto-based products, as well as the corresponding subsequent products were predicted by Condensed Fukui Function. Our study can broaden the knowledge of the reactions of emerging contaminants with OH, and provide theoretical foundation for the optimization of UV/H O process.
ISSN:1879-1298