کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6465117 | 1422951 | 2017 | 10 صفحه PDF | دانلود رایگان |
- We systematically investigated the first step of SET reactions for 76 ACs with SO4â.
- ÎGSETâ decreases with an increase of electron donating character of substituents.
- The calculated kSET for the ACs were compared with their experimental k values.
- We proposed two fundamental SET reaction mechanisms for 76 ACs with SO4â.
Removal of aromatic contaminants (ACs) in waters by sulfate radical anion (SO4â) based advanced oxidation technology has been extensively studied. Three main mechanisms have frequently been used to account for the first step of radical oxidation of ACs: radical adduct formation, hydrogen atom abstraction, and single electron transfer (SET), among which the SET pathway is the least understood. In this study, we investigated the first step of SET reactions for 76 ACs with SO4â. The result shows that the Gibbs free energy (ÎGSETâ) of the reaction increases with a decrease of the electron donating character of the substituents on the ACs. The trend was then quantitatively corroborated by a Hammett type plot, indicating that the electrostatic interaction is the driving force for the SET pathway. Further, we compared the calculated second-order rate constants (kSET) for the ACs via the SET pathway with their experimental k values, and proposed two fundamental SET reaction mechanisms based on the identified intermediates. The thermodynamic and kinetic results obtained advance the mechanistic understanding of the SET pathway of radical and non-radical bimolecular reactions, and shed light on the applicability of SO4â in ACs removal during water treatment processes.
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Journal: Chemical Engineering Journal - Volume 327, 1 November 2017, Pages 1056-1065