화학공학소재연구정보센터
Journal of Hazardous Materials, Vol.344, 1165-1173, 2018
Quantitative structure-activity relationships for reactivities of sulfate and hydroxyl radicals with aromatic contaminants through single-electron transfer pathway
Sulfate radical anion (SO4 center dot-) and hydroxyl radical ((OH)-O-center dot) based advanced oxidation technologies has been extensively used for removal of aromatic contaminants (ACs) in waters. In this study, we investigated the Gibbs free energy (Delta G degrees(SET)) of the single electron transfer (SET) reactions for 76 ACs with SO4 center dot- and (OH)-O-center dot, respectively. The result reveals that SO4 center dot- possesses greater propensity to react with ACs through the SET channel than (OH)-O-center dot. We hypothesized that the electron distribution within the molecule plays an essential role in determining the Delta G degrees(SET) and subsequent SET reactions. To test the hypothesis, a quantitative structure-activity relationship (QSAR) model was developed for predicting Delta G degrees(SET) using the highest occupied molecular orbital energies (E-HOMO), a measure of electron distribution and donating ability. The standardized QSAR models are reported to be Delta G degrees(SET) = -0.97 x E-HOMO - 181 and Delta G degrees(SET) = -0.97 x E-HOMO - 164 for SO4 center dot- and (center dot) OH, respectively. The models were internally and externally validated to ensure robustness and predictability, and the application domain and limitations were discussed. The single-descriptor based models account for 95% of the variability for SO4 center dot- and (OH)-O-center dot. These results provide the mechanistic insight into the SET reaction pathway of radical and non-radical bimolecular reactions, and have important applications for radical based oxidation technologies to remove target ACs in different waters. (C) 2017 Elsevier B.V. All rights reserved.