Abstract
Environmentally persistent free radicals are pollutants recently detected in most environmental matrices such as fly ash, aerosols, soils and sediments. Their generation and transformation is poorly known, notably in the atmopshere. Here we modeled the effect of dioxygen O2, hydroxyl radical •OH, and nitrate radical NO3 on Cu(II)O surface-bound phenoxyl radical, using quantum chemical calculations and kinetics analysis. Results show that additional stabilization of the surface-bound phenoxyl radical is provided by the metal-oxide surface, implying that self-decomposition is not likely to occur. The addition reactions of hydroxyl and nitrate radicals with surface-mediated radicals are both thermodynamically and kinetically favorable, whereas the role of O2 appears negligible. The tropospheric lifetime of the Cu(II)O-based surface-bound phenoxyl radical is only few seconds to about one hour, in agreement with experimental observations from the literature.
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Acknowledgements
This research was jointly supported by the projects of the National Key Research and Development Program of China (2020YFA0907500) and the National Natural Science Foundation of China (91743204, 92043302, 21777181, 21976206).
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Pan, W., Chang, J., He, S. et al. Major influence of hydroxyl and nitrate radicals on air pollution by environmentally persistent free radicals. Environ Chem Lett 19, 4455–4461 (2021). https://doi.org/10.1007/s10311-021-01278-9
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DOI: https://doi.org/10.1007/s10311-021-01278-9