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| Titel |
Hydroxyl radical reactivity at the air-ice interface |
| VerfasserIn |
T. F. Kahan, R. Zhao, D. J. Donaldson |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 10, no. 2 ; Nr. 10, no. 2 (2010-01-26), S.843-854 |
| Datensatznummer |
250007978
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| Publikation (Nr.) |
 copernicus.org/acp-10-843-2010.pdf |
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| Zusammenfassung |
| Hydroxyl radicals are important oxidants in the atmosphere and in natural
waters. They are also expected to be important in snow and ice, but their
reactivity has not been widely studied in frozen aqueous solution. We have
developed a spectroscopic probe to monitor the formation and reactions of
hydroxyl radicals in situ. Hydroxyl radicals are produced in aqueous
solution via the photolysis of nitrite, nitrate, and hydrogen peroxide, and
react rapidly with benzene to form phenol. Similar phenol formation rates
were observed in aqueous solution and bulk ice. However, no reaction was
observed at air-ice interfaces, or when bulk ice samples were crushed prior
to photolysis to increase their surface area. We also monitored the
heterogeneous reaction between benzene present at air-water and air-ice
interfaces with gas-phase OH produced from HONO photolysis. Rapid phenol
formation was observed on water surfaces, but no reaction was observed at
the surface of ice. Under the same conditions, we observed rapid loss of the
polycyclic aromatic hydrocarbon (PAH) anthracene at air-water interfaces,
but no loss was observed at air-ice interfaces. Our results suggest that the
reactivity of hydroxyl radicals toward aromatic organics is similar in bulk
ice samples and in aqueous solution, but is significantly suppressed in the
quasi-liquid layer (QLL) that exists at air-ice interfaces. |
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