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| Titel |
Investigation of the hygroscopic properties of Ca(NO3)2 and internally mixed Ca(NO3)2/CaCO3 particles by micro-Raman spectrometry |
| VerfasserIn |
Y. J. Liu, T. Zhu, D. F. Zhao, Z. F. Zhang |
| 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 ; 8, no. 23 ; Nr. 8, no. 23 (2008-12-09), S.7205-7215 |
| Datensatznummer |
250006491
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| Publikation (Nr.) |
 copernicus.org/acp-8-7205-2008.pdf |
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| Zusammenfassung |
| To understand and predict the role of mineral aerosol particles processed by
reactive nitrogen species in the atmosphere, the hygroscopic properties of
both Ca(NO3)2 and Ca(NO3)2-containing mineral particles
must be well understood. Using a micro-Raman system, the hygroscopic
behaviors of micro-sized individual Ca(NO3)2 and internally mixed
Ca(NO3)2/CaCO3 particles in both dehumidifying and
humidifying processes were investigated systematically. In addition to
accurate quantification of the dependence of water content on relative
humidity (RH), significant new spectroscopic evidence related to chemical
structure was also obtained to confirm the occurrence of amorphous solid
state and to better understand the phase transition process. The
Ca(NO3)2 particles exhibit reversible behavior in the
dehumidifying and humidifying processes; they are in the state of solution
droplets above 10% RH and amorphous hydrates below 7% RH, and phase
transition occurs at 7–10% RH. The hygroscopic behavior of
Ca(NO3)2/CaCO3 particles is identical to that of pure
Ca(NO3)2 particles, suggesting a negligible effect of the slightly soluble CaCO3
inclusion on the hygroscopic behavior of a(NO3)2/CaCO3 particles. |
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