Thermal Characterization of Aminium Nitrate Nanoparticles

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• 作者：Kent Salo ; Jonathan Westerlund ; Patrik U. Andersson ; Claus Nielsen ; Barbara D鈥橝nna ; Mattias Hallquist
• 刊名：Journal of Physical Chemistry A
• 出版年：2011
• 出版时间：October 27, 2011
• 年：2011
• 卷：115
• 期：42
• 页码：11671-11677
• 全文大小：837K
• 年卷期：v.115,no.42(October 27, 2011)
• ISSN：1520-5215

文摘

Amines are widely used and originate from both anthropogenic and natural sources. Recently, there is, in addition, a raised concern about emissions of small amines formed as degradation products of the more complex amines used in CO₂ capture and storage systems. Amines are bases and can readily contribute to aerosol mass and number concentration via acid鈥揵ase reactions but are also subject to gas phase oxidation forming secondary organic aerosols. To provide more insight into the atmospheric fate of the amines, this paper addresses the volatility properties of aminium nitrates suggested to be produced in the atmosphere from acid鈥揵ase reactions of amines with nitric acid. The enthalpy of vaporization has been determined for the aminium nitrates of mono-, di-, trimethylamine, ethylamine, and monoethanolamine. The enthalpy of vaporization was determined from volatility measurements of laboratory generated aerosol nanoparticles using a volatility tandem differential mobility analyzer set up. The determined enthalpy of vaporization for aminium nitrates range from 54 up to 74 kJ mol^鈥?, and the calculated vapor pressures at 298 K are around 10^鈥? Pa. These values indicate that aminium nitrates can take part in gas-to-particle partitioning at ambient conditions and have the potential to nucleate under high NO_x conditions, e.g., in combustion plumes.