Hannover 2010 – wissenschaftliches Programm

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UP: Fachverband Umweltphysik

UP 6: Aerosols

UP 6.3: Vortrag

Mittwoch, 10. März 2010, 18:15–18:30, M 11

Efflorescence, deliquescence and crystal structures of ternary aerosols — •Lennart Treuel, Alice Sandmann, Stefan Graß, and Reinhard Zellner — Universität Duisburg-Essen, Essen, Germany

The work presented here combines experimental and theoretical studies of the thermodynamics of atmospherically relevant aerosols. The phase behaviour of ammonium salts and their ternary mixtures with water and a range of selected dicarboxylic acids have been experimentally investigated and the results have been modelled with current state of the art thermodynamic aerosol models. The influence of the dicarboxylic acid concentration on the deliquescence relative humidity (DRH) has been studied for a multitude of dicarboxylic acids. Furthermore, the influence of hydrophilic and hydrophobic insoluble substances on the efflorescence and subsequent deliquescence was investigated and atmospheric implications of these findings are discussed. In addition to the measurements on the dependence of the DRH on temperature and concentration, the crystal structures resulting from the efflorescence of highly supersaturated binary and ternary aerosols have also been determined for the first time using Raman Scanning Microscopy, Powder X-Ray Diffractometry and Environmental Scanning Electron Microscopy (ESEM). The results from these studies elucidate the crystal structures and the spatial distribution of crystals formed during the efflorescence process of complex ternary mixtures, thus enhancing the understanding of the thermodynamic processes governing the deliquescence.