Atmos. Chem. Phys. Discuss., 13, 549-580, 2013
© Author(s) 2013. This work is distributed
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This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Modeling the surface tension of complex, reactive organic-inorganic mixtures
A. N. Schwier1,*, G. A. Viglione1, Z. Li1,**, and V. F. McNeill1
1Department of Chemical Engineering, Columbia University, New York, NY 10027, USA
*now at: Université Blaise Pascal, Laboratoire de Météorologie Physique, CNRS/OPGC, UMR6016, France
**now at: University of Florida, Department of Chemical Engineering, USA

Abstract. Atmospheric aerosols can contain thousands of organic compounds which impact aerosol surface tension, affecting aerosol properties such as cloud condensation nuclei (CCN) ability. We present new experimental data for the surface tension of complex, reactive organic-inorganic aqueous mixtures mimicking tropospheric aerosols. Each solution contained 2–6 organic compounds, including methylglyoxal, glyoxal, formaldehyde, acetaldehyde, oxalic acid, succinic acid, leucine, alanine, glycine, and serine, with and without ammonium sulfate. We test two surface tension models and find that most reactive, complex, aqueous organic mixtures which do not contain salt are well-described by a weighted Szyszkowski–Langmuir (S–L) model which was first presented by Henning et al. (2005). Two approaches for modeling the effects of salt were tested: (1) the Tuckermann approach (an extension of the Henning model with an additional explicit salt term), and (2) a new implicit method proposed here which employs experimental surface tension data obtained for each organic species in the presence of salt used with the Henning model. We recommend the use of method (2) for surface tension modeling because the Henning model (using data obtained from organic-inorganic systems) and Tuckermann approach provide similar modeling fits and goodness of fit (χ2) values, yet the Henning model is a simpler and more physical approach to modeling the effects of salt, requiring less empirically determined parameters.

Citation: Schwier, A. N., Viglione, G. A., Li, Z., and McNeill, V. F.: Modeling the surface tension of complex, reactive organic-inorganic mixtures, Atmos. Chem. Phys. Discuss., 13, 549-580, doi:10.5194/acpd-13-549-2013, 2013.
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