Aqueous atmospheric aerosol droplets have a major impact on the Earth’s radiation budget, yet are one of the largest sources of uncertainty in climate modeling.  Part of this uncertainty arises from the complex nature of individual aerosol droplets, with hundreds of dissolved salt and water-soluble organic components. Thermodynamic predictions of these complex micro-environments at atmospherically relevant temperatures and relative humidities (RH) are essential for accurate determination of atmospheric chemistry properties and particle processes. For example, the calculation of gas-liquid-solid equilibrium partitioning of water, electrolyte, and soluble organic components requires thermodynamic models for water content and solute activities. Likewise, predictions of particle morphologies, or mixing states, require predictions of liquid-liquid and liquid-vapor interfacial energies. <br/> <br/>In this presentation, statistical mechanical methods will be applied to aqueous solutions and surfaces of multicomponent, electrolyte-containing aerosol particles over a complete range of RH, with a particular focus on thermodynamic properties at high ionic strengths.  Equations for Gibbs free energy, solvent and solute activity, solute concentration, and interfacial tension are derived using lattice modeling with an adsorption isotherm framework. Recent developments for treating partial dissociation and association of solutes in solution, and competitive solute adsorption at surfaces, will be highlighted.

Lattice-based adsorption isotherms for solute activities and surface tensions of complex aqueous solutions

254th National Meeting (2017)

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