Phase, Interfacial, Derivative and Transport Properties of Aqueous Systems with the Soft-SAFT EoS

 

Water is a fascinating molecule that exhibits a high complex non-ideal behaviour both as a pure fluid and in mixtures from a thermophysical point of view. The modelling of water and their mixtures is still an issue for scientists, as there is still not any single model able to accurately reproduce all its thermophysical properties. However, aqueous systems are present everywhere, and reliable tools are needed.

The goal of this contribution is to present a simple but quite efficient model, within the framework of the soft-SAFT molecular-based equation of state, for representing an important amount of thermophysical properties of water and several aqueous systems, including  water + CO₂, water + 1-alkanols and water + ionic liquids. The vapour-liquid and liquid-liquid equilibria of these systems are described in a wide range of temperatures and pressures in good agreement with the experimental data. The calculation of the interfacial tension of some of these mixtures is adressed using the Density Gradient Theory approach into soft-SAFT, while the viscosity of these mixtures is also evaluated using the Free-Volume-Theory (FVT). A further discussion about the ability of the model to calculate some derivative and excess properties of interest is  included.

 

Acknowledgements: F. Llovell acknowledges a TALENT fellowship from the Generalitat de Catalunya. This work was partially financed by the Spanish Government under projects CTQ2008-05370/PPQ and CEN-2008-1027. Additional support from Carburos Metįlicos and the Catalan Government was also provided (2009SGR-666).