An electrolyte CPA equation of state for mixed solvent electrolytes

Abstract

Despite great efforts over the past decades, thermodynamic modeling of electrolytes in mixed solvents is still a challenge today. The existing modeling frameworks based on activity coefficient models are data‐driven and require expert knowledge to be parameterized. It has been suggested that the predictive capabilities could be improved through the development of an electrolyte equation of state. In this work, the Cubic Plus Association (CPA) Equation of State is extended to handle mixtures containing electrolytes by including the electrostatic contributions from the Debye–Hückel and Born terms using a self‐consistent model for the static permittivity. A simple scheme for parameterization of salts with a limited number of parameters is proposed and model parameters for a range of salts are determined from experimental data of activity and osmotic coefficients as well as freezing point depression. Finally, the model is applied to predict VLE, LLE, and SLE in aqueous salt mixtures as well as in mixed solvents. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2933–2950, 2015

Prediction of thermodynamic properties of aqueous electrolyte solutions using equation of state

“…Deviation from experimental data at low temperature is relatively high, especially at ambient condition while it decreases as temperature increases. The experimental infinite dilution heat capacity of aqueous NaCl solution at ambient condition is about −85 J/mol K while it was predicted about −340 J/mol K by M‐Mogensen et al using electrolyte CPA EOS . In this work it was predicted −10 J/mol K, however this result is not surprising but reveals that present work gives acceptable results.…”

Influence of electrolytes on liquid-liquid equilibria of water/1-butanol and on the partitioning of 5-hydroxymethylfurfural in water/1-butanol

“…In order to quantitatively describe the LLE data of water/1-butanol/glycerol/salt, the binary interaction parameters between water and glycerol, 1-butanol and glycerol, as well as NaCl and glycerol were correlated to the respective LLE data of that quaternary system. The application of thermodynamic approaches to model LLE containing electrolytes has been reviewed by Wang et al [23], and the reader is also referred to some other works [24,25].…”

110th Anniversary: Theory of Activity Coefficients for Lithium Salts in Aqueous and Nonaqueous Solvents and in Solvent Mixtures

“…The arithmetic average of the solvated ion diameters σand σ + determines σ. To quantify the extent of cation solvation, we set σ + as the crystallographic diameter of the cation, σ + x (crystallographic is denoted with superscript x) plus a contribution from the solvent diameter (24) where is a sphericity factor accounting for how the solvent molecules orient around the cation and how tightly they bind to the cation. For a spherical solvent molecule that tightly binds to the cation, ω s = 1, while ω s = 0 when the cation is not solvated.…”