TY - JOUR
T1 - A Simple G-Excess Model for Concentrated Aqueous Electrolyte Solutions
AU - Macías-Salinas, Ricardo
N1 - Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/5/9
Y1 - 2019/5/9
N2 - A simple yet accurate thermodynamic model was developed here to represent the nonideal behavior of single electrolytes in water at very high molalities and within a wide temperature range. The present model was obtained from an analytical expression of the excess Gibbs free energy (G-excess) which comprises three major contributions; in this context, a chemical term in the model handles the most predominant short-range ion-solvent interactions by means of a chemical equilibrium approach based on a stepwise ion solvation, whereas another term in the model of physical nature also contributes in describing the aforementioned interactions by incorporating a simple Margules equation, and last, a continuum-solvent term given by the explicit mean-spherical-approximation (MSA) expression serves to account for long-range ion-ion forces. The resulting G-excess model was applied to the representation of experimental mean ionic activity coefficients and osmotic coefficients of various representative aqueous electrolyte solutions: AgNO3, CaCl2, HCl, HClO4, HF, HNO3, KF, KOH, LiBr, LiCl, LiNO3, NaCNS, NaOH, NH4NO3, ZnBr2, and ZnCl2 salts in water at 25 °C (and from 0 up to 300 °C only in the case of KOH) and at high concentrations (up to 83.263 M). The results indicated a very good agreement between the experimental data and those calculated using the present G-excess model for the majority of the electrolyte solutions considered here.
AB - A simple yet accurate thermodynamic model was developed here to represent the nonideal behavior of single electrolytes in water at very high molalities and within a wide temperature range. The present model was obtained from an analytical expression of the excess Gibbs free energy (G-excess) which comprises three major contributions; in this context, a chemical term in the model handles the most predominant short-range ion-solvent interactions by means of a chemical equilibrium approach based on a stepwise ion solvation, whereas another term in the model of physical nature also contributes in describing the aforementioned interactions by incorporating a simple Margules equation, and last, a continuum-solvent term given by the explicit mean-spherical-approximation (MSA) expression serves to account for long-range ion-ion forces. The resulting G-excess model was applied to the representation of experimental mean ionic activity coefficients and osmotic coefficients of various representative aqueous electrolyte solutions: AgNO3, CaCl2, HCl, HClO4, HF, HNO3, KF, KOH, LiBr, LiCl, LiNO3, NaCNS, NaOH, NH4NO3, ZnBr2, and ZnCl2 salts in water at 25 °C (and from 0 up to 300 °C only in the case of KOH) and at high concentrations (up to 83.263 M). The results indicated a very good agreement between the experimental data and those calculated using the present G-excess model for the majority of the electrolyte solutions considered here.
UR - http://www.scopus.com/inward/record.url?scp=85065621837&partnerID=8YFLogxK
U2 - 10.1021/acs.jced.8b01176
DO - 10.1021/acs.jced.8b01176
M3 - Artículo
SN - 0021-9568
VL - 64
SP - 2193
EP - 2206
JO - Journal of Chemical and Engineering Data
JF - Journal of Chemical and Engineering Data
IS - 5
ER -