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The molecular thermodynamic model established by Hu, Xu and Prausnitz for gas solubility in nonpolar solvents is extended to polar and electrolyte solution systems. The influence of ion charge on the Helmholtz energy of fluid mixtures is taken into account by considering the interactions between the charge of ions located in the first coordination shell and the dipole or induced dipole of the central solute molecules. The contribution of the ions outside the first coordination shell can be neglected owing to the symmetrical distribution of the positive and negative ions with respect to the central solute molecule. The model in this paper includes a correlation equation for the effective hard sphere diameter of ions and the Pauling’s crystal diameter, σ=ησ~(crystal), where η=-6.645+747.2511/T+2.95392×10~(-2)T-5.05798×10-~5T~2+3.2431×10~(-8)T~3, for T>453.15 K, η=1.021. Henry’s constants of various gases in water, alcohols, ketones, halogenated aromatics and naphthalene substitutes are calculated. For all of the 81 systems with 13 solvents whose maximum dipole moment is 2.83 Debye, satisfactory results are obtained with the use of only one adjustable parameter over a wide temperature range of 193.15—573.15 K. The results of calculations for 78 systems of gas solubility in 1-1 type electrolytic solutions indicate that this model can predict the Henry’s constants of gases in electrolytic solutions over a wide temperature range and a wide concentration range for electrolytes with the use of molecular parameters of gases in water only.
The molecular of thermodynamic model established by Hu, Xu and Prausnitz for gas solubility in nonpolar solvents is extended to polar and electrolyte solution systems. The influence of ion charge on the Helmholtz energy of fluid mixtures is taken into account by considering the interactions between the charge of ions located in the first coordination shell and the dipole or induced dipole of the central solute molecules. The contribution of the ions outside the first coordination shell can be neglected owing to the symmetrical distribution of the positive and negative ions with respect to the central solute molecule . The model in this paper includes a correlation equation for the effective hard sphere diameter of ions and the Pauling’s crystal diameter, σ = ησ ~ (crystal) where η = -6.645 + 747.2511 / T + 2.95392 × 10 -2 T-5.05798 × 10- ~ 5T ~ 2 + 3.2431 × 10 -8 T ~ 3, for T> 453.15 K, η = 1.021. Henry’s constants of various gases in water, alcohols, ketones, halogenated aromatics and naphthalene substitut es are calculated. For all of the 81 systems with 13 solvents whose maximum dipole moment is 2.83 Debye, satisfactory results are obtained with the use of only one adjustable parameter over a wide temperature range of 193.15-573.15 K. The results of calculations for 78 systems of gas solubility in 1-1 type electrolytic solutions indicate that this model can predict the Henry’s constants of gases in electrolytic solutions over a wide temperature range and a wide concentration range for electrolytes with the use of molecular parameters of gases in water only.