On the Correlation of the Activity Coefficients in Aqueous Electrolyte Solutions Using the K-MSA Model

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• 作者：C. Ghotbi ; G. Azimi ; V. Taghikhani ; and Juan H. Vera
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2003
• 出版时间：March 19, 2003
• 年：2003
• 卷：42
• 期：6
• 页码：1279 - 1284
• 全文大小：70K
• 年卷期：v.42,no.6(March 19, 2003)
• ISSN：1520-5045

文摘

The objective of this work is to extend the Kelvin mean spherical approximation (K-MSA) modelto correlate the mean and individual ionic activity coefficients for symmetric and asymmetricelectrolyte solutions at different concentrations and at different temperatures. Revised valuesof the parameters for the mean and individual ionic activity coefficients of 1:1 electrolytes andnew values of the parameters for the mean ionic activity coefficients of asymmetric electrolytesare presented. The effect of the short-range electrostatic term (P_n) at different size ratios of theions is examined. Assuming a constant anion diameter and a composition-dependent diameterfor the cation, the K-MSA model gives realistic cation-hydrated diameters, in comparison withtheir crystallographic Pauling diameters. Notably, for both symmetric and asymmetric electrolytes, the like and unlike ionic radial distribution function at contact value are positive over allof the concentration and temperature ranges studied. The results obtained from the K-MSAmodel compare favorably with those obtained from the Boublik-Mansoori-Carnahan-Starling-Leland mean spherical approximation and Pitzer models for the mean ionic activity coefficientsand with those obtained with the Khoshkbarchi-Vera model for the individual ionic activitycoefficients.