A systematic comparison of nine models formed by various combinations of three Debye-Hückel expressions and three local-composition expressions for representation of nonideality in electrolyte solutions

Abstract

The thermodynamic properties of electrolyte solutions are considered to be the sum of two contributions, one long-range and one short-range. Three Debye-Hückel expressions (Fowler and Guggenheim, 1949; Pitzer, 1973; Liu, Harvey and Prausnitz, 1989) have been applied to account for long-range contributions, and three local-composition expressions (NRTL type; Wilson type; Modified Wilson type) have been applied to account for short-range contributions. The nine models formed by various combinations of the three Debye-Hückel expressions and the three local-composition expressions have been systematically compared based on the same data and the same regression program. The Debye-Hückel expressions of Fowler-Guggenheim and Pitzer affect the results identically. The Debye-Hückel expression of Liu et al. can greatly improve the results. When using the Debye-Hückel expression of Liu et al., the deviations are generally less than one-tenth of those when using two other Debye-Hückel expressions. The local-composition expressions of NRTL type and Wilson type give qualitatively identical effects on deviation. The results when using the local-composition expression of the modified Wilson type, due to its more adjustable parameters, are better than those when using the other two local-composition expressions.