TY - JOUR

T1 - Comparison of the Debye–Hückel and the Mean Spherical Approximation Theories for Electrolyte Solutions

A1 - Maribo-Mogensen,Bjørn

A1 - Kontogeorgis,Georgios M.

A1 - Thomsen,Kaj

AU - Maribo-Mogensen,Bjørn

AU - Kontogeorgis,Georgios M.

AU - Thomsen,Kaj

PB - American Chemical Society

PY - 2012

Y1 - 2012

N2 - The thermodynamics of electrolyte solutions has been investigated by many scientists throughout the last century. While several theories have been presented, the most popular models for the electrostatic interactions are based on the Debye–Hückel and mean spherical approximation (MSA) theories. In this paper we investigate the differences between the Debye–Hückel and the MSA theories, and comparisons of the numerical results for the Helmholtz energy and its derivatives with respect to temperature, volume and composition are presented. The investigation shows that the nonrestricted primitive MSA theory performs similarly to Debye–Hückel, despite the differences in the derivation. We furthermore show that the static permittivity is a key parameter for both models and that in many cases it completely dominates the results obtained from the two models. Consequently, we conclude that the simpler Debye–Hückel theory may be used in connection with electrolyte equations of state without loss of accuracy.

AB - The thermodynamics of electrolyte solutions has been investigated by many scientists throughout the last century. While several theories have been presented, the most popular models for the electrostatic interactions are based on the Debye–Hückel and mean spherical approximation (MSA) theories. In this paper we investigate the differences between the Debye–Hückel and the MSA theories, and comparisons of the numerical results for the Helmholtz energy and its derivatives with respect to temperature, volume and composition are presented. The investigation shows that the nonrestricted primitive MSA theory performs similarly to Debye–Hückel, despite the differences in the derivation. We furthermore show that the static permittivity is a key parameter for both models and that in many cases it completely dominates the results obtained from the two models. Consequently, we conclude that the simpler Debye–Hückel theory may be used in connection with electrolyte equations of state without loss of accuracy.

UR - http://pubs.acs.org/doi/full/10.1021/ie2029943

U2 - 10.1021/ie2029943

DO - 10.1021/ie2029943

JO - Industrial & Engineering Chemistry Research

JF - Industrial & Engineering Chemistry Research

SN - 0888-5885

IS - 14

VL - 51

SP - 5353

EP - 5363

ER -