
TY  - JOUR
A1  - Nordholm, S 
T1  - Generalized van der Waals theory. XII. Application to ionic solutions
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1984
VL  - 37
IS  - 1
SP  - 1
EP  - 22
KW  - 
UR  - https://doi.org/10.1071/CH9840001 
N2  - The recently developed generalized van der Waals (GvdW) theory of fluids is applied to ionic solutions, and shown to yield the Poisson-Boltzmann equation when short-range effects are neglected, and the Debye-Huckel theory when non-linear effects are also neglected. The linear GvdW theory, retaining excluded-volume and energetic correlation effects, then yields a corrected Debye-Huckel (CDH) theory. We consider electrolytes in the restricted primitive model and find that the excluded-volume effects then vanish. Two different methods for the evaluation of the energetic correlation effects are examined. In the first method, these effects are treated in a simple local approximation which leads to a DH theory with a decreased Debye length valid as long as this length is much greater than the hard-sphere diameter of the ions. In the second method, we assume a DH-type charge density, a constant number density and determine the Debye length by minimizing the linearized GvdW free-energy functional. The results for the internal energy, osmotic coefficient and mean ionic activity coefficient of 1-1 and 2-2 electrolytes in the concentration range 0-2 M are obtained and compared with corresponding simulation results. The agreement is good for 1-1 electrolytes, but significant deviations are observed for 2-2 electrolytes. 
ER  -

