Comparison among Pitzer-type Models for the Osmotic and Activity Coefficients of Strong Electrolyte Solutions at 298.15 K

In this work three Pitzer-type models were compared: the original one, the Archer model (an extended Pitzer model) with ionic strength dependence in the third virial coefficient, and the PIH model that uses as an adjusting parameter the closest approach constant. The performance of these models in correlating the osmotic and activity coefficient of 1:1, 1:2, 1:3, 1:4, 2:1, 2:2, 3:1, 3:2, and 4:1 aqueous electrolyte solutions was tested using experimental data sets for 245 single electrolyte aqueous solutions. The absolute average percentage deviations were 0.78, 1.18, and 3.56% for the Archer, PIH, and Pitzer models, respectively.