Nonrandom two-liquid activity coefficient model for aqueous polyelectrolyte solutions

A comprehensive thermodynamic model is established to describe the thermodynamic properties of solvent water and mobile ions in aqueous polyelectrolyte solutions. The model accounts for excess Gibbs free energy of aqueous polyelectrolyte solutions with two contributions: (1) the long-range electrostatic polyion-ion interactions treated with Manning's limiting law and the long-range electrostatic ion-ion interactions treated with the Pitzer-Debye-Huckel equation, and (2) the short-range molecule-molecule, molecule-ion and ion-ion interactions treated with the electrolyte nonrandom two-liquid equation. Validated with extensive data sets of osmotic coefficients and mobile ion activity coefficients, the model is capable of systematically correlating and extrapolating thermodynamic properties of aqueous polyelectrolyte solutions. (C) 2019 Elsevier B.V. All rights reserved.