Modification of e-CPA for estimating phase equilibria and development of predictive models for electrical conductivity in aqueous electrolyte solutions

Abstract

We modify the electrolyte cubic plus association equation of state (e-CPA EoS) and inetgrate it with two electrical conductivity models to estimate the electrical conductivity of 11 monovalent electrolytes solutions in water. The e-CPA EoS is modified by including the ion-ion and ion-solvent association interactions and tuned using experimental data of mean ionic activity coefficient and density of the electrolyte solutions. The modified e-CPA model shows a better performance in estimating the bubble pressure data. The hybridization of two electrical conductivity models with e-CPA results in two predictive models for estimating the electrical conduction of dilute and concentrated electrolyte solutions. Finally, we generalize these predictive models by correlating their model fitting parameters to the electrolyte physical parameters such as mean hard-sphere diameter or to association volume. The two predictive electrical conductivity models estimate electrical conductivity with AARD of 11.15 % and 13.87 % over wide ranges of temperature and electrolyte concentration.