Electrolyte solutions: from thermodynamic and transport property models to the simulation of industrial processes

Recent advances in modeling thermodynamic and transport properties of electrolyte solutions are reviewed. In particular, attention is focused on mixed-solvent electrolyte models, equations of state for high-temperature and supercritical electrolyte systems and transport property models for multicomponent, concentrated solutions. The models are analyzed with respect to their capability of computing thermodynamic and transport properties in wide ranges of conditions and composition (i.e. for aqueous or mixed-solvent, dilute or concentrated solutions). Various frameworks for the development of electrolyte models are discussed, i.e. models that treat electrolytes on a completely dissociated or undissociated basis and those that take into account the speciation of solutions. A new mixed-solvent electrolyte model is developed for the simultaneous calculation of speciation and phase equilibria. The role of speciation is discussed with respect to the representation of the thermodynamic properties of mixed-solvent electrolyte solutions and diffusion coefficients in aqueous systems. (C) 2002 Elsevier Science B.V. All rights reserved.