ePC-SAFT revised

So far, the electrolyte PC-SAFT equation of state developed in Cameretti et al. (2005) has been applied to model solution densities, vapor–liquid equilibria (VLE), liquid–liquid equilibria (LLE), and solid–liquid equilibria (SLE) of solutions containing electrolytes. For that purpose, two ion-specific parameters were used to characterize any ion: the diameter of the solvated ion and the dispersion-energy parameter between ion and solvent. Dispersion was only considered between ions and solvents. Considering the small number of adjustable parameters, this approach yielded acceptable results especially for low and moderate electrolyte concentrations. However, for high salt concentrations, a distinct deviation between modeled and experimental data was observed.In this work a new modeling approach is suggested that accounts explicitly also for dispersion interactions between anions and cations. This yields a much more precise description of electrolyte solutions at higher concentrations compared to original ePC-SAFT. With this new approach it is also possible to directly model weak electrolyte solutions without using an additional approach that accounts for ion-pair formation.The new approach for applying ePC-SAFT is now able to model phase equilibria (VLE, LLE, SLE) of ternary electrolyte solutions containing water, organic solvents, salts, and amino acids even at high salt concentrations in good agreement with experimental data.