Optimization of Vapor-Liquid Distillation in Water + Acetic Acid + Sodium Acetate Systems for Chemical Recovery Processes: Application of the Modified UNIQUAC-PDH Model Based on Experimental Data

Accurate prediction of vapor-liquid equilibrium (VLE) in electrolyte systems is critical for optimizing separation processes in chemical and mineral processing industries, particularly in the recovery of valuable acids and salts from aqueous streams. In this study, a modified UNIQUAC model integrated with the Pitzer-Debye-Hückel (M-UNIQUAC-PDH) thermodynamic framework is applied to correlate the VLE behavior of the ternary water + acetic acid + sodium acetate system - a representative electrolytic mixture encountered in hydrometallurgical and chemical recycling operations. The Peng-Robinson equation of state (PR EOS) was employed for vapor-phase calculations. Experimental VLE data spanning the temperature range of ۳۷۳.۳۵-۳۹۳.۸۵ K were used to determine binary interaction parameters, with ۱۷۳ data points successfully correlated. Results demonstrate that the M-UNIQUAC-PDH model significantly outperforms the conventional UNIQUAC model, achieving a total average absolute deviation (%AAD) of only ۷.۶%. This enhanced predictive capability enables more efficient design and scale-up of distillation units for selective recovery of acetic acid and sodium acetate from industrial effluents, offering practical benefits in resource conservation and waste minimization within material and mineral processing technologies. The proposed methodology provides a robust, physics-based tool for modeling complex electrolyte phase behavior relevant to sustainable materials engineering.

Keywords:

Vapor-Liquid Equilibrium , Electrolyte System , Modified UNIQUAC Model