Application of the e-NRTL model to electrolytes in mixed solvents methanol-, ethanol- water, and PEG-water

Abstract

In this work, the e-NRTL binary interaction parameters for the alcohol-water (ethanol-water and methanol-water), electrolyte-alcohol (NaBr-methanol, NaBr-ethanol, NaCl-methanol, NaCl-ethanol, KCl-methanol and KCl-ethanol), PEG (polyethylene glycol)-water (PEG1000-, PEG4000- and PEG6000-water) and electrolyte-PEG (NaCl and KCl-PEG4000-water, KCl-PEG1000-water, LiCl-PEG4000-Water, CsCl-PEG (PEG1000, PEG4000 and PEG 6000)-Water) were evaluated by the non-linear regression of experimental data at different temperatures, reported in the literature. The application used was able to evaluate the impact of the NRTL, Debye-Hückel and Born contributions on the activity coefficients of a salt (or an electrolyte) in different media. In addition, the solubility constants, and the free energy of transfer on the molar scale of NaCl, KCl and NaBr in alcohol-water mixed solvents (methanol-water and ethanol-water at different temperatures) were evaluated by using the e-NRTL model and the binary interaction parameters previously computed. It was reached an excellent correlation of the experimental data of water activity, mean activity coefficient and osmotic pressure data of ethanol-water and methanol-water solutions, electrolyte-alcohol systems, and electrolyte-PEG, respectively. The presence of PEG and alcohol in solution had a great influence on the solubility of the solid phases.