Thermodynamic study and modeling of the (KCl + diethanolamine + water) ternary system based on potentiometric measurements at T = (298.2 and 308.2) K

In this research, modeling and determination of thermodynamic properties of the (KCl + diethanolamine + water) ternary system were reported using the potentiometric method. The potentiometric measurements were carried out on the galvanic cell of type: Ag | AgCl | KCl (m), diethanolamine (wt%), H2O (1-wt) %|K-ISE, in various mixed solvent system containing 5, 10, 15, and 20% mass fractions of diethanolamine over ionic strength ranging from 0.0110 to 2.8499 mol.kg− 1 at T = (298.2 and 308.2) K and P = 0.1 MPa. The obtained results were interpreted by using Debye-Hückel extended equation, Pitzer ion interaction and Pitzer-Simonson-Clegg models. Then, the parameters for each of them were determined and utilized to calculate the values of mean activity coefficients, the osmotic coefficients, the excess Gibbs free energy and the solvent activity for the series under investigated system.