Measuring boundaries in phase diagrams of ternary systems using titration calorimetry

Solid–Liquid Phase Equilibrium in the Na₂CO₃+Na₂SO₄+H₂O System at 298.15 K and 101 kPa by Isothermal Titration Microcalorimetry

“…e transformation points were determined from these curves, as indicated by the red arrows in Figure 2(a) and Figure 3(a). e differentiation method can also be adopted to determine the turning points of a system (Nai et al, 2021), especially for a system that has a clear turning point. e composition was accurately determined for the liquidus lines neighboring the single liquid phase using Mode 1, so Mode 2 did not need to be used to obtain these points.…”

“…More importantly, the thermodynamic parameters are directly obtained using this method, and classical thermodynamics can contribute to the understanding of solution behavior. In our previous studies, ITC proved to be a feasible and convenient method for constructing several types of phase diagrams of ternary systems (Bao et al, 2019;Zhang et al, 2020;Nai et al, 2021). Considering the degree of freedom of a ternary system, the phase diagram of a planar equilateral triangle can be drawn under constant temperature and pressure.…”

“…If the thermal e ect is collected during the titration, the break in the slope of the obtained thermogram corresponds to the region boundary. Hence, ITC is well-suited for determining the phase diagrams of salt-water systems, such as NaCl-NaOH-H 2 O (Dhenain et al, 2013) or KCl-KNO 3 -H 2 O (Nai et al, 2021). However, although the phase diagrams studied by the titration method are relatively simple, they consider neither hydrated salts nor double salts in salt-water systems.…”

Explanation and Exploration of the Isothermal Titration Curve for the NaCl + Na2SO4+ H2O System at 298.15 K and 102.2 kPa

“…In our previous studies, ITC has been proved to be a feasible and convenient method to construct several types of phase diagrams of ternary systems. 16 − 18 As theoretical calculations providing an accurate prediction of the solubility limits of a solid component in binary mixtures are not yet available, experimental studies are necessary to determine the solid–liquid phase equilibria in ternary systems, such as the NaCl + Na 2 SO 4 + H 2 O system investigated in this paper. The Pitzer model is used to analyze the experimental data to determine the solid–liquid equilibrium.…”

“…In this way, these lines, which represent the locus of the maximum solubility data points, are readily obtained by plotting these points. In our previous studies, ITC has been proved to be a feasible and convenient method to construct several types of phase diagrams of ternary systems. − As theoretical calculations providing an accurate prediction of the solubility limits of a solid component in binary mixtures are not yet available, experimental studies are necessary to determine the solid–liquid phase equilibria in ternary systems, such as the NaCl + Na 2 SO 4 + H 2 O system investigated in this paper. The Pitzer model is used to analyze the experimental data to determine the solid–liquid equilibrium. , This model is very efficient at predicting the behavior of electrolyte solutions ranging from infinitely diluted solutions to very concentrated ones; furthermore, the activity and osmotic coefficients as well as the activity product can be calculated using the corresponding Pitzer parameters.…”