Thermodynamic Properties of LiCl + MgSO₄ + H₂O at Temperatures from 273.15 K to 373.15 K and Representation with Pitzer Ion-Interaction Model

Abstract

Osmotic coefficients, water activities, and vapor pressures for the systems of LiCl + H 2 O, MgSO 4 + H 2 O, and LiCl + MgSO 4 + H 2 O over the ionic strength ranges from I = (0.5552 to 7.0004, 4.1028 to 22.6048, and 1.1982 to 20.5863) mol·kg −1 respectively at T = (273.15, 298.15, 323.15, 348.15, and 373.15) K were determined by the isopiestic method with an improved simple apparatus. Aqueous CaCl 2 solution was chosen as a reference standard. The measured osmotic coefficients for the binary solutions of LiCl + H 2 O and MgSO 4 + H 2 O were in agreement with those from the literature. The experimental data of osmotic coefficients for the ternary mixtures were represented by using the Pitzer ion-interaction model; the expressions for the temperature dependencies of the model parameters were given. The standard deviations of all the measured osmotic coefficient data from those calculated by using the model over the temperature range were estimated. A set of model equations of apparent molar enthalpy and excess heat capacity for the mixtures as functions of molality and temperature were obtained by differentiating the model equations of excess Gibbs free energy. The mean activity coefficients, relative apparent molar enthalpies, and excess heat capacities were calculated by using the corresponding equations. The effects of composition and temperature on these thermodynamic properties were discussed.

Theoretical and practical investigation of ion–ion association in electrolyte solutions

“…8,141,158,160,[186][187][188] for the MIAC, from ref. 141,160,186,[188][189][190][191][192][193] for the osmotic coefficient, from ref. 163,177 for the electrical conductivity, and from ref.…”

Mean Activity Coefficients and Phase Diagram in NaBr–SrBr2–H2O Solutions at 308.2 K

“…Over the past few years, several researchers have conducted studies on the thermodynamic properties of salt lake brines in the Qaidam Basin. For instance, KCl–RbCl–H 2 O from T = 298.15 K to T = 323.15 K and LiCl–MgSO 4 –H 2 O from 273.15 to 373.15 K were studied. Researchers have also carried out studies on the thermodynamic properties of electrolyte solutions. − Thermodynamic properties of electrolyte solutions such as the activity coefficient, osmotic coefficient, and excess Gibbs energy have been used to study related projects in different fields.…”