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

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• 作者：Jie Zhang ; Dongdong Li ; Yan Yao ; Bai Sun ; Dewen Zeng ; Peng-Sheng Song
• 刊名：Journal of Chemical & Engineering Data
• 出版年：2016
• 出版时间：July 14, 2016
• 年：2016
• 卷：61
• 期：7
• 页码：2277-2291
• 全文大小：577K
• 年卷期：0
• ISSN：1520-5134

文摘

Osmotic coefficients, water activities, and vapor pressures for the systems of LiCl + H<sub>2sub>O, MgSO<sub>4sub> + H<sub>2sub>O, and LiCl + MgSO<sub>4sub> + H<sub>2sub>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<sup>–1sup> 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<sub>2sub> solution was chosen as a reference standard. The measured osmotic coefficients for the binary solutions of LiCl + H<sub>2sub>O and MgSO<sub>4sub> + H<sub>2sub>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.