电动势法对0、15、35℃时LiCl─Li_2SO_4─H_2O体系中LiCl

Studies of the Activity Coefficients of LiCl for LiCl─Li_2SO_4─H_2O System at 0, 15, 35℃ by Emf Method

电动势法测定水盐体系的平均活度系数是进行热力学性质研究的一个重要方面．近年来，运用Ｐｉｔｚｅｒ离子相互作用模式在更高的浓度和更广的温度范围内来预测水盐体系的溶解度和热力学性质［２，３］．本文是对２５℃时电动势法对ＬｉＣｌ─Ｌｉ２ＳＯ４─Ｈ２Ｏ体系中ＬｉＣｌ的平均活度系数（γ±ＬｉＣｌ）测定［４］的继续和补充。

Emf measurements were made on the cell without liquid junction:Li─ISE |LiCl (m1), Li2SO4 (m2)|Ag/AgCl.The performances of the electrode pairs constructed in our laboratory were tested and exhibited near-Nernstian behavior. The mean activity coefficients of LiCl for the system LiCl- Li2SO4-H2O have been investigated by the emf values at temperatures of 0. 15. 35℃ and constant total ionic strengths of 0. 05, 0. 1. 0. 5, 1. 0, 2. 0, 3. 0 and 5. 0mol.kg-1.The thermodynamic properties are interpreted by use of Harned's empirical equations and Pitzer's ion interaction approach including the contribution of higher order electrostatic terms. The experimental results obey Harned's rule and are described by using Pitier equations satisfactorily. The activity coefficients of Li2SO4 for the system in the experimental temperature range were reported.