The semi-ideal solution theory for mixed ionic solutions at solid-liquid-vapor equilibrium.
The semi-ideal solution theory for mixed ionic solutions at solid-liquid-vapor equilibrium.
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DOI：
10.1021/jp0542672
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发表时间：
2006-03
期刊：
影响因子：
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通讯作者：
Yu-feng Hu;S. Fan;D. Liang
中科院分区：
文献类型：
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作者：
Yu-feng Hu;S. Fan;D. Liang
用半理想溶液理论描述了非理想电解质溶液M（i）X（i）-（NY）sat-H_2 O（i = 1和2）在NY和H_2 O活度不变的条件下混合过程中热力学性质的变化，包括浓度、化学势、所有M（i）X（i）的活度、吉布斯自由能、焓、熵、热性质和体积性质。该理论指出，在NY和H2O活度相等的条件下，表征离子-溶剂相互作用的平均水合数在混合物中与在子系统中具有相同的值，并且如果来自离子-溶剂相互作用的贡献，则混合这些非理想电解质溶液的过程与混合理想溶液的过程一样简单。离子相互作用的溶剂活性被假定为是相同的混合物中，在其子系统，这已被证明的Pitzer方程的计算。因此，建立了一系列新的线性方程，用于描述这些非理想溶液以及等摩尔分数NY和H_2O的理想溶液M（i）X（i）-（NY）sat-H_2 O（i = 1和2）混合过程中的热力学性质。从这些方程出发，从理论上导出了广泛应用的经验Zdanovskii规则，并从理论上确定了等压平衡下McKay-Perring方程中的重要常数，并与文献报道的18种混合物的实验结果进行了比较。在298.15K下对BaCl_2-LaCl_3-H_2 O、NaCl-BaCl_2-LaCl_3-H_2 O和NaCl-LaCl_3-BaCl_2·2 H_2 O（sat）-H_2 O体系进行了等压测量。结果被用来检验新的线性浓度关系，并取得了良好的协议。用新的活度系数预测方程计算了M_1X_1-M_2X_2-（NY）sat-H_2 O体系中M（i）X（i）的活度系数，并与Pitzer方程的计算结果进行了比较，两者吻合较好。
The semi-ideal solution theory has been presented to describe the changes in thermodynamic properties accompanying the process of mixing the nonideal electrolyte solutions M(i)X(i)-(NY)sat-H2O (i = 1 and 2) at constant activities of NY and H2O, including concentration, chemical potential, activities of all M(i)X(i), Gibbs free energy, enthalpy, entropy, thermal properties, and volumetric properties. The theory states that, under the conditions of equal activities of NY and H2O, the average hydration numbers characterizing the ion-solvent interactions have the same values in the mixture as in the subsystems and the process of mixing these nonideal electrolyte solutions is as simple as that of mixing the ideal solutions if the contributions from the ion-ion interactions to the solvent activity are assumed to be the same in the mixture as in its subsystems, which has been justified by the calculations of the Pitzer equation. Therefore, a series of novel linear equations are established for the thermodynamic properties accompanying the process of mixing these nonideal solutions as well as mixing the ideal solutions M(i)X(i)-(NY)sat-H2O (i = 1 and 2) of equal mole fractions of NY and H2O. From these equations, the widely applied empirical Zdanovskii's rule is derived theoretically, and the important constant in the McKay-Perring equation under isopiestic equilibrium is determined theoretically, which has been substantiated by comparisons with the experimental results for 18 mixtures reported in the literature. Isopiestic measurements have been made for the systems BaCl2-LaCl3-H2O, NaCl-BaCl2-LaCl3-H2O, and NaCl-LaCl3-BaCl2.2H2O(sat)-H2O at 298.15 K. The results are used to test the novel linear concentration relations, and the agreement is excellent. The novel predictive equation for the activity coefficient of M(i)X(i) in M1X1-M2X2-(NY)sat-H2O has been compared with the calculations of the Pitzer equation, and the agreement is good.