Abstract The isopiestic equilibria for the systems {Li2B4O5(OH)4 + H2O}, {LiB5O6(OH)4 + H2O} and {Li2B4O5(OH)4 + LiB5O6(OH)4 + H2O} at 288.15 K and ambient pressure were measured by the isopiestic method using a modified gravimetric isopiestic apparatus. The water activities and osmotic coefficients were determined based on the sodium chloride standard reference solution. On the basis of Pitzer model, an extended Pitzer model was developed to describe the thermodynamic properties of the aqueous systems containing different forms of lithium borates, then the Pitzer single salt parameters β(0), β(1), β(2) and Cϕ for the binary systems {Li2B4O5(OH)4 + H2O} and {(LiB5O6(OH)4 + H2O} and mixing ion-interaction parameters θ B 4 O 5 OH 4 , B 5 O 6 OH 4 and ψ Li , B 4 O 5 OH 4 , B 5 O 6 OH 4 for the ternary system {Li2B4O5(OH)4 + LiB5O6(OH)4 + H2O} were fitted with the experimental osmotic coefficients using the Fortran 97 program. Meanwhile, the water activities were calculated by the Pitzer parameters, and the good agreement between the calculated water activities and experimental results of this ternary system indicated that the Pitzer parameters obtained in this work were reliable.

中文翻译：

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三元系统 {Li2B4O5(OH)4) + LiB5O6(OH)4 + H2O} 及其子系统在 288.15 K 和环境压力下的等压测量和热力学模型

摘要 测量了体系 {Li2B4O5(OH)4 + H2O}、{LiB5O6(OH)4 + H2O} 和 {Li2B4O5(OH)4 + LiB5O6(OH)4 + H2O} 在 288.15 K 和环境压力下的等压平衡通过使用改进的重力等压装置的等压方法。水分活度和渗透系数以氯化钠标准参比溶液为基础测定。在Pitzer模型的基础上，建立了一个扩展的Pitzer模型来描述含不同形式硼酸锂的水体系的热力学性质，然后得到Pitzer单盐参数β(0)、β(1)、β(2)和二元系统 {Li2B4O5(OH)4 + H2O} 和 {(LiB5O6(OH)4 + H2O} 和混合离子相互作用参数 θ B 4 O 5 OH 4 , B 5 O 6 OH 4 和 ψ Li , B 的 Cϕ 4 O 5 OH 4 , B 5 O 6 OH 4 用于三元系统{Li2B4O5(OH)4 + LiB5O6(OH)4 + H2O} 使用 Fortran 97 程序拟合实验渗透系数。同时，利用Pitzer参数计算了水活度，计算出的水活度与该三元体系的实验结果吻合良好，表明本文得到的Pitzer参数是可靠的。