298.2 K下KCl在三甘醇-水体系中的热力学性质研究  

Thermodynamic Properties of KCl in the System of Triethylene Glycol-Water at 298.2 K

作　　者：解佩敬 杜燕萍[1] 杨思蒙 刘斌[1] 常薇[1] 侯海云[1] 王宁[1] 杨嘉琳 XIE Peijing;DU Yanping;YANG Simeng;LIU Bin;CHANG Wei;HOU Haiyun;WANG Ning;YANG Jialin(School of Environmental and Chemical Engineering,Xi’an Polytechnic University,Xi’an Key Laboratory of Textile Chemical Engineering Auxiliaries,Xi’an,710048,China)

机构地区：[1]西安工程大学环境与化学工程学院,西安市纺织化工助剂重点实验室,陕西西安710048

出　　处：《盐湖研究》2024年第6期25-31,共7页Journal of Salt Lake Research

基　　金：国家自然科学基金青年科学基金项目(21703165)。

摘　　要：电解质溶液的热力学性质是海卤水开发利用的重要基础。文章采用钾离子选择性电极(K-ISE)和氯离子选择性电极(Cl-ISE),组成电池:K−ISE|KCl(m),三甘醇(TEG)(w),H_(2)O(1−w)|Cl−ISE,测量了298.2 K时KCl在TEG+H_(2)O(TEG的质量分数wt%=0,0.10,0.20,0.30和0.40)混合溶剂中的电动势。通过Nernst方程分别与扩展的Debye-Hückel模型和Pitzer模型结合,得到了KCl+TEG+H_(2)O体系的热力学性质:活度系数(γ_(±))、标准迁移吉布斯自由能(△G■_(t))和原水化数(n_(hydr))。结果表明,扩展的Debye-Hückel和Pitzer模型均能准确描述该体系;氯化钾的活度系数随混合体系中KCl含量的增加而减小,随混合溶剂中TEG含量的增加而减小;△G■_(t)>0,说明KCl从水中迁移到(TEG+H_(2)O)混合溶剂的过程是非自发行为。研究结果为盐-混合溶剂体系提供了热力学数据。The thermodynamic properties of electrolyte solutions are an important basis for many industrial processes such as sea brine development,separation and purification processes,environmental biochemical and seawater pretreatment processes.Ion-selective electrodes(ISE)were used in the experiment to form the following the cell:K−ISE|KCl(m),triethylene glycol(TEG)(w),H_(2)O(1-w)|Cl−ISE,this work measured the electromotive force value of KCl in a mixed solvent of TEG-H_(2)O(mass fraction of TEG wt%=0,0.10,0.20,0.30 and 0.40)at 298.2 K.By combined the Nernst equation with the extended Debye-Hückel and Pitzer models,the thermodynamic properties of KCl+TEG+H_(2)O system,including activity coefficients(γ_(±)),the standard Gibbs energies of transference(△G■_(t)),and primary hydration number(n_(hydr)).The comparison results show that both the extended Debye-Hückel and Pitzer models can accurately describe the system.Theγ±decreases with the increase of molality of KCl and decreases with the increase of TEG content in the mixed solvent;△G■_(t)>0,indicates that the transference of KCl from water to the(TEG+water)solvent mixture is not spontaneous.The results provide thermodynamic data for the salt-solvent mixture system.

关 键 词：电动势法 KCL 三甘醇 活度系数 PITZER模型 

分 类 号：O642.542[理学—物理化学]