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.
作者
解佩敬
杜燕萍
杨思蒙
刘斌
常薇
侯海云
王宁
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)
出处
《盐湖研究》
CAS
CSCD
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)。
关键词
电动势法
KCL
三甘醇
活度系数
PITZER模型
Potentiometric method
KCl
Triethylene glycol
Activity coefficients
Pitzer model
