Thermodynamic Properties of KCl in the System of Triethylene Glycol-Water at 298.2 K
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),H2O(1-w)|Cl-ISE,this work measured the electromotive force value of KCl in a mixed solvent of TEG-H2O(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+H2O system,including activity coefficients(γ±),the standard Gibbs energies of transference(△G(⊕)t),and primary hydration number(nhydr).The com-parison results show that both the extended Debye-Hückel and Pitzer models can accurately describe the sys-tem.The y±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.
Potentiometric methodKClTriethylene glycolActivity coefficientsPitzer model
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维普
