摘要
研究了 35℃NaCl KCl H2 O三元体系的活度系数 .用Na+ 、K+ 和Cl-的离子选择性电极分别测得了 (0 .1～ 1.5mmol/L)不同离子强度下该体系中NaCl和KCl的平均活度系数 .回归了该体系Pitzer方程的相互作用参数 .实验值与计算值最大相对误差为 5 .6 % ,而平均相对误差为 2 .3% .
That the activity coefficient of mixed electrolyte solution is determined using ISE has become a simple and practicable method. There are a lot of Na+? K+? Cl-? SO 4 2-and a little Ca 2+ in the seawater and saline. The study of these ionic mean activity coefficients is very important in the designing and exploiting technology for the industry of producing salt, seawater desalinization and so on. The object of this text is the ternary system of NaCl-KCl-H 2O at 35℃. The experiment device of determining the ionic average activity coefficients of electrolyte solutions has been set up. The electromotive force of pure NaCl and KCl aqueous solution has been determined using the ion selective electrode at 35℃. The electrode constants have been regressed. The mean relative error about the activity coefficient of KCl solution is 0.9% between the calculated value of Pitzer equation and the calculated value of regression. The mean relative error about the activity coefficient of NaCl solution is 1.5% between the calculated value of Pitzer equation and the calculated value of regression. The linearity connection of the electromotive force vs the logarithm value of activity is very good within the experiment concentration. This indicates the determination method and the experiment equipment are reliable and the determined data are believable. The ionic average activity coefficients of NaCl and KCl have been determined in the ternary mixture system of NaCl-KCl-H 2O at 35℃ using the ion selective electrode. The concentration of the mixed electrolyte solutions is 0.1～1.5 mmol/L in six groups altogether. The interaction parameters of the Pitzer equation have been regressed. The maximal relative error between the experiment value and the calculated value is 5.6% and the mean relative error is 2.3%.
