Measurements and Calculations mean activity coefficients of KI in the KI–KCl–H2O ternary system at 298.15 K

• Published in: Journal of molecular liquids Vol. 346; p. 117933
• Main Authors: Wang, Wei, Sang, Shi-Hua, Ren, Hong-Bao, Zheng, Lin, Pan, Jin-Gong
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.01.2022
• Subjects: Activity coefficient; Ion selective electrode; Pitzer equation; Potassium chloride; Potassium iodide; Ion selective electrode; Activity coefficient; Pitzer equation; Potassium iodide; Potassium chloride
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2021.117933

Plot of lnγ±KI vs yb for different ionic strengths I in the KI–KCl–H2O ternary system at 298.15 K. [Display omitted] •Activity coefficients study aiming at underground brine.•Measurements and calculations of the mean activity coefficients in the ternary system.•Using Pitzer electrolyte solution theory to calculated the experimental results.•Playing a fundamental role to bulid a thermodynamic framework. Compared to the current popular methods for measuring the mean activity coefficient of the ternary aqueous solution, electromotive force method has certain advantages of rapidity and sensitivity. Herein, The electromotive force measurements were performed on the cell of the type: K–ISE|KI (m1), KCl (m2)|I–ISE, which consists of a potassium-ion combination ion selective electrode (ISE) and iodide-ion combination ion selective electrode (ISE) without a liquid junction. We chose the total ionic strength I range from 0.0100 to 1.0000 mol·kg−1 for different ionic strength fractions yb of KCl with yb = (0.0, 0.2, 0.4, 0.6, 0.8). The experimental results show that the mean activity coefficients of KI can be calculated well by using the Pitzer models and Nernstian equation. Moreover, the Pitzer ion interaction parameters of θCl,I and ψK,I,Cl were fitted using Pitzer’s equations, and the two parameters were used to calculated the mean activity coefficients of KCl in the KI–KCl–H2O ternary system. Accordingly, the osmotic coefficients, water activities, and excess Gibbs free energies in the mixtures were studied in the KI–KCl–H2O ternary system.