Aqueous Binary Lanthanide(III) Nitrate Ln(NO3)3 Electrolytes Revisited: Extended Pitzer and Bromley Treatments
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- 作者：Sayandev Chatterjee ; Emily L. Campbell ; Doinita Neiner ; Natasha K. Pence ; Troy A. Robinson ; Tatiana G. Levitskaia
- 刊名：Journal of Chemical & Engineering Data
- 出版年：2015
- 出版时间：October 8, 2015
- 年：2015
- 卷：60
- 期：10
- 页码：2974-2988
- 全文大小：932K
- ISSN：1520-5134
文摘
To date, only limited thermodynamic models describing activity coefficients of the aqueous solutions of lanthanide ions are available. This work expands the existing experimental osmotic coefficient data obtained by classical isopiestic technique for the aqueous binary trivalent lanthanide nitrate Ln(NO3)3 solutions using a combination of water activity and vapor pressure osmometry measurements. The combined osmotic coefficient database for each aqueous lanthanide nitrate at 25 掳C, consisting of literature available data as well as data obtained in this work, was used to test the validity of Pitzer and Bromley thermodynamic models for the accurate prediction of mean molal activity coefficients of the Ln(NO3)3 solutions in wide concentration ranges. The new and improved Pitzer and Bromley parameters were calculated. It was established that the Ln(NO3)3 activity coefficients in the solutions with ionic strength up to 12 mol kg鈥? can be estimated by both Pitzer and single-parameter Bromley models, even though the latter provides for more accurate prediction, particularly in the lower ionic strength regime (up to 6 mol kg鈥?). On the other hand, for the concentrated solutions, the extended three-parameter Bromley model can be employed to predict the Ln(NO3)3 activity coefficients with remarkable accuracy. The accuracy of the extended Bromley model in predicting the activity coefficients was greater than 鈭?95 % and 鈭?90 % for all solutions with the ionic strength up to 12 mol kg鈥? and 20 mol kg鈥?, respectively. This is the first time that the activity coefficients for concentrated lanthanide solutions have been predicted with such a remarkable accuracy.