Uptake of Ba2+ ions by natural bentonite and CaCO3: a radiotracer, EDXRF and PXRD study
Date
2002Source Title
Journal of Radioanalytical and Nuclear Chemistry
Print ISSN
0236-5731
Publisher
Akademiai Kiado Rt.
Volume
254
Issue
3
Pages
563 - 568
Language
English
Type
ArticleItem Usage Stats
193
views
views
174
downloads
downloads
Abstract
Ba2+ uptake by natural bentonite, CaCO3 in addition to a number of bentonite-CaCO3 mixtures with variable compositions as a function of pH and Ba2+ concentration was studied. Radiotracer method, EDXRF, and PXRD were used. The results of radiotracer experiments showed that the uptake of Ba2+ by CaCO3 was larger than its uptake by natural bentonite samples, particularly at low initial concentrations of Ba2+ and higher pH values. This finding was supported by the EDXRF results, According to the sorption data, the apparent ΔG° values of sorption were in the range -9±1 to -13±3 kJ/mol. The PXRD studies revealed the formation of BaCO3 upon sorption of Ba2+ on pure CaCO3 and on some of the bentonite-CaCO3 mixtures.
Keywords
Barium ionBentonite
Calcium carbonate
Tracer
Adsorption
Adsorption kinetics
Chemical composition
Diffraction
Hydration
pH
Radioactive waste
Radioactive waste storage
X ray fluorescence
X ray powder diffraction