In this study, the original tourmaline and beryl mineral samples have been collected from a Brazilian pegmatite. The objective of this study was to examine the adsorption behavior of uranyl from aqueous solution on Brazilian cyclosilicate samples. The cyclosilicate samples were characterized by elemental analysis, X-ray diffraction, and nitrogen adsorption–desorption. The ability of these minerals to remove the U(VI) from aqueous solution was followed by a series of adsorption isotherms, using a batchwise process. The adsorption maximum was determined to be 2.95 and 2.60×10 −4 molg −1 for beryl and tourmaline mineral samples, respectively. The energetic effects caused by radionuclide cation adsorption were determined through calorimetric titrations. Thermodynamics indicated the existence of favorable conditions for such U(VI)–OH interactions.
