Journal of the Brazilian Chemical Society
versión impresa ISSN 0103-5053
GUERRA, Denis L.; VIANA, Rúbia R. y AIROLDI, Claudio. Adsorption of thorium(IV) on chemically modified Amazon clays. J. Braz. Chem. Soc. [online]. 2009, vol.20, n.6, pp. 1164-1174. ISSN 0103-5053. http://dx.doi.org/10.1590/S0103-50532009000600023.
Kaolinite and smectite clay samples from the Amazon region, Brazil, were modified with 2-mercaptobenzimidazole (MBI) using homogeneous and heterogeneous routes. The modified clay samples (KHOM, SHOM, KHET and SHET) were characterized by textural analysis, SEM and 13C NMR spectroscopy. The chemically modified clay samples showed modifications of their physical-chemical properties including: specific area 48.0 (S) to 869.8 m2 g-1 (SHET). The ability of these materials to remove thorium(IV) from aqueous solution was followed by a series of adsorption isotherms adjusted to a Sips equation at room temperature, and pH 2.0. The maximum number of moles adsorbed was determined to be 8.29, 8.86, 9.57 and 9.89 10-1 mmol g-1 for KHOM, KHET, SHOM and SHET, respectively. The energetic effects (ΔintH, ΔintG and ΔintS) caused by thorium(IV) cation adsorption were determined through calorimetry.
Palabras llave : kaolinite; smectite; thorium; adsorption; thermodynamic.