Resumen

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 (K_HOM, S_HOM, K_HET and S_HET) 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 (S_HET). 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 K_HOM, K_HET, S_HOM and S_HET, respectively. The energetic effects (Δ_intH, Δ_intG and Δ_intS) caused by thorium(IV) cation adsorption were determined through calorimetry.

Palabras llave : kaolinite; smectite; thorium; adsorption; thermodynamic.