Adsorption of thorium(IV) on chemically modified Amazon clays

• Autor(a) principal: Guerra,Denis L.
• Data de Publicação: 2009
• Outros Autores: Viana,Rúbia R., Airoldi,Claudio
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of the Brazilian Chemical Society (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532009000600023
• topic: kaolinite; smectite; thorium; adsorption; thermodynamic

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 (ΔintH, ΔintG and ΔintS) caused by thorium(IV) cation adsorption were determined through calorimetry.