Adsorption of thorium cation on modified clays MTTZ derivative.
Diquite (D) and bentonite (B) mineral samples from the Amazon region, Brazil, were modified by MTTZ derivative (5-mercapto-1-methyltetrazole) using heterogeneous route. These materials were characterized by textural and elemental analysis, transmission electron microscopy (TEM), power X-ray diffraction and (13)C NMR spectroscopy. The chemically modified clay (D(MTTZ) and B(MTTZ)) samples showed modification of its physical-chemical properties including: specific area 41.4 (B) to 398.5m(2)g(-1) (B(MTTZ)) and 25.0 (D) to 178.8m(2)g(-1) (D(MTTZ)). The adsorption experiments performed under batch process with Th(IV) concentration, pH and contact time as variables. The ability of these materials to remove thorium from aqueous solution was followed by a series of adsorption isotherms adjusted to a Sips equation at room temperature and pH 2.0, with variable concentration of Th(IV). The maximum number of moles adsorbed was determined to be 10.45 x 10(-2) and 12.76 x 10(-2)mmol g(-1) for D(MTTZ) and B(MTTZ), respectively. The energetic effects (Delta(int)H degrees , Delta(int)G degrees and Delta(int)S degrees ) caused by thorium cation adsorption were determined through calorimetric titrations.
Chemistry Institute, State University of Campinas, São Paulo, Brazil. dlguerra@iqm.unicamp.br
Denis L
DL
Guerra
Rúbia R
RR
Viana
Claudio
C
Airoldi
D000327:Adsorption; D000538:Aluminum Silicates; D000077215:Clay; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D046529:Microscopy, Electron, Transmission; D013816:Thermodynamics; D013910:Thorium / Q000737:chemistry*; D014961:X-Ray Diffraction
D000538:Aluminum Silicates; D013910:Thorium; D000077215:Clay