Adsorption of thorium cation on modified clays MTTZ derivative

• Published in: Journal of hazardous materials Vol. 168; no. 2; pp. 1504 - 1511
• Main Authors: Guerra, Denis L., Viana, Rúbia R., Airoldi, Claudio
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15-09-2009; Elsevier
• Subjects: Adsorption; Aluminum Silicates; Applied sciences; Bentonite; Chemical engineering; Diquite; Exact sciences and technology; Hydrogen-Ion Concentration; Magnetic Resonance Spectroscopy; Microscopy, Electron, Transmission; Pollution; Thermodynamic; Thermodynamics; Thorium; Thorium - chemistry; X-Ray Diffraction; Bentonite; Diquite; Adsorption; Thorium; Thermodynamic; Elementary analysis; Radioactive pollution; Chemical analysis; Adsorption isotherm; NMR spectrometry; Radioisotope; X ray diffraction; Transmission electron microscopy; Batchwise; pH; Chemical properties; Aqueous solution
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2009.03.034

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
13C 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 398.5
m
2
g
−1 (B
MTTZ) and 25.0 (D) to 178.8
m
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
×
10
−2 and 12.76
×
10
−2
mmol
g
−1 for D
MTTZ and B
MTTZ, respectively. The energetic effects (Δ
int
H°, Δ
int
G° and Δ
int
S°) caused by thorium cation adsorption were determined through calorimetric titrations.