Bentonite: Al ? Si k xanes characterization for this clay treated at two temperature

L. ANDRINI; R.M. TOJA ; M.R. GAUNA; F. REQUEJO; N.M. RENDTORFF

Campinas

Otro; 25th Annual Users Meeting of the Brazilian Synchrotron Light Laboratory (RAU/LNLS); 2015

LNLS - CNPEM

Bentonite is an absorbent aluminium phyllosilicate (Smatitec 2:1 group) and Montmorillonite is the best known member of the this group [1]. Bentonites are highly valued for their sorptive properties, which stem from their high surface area and their tendency to absorb water in the interlayer sites [2] which are most extensively used are Na-Bentonite and Ca- Bentonite [3] as it are called in the industry. We studied by Al ? Si K XANES a predominantly Na-Bentonite before and after thermal treatment at 800°C and 1050°C to correlate the information obtained with this technique with that obtained by conventional Xray Diffraction, and clarify and assign the structural changes. The results from the Si K XANES spectra show no major structural changes attributed to the Si sites, but there are significant changes in the Si 3p-holes density which increases due to thermal treatment. The results from the Al K XANES spectra show significant structural changes. The shoulder associated at AlO4 disappear with the thermal treatment and the first main peak has a broadening for higher temperature. The same goes for the second main peak but more intensely. This is assignable to splits Al 3p-levels due to the effects of crystal ligand field in Al morphological reconfiguration.