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

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

Campinas

Otro; 25th Annual users meeting, LNLS; 2015

CNPEM LNLS

Bentonite is an absorbent aluminium phyllosilicate (Smatitec 2:1 group) and Montmorilloniteis the best known member of the this group [1]. Bentonites are highly valued for theirsorptive properties, which stem from their high surface area and their tendency to absorbwater 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 apredominantly Na-Bentonite before and after thermal treatment at 800°C and 1050°C tocorrelate the information obtained with this technique with that obtained by conventional XrayDiffraction, and clarify and assign the structural changes. The results from the Si KXANES spectra show no major structural changes attributed to the Si sites, but there aresignificant changes in the Si 3p-holes density which increases due to thermal treatment. Theresults from the Al K XANES spectra show significant structural changes. The shoulderassociated at AlO4 disappear with the thermal treatment and the first main peak has abroadening for higher temperature. The same goes for the second main peak but moreintensely. This is assignable to splits Al 3p-levels due to the effects of crystal ligand field inAl morphological reconfiguration.