Bentonite: Al ? Si K XANES characterization for this clay treated at two temperature

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

Campinas

Otro; Annual Users Meeting LNLS/CNPEM; 2015

LNLS/CNPEM

Bentoniteis an absorbent aluminium phyllosilicate (Smatitec 2:1 group) and Montmorilloniteis the best known member of the this group [1]. Bentonites are highly valuedfor their sorptive properties, which stem from their high surface area andtheir tendency to absorb water in the interlayer sites [2] which are mostextensively used are Na-Bentonite and Ca-Bentonite [3] as it are called in theindustry.We studiedby Al ? Si K XANES a predominantly Na-Bentonite before and after thermaltreatment at 800°C and 1050°C tocorrelate the information obtained with this technique with that obtained by conventionalX-ray Diffraction, and clarify and assign the structural changes.The resultsfrom the Si K XANES spectra show no major structural changes attributed to the Sisites, but there are significant changes in the Si 3p-holes density whichincreases due to thermal treatment.The resultsfrom the Al K XANES spectra show significant structural changes. The shoulderassociated at AlO4 disappear with the thermal treatment and thefirst main peak has a broadening for higher temperature. The same goes for thesecond main peak but more intensely. This is assignable to splits Al 3p-levels dueto the effects of crystal ligand field in Al morphological reconfiguration. [1] P.F.Luckhum, S. Rossi, Adv. Colloid InterfuceSci. 82 (1999) 43-92.[2] G.E.Christids, P.W. Scott, A.C. Dunham,  Appl. Clay. Sci. 12 (1997) 329-347.[3] H.H.Murray, Clay Minerals 34 (1999) 39-49.