Structure Analysis of Intercalated Clays Using Combination of Molecular Simulations, Powder Diffraction and IR Spectroscopy

Abstract

Combination of molecular simulations with x-ray powder diffraction and TR spectroscopy has been used to study the structure of montmorillonites, intercalated with aluminium complex cations. Two different intercalating species have been investigated: (1) Keggin cation - ideal and hydrolysed and (2) gibbsite-like polymers, arranged in two layers in the interlayer of montmorillonites. The results of molecular simulations showed, that for Keggin cations, the crystal packing depends on the degree of hydrolysis, exhibiting the basal spacings within the range 19.38 - 20.27 (10(-10)m). I, case of gibbite-like polymers, arranged in two layers in the interlayer, basal spacings within the range 19.58 - 20.06 (10(-10)m) have been found, in dependence on the mutual position of Al-OH polymers. Results of molecular simulations showed, that no two-dimensional ordering of complex cations and no reggular stacking of layers can occure in the interlayer of montmorillonites. All the conclusions of modelling were in agreement with the results of XRD analysis.