Thermoanalytische Untersuchungen an Schichtmaterialien: Der Einfluβ der Kationen auf das thermische Verhalten

Abstract

Aluminium-free layered silicates of the metal silicate hydrate type (M-SH) comprise an interesting supplement to the well-known zeolite-like porous materials. Their specific properties allow these materials to be used as catalysts, adsorbents and ion-exchangers. Comparative X-ray diffraction and thermoanalytical investigations (TG and DSC) have shown that the thermoanalytical methods are useful to follow the process of structure formation of ilerite. The interlayer cations influence the properties of the different ilerites. In particular, the hydration behaviour of ilerite is affected. Thus, H⁺- and DTMA⁺-ilerite are stable up to temperatures of about 800°C, while the as-synthesized Na-form loses water irreversibly at about 150°C, is dehydroxylated, and is then desomposed structurally at about 400°C. The course of the dehydration exhibits significant differences for the various cation forms.