Investigation of surface phenomena on solid catalysts by simultaneous TG and DTA

Abstract

Simultaneous thermogravimetry and DTA were used to investigate the phenomena of adsorption, desorption and surface reactions of water vapour on NaX and NaYtype and NaX-exchanged zeolites, and silica and alumina gels treated with sodium hydroxide. On the basis of the quantitative results, it was possible to give an interpretation of the surface phenomena and to establish the existence of various active centres on the surface of the catalysts. Water in zeolites is probably bound by oxygen-alkali metal bonds.