TGA-DTA study on calcination of zeolitic catalysts

Template decomposition upon calcination of EMO and EMT zeolites has been studied using thermal analysis techniques. For both samples, desorption of water occurs below 200 degrees C and template decomposition at 250-450 degrees C. It is concluded that the template decomposition in EMO and EMT zeolites is relatively slow and is not structure-sensitive; it is accompanied by rapid desorption of the products, XRD studies on the calcined samples show no decrease in their crystallinity. However, both NMR- and IR-spectroscopy indicate partial distortion of the framework and formation of Lewis acid sites. A non-destructive activation of zeolites prepared with organic templates is proposed. (C) 1997 Elsevier Science B.V.