Fig. 2 showsXRDpatterns for the products obtained bymicrowave
heating. It can be seen that the product, obtained after hydrothermal
synthesis of 4 h at 190 C by microwave heating, was composed of
mordenite crystals and some amorphous materials but without any
other crystalline phases. Puremordenite crystalswere obtained after
hydrothermal synthesis of 6 h. The intensity of the peaks changed
little when the reaction time was prolonged to 12 h. This is more
clearly illustrated in Fig. 3,which shows the relationship between the
relative crystallinity and the crystallization time. As revealed in Fig. 3,
the crystallization ratewas almost constant during the first six hoursof hydrothermal treatment, after which an equilibrium seems to be
reached