Structural and Morphological Transformations of the (NH4, Na)-exchanged Zeolites 4A, 13X and Synthetic Mordenite by Thermal Treatment

Thermal treatment of (NH4, Na)-exchanged zeolites 4A and 13X results in the formation of an amorphous phase (T < 1000 °C) and a crystalline phase of mullite at temperatures above 1000 °C. No structural changes have been noticed for the (NH4, Na)-exchanged synthetic mordenite treated under the same conditions. Scanning electron microscopy (SEM), X-ray powder diffraction, Fourier transform infrared (FT-IR) spectroscopy and particle size analysis were used to characterize the initial materials and the obtained products