Characterization of the formation of NaA zeolite membrane under microwave radiation

The use of scanning electron microscopy (SEM) to identify the formation stages of NaA zeolite membrane under microwave radiation was analyzed. The peaks from the synthesized membranes consisted of those of the NaA crystals and of α-Al2O3 substrate. After 5 minute microwave radiation, the diffraction peaks of NaA were found very weak and their intensities increased as the reaction was extended to 25 minutes. The growth and crystallization process occurred in 5-25 minutes of microwave radiation. The thickness of the membrane was uneven from the first stage. The SEM results were found consistent with the results of x-ray diffraction (XRD) and gas permeation meaurements.