A NOVEL AND EFFICIENT METHOD FOR THE DIRECT AND RAPID SYNTHESS OF NANOCRYSTALLINE ZEOLTES BY SUPERCRITICAL WATER MEDUM

Nanocrystalline zeolites with narrow size distributions of less than 40 nm have been synthesized in a supercritical water medium using various reactants and batch compositions. Zeolites of analcime (ANA), FAU and a mixture of FAU and LTA were synthesized and extensively characterized by using powder Xray diffraction (XRD) and transmission electron microscope (TEM). Results show a decrease in particle size, high purity and product yields.What is more, in comparison with the low-temperature hydrothermal method, the duration time has decreased from many hours or days (depending on the reacting source) to a few minutes (~10 min) which is noteworthy in terms of energy consumption.