Low Temperature Synthesis of Zeolite Using Ultrasonic Energy

A zeolite 4A was prepared at a low temperature of 60 degrees C for 4 h by ultrasonic irradiation of a kaolin-sodium hydroxide-water mixture using a commercial ultrasonic cleaner operating at a frequency of 47 kHz, whereas no zeolite 4A was crystallized at the same temperature and for the same time by the conventional process. Ultrasonic irradiation led to accelerated kinetics of the crystallization of the zeolite phase as detected by X-ray diffractometry, scanning electron microscopy, and Fourier-transform infrared spectroscopy. It is expected that this process may be used to synthesize different types of zeolite at lower temperature and shorter time than those required for the conventional process, with energy saving and at lower production cost.