Effects of heating methods on synthesis of zeolites

Hydrothermal methods have been most frequently applied in the synthesis of zeolites. Microwave heating was applied in the step of crystallization and it was compared with conventional heating such as direct heating with reflux or autogeneous condition. microwave irradiation heats up the precursor gel in a fast and homogeneous way through dielectric heating, thereby making it possible to reduce the synthesis time by several orders of magnitude. Crystallinity is as good as conventional heating methods, though the size of particles is smaller. Spherical morphology of SOD type of zeolite appeared when microwave was applied for the gel composition where LTA type of zeolite is the only phase with conventional heating methods. Different heating methods in the hydrothermal synthesis of zeolites may effect a change of phase or morphology. Copyright (2003) AD-TECH - International Foundation for the Advancement of Technology Ltd