SYNTHESIS OF ZEOLITE A CRYSTALS IN THE PRESENCE OF CRYSTAL GROWTH INHIBITORS BY MICROWAVE-ASSISTED HYDROTHERMAL TECHNIQUE

摘要

Zeolite A crystals were synthesized at 100°C from sodium metasilicate and aluminium foil by microwave assisted hydrothermal technique. It was confirmed by using X-ray diffraction technique that zeolite A was produced. The influence of heating rate on the zeolite crystal size was investigated using 2.5°C/min, 7.5°C/min, and 50°C/min. It was shown that the low heating rate resulted in larger crystal size with high crystallinity. To evaluate the effect of crystal growth inhibitors (GCIs) on the zeolite synthesis and crystal size, three types of CGIs, namely Poly Ethylene Glycol (PEG); Poly Ethylene Glycol-Methyl Ether (PEG-ME); and Brij-96, were utilized. It was found that PEG gave the best result in termsof zeolite size compared to the other two CGIs by resulting in reduction of the size of zeolite A crystals into about half compared to that without CGI.