Ultra Stable Zeolite Y, Preparation and Dealumination

Steamed HY or ultrastable Y (H-USY) zeolites are active hydrocarbon cracking catalysts. It concludes that the large enhancement in cracking activity by steaming is due to increase in external surface area of the zeolite crystals and possibly a small increase in the specific initiation activity of each site. Dealumination of steamed zeolite by nitric acid, acid form of EDTA and oxalic acid treatment was investigated. The results showed that these acids are effective in removing non-framework Al as well as framework Al from the crystal. The collapse of crystal framework is depended on degree of dealumination.