Influence of Phosphate Modification on the Structure and Surface Property of Ultrastable Y Zeolite

The influence of phosphate modification on the structure and surface property of ultrastable Y zeolites was investigated using different analytical methods such as MAS-NMR,XRD,FT-IR and pyridine-FT-IR.The results show that if the phosphate content is low,monomeric phosphate is mainly formed.It can reduce the amount of stronger acid and increase the amount of weaker acid on the surface of zeolite.When the phosphate content is high,polymeric phosphate comes into being and the amount of stronger acid and weaker acid obiviously decrease.After hydrothermal treatment,extraframework alumina is formed which can easily react with polymeric phosphate but not monomeric phosphate,so that tetrahedral non-alumina is formed out of framework.