Dealuminated Beta Zeolite Modified by Alkaline Earth Metals

Abstract

Alkaline Earth metals (Mg, Sr, and Ca) were incorporated into the dealuminated mesoporous beta zeolite (DeAlBeta) by the two-step postsynthesis method. Physicochemical properties of both unmodified and alkaline Earth metal-modified DeAlBeta zeolite were characterized by XRD, DR UV-vis, FTIR, TPD of NH3 and CO2, NMR, and XPS. The dealumination of beta zeolite led to decrease of its acidity and basicity. The incorporation of alkaline Earth metals into the framework of dealuminated beta zeolite did not affect its structure. The modification of DeAlBeta with a small amount of alkaline Earth metals increases the number of acidic centers, which may be related to the formation of framework Mg (Ca or Sr) (II) Lewis acidic sites.