Hong-Xin Li

Low-silica EMT/FAU intergrowth zeolites with Si/Al = 1.0

Abstract Low-silica EMT/FAU intergrowth zeolite with Si/Al ratio of 1.0 was prepared by post-synthetic treatment of siliceous EMT zeolite (Si/Al=3.3) in a caustic solution containing Al(OH) 3 , NaOH, and KOH. This is an unusual approach to the synthesis of low-silica zeolite. The low-silica EMT/FAU intergrowth material is highly crystalline and contains greater than 50% EMT phase. Intermediate EMT/FAU products from the post-synthetic treatment were also isolated and characterized by XRD, 29 Si and 27 Al MAS NMR, TGA and SEM. The data suggest that the formation of low-silica EMT/FAU from siliceous EMT, unlike conventional hydrothermal zeolite syntheses and other post-synthetic modifications, involves several steps such as framework dissociation, aluminum insertion, seeding and recrystallization.