Preparation of Low-silica EMT/FAU Zeolite
Publication Date: 2003-Sep-12
The IP.com Prior Art Database
Faujasite-type zeolites (FAU) have been synthesized hydrothermally with a wide range of composition from Y zeolites with Si/Al ratios as high as 5 to a low-silica X zeolite (LSX) with a Si/Al ratio of 1.0. A closely related structure to FAU is the hexagonal polymorph denoted with EMT. EMT zeolites with Si/Al ratios from 3.0 to 5.0 have been synthesized hydrothermally by Delprato et al. using 18-crown-6 ether as a structural directing agent [ref. 1]. Davis reported the synthesis of VPI-6, an intergrowth of EMT/FAU with Si/Al ratio of about 1.2 [ref. 2]. However, the synthesis of VPI-6 is rather complicated and the materials obtained had low micropore volumes. Low-silica EMT zeolite with Si/Al ratio of 1.0 has not been reported. Low-silica zeolites have potential uses for laundry detergents and air separation adsorbents, both of which require the highest possible ion-exchange capacity of zeolites. This paper discloses the preparation of low-silica EMT/FAU intergrowth zeolites with Si/Al ratio as low as 1.0.