In-situ crystallization of macroporous MFI-type zeolites.

Macro-microporous silicate-1 zeolites(MFI crystalline form) were synthesized via the "dissolution-recrystallization process", utilizing monodisperse silica spheres (500 nm) as the silica source and macroporous templates, as well as tetrapropylammonium hydroxide as the microporous template, to enable in-situ formation of the macropores. The samples displayed macropore diameters ranging between 150 ~ 350 nm, a specific surface area of 350 m²/g, and a total pore volume of 0.24 cm³/g. The influence of synthetic conditions, such as crystal time, the addition of ethanol, the drying method, the amount of structure directing agent and the size of silica spheres, on the introduction of macropores was revealed. On this basis, macroporous ZSM-5 zeolites were further successfully synthesized with aluminum atoms incorporated into the pure silica zeolite framework. [ABSTRACT FROM AUTHOR]