Shape-controlled synthesis of monolithic ZSM-5 zeolite with hierarchical structure and mechanical stability

Columned ZSM-5 zeolite monoliths with hierarchical structure and excellent mechanical strength were successfully prepared by a hydrothermal transformation method. The pre-formed extrudates of aluminosilicate embedded with β zeolite were subjected to a hydrothermal synthesis system and the hierarchical porous ZSM-5 zeolite monoliths with the same columned shape were obtained after the hydrothermal treatment. The intra-particle hollow structure formed during hydrothermal synthesis was attributed to the digestion of inner β zeolite accompanying with the growth of ZSM-5 zeolite shell. The related data of X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) analysis, N2-sorption experiment and mercury intrusion prosimetry (MIP), showed ZSM-5 zeolite monolith had enriched multi-porosity and excellent mechanical stability, which contribute to its further application in field of catalysis and separation. The obtained hierarchical ZSM-5 zeolite monoliths showed superior catalytic performance in α-pinene isomerization for their proper acidity and good diffusion, compared with the ZSM-5 zeolite sample prepared from the precursor without β zeolite.