Zeolitization of diatomite to prepare hierarchical porous zeolite materials through a vapor-phase transport process

In this study, we report a new, simple approach to the preparation of hierarchical structured zeolites through transforming the diatomaceous silica into zeolite by a vapor-phase transport (VPT) method. The morphology and macro-porosity of the diatomite are well preserved even in the samples with zeolite content higher than 50%. The products possess high mechanical strength and hydrothermal stability, and are thus promising for application in catalysis, adsorption and separation. The influence of the zeolite structures, the amount of adsorbed seeds, and the VPT treatment time and temperature on the crystallinity of the resulting materials are discussed. Powder XRD, SEM, TEM, IR and N-2 adsorption-desorption measurements are employed to monitor the VPT treatment process.