Preparation of High-Quality ZSM-22 Nanocrystals by the Seed-Assisted Method from Industrial Raw Materials

It is of great importance to deeply understand the engineering scale-up process of synthesis of zeolite in both fundamental research and industrial applications. Here we report high-quality ZSM-22 nanocrystals synthesized from industrial raw materials by adding ZSM-22 seed at 20-L scale. The optimal synthesis conditions and the influence of seed during the synthesis of ZSM-22 using industrial materials are investigated. The role of the seed in the zeolite synthesis is to promote nucleation and the quality of ZSM-22. From the results of XRD patterns, N₂ sorption, ²⁷Al NMR spectra, SEM image, TEM image, and NH₃-TPD profiles characterization, it is found that adding seed is an effective method for synthesis of ZSM-22 using the industrial raw materials. A successful synthesis of ZSM-22 nanocrystals is proved with two different silica sol as indicated by the XRD patterns. High-quality ZSM-22 nanocrystals are successfully synthesized by a seeded approach and this synthesis can be scaled up to a 20-L reactor without obvious change in the zeolite properties and exhibits comparable catalytic performance with commercial ZSM-22 in butanol to hydrocarbon reaction.