Construction of immobilized spherical TS-1 molecular sieve membranes using oriented aggregation of nanocrystals

Molecular sieve membranes are widely used in separation and catalysis due to their good chemical and thermal stability, resistance to contamination, long life, and easy modification. Although immobilized molecular sieve membranes combine catalytic reactivity with recycling separation properties, preparing high-performance TS-1 molecular sieve membrane catalysts is still challenging. In this study, the oriented aggregation of nanocrystals was used in constructing molecular sieve membrane catalysts. By interfering with the crystallization of TS-1, pre-crystal modification with cetyltrimethoxysilane was employed to change the crystal growth behavior. Thus, uniform and dense molecular sieve membranes were prepared through the modulated crystallization of TS-1. This method reduced the requirements of the carrier surface properties for the loading of the membrane layer to enable the construction of membrane layers on carriers of different materials and shapes. Using this method, the effective H 2 O 2 utilization and the epichlorohydrin yield of the micron-sized spherical film catalyst prepared with the inexpensive templating agent TPABr in the chloropropene epoxidation reaction reached 95.89% and 90.22%, respectively.