The role of seed in the synthesis of molecular sieves
Molecular sieves have been widely used as catalyst or adsorbent in petroleum refining and fine chemical industries.The synthetic chemistry of molecular sieve has advanced significantly in recent years,and the role of seed crystal in zeolite synthesis has become a research hotspot.Here the research progress of the role of seed in molecular sieve synthesis is reviewed and the impacts of seed are concluded to five aspects:accelerating crystallization rate,broadening the silica to alumina ratios of product,regulating product morphology,substituting organic templates and other functions.The focus is the role of seed crystal in the formation of molecular sieves with special morphology and the substitution of seed for organic template agent.According to the nucleation and growth mechanisms of molecular sieve,the principles of different effects of seed crystal in the synthesis process were analyzed,and it was revealed that the reduction of the activation energy of molecular sieve nucleation by seed crystal was the basis for its different effects.From the perspective of clean production,it is proposed that the specific structural changes of seed crystal in the process of molecular sieve synthesis and the synthesis of molecular sieve with high performance using seed crystal instead of organic template agent will become the focus of future research.
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