Synthesis of nanosized Silicalite-1 in F−media

• DOI: 10.1016/j.micromeso.2015.11.043
• Publication Date: 2015-12-12T09:13:13Z
• Authors: Kun Jiao; Xiangyu Xu; Zhi Lv; Jiaqing Song; Mingyuan He; Hermann Gies
• Keywords: Hydrothermal Synthesis; Crystal (programming language); Dispersity; Particle (ecology)

Abstract This paper reports on the successful crystallization of monodisperse, highly crystalline, nanosized zeolite Silicalite-1 crystals in fluoride media by using an active silica gel as silica source and tetrapropylammonium fluoride as structure directing agent. The synthesis procedure is hydrothermal dynamic crystallization. The silica/water ratio and synthesis temperature were reduced to optimize the number of crystal nuclei and control the rate of crystallization for obtaining nanosized zeolite crystals. Meanwhile, F − ions were used to partly replace OH − ions in the synthesis system to obtain zeolite products with high crystallinity. Analytical results of XRD-, SEM-, Dynamic Light Scanning- (DLS) IR-, Simultaneous Thermal Analysis- (STA) and N 2 adsorption and desorption experiments show that the average particle size of zeolite Silicalite-1 product is about 45 nm and shows high crystallinity. The F − containing Silicalite-1 zeolite sample was compared with an industrial ZSM-5 zeolite sample and it shows obvious advantages in both reduced particle size and enhanced crystallinity.