title: Pioneering In Situ Recrystallization during Bead Milling: A Top-down Approach to Prepare Zeolite A Nanocrystals.
abstract: Top-down approach has been viewed as an efficient and straightforward method to prepare nanosized zeolites. Yet, the mechanical breaking of zeolite causes amorphization, which usually requires a post-milling recrystallization to obtain fully crystalline nanoparticles. Herein we present a facile methodology to prepare zeolite nanocrystals, where milling and recrystallization can be performed in situ. A milling apparatus specially designed to work under conditions of high alkalinity and temperature enables the in situ recrystallization during milling. Taking zeolite A as an example, we demonstrate its size reduction from ~3 μm to 66 nm in 30 min, which is quite faster than previous methods reported. Three functions, viz., miniaturization, amorphization and recrystallization were found to take effect concurrently during this one-pot process. The dynamic balance between these three functions was achieved by adjusting the milling period and temperature, which lead to the tuning of zeolite A particle size. Particle size and crystallinity of the zeolite A nanocrystals were confirmed by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and water adsorption-desorption. This work presents a pioneering advancement in this field of nanosized zeolites, and will facilitate the mass production as well as boost the wide applications of nanosized zeolites.
authors.affiliation: The University of Tokyo, Department of Chemical System Engineering, Tokyo, 113-8656, Japan.
authors.forename: Chokkalingam
authors.initials: C
authors.lastname: Anand
authors.affiliation: The University of Tokyo, Department of Chemical System Engineering, Tokyo, 113-8656, Japan.
authors.forename: Yudai
authors.initials: Y
authors.lastname: Yamaguchi
authors.affiliation: The University of Tokyo, Department of Chemical System Engineering, Tokyo, 113-8656, Japan.
authors.forename: Zhendong
authors.initials: Z
authors.lastname: Liu
authors.affiliation: The University of Tokyo, Department of Chemical System Engineering, Tokyo, 113-8656, Japan.
authors.forename: Sayoko
authors.initials: S
authors.lastname: Ibe
authors.affiliation: The University of Tokyo, Department of Chemical System Engineering, Tokyo, 113-8656, Japan.
authors.forename: Shanmugam P
authors.initials: SP
authors.lastname: Elangovan
authors.affiliation: Ashizawa Finetech Ltd., Akanehama 1-4-2, Narashino, Chiba, 275-8572, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Ishii
authors.affiliation: Ashizawa Finetech Ltd., Akanehama 1-4-2, Narashino, Chiba, 275-8572, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Ishikawa
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki 305-8565, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Endo
authors.affiliation: The University of Tokyo, Department of Chemical System Engineering, Tokyo, 113-8656, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Okubo
authors.affiliation: The University of Tokyo, Department of Chemical System Engineering, Tokyo, 113-8656, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Wakihara