Synthesis of Zeolitic Imidazolate Framework-8 Particles of Controlled Sizes, Shapes, and Gate Adsorption Characteristics Using a Central Collision-Type Microreactor

Jul 8, 2026

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Controlling the particle size and shape of soft metal-organic framework compounds is essential for regulating adsorption-induced structural transitions that create distinct stepwise “gate” adsorption behavior. This study shows that intensive mixing in a central collision-type microreactor enables reproducible synthesis of monodisperse ZIF-8 particles. In this flow process, initial mixing conditions mainly set particle size (50 nm to 2 µm), while subsequent aging temperature determines particle shape (cube to chamfered cube to rhombic dodecahedron). Both size and shape govern adsorption characteristics.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages10

Reading Time25 min

Introduction

Porous coordination polymers and gate adsorption

Role of particle size in adsorption behavior

Motivation for controlled synthesis using microreactors

Chemical Engineering Journal 313 (2017) 724–733 Contents lists available at ScienceDirect Chemical Engineering Journal journal [homepage: www. elsevier. com/locate/cej](homepage: www. elsevier. com/locate/cej) Synthesis of zeolitic imidazolate framework-8 particles of controlled sizes, shapes, and gate adsorption characteristics using a central collision-type microreactor Satoshi Watanabe ⇑, Shuji Ohsaki, Tatsuya Hanafusa, Kento Takada, Hideki Tanaka, Kazuhiro Mae, Minoru T. Miyahara ⇑ Department of Chemical Engineering, Kyoto University, Katsura, Nishikyo, Kyoto 615-8510, Japan | h i g h l i g h t s 􀀁 ZIF-8 particles are synthesized using a central collision-type microreactor. 􀀁 Excellent mixing performance of the microreactor enables reproducible synthesis. 􀀁 Particle size is determined by the mixing process in the microreactor. 􀀁 Particle shape is controlled by temperature during the aging process after mixing. 􀀁 Gate adsorption properties of ZIF-8 particles depends on the particle size and shape. | g r a p h i c a l a b s t r a c t | | --- | --- | | a r t i c l e i n f o | a b s t r a c t Controlling the particle size and shape of soft metal-organic framework compounds is crucial for understanding and regulating the adsorption-induced structural transitions that lead to the unique stepwise adsorption behavior of these materials. The present study demonstrates that the intensive mixing facilitated by a microreactor enables the synthesis of monodisperse zeolitic imidazolate framework-8 (ZIF-8) particles with high reproducibility. In the ﬂow microreactor process used in this study, the particle size is predominantly determined by the reaction conditions during the initial mixing in the microreactor. On the other hand, the particle shape depends upon the temperature during the subsequent aging process. The technique proposed in this study is additive-free and allows control of both particle size from 50 nm to 2 lm and particle shape from cube to chamfered cube to rhombic dodecahedron, simply by adjusting the concentration of feed solutions and reaction temperature. Furthermore, we demonstrate that both particle size and particle shape are key physical parameters determining the adsorption characteristics of ZIF-8 particles. 􀀁 2016 Elsevier B.V. All rights reserved. | | Article history: Received 28 October 2016 Received in revised form 19 December 2016 Accepted 26 December 2016 Available online 27 December 2016 | | | Keywords: Metal-organic frameworks Gate adsorption Microreactors Crystal growth Nucleation Mixing | | 1. Introduction Porous coordination polymers (PCPs) and metal-organic frameworks (MOFs) are porous crystals formed through the self- ⇑ Corresponding authors. E-mail addresses: [nabe@cheme.kyoto-u.ac.jp](nabe@cheme.kyoto-u.ac.jp) (S. Watanabe), miyahara@cheme. [kyoto-u.ac.jp](kyoto-u.ac.jp) (M.T. Miyahara). assembly of metal ions and organic ligands with coordination bonding among the constituents [1,2]. Some of the important features of PCPs include large surface area, highly regular pore structure, and tunable pore size, which may be achieved by altering the metal ion-organic ligand combinations. In addition to these features, speciﬁc types of PCPs exhibit ﬂexible frameworks, as a result of which structural transitions occur in response to external stimuli. Such PCPs are also referred to as soft porous crystals (SPCs) [http://dx.doi.org/10.1016/j.cej.2016.12.118](http://dx.doi.org/10.1016/j.cej.2016.12.118) [1385-8947/](1385-8947/)􀀁 2016 Elsevier B.V. All rights reserved. S. Watanabe et al. /Chemical Engineering Journal 313 (2017) 724–733 725 [3]. Such SPCs typically exhibit an abrupt increase in the adsorption amount at a threshold pressure due to transition from anon-porous to a porous structure [4–6]. This type of adsorption behavior is referred to as ‘‘gate” adsorption and is analogous to the opening and closing of a gate. Co

FAQs

What role does the central collision-type microreactor play in ZIF-8 synthesis?

The microreactor provides intensive mixing that enables reproducible synthesis of monodisperse ZIF-8 particles.

Which process steps primarily control ZIF-8 particle size and shape?

Particle size is predominantly determined by reaction conditions during the initial mixing, while particle shape depends on the temperature used during the subsequent aging process.

How does particle size and shape affect ZIF-8 gate adsorption properties?

Both particle size and particle shape are identified as key physical parameters that determine the adsorption characteristics of ZIF-8 particles.

Jul 8, 2026

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