(114d) Granulation of Soft Porous Crystal Particles
In the present study, we focused on Zeolitic Imidazolate Framework-8 (ZIF-8) which is classified as an SPC. ZIF-8 consists of zinc ions and 2-methylimidazolate linkers, and exhibits intra-framework flexibility which stems from a rotation of linkers. We employed a high shear mixing granulator to establish the granulation process of ZIF-8 particles (650 nm) with water and hydroxypropyl cellulose (HPC) as a binder. As a result, we successfully obtained the granules of ZIF-8 with the size of ca. 200 µm under the condition of 5 wt% of HPC and 42 wt% of water. BET surface areas calculated from N2 adsorption isotherms at 77 K were 1696 and 1540 m2/g for ZIF-8 particles and the granules, respectively. Also, the reposed angle and compressibility decreased from 50.2° to 37.8° and from 42% to 7 %. These results suggest that we obtained the granules with a less loss of the adsorption capacity and improvement of the fluidity. We also investigated the effect of the concentration of HPC and the size of ZIF-8 particles on the granulation process, and the control of the granule size and the granule size dependence of the gate adsorption will be discussed.
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