Granulation and Shaping of Metal-Organic Frameworks

Abstract

IntroductionShaping and forming of metal-organic frameworks (MOFs) are essential for practical applications like adsorption/separation and catalysis, which require structuring of the nano-/microcrystalline fine powders of MOFs into a macroscopic body [1][2][3][4][5][6][7]. When a process for catalysis or adsorptive separation is scaled up to the pilot or commercial scale, the form in which an active catalyst or adsorbent is used is decisive in determining the ultimate performance of the unit [8][9][10]. In this respect, the size and shape of the target material require a compromise between minimizing pore diffusion effects in the material particles, for which small particles are necessary, and minimizing the pressure drop across the reactor, which requires large particle sizes [11]. The shaped MOFs should maintain excellent performance shown by the original powder forms based on their high porosity, crystallinity, and flexibility [12]. Therefore, the proper selection of the shaping or forming process is important in the MOF research field for chemical engineering and industrial applications. As the shaping methods are often proprietary and often more of an art than a science, the exact procedures are rarely disclosed.The shaped MOFs can also be prepared using techniques (Figure 18.1) that have typically been utilized for synthesizing catalysts and adsorbents from porous materials, such as pressing, extrusion, granulation and spray drying, foaming, casting, and coating. Well-shaped bodies have been produced in the forms of pellets, tablets, monoliths, granules, and spheres [13][14][15][16]. However, to utilize shaped MOFs successfully for industrial applications, they should have sufficient mechanical strength, chemical stability, attrition resistance, maximal bulk density, and minimal wasted space in the storage vessel [17][18][19][20][21][22][23][24]. As the performance of shaped MOFs for industrial or large-scale applications depends on several parameters, including the mass-and heat-transfer properties, gas diffusion kinetics, pressure drop across material, mechanical strength, and volumetric efficiency, achieving high mechanical integrity of the structured MOF is critical to the performance in real engineering processes. The Chemistry of Metal-Organic Frameworks: Synthesis, Characterization, and Applications, First Edition. Edited by Stefan Kaskel.

CO2 Capture and Separations Using MOFs: Computational and Experimental Studies

“…544 Several shaping methods of MOFs developed in last years, including granulation, spray drying, extrusion, and pressing, have been detailed by Lee et al in a recently published book chapter. 545 Here, we introduce the current development trends of this topic and highlight some recent studies with new shaping methods.…”

Surviving Under Pressure: The Role of Solvent, Crystal Size, and Morphology During Pelletization of Metal–Organic Frameworks

“…Forming the as-synthesized MOF powders into a suitable-shaped body is an essential step toward any MOF application. Extensive research has been performed by multiple research groups in this area. − In these reports, several forming techniques have been examined to generate the optimal form of MOFs for desired applications, including granulation, , extrusion, spray-drying, monolith formation, and pelletization …”

Microporous 3D Graphene-like Zeolite-Templated Carbons for Preferential Adsorption of Ethane

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