Understanding the Effects of Binders in Gas Sorption and Acidity of Aluminium Fumarate Extrudates.

Miguel Rivera‐Torrente,Nikolaos Nikolopoulos,Danny Kroon,Dirk De Vos,Gareth T. Whiting,Rifan Hardian,Bert M. Weckhuysen,Marie‐Vanessa Coulet,Carlos Marquez,Sandrine Bourrelly

doi:10.1002/chem.202103420

Miguel Rivera‐Torrente, Nikolaos Nikolopoulos + Show 8 more

Open Access

https://doi.org/10.1002/chem.202103420

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Abstract

Understanding the impact of shaping processes on solid adsorbents is critical for the implementation of MOFs in industrial separation processes or as catalytic materials. Production of MOF‐containing shaped particles is typically associated with loss of porosity and modification of acid sites, two phenomena that affect their performance. Herein, we report a detailed study on how extrusion affects the crystallinity, porosity, and acidity of the aluminium fumarate MOF with clays or SiO2 gel binders. Thorough characterization showed that the clay binders confer the extrudates a good mechanical robustness at the expense of porosity, while silica gel shows an opposite trend. The CO2 selectivity towards CH4, of interest for natural gas separation processes, is maintained upon the extrusion process. Moreover, probe FTIR spectroscopy revealed no major changes in the types of acid sites. This study highlights that these abundant and inexpensive clay materials may be used for scaling MOFs as active adsorbents.

Highlights

Metal-Organic Frameworks (MOFs) are a class of porous coordination polymers that have been intensely investigated for their applications in a broad range of fields, such as catalysis, chemical sensing, drug delivery or gas sorption and separation.[1,2] their potential has been proven in many proof-of-concept studies, the majority of them were performed with powdered samples, hampering their direct implementation as functional materials at the industrial scale
It is worth mentioning that we focused on mesopores in this work, so the use of non-local density functional theory (NLDFT) for calculating the micropore size distribution was not considered
It has been shown that millimeter-sized bodies containing up to 50 wt% of aluminum fumarate MOF adsorbent can be prepared by extrusion technique and that clay or SiO2 gel can be used as binders

Summary

Introduction

Metal-Organic Frameworks (MOFs) are a class of porous coordination polymers that have been intensely investigated for their applications in a broad range of fields, such as catalysis, chemical sensing, drug delivery or gas sorption and separation.[1,2] their potential has been proven in many proof-of-concept studies, the majority of them were performed with powdered samples, hampering their direct implementation as functional materials at the industrial scale. This suggests that the fraction of available pores in the mesopore size range is dominated by the mesopores formed between the binder (Table 1) and the MOF, and those of the MOF component of the extrudate as no mesopores are present in the montmorillonite and bentonite clays.

Results

Conclusion