Investigating the Effect of Alumina Shaping on the Sorption Properties of Promising Metal-Organic Frameworks

Three promising MOF candidates, UiO-66(Zr), MIL-100(Fe) and MIL-127(Fe) are shaped through granulation with a rho-alumina binder. Subsequently, changes in the surface characteristics and adsorption performance are evaluated through adsorption microcalorimetry at 303 K with several common probes (N<sub>2</sub>, CO<sub>2</sub>, CO, CH<sub>4</sub>, C<sub>2</sub>H<sub>6</sub>, C<sub>3</sub>H<sub>8</sub>, C<sub>3</sub>H<sub>6</sub> and C<sub>4</sub>H<sub>10</sub>), generating a detailed picture of adsorbate-adsorbent interactions. Vapour adsorption experiments with water and methanol were further used to gauge changes in hydrophobicity caused by the addition of the alumina binder. Upon shaping, a decrease in gravimetric capacity and specific surface area is observed, accompanied by an increased capacity on a volumetric basis, attributed to densification induced by the shaping process, as well as a surprising lack of pore environment changes. However, the magnitude of these effects depends on the MOF, suggesting a high dependence on material structure. Out of the three materials, MIL-127(Fe) shows the least changes in adsorption performance and is highlighted as a promising candidate for further study.