Dynamic sorption properties of Metal-Organic Frameworks for the capture of methyl iodide

In this work, methyl iodide (CH3I) sorption properties of Metal-Organic Frameworks (MOFs) were experimentally studied. CH3I adsorption capacities were determined at 35 degrees C for the different prototypical selected MOFs, MIL-53(Al), MIL-100(Al), MIL-120(Al), CAU-1(Al), UiO-66(Zr), HKUST-1(Cu) and ZIF-8(Zn) from fixed-bed reactor measurements by using infrared spectroscopy. Quantitative exploitation of breakthrough curves reveals higher sorption performances (Q(sat) up to 425 mg/g) for materials showing pore size and geometry well-adjusted to CH3I dimension, such as MIL-120(Al), MIL-53(Al) and HKUST-1(Cu). In situ DRIFTS (Diffuse Reflection Infrared Fourier Transform Spectroscopy) experiments were also carried out in order to further investigate the interaction modes of physisorbed CH3I species within MIL-53 and MIL-120 compounds. For MIL-120, the confinement of adsorbed mg molecules within the pores is strengthened by specific interactions with the ligand and hydroxyl groups. For a breathing compound like MIL-53(Al), the adsorption measurement confirmed a swelling related to CH3I adsorption.