A microporous Al trimesate-based Metal Organic Framework (MOF), denoted MIL-96(Al), was selected as a porous hybrid filler for the processing of Mixed Matrix Membranes (MMMs) for CO 2 /N 2 post combustion separation. First, the structural model of MIL-96(Al) initially reported was revisited using a combination of synchrotron-based single crystal X-ray diffraction (XRD), solid state Nuclear Magnetic Resonance (NMR) spectroscopy and Density Functional Theory (DFT) calculations. In a second step, pure MIL-96 (Al) crystals differing by their size and aspect ratio, including anisotropic hexagonal platelets and nanoparticles of about 70 nm in diameter, were prepared. Then, a combination of in situ IR spectroscopy, single gas and CO 2 /N 2 co-adsorption experiments, calorimetry and molecular simulations revealed that MIL-96(Al) nanoparticles show a relatively high CO 2 affinity over N 2 owing to strong interactions between CO 2 molecules and several adsorption sites such as Al 3+ Lewis centers, coordinated water and hydroxyl groups. Finally, the high compatibility between MIL-96(Al) nanoparticles and the 6FDA-DAM polymer allowed the processing of homogeneous and defect-free MMMs with a high MOF loading (up to 25 wt%) that outperform pure polymer membranes for CO 2 /N 2 separation.

MIL-91(Ti) is shown to be one of the very few MOFs of real interest for CO2 capture.

No abstract

One of the most promising technologies, with a low energy penalty, for CO2 capture from diverse gas mixtures is based on the adsorption process using adsorbents. Many efforts are still currently deployed to search for water stable porous metal–organic frameworks (MOFs) with high CO2 affinity combined with large CO2 uptake. In this context, we have selected the water stable and easily scalable Al-based MOF MIL-160 showing an ultramicroporosity and potential interacting sites (hydroxyl and furan), both features being a priori relevant to favor the selective adsorption of CO2 over other gases including H2, N2, CH4, and CO. Density functional theory (DFT) and force-field-based grand-canonical Monte Carlo (GCMC) simulations were first coupled to predict the strength of host/guest interactions and the adsorption isotherms for all guests as single components and binary mixtures. This computational approach reveals the promises of this solid for the selective adsorption of CO2 with respect to these other investigated gases, controlled by a combination of thermodynamics and confinement effects. These predicted performances were further supported by real-coadsorption measurements performed on shaped samples which indicated that MIL-160­(Al) shows promising performance for the selective CO2 capture in post- and pre-combustion conditions.