title: Comparison of the behavior of metal-organic frameworks and zeolites for hydrocarbon separations.
abstract: The objective of this work was to study the adsorption and separation of the most important families of hydrocarbon compounds on metal-organic frameworks (MOFs), in comparison with zeolites. For this purpose, we have selected four probe molecules, each of them representing one of these families, i.e., o- and p-xylene as aromatics, 1-octene as an alkene, and n-octane as an alkane. The separation of these four molecules was studied by binary breakthrough experiments. To represent the large diversity of MOF structures, the experiments were carried out with (i) two MOFs with coordinatively unsaturated metal sites (CUS), i.e., Cu-btc (HKUST-1) and CPO-27-Ni, (ii) a MOF with an anionic framework and extraframework cations, i.e. RHO-ZMOF, and (iii) two rather apolar zeolitic imidazolate framework (ZIF) materials with different pore sizes, i.e. ZIF-8 and ZIF-76. Zeolite NaY and zeolite β were used as polar and apolar reference adsorbents, respectively. The results can be briefly summarized as follows: ZIFs (not carrying any polar functional groups) behave like apolar adsorbents and exhibit very interesting and unexpected molecular sieving properties. CUS-MOFs behave like polar adsorbents but show the specificity of preferring alkenes over aromatics. This feature is rationalized thanks to DFT+D calculations. MOFs with extraframework cations behave like polar (cationic) zeolites.
authors.affiliation: Equipe Matériaux à Porosité Controlée (MPC), Institut de Science des Matériaux de Mulhouse (IS2M), LRC CNRS-UHA 7228, ENSCMu, 3 rue Alfred Werner, 68093 Mulhouse Cedex, France.
authors.forename: David
authors.initials: D
authors.lastname: Peralta
authors.forename: Gérald
authors.initials: G
authors.lastname: Chaplais
authors.forename: Angélique
authors.initials: A
authors.lastname: Simon-Masseron
authors.forename: Karin
authors.initials: K
authors.lastname: Barthelet
authors.forename: Céline
authors.initials: C
authors.lastname: Chizallet
authors.forename: Anne-Agathe
authors.initials: AA
authors.lastname: Quoineaud
authors.forename: Gerhard D
authors.initials: GD
authors.lastname: Pirngruber