Transient breakthroughs of CO2/CH4 and C3H6/C3H8 mixtures in fixed beds packed with Ni-MOF-74

• Highly selective separation of C3H6 over C3H8 and CO2 over CH4 on Ni-MOF-74.
• Simulation methodology for transient breakthroughs in fixed-bed adsorbers.
• Inclusion of intra-crystalline diffusion improves the quality of the simulations.
• Good agreement between breakthrough experiments and simulations.
• Ni-MOF-74 is a promising candidate for C3H6/C3H8 and CO2/CH4 separations.

The metal-organic framework Ni-MOF-74 was synthesized and then characterized by XRD, SEM, and N2 adsorption techniques. The unary isotherms of CO2, CH4, C3H6, and C3H8 on Ni-MOF-74 were measured by means of a volumetric method. The Langmuir–Freundlich model appropriately describes the adsorption equilibrium data. The selective separations of two mixtures CO2/CH4 and C3H6/C3H8 on Ni-MOF-74 were experimentally investigated by a breakthrough-column technique. Simulations of transient breakthroughs for the two mixtures agree well with the experimental data. In addition, with the inclusion of intra-crystalline diffusion into the simulations, the quality of the simulated breakthrough curves are improved and agree better with the experimental data. The results indicate that Ni-MOF-74 might be a candidate for the removal of C3H6 from C3H6/C3H8 mixtures and for the efficient separation of CO2 from CH4.

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