MIL-160(Al) as a Candidate for Biogas Upgrading and CO₂ Capture by Adsorption Processes

The microporous bioderived Al dicarboxylate MIL-160(Al) MOF in its shaped form has been evaluated as a candidate for biogas upgrading (BU) and/or carbon capture and storage (CCS) by studying adsorption isotherms of CO₂, CH₄, and N₂ at 313, 343, and 373 K until 8 bar. The isotherms disclosed the following loading capacities: 4.2 (CO₂), 2.07 (CH₄), and 0.69 (N₂) mol/kg at 5.8 bar and 313 K, which fitted with the dual-site Langmuir model. The linear-driving-force coefficients (LDFs) for CO₂ and CH₄ calculated from uptake rate experiments are in the order of 0.021–0.096 and 0.041–0.165 s^–1 at 313 K between 0.11 and 2.76 bar, respectively. The Response Surface Methodology (RSM) was also applied to maximize the selectivity for mixtures CO₂/CH₄ and CO₂/N₂ with interest for BU or CCS. Breakthrough curve experiments with mixtures CO₂/CH₄ and CO₂/N₂ at the optimum selectivity conditions were developed and simulated using ASPEN Adsorption. This work clearly demonstrates the potential of MIL-160(Al) to be used in BU- and/or CCS-related applications.