Adsorption of Carbon Dioxide, Methane, and Nitrogen on Zn(dcpa) Metal-Organic Framework

Adsorption-based processes using metal-organic frameworks (MOFs) are a promising option for carbon dioxide (CO2) capture from flue gases and biogas upgrading to biomethane. Here, the adsorption of CO2, methane (CH4), nitrogen (N2) on Zn(dcpa) MOF (dcpa (2,6-dichlorophenylacetate)) is reported. The characterization by powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), N2 physisorption at 77 K shows that it stable up 650 K, confirms previous observations suggesting framework flexibility upon exposure guest molecules. equilibrium isotherms pure components (CO2, CH4, N2), measured 273–323 35 bar, Langmuirian, except CO2 273 which exhibits stepwise shape with hysteresis. latter accurately interpreted in terms osmotic thermodynamic theory, further refinement assuming free energy difference between two metastable structures normally distributed variable due existence different crystal sizes defects real sample. ideal selectivities equimolar mixtures CO2/N2 CO2/CH4 1 bar 303 12.8 2.9, respectively, large enough be usable pressure swing adsorption.