Adsorption of Carbon Dioxide and Nitrogen in Co3(ndc)3(dabco) Metal–Organic Framework

Metal-organic frameworks (MOFs) are promising materials for processes such as carbon dioxide (CO₂) capture or its storage. In this work, the adsorption of CO₂ and nitrogen (N₂) in Co₃(ndc)₃(dabco) MOF (ndc: 2,6-naphthalenedicarboxylate; dabco: 1,4-diazabicyclo[2.2.2]octane) is reported for the first time over the temperature range of 273-323 K and up to 35 bar. The adsorption isotherms are successfully described using the Langmuir isotherm model. The heats of adsorption for CO₂ and N₂, determined through the Clausius-Clapeyron equation, are 20-27 kJ/mol and 10-11 kJ/mol, respectively. The impact of using pressure and/or temperature swings on the CO₂ working capacity is evaluated. If a flue gas with 15% CO₂ is fed at 6 bar and 303 K and regenerated at 1 bar and 373 K, 1.58 moles of CO₂ can be captured per kg of MOF. The analysis of the multicomponent adsorption of typical flue gas streams (15% CO₂ balanced with N₂), using the ideal adsorbed solution theory (IAST), shows that at 1 bar and 303 K, the CO₂/N₂ selectivity is 11.5. In summary, this work reports essential data for the design of adsorption-based processes for CO₂ capture using a Co₃(ndc)₃(dabco) MOF, such as pressure swing adsorption (PSA).