Ultramicroporous metal-organic framework for efficient carbon dioxide capture from flue gas and natural gas

Carbon dioxide capture from flue gas (CO2/N2) and natural gas (CO2/CH4) is a challenging and cost-effective task. In this paper, ultramicroporous metal-organic frameworks (MOFs) (Co-norf and Ni-norf) are synthesized to realize the efficient separation of CO2/N2 and CO2/CH4 by metal ion regulation. The Ideal Adsorption Solution Theory (IAST) was calculated to evaluate the adsorption selectivity of activated Co-norf and Ni-norf for CO2/N2 (v/v = 15/85) mixtures and CO2/CH4 mixtures. The CO2/N2 selectivity of Co-norf and Ni-norf at 100 kPa was 734 and 96, respectively, which corresponds to an almost 7.6-fold increase by metal ion modulation. The specific binding sites of CO2 molecules within the pore channels were obtained by grand canonical Monte Carlo simulation (GCMC). Dynamic breakthrough experiments respond to the actual separation in systems simulating flue gas and natural gas, where the higher saturation adsorption and longer retention time proved that Co-norf is an ideal material for CO2 capture and separation. The present work provides a feasible approach for the application of MOF in gas separation.