A Water-Stable Twofold Interpenetrating Microporous MOF for Selective CO2 Adsorption and Separation

Self-assembly of bent dicarboxylate linker 4,4'-sulfonyldibenzoic acid (H2SDB) and flexible N,N-donor spacer 1,4-bis(4-pytidyI)-2,3-diaza-1,3-butadiene (L) with Co(NO3)(2)center dot 6H(2)O forms a twofold interpenetrated {[Co-2(SDB)(2)(L)]center dot(H2O)(4)center dot(DMF)}(n) (IITKGP-6) network via solvothermal synthesis with sql(2,6L1) topology, which is characterized by Fourier transform infrared spectroscopy, thermogravirnetric analysis, elemental analysis, powder X-ray diffraction (XRD), and single-crystal XRD. The framework is microporous with a solvent-accessible volume of 25.5% and forms a one-dimensional channel along [1-1 0] direction with the dimensions of similar to 3.4 X 5.0 angstrom(2). As the stability of metal-organic frameworks (MOFs) in the presence of water is a topic of significant importance while considering them for practical applications, this framework reveals its high stability toward water. The desolvated framework shows modest uptake of CO2 (50.6 and 37.4 cm(3) g(-1) at 273 and 295 K under 1 bar pressure, respectively), with high selectivity over N-2 and CH4. Ideal adsorbed solution theory calculations show that the selectivity values of CO2/N-2 (15:85) are 51.3 at 273 K and 42.8 at 295 K, whereas CO2/CH4 (50:50) selectivity values are 36 at 273 K and 5.1 at 295 K under 100 kPa. The high CO2 separation selectivity over N-2 and CH4 along with its water stability makes this MOP a potential candidate for CO2 separation from flue gas mixture and landfill gas mixture as well.