Targeted capture and pressure/temperature-responsive separation in flexible metal-organic frameworks

Based on an in-house-constructed separation apparatus, controlled and targeted CO2 and CH4 capture, respectively, from binary mixtures (CO2/CH4 or CH4/N-2) has been realized on two flexible MOFs, [Cu(dhbc)(2)(4,4'-bipy)] and [Cu(4,4'-bipy)(2)(BF4)(2)], in the form of a packed bed of particles. These gas mixtures were effectively separated on the flexible MOFs by using a unique two-stage separation technique. Molecular dynamic simulations have been performed to assess the atomistic interactions of small molecules in flexible MOFs that directly influence the dynamic gas separation. Furthermore, the structural stability and the effect of H2O on these gas separations have been investigated, and the results suggest that the flexible MOFs show significantly improved gas separation performances.