Separation of CO₂ Mixtures Using Zn(bdc)(ted)_0.5 Membranes and Composites: A Molecular Simulation Study

We used grand canonical Monte Carlo and equilibrium molecular dynamics simulations to compute adsorption isotherms and self-diffusivities of CH 4 /H 2 mixtures in a nanoporous metal organic framework Zn(bdc)(ted) 0.5 in our recent study ( J. Phys. Chem. C 2010, 114, 13047). In this work, we extended our calculations to CO 2 /CH 4 and CO 2 /H 2 mixtures by computing adsorption selectivity, diffusion selectivity, and permeation selectivity of Zn(bdc)(ted) 0.5 for these gas mixtures. Performance of several composite membranes including Zn(bdc)(ted) 0.5 as filler particles in polymer matrices was also examined for separation of CO 2 from CH 4 and H 2 using a combination of atomistic and continuum modeling. Results showed that adding even a small volume fraction of Zn(bdc)(ted) 0.5 into polymers can significantly enhance the gas permeability and carry the polymer/Zn(bdc)(ted) 0.5 composite membranes above the current upper bound established for pure polymer membranes.