(159a) Prediction of CO2 Separation in Functional Porous Aromatic Frameworks From Molecular Simulation

Recently, a new class of porous material, porous aromatic frameworks (PAFs) was synthesized with the highest surface area to date. One such PAF (PAF-1) has diamond-like structures with biphenyl building blocks and exhibits exceptional thermal and hydrothermal stabilities outperforming porous MOFs. In this study, PAFs were investigated as a model functional porous-carbon system for gas separation using grand-canonical Monte Carlo (GCMC) simulation. Simulated adsorption isotherms of H2 and CO2 in PAF-1 match well with the experimental data. Then new PAFs were designed by adding various functional groups on the biphenyl building blocks and investigated for CO2/CH4 and CO2/N2 mixture separation. At ambient condition, these functional PAFs show exceptionally high selectivities for CO2/CH4 and CO2/N2 mixture. The charges of the framework have a significant effect on the selectivity, which is found to decrease by an order of magnitude when the electrostatic interactions are switched off. These selectivities are much larger than those reported in neutral metal?organic frameworks (MOFs) and covalent-organic frameworks (COFs).