Selective Adsorption-Based Separation of Flue Gas and Natural Gas in Zirconium Metal-Organic Frameworks Nanocrystals.

Carbon capture from flue gas and natural gas offers a green path to construct a net-zero emissions economic system. Selective adsorption-based gas separation by employing metal-organic frameworks (MOFs) is regarded as a promising technology due to the advantages of simple processing, easy regeneration and high efficiency. We synthesized two Zirconium MOFs (UiO-66 and UiO-66-NH) nanocrystals for selective capture and further removal of CO from flue gas and natural gas. In particular, UiO-66-NH nanocrystals have a smaller grain size, a large amount of defects, and pending -NH groups inside their pores which display effective CO selective adsorption abilities over CH and N with the theoretical separation factors of 20 and 7. This breakthrough experiment further verified the selective adsorption-based separation process of natural gas and flue gas. In one further step, we used the Monte Carlo simulation to investigate the optimized adsorption sites and energy of CO, N and CH molecules in the gas mixture. The significantly large adsorption energy of CO (0.32 eV) over N (0.19 eV) and N (0.2 eV) may help us to reveal the selective adsorption mechanism.