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(2)) nanocrystals for selective capture and further removal of CO(2) from flue gas and natural gas. In particular, UiO-66-NH(2) nanocrystals have a smaller grain size, a large amount of defects, and pending –NH(2) groups inside their pores which display effective CO(2) selective adsorption abilities over CH(4) and N(2) 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(2), N(2) and CH(4) molecules in the gas mixture. The significantly large adsorption energy of CO(2) (0.32 eV) over N(2) (0.19 eV) and N(2) (0.2 eV) may help us to reveal the selective adsorption mechanism.