Selective CO₂ Capture from Flue Gas Using Metal–Organic Frameworks―A Fixed Bed Study

Abstract

It is important to capture carbon dioxide from flue gas, which is considered one of to be the main cause of global warming. CO₂/N₂ separation by novel adsorbents is a promising method for reducing CO₂ emission. Meanwhile, water effects on CO₂ adsorption and CO₂/N₂ selectivity is critical to enable utilization of the adsorbents in practical applications. In this paper, Ni/DOBDC (Ni-MOF-74 or CPO-27-Ni) was synthesized through a solvothermal reaction, and the pellet sample was used in a fixed-bed CO₂/N₂ breakthrough study with and without H₂O. The Ni/DOBDC pellet has a high CO₂ capacity of 3.74 mol/kg at 0.15 bar and a high CO₂/N₂ selectivity of 38, which is much higher than those of reported metal–organic frameworks and zeolites under dry conditions. Trace amounts of water can affect CO₂ adsorption capacity as well as CO₂/N₂ selectivity for the Ni/DOBDC. However, Ni/DOBDC can retain a significant CO₂ capacity of 2.2 mol/kg and a CO₂/N₂ selectivity of 22 at 0.15 bar CO₂ with 3% RH water. These results indicate a promising future for use of the Ni/DOBDC in capturing CO₂ from flue gas