Selective CO 2 Capture from Flue Gas Using Metal–Organic Frameworks―A Fixed Bed Study

It is important to capture carbon dioxide from flue gas, which is considered one of to be the main cause of global warming. CO 2 /N 2 separation by novel adsorbents is a promising method for reducing CO 2 emission. Meanwhile, water effects on CO 2 adsorption and CO 2 /N 2 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 CO 2 /N 2 breakthrough study with and without H 2 O. The Ni/DOBDC pellet has a high CO 2 capacity of 3.74 mol/kg at 0.15 bar and a high CO 2 /N 2 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 CO 2 adsorption capacity as well as CO 2 /N 2 selectivity for the Ni/DOBDC. However, Ni/DOBDC can retain a significant CO 2 capacity of 2.2 mol/kg and a CO 2 /N 2 selectivity of 22 at 0.15 bar CO 2 with 3% RH water. These results indicate a promising future for use of the Ni/DOBDC in capturing CO 2 from flue gas.