Polyamine-Decorated Metal-Organic Framework Adsorbents for CO2 Capture

A series of polyethyleneimine (PEI) based MIL-101(Cr) adsorbents with different PEI loadings were reported in the present work. Although the surface area and pore volume of MIL-101(Cr) decreased significantly after loading PEI, all the resulting composites exhibited dramatically enhanced CO₂ adsorption capacity at low pressures. At 100 wt% PEI loading, the CO₂ adsorption capacity at 0.15 bar reached a very competitive value of 4.2 mmol g^-1 at 25 ^oC, and 3.4 mmol g^-1 at 50 ^oC. More importantly, the resulting adsorbents displayed rapid adsorption kinetics and ultrahigh selectivity for CO₂ over N₂ in the designed flue gas with 0.15 bar CO₂ and 0.75 bar N₂. The CO₂ over N₂ selectivity was up to 770 at 25 ^oC, and 1200 at 50 ^oC. We believe that the PEI based metal-organic frameworks is an attractive adsorbent for CO₂ capture