Polyethyleneimine Incorporated Metal-Organic Frameworks Adsorbent for Highly Selective CO2 Capture

A series of polyethyleneimine (PEI) incorporated MIL-101 adsorbents with different PEI loadings were reported for the first time in the present work. Although the surface area and pore volume of MIL-101 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 degrees C, and 3.4 mmol g(-1) at 50 degrees C. More importantly, the resulting adsorbents displayed rapid adsorption kinetics and ultrahigh selectivity for CO2 over N-2 in the designed flue gas with 0.15 bar CO2 and 0.75 bar N-2. The CO2 over N-2 selectivity was up to 770 at 25 degrees C, and 1200 at 50 degrees C. We believe that the PEI based metal-organic frameworks is an attractive adsorbent for CO2 capture.