A pure amine-functionalized MIL-101(Cr) has been synthesized for the first time by a simple method. The as-prepared nanoparticles are around 50 nm. In addition, the resulting amine-functionalized MIL-101(Cr) displayed excellent CO 2 adsorption capacity, up to 15 mmol g 21 at 16 uC.

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°C, and 3.4 mmol g−1 at 50°C. 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°C, and 1200 at 50°C. We believe that the PEI based metal-organic frameworks is an attractive adsorbent for CO2 capture.

A clear separation: A post-synthetic functionalization method is reported to obtain a highly permselective zeolitic imidazolate framework (ZIF-90) membrane. The intercrystalline defects of the ZIF-90 membrane are minimized to enhance the separation selectivity while a high permeance is maintained.