Ethylenediamine-incorporated MIL-101(Cr)-NH2 metal-organic frameworks for enhanced CO2 adsorption

Ethylenediamine (EA)-incorporated MIL-101(Cr)-NH2 adsorbents were prepared for CO2 adsorption. First, MIL-101(Cr)-NH2 was directly prepared by the solvothermal method, followed by the EA incorporation inside the pores of MIL-101(Cr)-NH2. The prepared samples were characterized by N-2 porosimetry, field-emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectrometry, thermogravimetric, and powder X-ray diffraction analyses. The effects of ethylenediamine loading in MIL-101(Cr)-NH2 on the CO2 adsorption capability were systematically investigated. EA-incorporated MIL-101(Cr)-NH2 showed CO2 adsorption capacity of ca. 3.4 mmol/g, which was similar to 62% higher than the pristine MIL-101(Cr)-NH2. In addition, the amine-grafted MOF samples showed good regenerability and stability after consecutive adsorption-desorption cycles at ambient conditions. These suggest that introduction of alkylamine molecules into the pores of metal-organic frameworks can be a promising strategy to improve the CO2 soprtion ability of MOFs.