Fabrication of Crystalline Microporous Membrane from 2D MOF Nanosheets for Gas Separation.

Abstract

Metal-organic frameworks (MOFs)-based membranes have shown great potentials as applications in gas separation. In this work, a uniform membrane based on 2D MOF Ni3 (HITP)2 (HITP=2,3,6,7,10,11-hexaaminotriphenylene) was fabricated on ordered macroporous AAO via the filtration method. To fabricate the membrane, we obtained the Ni3 (HITP)2 nanosheets as building blocks via a soft-physical exfoliation method successfully that were confirmed by AFM and TEM. We also studied the H2 , CO2 and N2 adsorption isotherms of Ni3 (HITP)2 powder at room temperature, which shows Ni3 (HITP)2 has high heats of adsorption for CO2 and high selectivity of CO2 over N2 . Gas permeation tests indicate that the Ni3 (HITP)2 membrane shows high permeance and selectivity of CO2 over N2 , as well as good selectivity of H2 over N2 . The ideal separation factors of CO2 /N2 and H2 /N2 from sing-gas permeances are 13.6 and 7.8 respectively, with CO2 permeance of 3.15×10-6 mol⋅m-2 ⋅s-1 ⋅Pa-1 . The membrane also showed good stability, durability and reproducibility, which are of potential interest for practical applications in the CO2 separations.