Fabrication of crystalline microporous membrane from 2D MOF nanosheets for gas separation.

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 Ni-3(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 Ni-3(HITP)(2) nanosheets as building blocks via a soft-physical exfoliation method successfully that were confirmed by AFM and TEM. We also studied the H-2, CO2 and N-2 adsorption isotherms of Ni-3(HITP)(2) powder at room temperature, which shows Ni-3(HITP)(2) has high heats of adsorption for CO2 and high selectivity of CO2 over N-2. Gas permeation tests indicate that the Ni-3(HITP)(2) membrane shows high permeance and selectivity of CO2 over N-2, as well as good selectivity of H-2 over N-2. The ideal separation factors of CO2/N-2 and H-2/N-2 from sing-gas permeances are 13.6 and 7.8 respectively, with CO2 permeance of 3.15x10(-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.