To improve the economic benefits of CO2 capture in flue gas
a novel N2 selective zeolitic imidazolate framework-8 (ZIF-8) composite membrane has been designed in this work. The zinc ion (Zn2+) was tightly adhered to the polysulfone support by chelating crosslinked chitosan matrix. The ZIF-8 seeding layer was prepared by zinc ion coordinated with 2-methylimidazole (Hmim)
and then the dense ZIF-8 composite membrane was prepared by the secondary growth method. The morphological structure of ZIF-8 composite membrane was characterized by FTIR
XRD and SEM. And the results showed that the dense ZIF-8 composite membrane has been prepared. The effects of the time of secondary growth
the concentration of Zn2+ solution
the continuous test time and feed gas pressure on gas separation performance of ZIF-8 composite membrane were systematically investigated by pure gas
and the gas transport mechanism was analyzed. In addition
the separation performance of membranes was investigated by CO2/N2 mixed gas. At testing temperature of 25℃ and feed gas pressure of 0.1 MPa
N2 permeance and N2/CO2 selectivity were 523 GPU and 19 for pure gas
respectively. While N2 permeance and N2/CO2 selectivity were 517 GPU and 18 for mixed gas under the same condition
respectively. The results showed that the ZIF-8 composite membrane could preferentially permeate N2 in the flue gas. The ZIF-8 composite membrane contained many CO2 active adsorption sites
so that CO2 was adsorbed in the membrane and was not easily desorbed from the downstream side of the membrane
and N2 could preferentially permeate
which provided a new idea for the preparation of N2 selective membrane.