Acta Chimica Sinica ›› 2020, Vol. 78 ›› Issue (8): 805-814.DOI: 10.6023/A20040128 Previous Articles    



付静茹, 贲腾   

  1. 吉林大学化学学院 长春 130012
  • 投稿日期:2020-04-28 发布日期:2020-06-11
  • 通讯作者: 贲腾
  • 基金资助:

Fabrication of a Novel Covalent Organic Framework Membrane and Its Gas Separation Performance

Fu Jingru, Ben Teng   

  1. College of Chemistry, Jilin University, Changchun 130012
  • Received:2020-04-28 Published:2020-06-11
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Nos. 91956108, 21871103), "111" Project (No. BP0719036) and the Science and Technology Department of Jilin Province Foundation (No. 20180414009GH).

Herein, we employ 2,5-dimethoxyterephthalaldehyde (DMTA) containing ether oxygen group in the structure as the construction unit to react with tetra-(4-anilyl)-methane (TAM) through Schiff-based condensation reaction in a Teflon-lined autoclave to synthesize a novel three-dimensional covalent organic framework named DMTA-COF. Furthermore, the condensation reaction was confirmed by Fourier transform infrared spectroscopy (FT-IR). The crystal structure of DMTA-COF was analyzed by the powder X-ray diffraction (PXRD) measurement in conjunction with structural simulation. The morphology, thermal stability, porosity and pore distribution of DMTA-COF were measured by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and N2 adsorption-desorption at 77 K. The high affinity for CO2 adsorption was also confirmed by low pressure CO2 sorption. Considering the relatively small pore size and the strong CO2 adsorption interaction of DMTA-COF due to an abundant of ether oxygen group and imine linkage, we synthesized one continuous supported DMTA-COF membrane for H2/CO2 separation. In our study, the porous Al2O3 support surface was first coated with polyaniline (PANI) and was then further functionalized with aldehyde groups by reaction with DMTA at 150 ℃ for 1 h. Finally, in situ growth of the COF membrane utilizing the covalent linkage yielded a novel continuous DMTA-COF membrane. X-ray diffraction (XRD) result indicated that the DMTA-COF membrane was pure phase and had high crystallinity. From SEM characterization, we could see that the DMTA-COF membrane was compact and well intergrowth and adhered to the support tightly. Gas separation performance results shown that DMTA-COF membrane had a high H2 permeance and selectivity of H2/CO2. For DMTA-COF membrane, the 1∶1 binary mixture gas separation factors of H2/CO2 calculated as the gas molar ratios in permeate and retentate side was 8.3 at room temperature and atmospheric pressure. And H2/CO2 separation factor of DMTA-COF membrane exceeded the corresponding Knudsen coefficient (4.7), with H2 permeance of up to 6.3×10-7 mol·m-2·s-1·Pa-1. Because of its outstanding characteristics, the novel DMTA-COF membrane is expected to be widely used in the field of H2 purification and separation.

Key words: covalent organic framework, crystal structure, membranes, gas separation, H2 purification