Acta Physico-Chimica Sinica ›› 2020, Vol. 36 ›› Issue (1): 1901079.doi: 10.3866/PKU.WHXB201901079

Special Issue: Special Issue in Honor of Academician Youqi Tang on the Occasion of His 100th Birthday

• Article • Previous Articles     Next Articles

Fabrication of Polymer-Supported Metal Organic Framework Membrane and Its Gas Separation Performance

Jingru Fu1,Teng Ben1,Shilun Qiu2,*()   

  1. 1 College of Chemistry, Jilin University, Changchun 130012, P. R. China
    2 State Key Laboratory of Inorganic Synthesis and Preparation Chemistry, Jilin University, Changchun 130012, P. R. China
  • Received:2019-01-29 Accepted:2019-02-26 Published:2019-03-06
  • Contact: Shilun Qiu E-mail:sqiu@jlu.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(21390394);the National Natural Science Foundation of China(21471065);the National Natural Science Foundation of China(21871103);the Science and Technology Department of Jilin Province Foundation, China(20180414009GH)

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Abstract:

The fabrication of compact, continuous, and large-scale metal organic framework (MOF) membranes with high permeability and H2/CO2 selectivity remains challenging because of the wake interaction between the MOF membrane and the substrate. In addition, substrates with smooth and plain surfaces and suitable pore size are required to prepare high-quality MOF membranes because it is difficult to obtain dense and continuous MOF membranes on a substrate with large pores and rough surfaces. To overcome these challenges, numerous MOF membrane growth methods have emerged, including in situ (direct) growth, secondary (seeded) growth, and layer-by-layer growth methods as well as electrostatic spinning and the chemical modification of the substrate. Among these methods, usage of substrates suitable for surface-functionalization is a promising technique. Herein, Al2O3 was selected as the substrate and was coated with PIM-1 (one polymer of intrinsic microporosity), followed by carboxylation of PIM-1 to furnish a large number of carboxyl groups on the surface. In situ growth of the MOF membrane using the interactions between the carboxyl group and the metal yielded two types of compact, continuous, and large-scale polymer-supported MOF membranes (PIM-1-COOH/ZIF-8 and PIM-1-COOH/HKUST-1). Furthermore, the fabricated polymer-supported MOF membrane structures were investigated by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). Gas separation experiments were performed to explore the gas permeability and selectivity of the prepared MOF membranes. The XRD characterization confirmed the pure phase and high crystallinity of the MOF membranes. The SEM images showed that the MOF membranes were compact and continuous with a tight combination between the MOF crystal membrane and the substrate. Gas separation measurements showed that both MOF membranes exhibited high H2 permeability and selectivity for H2/CO2. For the PIM-1-COOH/ZIF-8 and PIM-1-COOH/HKUST-1 membranes, the 1 : 1 binary mixtures gas separation factors of H2/CO2 calculated as the gas molar ratios in the permeate and retentate side 7.32 and 9.69, respectively, at room temperature and atmospheric pressure. The H2/CO2 mixture separation factors of the two MOF membranes exceeded the corresponding Knudsen constants (4.7), with H2 permeances higher than 3.16 × 10-6 and 1.14 × 10-6 mol·m-2·s-1·Pa-1, respectively. The ideal separation factors of H2/CO2 of both MOF membranes calculated as the ratio of single gas permeances were 7.70 and 12.04, respectively, with the respective H2 permeances of up to 3.73 × 10-6 and 3.86 × 10-6 mol·m-2·s-1·Pa-1. Because of their outstanding characteristics, these novel MOF membranes can be widely used in the fields of H2 purification and separation.

Key words: Membrane, Polymer, Metal organic frameworks, Gas separation, Hydrogen purity