A zeolitic imidazolate framework with uncoordinated cyano groups in mixed matrix membranes for efficient propylene/propane separation

Guangli Yu, Ziyang Wang, Junchao Dong, Fei Ni, Dandan Song, Terence Xiaoteng Liu*, Zhanhui Yuan, Kangjun Wang*, Xiaoqin Zou*

*Corresponding author for this work

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Abstract

Membrane technology is poised to substantially lower the energy consumption involved in the separation of C3H6 from C3H8. However, the quest for suitable membrane materials for this critical process remains an ongoing challenge. Herein, a novel metal–organic framework (MOF) having cyano groups, thus referring to CN-ZIF-8, has been successfully identified and developed as productive nanofillers into 6FDA-DAM polymer. Unlike ZIF-8, CN-ZIF-8 exhibits a stronger affinity for C3H6 and demonstrates favorable thermodynamic selectivity for recognizing it from C3H8 due to the presence of dangling cyano groups, as confirmed by gas sorption. The optimal membrane with a 15 wt% CN-ZIF-8 loading evinces improved separation performance in terms of ≥80 % increase in ideal selectivity (∼23.6) and 144 % in C3H6 permeability (∼379.8 Barrer) compared to the pristine 6FDA-DAM membrane. Mixed gas separation of a 50C3H6:50C3H8 delivers remarkable separation results, out-performing the current trade-off limits associated with conventional polymer membranes. The synergistic effects of high gas solubility and the unique diffusivity behavior of CN-ZIF-8 effectively discriminate C3H6 from C3H8. This study offers valuable insights into the exploration and the design of MOFs intended for the industrial C3H6/C3H8 separation.
Original languageEnglish
Article number159352
Number of pages10
JournalChemical Engineering Journal
Volume505
Early online date6 Jan 2025
DOIs
Publication statusPublished - 1 Feb 2025

Keywords

  • C H /C H separation
  • CN-ZIF-8
  • Metal organic frameworks
  • Separation membranes
  • Thermodynamic selectivity

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