Synthesis of tungsten-doped MFI zeolite membranes with improved performance for CO2/N2 separation

Li Peng, Li Zhao, Guang Pan, Xuehong Gu

Research output: Contribution to journalArticlepeer-review

Abstract

The separation of CO2 from N2 using MFI-type zeolite membranes relies on a mechanism dominated by adsorption and diffusion processes. In this investigation, we employed a tungsten (W) doping approach to elevate the CO2 separation selectivity of MFI zeolite membranes. Isothermal adsorption assessments demonstrated an elevated heat of adsorption (Qst) for CO2 and a reduced pore sizes after W doping, corroborating the enhanced CO2/N2 separation efficiency observed. Specifically, the W-doped MFI membrane exhibited a selectivity of 38.8 under dry conditions, a substantial improvement over the 8.7 selectivity achieved by the undoped Si-MFI membrane, while the CO2 permeance remained comparable (3.9 × 10−7 vs 4.5 × 10−7 mol m−2 s−1·Pa−1). Furthermore, the incorporation of tungsten curtails the formation of silanol groups by stabilizing the zeolite framework via energetically favorable W–O–Si linkages. These linkages diminish silanol-related defects, typically prone to water adsorption, thereby enhancing the membrane's hydrophobicity. Consequently, the W-doped MFI membrane maintains a CO2/N2 selectivity of 29.5 and a CO2 permeance of 1.8 × 10−7 mol m−2 s−1·Pa−1 in the humid environments, outperforming most reported zeolite membranes and showing potential ability for practical post-combustion carbon capture applications.

Original languageEnglish
Article number124185
JournalJournal of Membrane Science
Volume729
DOIs
StatePublished - Jun 2025

Keywords

  • CO capture
  • CO/N separation
  • Humid condition
  • MFI zeolite membrane
  • Tungsten doping

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