Core–shell adsorbents by electrospun MOF-polymer composites with improved adsorption properties: Theory and experiments

Mitchell R. Armstrong, Bohan Shan, Joseph Winarta, Bin Mu

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


A new class of core–shell adsorbents has been created by electrospun metal–organic framework (MOF) particles embedded in polymer nanofibers, which have provided many unique properties compared to the existing MOF coating technologies. For the first time, we demonstrate the improved adsorption selectivity of CO2 over N2 using electrospun polymer/ZIF-8 adsorbents in experiments. Furthermore, an analytical model based on the assumption that the diffusivity in core is 10 times higher than that in shell is developed to describe the theory of improved selectivity for core–shell adsorbents that is validated against a more accurate finite element model developed in COMSOL. Our model shows three regimes including exclusive shell uptake, linear core uptake, and asymptotic core uptake. These regimes are related to material properties and uptake times, which could be used as design criteria to balance core stability, maximum selectivity, and maximum uptake. An advanced HAADF STEM tomography (Movie S1) shows that the shell thickness in the case of polymer/ZIF-8 is on the order of 10 nm, allowing the regime of maximum selectivity to be realized. Kinetically limited adsorption tests at 45°C demonstrate that these composite fibers can perform in a regime of selectivity and uptake for the separation of CO2 and N2 that is unobtainable by either the MOF or fiber independently, showing a great potential for postcombustion CO2 capture.

Original languageEnglish (US)
Article numbere16816
JournalAIChE Journal
Issue number2
StatePublished - Feb 1 2020


  • adsorption/gas
  • composite adsorbent
  • core–shell structure
  • electrospun nanofiber nanoparticle composites
  • metal–organic frameworks

ASJC Scopus subject areas

  • Biotechnology
  • Environmental Engineering
  • General Chemical Engineering


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