Enhancing effect of UV activation of graphene oxide on carbon capture performance of metal-organic framework / graphene oxide hybrid adsorbents

Anish Mathai Varghese, K. Suresh Kumar Reddy, Nidhika Bhoria, Swati Singh, Jeewan Pokhrel, Georgios N. Karanikolos

Research output: Contribution to journalArticlepeer-review

35 Scopus citations

Abstract

Ability to capture carbon dioxide from diverse sources and conditions is vital in mitigating the impact of continuously increasing CO2 levels into the atmosphere. Here, we developed a novel adsorbent based on Cu-BTC metal–organic framework (HKUST-1) and UV-irradiated graphene oxide (UV-GO) by in-situ growth, and assessed its CO2 capture performance. The effect of the pre-growth UV activation of the GO counterpart on the chemical characteristics, microstructure, morphology, thermal behavior, and textural properties of the resulting hybrid adsorbent was evaluated. Equilibrium CO2 adsorption isotherms and capture capacity were determined, while selectivity, regenerability, kinetics, and enthalpy of adsorption were evaluated as well. Water adsorption studies and stability, as well as CO2 adsorption under the effect of humidity were also examined as to assess the capability of the hybrid adsorbents to capture CO2 from humid mixtures. Formation of additional micro- and mesopores compared to pure HKUST-1 crystals was realized, which was enhanced upon 10-h UV treatment of the GO counterpart (HKUST-1@10UV-GO). Indicatively, the HKUST-1@10UV-GO hybrid adsorbent exhibited a CO2 adsorption capacity of 5.14 mmol g−1 at 25 °C and 1 bar corresponding to a 45% increase compared to pure HKUST-1, accompanied with significantly enhanced CO2 adsorption kinetics at higher temperatures. Comparing the adsorption performance at different temperatures (0, 25, 40, and 60 °C), a high CO2 uptake of 9.5 mmol/g was evidenced for the HKUST-1@10UV-GO at 0 °C and 1 bar. Furthermore, the UV-treated hybrid adsorbents exhibited higher CO2/N2 selectivity at 100 mbar rendering them promising for capture from low CO2 concentration sources. Interestingly, the CO2 uptake of HKUST-1@10UV-GO was not compromised in the presence of low amount of water (10% RH), rather it was slightly increased (by up to 3.2%), while hydrophilicity was suppressed compared to pure MOF, which brings an additional advantage for capture from humid mixtures.

Original languageBritish English
Article number129677
JournalChemical Engineering Journal
Volume420
DOIs
StatePublished - 15 Sep 2021

Keywords

  • Adsorbents
  • Adsorption
  • Capture
  • Carbon dioxide
  • CO
  • Graphene oxide
  • Hybrids
  • MOF
  • UV

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