Molecules (Oct 2022)

Porous Structure of β-Cyclodextrin for CO<sub>2</sub> Capture: Structural Remodeling by Thermal Activation

  • Tianxiang Guo,
  • Runan Zhang,
  • Xilai Wang,
  • Lingfeng Kong,
  • Junpeng Xu,
  • Huining Xiao,
  • Alemayehu Hailu Bedane

DOI
https://doi.org/10.3390/molecules27217375
Journal volume & issue
Vol. 27, no. 21
p. 7375

Abstract

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With a purpose of extending the application of β-cyclodextrin (β-CD) for gas adsorption, this paper aims to reveal the pore formation mechanism of a promising adsorbent for CO2 capture which was derived from the structural remodeling of β-CD by thermal activation. The pore structure and performance of the adsorbent were characterized by means of SEM, BET and CO2 adsorption. Then, the thermochemical characteristics during pore formation were systematically investigated by means of TG-DSC, in situ TG-FTIR/FTIR, in situ TG-MS/MS, EDS, XPS and DFT. The results show that the derived adsorbent exhibits an excellent porous structure for CO2 capture accompanied by an adsorption capacity of 4.2 mmol/g at 0 °C and 100 kPa. The porous structure is obtained by the structural remodeling such as dehydration polymerization with the prior locations such as hydroxyl bonded to C6 and ring-opening polymerization with the main locations (C4, C1, C5), accompanied by the release of those small molecules such as H2O, CO2 and C3H4. A large amount of new fine pores is formed at the third and fourth stage of the four-stage activation process. Particularly, more micropores are created at the fourth stage. This revealed that pore formation mechanism is beneficial to structural design of further thermal-treated graft/functionalization polymer derived from β-CD, potentially applicable for gas adsorption such as CO2 capture.

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