2D/3D amine functionalised sorbents containing graphene silica aerogel and mesoporous silica with improved CO2 sorption

Wenjing Wang, Julius Motuzas, Xiu Song Zhao, João C. Diniz da Costa

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

This work investigates the performance of amine functionalised 2D/3D sorbents for CO2 capture. The 2D/3D structures were based on a combination of flake-like reduced graphene-silica oxide (G-Si) aerogel and rod-like mesoporous silica SBA-15. The G-Si aerogel formed mainly silica microporous structures which enveloped graphene sheets. The SBA-15 displayed the classical rod-like mesoporous features with high pore volume. The addition of G-Si aerogel to SBA-15 for the amine functionalised samples significantly reduced the combined total surface area and pore volume. Interestingly, the CO2 sorption capacity increased and peaked for samples containing G-Si aerogel/SBA-15 at 1:20 mass ratio (4.7 wt%), though declining thereafter. This counterintuitive effect of increasing CO2 sorption capacity but decreasing surface area and pore volume was attributed to the special morphological features of the 2D/3D sorbent assembly. At these optimal conditions, the flake-like G-Si aerogel was well intercalated with the rod-like SBA-15. As a result, the inter-particle space formed between the flake-like and rod-like assembly accommodated TEPA which facilitate the mass transfer and reaction between the amine groups and CO2. These special 2D/3D morphological features delivered high CO2 sorption capacity of 6.02 mmol g−1. The 2D/3D sorbents were also very stable under sorption and desorption cycles whilst heat of sorption were up to 22% lower than the analogue 3D SBA-15/TEPA sorbent.

Original languageEnglish
Pages (from-to)381-389
Number of pages9
JournalSeparation and Purification Technology
Volume222
DOIs
Publication statusPublished - 1 Sep 2019

Keywords

  • 2D/3D sorbent
  • Amine
  • CO sorption
  • Graphene
  • Mesoporous silica

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