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Adsorption Characteristics of Carbon Dioxide Gas on a Solid Acid Derivative of β-Cyclodextrin

Guo, Tianxiang, Bedane, Alemayehu H., Pan, Yuanfeng, Shirani, Babak, Xiao, Huining, Eić, Mladen
Energy & Fuels 2017 v.31 no.4 pp. 4186-4192
Fourier transform infrared spectroscopy, adsorbents, adsorption, beta-cyclodextrin, carbon dioxide, energy-dispersive X-ray analysis, methane, nitrogen, oxygen, scanning electron microscopy, superoxide anion, surface area, temperature
A solid acid derivative of β-cyclodextrin was synthesized as an adsorbent for CO₂ capture. The adsorption characteristics, such as adsorption capacity, selectivity, and uptake rate, under different temperatures and gas pressures were analyzed. The results from scanning electron microscopy, energy-dispersive X-ray spectroscopy, Brunauer–Emmett–Teller (BET) sorption, Fourier transform infrared spectroscopy, andthermogravimetric analysis indicated that the dehydration and grafting of sulfonic groups changed the structure of β-cyclodextrin aggregates into a relatively homogeneous porous structure with a concave–convex surface. Meanwhile, the specific BET surface area and pore volume of the solid acid derivative were increased by 40 and 37 times compared to β-cyclodextrin aggregates. Thereby, the performance of the solid acid derivative of β-cyclodextrin toward CO₂ sorption was significantly enhanced, in which CO₂ adsorption capacity at 3.5 bar was increased to 1.78 mmol/g and the selectivity of CO₂ over N₂, O₂, and CH₄ at 298 K reached 7. Interestingly, there was no adsorption of nitrogen on the as-prepared solid acid derivative at 77 K based on BET sorption. Lowering the temperature is disadvantageous for N₂ adsorption but helpful to promote CO₂ capture, so that the high selectivity of CO₂ to N₂ sorption can be achieved.