Novel glucose-based adsorbents (Glc-Cs) with high CO2 capacity and excellent CO2/CH4/N2 adsorption selectivity

- Novel Glc-Cs adsorbents were synthesized by using starch sugar as carbon source.
- Glc-Cs exhibits superhigh surface area of 3153 m2/g and pore volume of 2.06 cm3/g.
- Glc-Cs possessed a high CO2 adsorption capacity up to 22.4 mmol/g at 30 bar.
- The selectivity of Glc-Cs was up to 66 and 27 for CO2/N2 and CO2/CH4, separately.
- CO2 desorption efficiency of Glc-Cs reached about 97-98%.

We reported novel glucose-based carbon materials (Glc-Cs) with high surface area, high CO2 adsorption capacity and excellent CO2/CH4/N2 selectivity. Starch sugar (glucose) was used as carbon source to prepare Glc-Cs, and then the resultant samples were characterized by N2 adsorption at 77 K, FTIR, TGA and SEM. CO2/CH4/N2 adsorption isotherms of Glc-Cs were separately measured and the isosteric heats of CO2/CH4/N2 adsorption on the samples were estimated. IAST theory was applied to predict the selectivity of the samples toward binary gas mixtures. The regenerability of the resultant materials was evaluated by means of experiments of CO2 adsorption-desorption cycles. Results showed that BET surface area and pore volume of the resultant Glc-Cs reached as high as 3153 m2/g and 2.056 cm3/g, respectively. Glc-Cs possessed not only excellent stability, but also super-high CO2 adsorption capacity up to 22.4 mmol/g at 30 bar, comparable or superior to many stable metal-organic frameworks (MOFs). Besides, Glc-Cs possessed excellent adsorption selectivity toward CO2/N2 and CO2/CH4 binary mixtures. For example, for CO2/N2 binary mixture, its IAST-predicted selectivity at 30 bar reached as high as 20 toward CO2/N2 (0.5:0.5) mixture and 66 toward CO2/N2 (0.15:0.85) mixture separately. For CO2/CH4 binary mixture, its IAST-predicted selectivity at 30 bar reached as high as 4.5 for CO2/CH4 (0.5:0.5) mixture and 27 for CO2/CH4 (0.1:0.9) mixture separately. Experiment of multiple cycles of CO2 adsorption-desorption showed that the Glc-Cs has excellent regenerability. CO2 desorption efficiency reached about 97-98%. Glc-Cs is a promising adsorbent for the separation of CO2/N2 and CO2/CH4 mixtures.

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