Novel glucose-based adsorbents (Glc-As) with preferential adsorption of ethane over ethylene and high capacity

Abstract In this work, we reported novel glucose-based adsorbents (Glc-As) with high C 2 H 6 /C 2 H 4 adsorption capacity and selectivity. Starch sugar (e.g., glucose, 50 wt%) was used as carbon source to prepare novel glucose-based carbon materials for C 2 H 6 /C 2 H 4 separation. The BET surface area of the resulting Glc-As can reach as high as 2073 m 2 /g, and their pore diameters fell into the region of micropores benefiting adsorption of light hydrocarbons. FTIR spectra and XPS were applied to analysize the surface chemistry of the samples. It showed the presence of O functionalities in Glc-As, and its contents decreased with increasing KOH/C ratio at which the sample was activated. Glc-As achieved superior high C 2 H 6 adsorption capacity of 7.98 mmol/g at 288 K and 1 bar, which was benefited from the abundant micropores. More importantly, Glc-As exhibited greatly preferential adsorption of C 2 H 6 over C 2 H 4 , with the C 2 H 6 /C 2 H 4 adsorption selectivity in the range of 2.02–5.98 at pressure below 100 kPa, higher than most reported adsorbents possessing preferential adsorption of C 2 H 6 over C 2 H 4 . This could ascribe to the higher polarizability and larger kinetic diameter of C 2 H 6 , resulting in its stronger interaction with the pore surfaces of Glc-As compared to C 2 H 4 , and exhibiting in significantly preferential adsorption of ethane over ethylene. Besides, adsorption heat calculation showed that the isosteric heats of C 2 H 6 adsorption on Glc-As were higher than the isosteric heats of C 2 H 4 . Fixed bed experiments showed that C 2 H 4 /C 2 H 6 mixture can be well separated in the fixed bed packed with Glc-As. In sum, Glc-As as new carbon materials possess not only excellent stability, but also excellent adsorption properties for separation of C 2 H 6 and C 2 H 4 , It would be promising adsorbents for the effective separation of ethane/ethylene.