Novel glucosamine-based carbon adsorbents with high capacity and its enhanced mechanism of preferential adsorption of C2H6 over C2H4

Abstract In this work, we synthesized a series of glucosamine-based carbon adsorbents with rich microporosity for effective C 2 H 6 /C 2 H 4 adsorptive separation. Glucosamine was chosen as precursor to synthesize new microporous glucosamine-based carbon adsorbents (MGAs) and the resultant adsorbents were then characterized. Results showed that the BET surface area and pore volume of the MGAs reached as high as 3189 m 2 /g and 1.92 cm 3 /g, respectively. The FTIR and XPS results showed the presence of abundant N/O groups on carbon surface. Ethane and ethylene adsorption isotherms of the materials were then measured. The effects of N/O functionalities and micropore sizes on C 2 H 6 and C 2 H 4 adsorption were also elaborated by using molecular simulation. Interestingly, the materials presented preferential adsorption of ethane over ethylene with its ethane adsorption capacity reaching 7.6 mmol/g under 1 bar and 25 °C. Its adsorption selectivity for ethane/ethylene (1:1) was improved and higher than many MOFs, being in the range of 2.2–6.8 at 2 H 6 /C 2 H 4 . An increase in amounts of surface N/O functionalities in the micropores with the aperture size in 6–10 A of MGAs played an important role in the enhanced interaction of C 2 H 6 with the surfaces, thus resulting in further improvement of ethane/ethylene selectivity. Fixed-bed breakthrough experiments demonstrated the complete separation of C 2 H 6 /C 2 H 4 mixture at room temperature by using the glucosamine-based carbons. These excellent adsorption properties make the glucosamine-based carbon materials a type of promising C 2 H 6 -selective adsorbents for the effective separation of C 2 H 6 /C 2 H 4 .