A green route to CO2 adsorption on biomass chitosan derived nitrogen-doped micropore-dominated carbon nanosheets by different activators

As urbanization spreads, more fossil fuels are continuously needed, though they cause air pollution to worsen. The capture and storage of CO 2 has become an area of intense research interest, as it could inhibit further environmental deterioration. Herein, a novel method of synthesizing nitrogen-doped carbon nanosheet adsorbents with highly developed microporosity is proposed. Using biomass chitosan and graphitic carbon nitride (g-C 3 N 4 ) as starting materials not only ensures economically favorable properties but is also makes the adsorbents ecologically friendly. The amount of nitrogen doping agent and varied activation temperatures were found to be capable of precisely controlling the pore structure and nitrogen content in the resulting product. The CO 2 capture capacity of the KOH-activated adsorbent under optimum conditions (a chitosan/graphitic carbon nitride weight ratio of 6 and activation temperature of 750 °C) was determined to be 3.91 mmol/g at 298 K and 1 bar. We also chose three different potassium salt activators to use in place of the strongly caustic KOH. The test results showed that the resulting porous carbon activated by KAc exhibited CO 2 uptakes of 3.54 (298 K) and 5.64 mmol/g (273 K) at 1 bar. This adsorbent also exhibited fast adsorption kinetics , remarkable recyclability , moderately isosteric heats of adsorption and good CO 2 selectivity over N 2 . The present work will provide new inspiration for biomass-based adsorbents for CO 2 capture.