CO2 adsorption at nitrogen-doped carbons prepared by K2CO3 activation of urea-modified coconut shell.

This article reports on the synthesis and characterization of porous nitrogen-doped carbons synthesized by carbonization of coconut shell followed by urea modification and K2CO3 activation. The as-synthesized samples were carefully characterized by various techniques. This series of samples demonstrate high CO2 uptake at 1bar, up to 3.71mmol/g at 25°C in addition to 5.12mmol/g at 0°C. Furthermore, these sorbents possess fast CO2 adsorption kinetics, stable reusability, moderate heat of CO2 adsorption, reasonable CO2/N2 selectivity, and high dynamic CO2 capture capacity under simulated flue gas conditions. It is found that, in addition to nitrogen content and narrow micropore volume, the pore size distribution of narrow micropore also plays a major role in determining the CO2 capture capacity under ambient condition. This work is intended to provide useful information and to inspire ways to develop new carbonaceous sorbents for removing CO2 from combustion flue gas.