N-doped porous carbon derived from polypyrrole for CO2 capture from humid flue gases

Anthropogenic carbon dioxide especially emitted from coal fired power plants is a major contributor to global warming. Various carbon capture materials have been developed to mitigate CO2 emissions. However, adsorbent materials that are tolerant to the humid condition of real flue gases are rare. Here we report a N-doped porous carbon derived from polypyrrole a nitrogen-rich polymer, which can be used to capture CO2 from humid flue gases. Obtained samples were analyzed by various characterizations likewise XRD, FTIR, SEM and XPS, moreover the CO2 adsorption capacities were measured at different temperatures and relative humidities. The results indicated that the porous carbon has achieved a high CO2 adsorption amount of 7.16 mmol/g (at 273 K and 100 kPa). Three equilibrium models were used to fit CO2 adsorption isotherms, and the selectivity of CO2/N-2 was calculated at flue gases condition (75% N-2 and 25% CO2) based on the IAST method which shows an excellent selectivity of 35 at 273 K (100 kPa). Furthermore, binary adsorption tests of H2O/CO2 were investigated experimentally at 308, 318 and 328 K, indicating that the N-doped carbon can still retain 64%, 58% and 43% of the CO2 adsorption capacity, respectively. The binary isotherm data was fitted well by LBET (Langmuir-BET) model, enabling it for future process modeling. This work confirmed the superiority of the N-doped carbon derived from polypyrrole that will help the development of CO2 capture from humid flue gases.