Synthesis of nitrogen doped activated carbon/polyaniline material for CO ₂2 adsorption

摘要

> The equilibrium adsorption isotherms of carbon dioxide and nitrogen on the nitrogen doped activated carbon (NAC) prepared by the chemical activation of a pine cone‐based char/polyaniline composite were measured using a volumetric technique. CO ₂ and N ₂ adsorption experiments were done at three different temperatures (298, 308, and 318?K) and pressures up to 16?bar, and correlated with the Langmuir, Freundlich, and Sips models. The Sips isotherm model presented the best fit to the experimental data. The N‐doped adsorbent showed CO ₂ and N ₂ adsorption capacity of 3.96?mmol·g ?1 and 0.86?mmol·g ?1 , respectively, at 298?K and 1?bar. The selectivity predicted by ideal adsorbed solution theory (IAST) model was achieved 47.17 for NAC at 1?bar and y _N2 ?=?0.85 which is a composition similar to flue gas. The results showed that NAC adsorbent has a high CO ₂ ‐over‐N ₂ selectivity in a binary mixture. The relatively fast sorption rate of CO ₂ on NAC compared to N ₂ indicates the stronger affinity between CO ₂ and amine groups. The isosteric heat of adsorption of CO ₂ by the NAC demonstrated the physico‐chemical adsorption of CO ₂ on the adsorbent surface. These data showed that prepared NAC could be successfully applied in separation of CO ₂ from N ₂ .