Nitrogen-rich layered carbon for adsorption of typical volatile organic compounds and low-temperature thermal regeneration

Abstract

Carbon-based adsorbents with a high adsorption capacity and low price have been widely used in the removal of volatile organic compounds (VOCs), but the poor gas selectivity and reusability limit their industrial applications. In this work, disc-like nitrogen-rich porous carbon materials (HAT-Xs) were synthesized to remove typical VOCs via adsorption. By controlling the synthesis temperature from 450 to 1000 °C, the C/N ratio of the HAT-Xs increased from 1.85 to 12.56. The HAT-650 synthesized at 650 °C with the high specific surface area of 305 m2 g−1 exhibits the highest adsorption capacity of 141 mg g−1 for ethyl acetate (which is 3.2 times for that of activated carbon), and 39.4 mg g−1 for n-hexane, 48.6 mg g−1 for toluene. Kinetic studies indicated that the adsorption is physical adsorption and that the interior surface diffusion is the main rate-determining step during the adsorption progress, the interior surface diffusion rate of ethyl acetate on HAT-650 is 1.455 mg g−1 min−0.5. At the same time, the desorption and reuse tests show that HAT-650 has excellent reusability with low desorption and regeneration temperature of 120 °C, and high desorption efficiency of 95.2% and that it could be a promising ethyl acetate adsorbent for industrial applications.