Tuning nitrogen species on natural biomass derived porous carbon for efficient acetone adsorption

In this study, gaseous ammonia (NH₃) is used as a nitrogen source to modify porous carbon prepared from bagasse by a facile one-pot successive process, namely carbonization in N₂ at 700–900 °C, thermal oxidation in atmospheric environment at 300 °C and nitrogen modification in NH₃ at 300 °C. The influences of carbonization temperature, thermal oxidation and NH₃ modification as well as their interactions have been carefully investigated. Quantitative analysis of surface functional groups reveals that after oxidation the active sites (C–OH and O[dbnd]C–OH) on the porous carbon are strongly related to the carbonization temperature, and this results in different ratios of amide nitrogen and pyridine nitrogen on the modified cabon. The molecular dynamics simulation shows that the binding force of amide nitrogen and acetone (5.821 kcal) is stronger than that of pyridine nitrogen and acetone (1.382 kcal), this explains the reason why the modified carbon with higher amide nitrogen has the better acetone adsorption performance. The acetone adsorption property of modified porous cabn can be increased by 44.5% as compared to the untreated porous carbon. This work provides a new perspective on nitrogen modification of the porous carbon from the low-valued biomass for the VOCs adsorption applications.