Facile and efficient nitrogen modified porous carbon derived from sugarcane bagasse for CO2 capture: Experimental and DFT investigation of nitrogen atoms on carbon frameworks

The use of sustainable feedstock and low-cost precursor is an important prerequisite in developing sorbents for CO2 capture. In this research, nitrogen-modified porous carbon materials with varying ratio of carbon-melamine (1:1, 1:2 and 1:3) were synthesized from a sustainable and green-initiated feedstock, sugarcane bagasse, and solid-state impregnation of melamine and investigated as alternative sorbent in CO2 capture. This gives an insight into the effect of increasing the nitrogen content of porous carbon material on CO2 capture. The CO2 uptake of the nitrogen-modified carbon was at least 35% more than that of the pristine porous carbon. Modified carbon with carbon-melamine ratio (1:2) demonstrates the highest CO2 uptake at ambient pressure and temperature (3.34 mmol/g), making it comparable to similar materials that have been reported. The superiority demonstrated by this adsorbent was attributed to a balance between its textural properties and chemical functionalization using nitrogen. The synthesized material also showed high selectivity and regeneration capacities. Adsorption of CO2 and N-2 on pristine and nitrogen modified carbon material was also examined using density functional theory (DFT) calculation at B3LYP/6-31G (d) level. The result obtained revealed that nitrogen-doped carbon material exhibited higher tendency to CO2 adsorption than pristine carbon material in accordance with the hard-soft acid-base (HSAB) principle. This work provides a new and efficient route for the synthesis of nitrogen modified carbon and application for similar adsorption processes.