Novel nitrogen enriched porous carbon adsorbents for CO2 capture: Breakthrough adsorption study

• Nitrogen enriched carbon materials were prepared by nanocasting technique.
• Carbonization temperature regulated their textural and chemical properties.
• Sample obtained at 700 °C exhibited the highest CO2 uptake of 0.676 mmol/g.
• CO2 adsorption on these materials followed pseudo-first order kinetic model.
• Temkin isotherm model explained the CO2 adsorption equilibrium data on C-700.

A range of novel nitrogen enriched porous carbons were obtained by varying carbonization temperature from 500 to 800 °C using nanocasting technique. Hexamethoxymethylmelamine (HMMM) and mesoporous silica were used as carbon precursor and template respectively. Prepared porous carbons were evaluated for their textural and chemical properties followed by CO2 adsorption–desorption performance by conducting breakthrough experiments. Evolution of nitrogen functionalities in carbon materials during the carbonization process was investigated by X-ray photoelectron spectroscopy. Porous carbons obtained at 700 °C showed the best textural properties among the prepared carbons. It exhibited the specific surface area of 463 m2/g and total pore volume of 0.48 cm3/g and showed equilibrium adsorption capacity of 0.676 mmol/g at 30 °C and 12.5% CO2 concentration. The adsorption capacity of C-700 was found to decrease with increase in adsorption temperature while it increased with increase in inlet CO2 concentration. CO2 adsorption kinetics on the prepared carbons was explained by pseudo-first order adsorption model. Three isotherm models were used to investigate the CO2 adsorption equilibrium data and among the studied models Temkin isotherm model was found to explain the equilibrium data suggesting the heterogeneous nature of carbon surface.