Study of CO₂ adsorption and separation using modified porous carbon

Porous carbon and La₂O₃/porous carbon materials are synthesized for the study of CO₂ adsorption and separation by the volumetric method. The synthesized adsorbents are characterized by X-ray diffraction, N₂ adsorption–desorption isotherms, Raman spectra and scanning electron microscopy with energy-dispersive X-ray analysis. Characterization results confirm the existence of porosity in the synthesized carbon materials and uniform distribution of lanthanum(III) oxide on porous carbon. The CO₂ adsorption capacity for porous carbon and La₂O₃/porous carbon is 21 and 33 cm³ g⁻¹, respectively, at 298 K and 1 bar. High adsorption of CO₂ is obtained for La₂O₃/porous carbon because of the electrostatic interaction between La₂O₃ and CO₂. Moreover, the N₂ adsorption capacity is 2.8 cm³ g⁻¹ for porous carbon and 2.2 cm³ g⁻¹ for La₂O₃/porous carbon at 298 K and 1 bar. The change in N₂ adsorption is due to the decrease in surface area. For La₂O₃/porous carbon, the selectivity of CO₂/N₂ is 33.5 and the heat of CO₂ adsorption is 36.5 kJ mol⁻¹ at low adsorption of CO₂. It also shows constant CO₂ adsorption capacity in each adsorption cycle.