Study of CO2 adsorption and separation using modified porous carbon

Porous carbon and La 2 O 3 /porous carbon materials are synthesized for the study of CO 2 adsorption and separation by the volumetric method. The synthesized adsorbents are characterized by X-ray diffraction, N 2 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 CO 2 adsorption capacity for porous carbon and La 2 O 3 /porous carbon is 21 and 33 cm 3 g −1 , respectively, at 298 K and 1 bar. High adsorption of CO 2 is obtained for La 2 O 3 /porous carbon because of the electrostatic interaction between La 2 O 3 and CO 2 . Moreover, the N 2 adsorption capacity is 2.8 cm 3 g −1 for porous carbon and 2.2 cm 3 g −1 for La 2 O 3 /porous carbon at 298 K and 1 bar. The change in N 2 adsorption is due to the decrease in surface area. For La 2 O 3 /porous carbon, the selectivity of CO 2 /N 2 is 33.5 and the heat of CO 2 adsorption is 36.5 kJ mol −1 at low adsorption of CO 2 . It also shows constant CO 2 adsorption capacity in each adsorption cycle.