Experimental study of CO2 and N2 adsorption on activated carbon

The present study as designed to assess the CO2 and N-2 adsorption isotherms on activated carbon (AC). The AC was characterized with SEM, XRD and N-2 isotherm. The CO2 and the N-2 adsorption experiments on the AC are performed at 298, 308 and 328 K and modelled by Langmuir model. The preferred selectivity (a (CO2/N2)) was obtained with the use of the Langmuir properties and the Henry coefficient (K-H) was found from the virial equation. The thermodynamic analysis of CO2 and N-2 adsorption which include the entropy loss (?S), the Gibbs free energy change (?G) and the surface potential (O) was calculated. The results reveal that the order of CO2 uptake on AC is higher than that of N-2. a((CO2/N2)) decreased with the increase of the temperature. The K-H values of CO2 on the AC are the most important, while the K-H values for N-2 are the least. The thermodynamic parameters which include O, Q(st), ?G and ?S are impacted by the porous structure of the AC.The adsorption affinity and the adsorption spontaneity of CO2 is the highest, while N-2 has the lowest adsorption spontaneity. Subsequently, CO2 exhibits a higher interaction with AC, in contrast to N2 which displays a slight interaction.the obtained results can be used to CO2 capture and to improve the efficiency of CO2 adsorption devices.