Adsorption of CO2 on Zeolite 13X and Activated Carbon with Higher Surface Area

Abstract

In this work, adsorption isotherms and adsorption kinetics of CO2 on zeolite 13X and activated carbon with high surface area (AC-h) were studied. The adsorption isotherms and kinetic curves of CO2 on the adsorbents were separately measured at 328 K, 318 K, 308 K, and 298 K and with a pressure range of 0–30 bar by means of the gravimetric adsorption method. The mass transfer constants and adsorption activation energy Ea of CO2 on the adsorbents were estimated separately. Results showed that at very low pressure the amounts adsorbed of CO2 on the zeolite 13X was higher than that on the AC-h, while at higher pressure, the amounts adsorbed of CO2 on the AC-h was higher than that on the zeolite 13X since the AC-h has a larger surface area and a larger total pore volume compared to the zeolite 13X. The adsorption kinetics of CO2 can be well described by the linear driving force (LDF) model. With the increase of temperature, the mass transfer constants of CO2 adsorption on both samples increased. The adsorption activation energy Ea for CO2 on the two adsorbents decreased with the increase of pressure. Furthermore, at low pressure the Ea for CO2 adsorption on the zeolite 13X was slightly lower than that on the AC-h, while at higher pressure the Ea for CO2 adsorption on the zeolite 13X was higher than that on the AC-h.