Adsorption of CO2 onto zeolite ZSM-5: Kinetic, equilibrium and thermodynamic studies

Abstract

The aim of this research is to evaluate the adsorption isotherms and the adsorption kinetics of CO2 on the zeolite ZSM-5. The sample was identified by FTIR, SEM, DRX, and N2 adsorption–desorption. The O2 adsorption isotherms of the adsorbent were evaluated at three temperature 318, 308 and 298 K with a volumetric method. Langmuir and Freundlich models were employed to fit the CO2 adsorption. The Langmuir model represented the best fit against the experimental data with a correlation coefficient (R2) of 0.99. The calculated thermodynamics parameters like Entropy, Enthalpy and Gibbs Free Energy showed that CO2 adsorption is a spontaneous and exothermic process. The CO2 adsorption kinetics curves on the adsorbent were calculated and then correlated with the linear driving force (LDF) model. The results showed that the mass transfer constants of CO2 adsorption on the adsorbent increased with rising of temperature. Moreover, the activation energy of CO2 adsorption on the adsorbent decreases with rising of pressure. Through adsorption technology, the obtained results can be applied to the CO2 separation and to evaluate the performance of CO2 adsorption systems.