Experimental Study of Adsorption on Activated Carbon for CO 2 Capture

The adsorption of carbon dioxide (CO2) on activated carbon (AC) prepared from olive trees has been investigated by using a fixed bed adsorption apparatus. The adsorption equilibrium and breakthrough curves were determined at different temperatures 30, 50, 70, and 90°C in order to investigate both kinetic and thermodynamic parameters. Maximum CO2 sorption capacity on AC ranged from 109.5 to 35.46 and from 129.65 to 35.55 mg CO2/g of AC for initial concentrations 10 and 13.725% vol., respectively. Different isotherm models are applied to mathematically model the CO2 adsorption, and on the basis of the estimated adsorption capacity by model and determination coefficient (r2), the Langmuir model provides a perfect fit to the experimental data owing to closeness of the r2 to unity. From the correlation coefficient, it is found that the pseudo-second-order model is well-fitted with the experimental data. In addition, it indicates that CO2 adsorption is a physical adsorption process and demonstrates a behavior of an exothermic reaction, which is consistent with the thermodynamic analysis. The results obtained in this study conclude that AC prepared from olive trees can be considered as adequate for designing a fixed bed cycle to separate carbon dioxide from flue gases and serve as a benchmark while searching for inexpensive and superior activated carbon production in future studies.