Adsorption of Carbon Dioxide on Coconut Shell Activated Carbon

The adsorption equilibrium of CO₂ was measured on coconut shell activated carbon by using a static volumetric method. Adsorption isotherms over the temperature ranged 308 K ~ 353 K were measured. The results showed that the capacities of adsorption of carbon dioxide on activated carbon at different temperatures were as follows: 308 K > 323 K > 338 K > 353 K. The absorption capacity increases with the decreasing temperature in the same pressure. The D-R equation was found better to fit the isotherm data for the adsorption of carbon monoxide, especially in 308 K and 323 K. Furthermore, Freundlich equation was chosen to calculate the heat of adsorption in this paper, the isosteric heat of adsorption was about 8 kJ/mol, and the results showed that the isosteric heat of adsorption for CO₂ decreased with the adsorbed amount increasing, and the process of adsorption is physical adsorption.