Adsorption of carbon dioxide by coconut activated carbon modified with Cu/Ce

A series of the coconut activated carbons (CAC) based absorbents modified with Cu and Ce (Cu/CAC, Cu/Ce/CAC) were prepared by impregnation technology for carbon dioxide capture. The adsocrption equilibriums of CO₂ on Cu/CAC and Cu/Ce/CAC were measured. The results showed that the adsorption capacity of CO₂ onto the activated carbon modified with Cu/Ce increased with the decreasing temperature in the same pressure. The adsorption capacity of CO₂ on Cu/CAC was higher than that of the blank CAC, and compared with the Cu/CAC, the adsorption capacity of CO₂ of Cu/Ce/CAC with the mass ratio of Cu/Ce=30 was improved at 298 and 303 K. In addition, the adsorption equilibrium data for CO₂ at various temperatures was fitted to Langmuir, Freundlich and D-R isotherm models. It was found that the D-R equation was the best model for fitting the adsorption data on Cu/Ce/CAC at different temperatures.