Adsorption of carbon dioxide using impregnated activated carbon promoted by Zinc

The effect of impregnation of activated carbon with Cr2O and Fe2O3 and promotion by Zn2+ on its adsorptive properties of carbon dioxide was studied using a volumetric adsorption apparatus at ambient temperature and low pressures. Slurry and solution impregnation methods were used to compare CO2 capture capacity of the impregnated activated carbon promoted by Zinc. The obtained adsorption isotherms showed that amount of CO2 adsorbed on the samples impregnated by Cr2O was increased about 20% in compare to raw activated carbon. The results also showed that Fe2O3 was not an effective impregnating species for activated carbon modification. Moreover slurry impregnation method showed higher CO2 adsorption capacity in comparison with solution impregnation method. Samples prepared by co-impregnation of two metal species showed more adsorption capacity than samples impregnated by just one metal species individually. Washing the impregnated samples by metal oxide resulted in 15% increase in CO2 adsorption capacities of activated carbons which can be attributed to the metal oxides removal covering the adsorption surface. Decreasing impregnation temperature from 95 to 25 °C in solution method showed a significant increase in CO2 adsorption capacity. Sips equation was found a suitable model fitting to the adsorption data in the range studied.