ADSORPTION AND DESORPTION OF SULFUR-DIOXIDE FROM SIMULATED FLUE-GAS ON ACTIVE-CARBON - THE EFFECT OF THE ASH CONTENT

Samples of active carbon with different ash contents were prepared from two commercial active carbons. They were submitted to a cyclic process of SO2 adsorption at 150-degrees-C from a gaseous mixture with a composition similar to that of flue gases, followed by subsequent desorption at 360-degrees-C with N2. If ashes are present in the carbons in significant quantities, they can markedly decrease the amount of SO2 adsorbed, in close relation to an oxidation of the carbonaceous matrix that causes a progressive loss of surface area and the formation of surface acidic functions. The presence of certain metals. such as iron, in the ashes increases the effects described above.