Influence of surface properties and iron addition on the SO2 adsorption capacity of activated carbons

When iron derivatives are added to low ash activated carbons having basic surface characteristics (obtained by suitable oxidation at 800°C with 2% of O₂ in N₂), certain materials are obtained showing high SO₂ sorbent properties from gaseous mixtures having a composition close to that of the flue gases. This behaviour seems to be related to the simultaneous presence of both basic surface sites promoting the initial adsorption of SO₂ and iron promoting the transformation of the adsorbed SO₂ into other, more stable forms. The sorbent properties of these activated carbons are more stable, following consecutive cycles, in the processes of adsorption and desorption of SO₂, than those shown by similar carbons with different surface characteristics.