ADSORPTION OF SO2 ONTO OXIDIZED AND HEAT-TREATED ACTIVATED CARBON-FIBERS (ACFS)

A series of activated carbon fibers (ACFs) and heat-treated oxidized A CFs prepared from phenolic fiber precursors have been studied to eluci date the role of pore size, pore surface chemistry and pore volume for the adsorption of SO(2)and its catalytic conversion to H2SO4. For unt reated ACFs, the initial rate of SO2 adsorption from flue gas was show n to be inversely related to pore size. Ar longer times, the amount of SO2 adsorbed from flue gas was dependent on both the pore size and po re volume. Oxidation of the ACFs, using an aqueous oxidant, decreased their adsorption capacity for SO2 from flue gas due to a decrease in p ore volume and repulsion of the SO2 from acidic surface groups. IT the se samples were heat-treated to desorb the oxygen containing function groups, the amount of SO2 adsorption increased. This increase in adsor ption capacity was directly correlated to the amount of CO2 evolved du ring heat-treatment of the oxidized ACFs. The amount of SO2 adsorbed f or these samples was related to the pore size, pore surface chemistry and pore volume. This analysis is explained in more derail in this pap er. (C) 1997 Elsevier Science Ltd.