Adsorption of sulfur dioxide on ammonia-treated activated carbon fibers

A series of activated carbon fibers (ACFs) and ammonia-treated ACFs prepare d from phenolic fiber precursors have been studied to elucidate the role of pore size, pore volume, and pore surface chemistry on adsorption of sulfur dioxide and its catalytic conversion to sulfuric acid. As expected, the in corporation of basic functional groups into the ACFs was shown as an effect ive method for increasing adsorption of sulfur dioxide. The adsorption capa city for dry SO2 did not follow specific trends; however the adsorption ene rgies calculated from the DR equation were found to increase linearly with nitrogen content for each series of ACFs. Much higher adsorption capacities were achieved for SO2 in the presence of oxygen and water due to its catal ytic conversion to H2SO4. The dominant factor for increasing adsorption of SO2 from simulated flue aas for each series of fibers studied was the weigh t percent of basic nitrogen groups present. In addition, the adsorption ene rgies calculated for dry SO2 were shown to be linearly related to the adsor ption capacity of H2SO4 from this flue g-as for all fibers. It was shown th at optimization of this parameter along with the pore volume results in hig her adsorption capacities for removal of SO2 from flue gases. (C) 2001 Else vier Science Ltd. All rights reserved.