Electrogenerative oxidation of dissolved sulfur dioxide with packed-bed anodes

An operating electrogenerative cell for the oxidation of dissolved sulfur dioxide at a packed-bed anode was tested. The study included a packed bed composed of Teflon-platinum composite electrodes of the gas diffusion type without backing, Pt deposited on a graphite packed bed, a graphite packed bed, and a graphite packed bed in which iodide ion was dissolved. The uncatalyzed graphite electrode gave currents of 15 mA/sq cm, and both the Pt-graphite and the iodide-mediated systems provided currents in the range of 100 mA/sq cm. Because of the substantial currents generated, variations of the anodes studied could be incorporated in the processing of waste effluents in the future.