A laboratory-scale investigation of SO2 scrubbing was carried out in two parts : (1) screening of catalysts, and (2) continuous runs in a 50 mm (diameter) x 190 mm trickle bed using periodic interruption ofliquid flow. The screening study disclosed that impregnating activated carbons with platinum substantially increased the activity for SO2 oxidation. However, the continuous runs indicated that 95% SO2 removal from simulated stack gas can be achieved with either an activated carbon or with one impregnated with Pt. Scrubbing at 80 degrees C removes much more SO2 from the gas phase than at room temperature and converts SO2 to H2SO4. Cycle periods should exceed 30 min and the duration of liquid Row through the trickle bed should be greater than 3 min. Projecting results to an industrial scale indicates that the impregnated carbon should be chosen if a high by-product sulfuric acid strength is needed. For installations handling large gas volumes, activated carbon is the preferred catalyst and only weak sulfuric acid can be produced. The advantage of periodic flow interruption appears to be higher by product acid strength and lower pressure drop in the scrubbing operation.