The gas sulphur dioxide (SO2) is one of the most important pollutants in the atmosphere. Owing to its harmful effects on human health and the environment, several processes to reduce its emission have been developed. Some of these processes are based on the conversion Of SO2 into SO3 in catalytic systems. In this study SO2 removal efficiency of activated carbon was investigated by using a laboratory-scale trickle-bed reactor (TBR). In the experiments air was fed continuously while SO2 (2.84% by volume in the gas stream) and the liquid phase (distilled water) were fed periodically. The experiments were performed at atmospheric pressure and room temperature at low liquid flow rates. At the end of each experiment activated carbon was regenerated by using distilled water and reused. The amount Of SO2 removed by liquid phase was determined by the titrimetric analysis of the liquid phase. As a result of the experiments performed at various flow rates (for the liquid between 12.0 and 64.5 ml min(-1) and for the gas between 411.4 and 1043.0 ml min(-1)), it was observed that the amount Of SO2 removal increased with liquid and gas flow rates. At 64.5 ml min(-1) liquid and 989.0 ml min(-1) gas flow rate, 97.5% removal was achieved.