The effects of cycle period, cycle split, and liquid flow rate on SO2 removal in a periodically operated trickle bed of activated carbon were investigated using a simulated flue gas containing 2500 ppm SO2. The highest measured SO2 removal was 98%. Temperature waves observed in the bed were the consequence of periodic flushing with liquid coupled with the exothermicities of SO2 absorption and its oxidation to SO3 as well as the endothermicity of evaporation, The outlet SO2 concentration from the trickle bed also varied and appeared to be closely related to the changing bed temperature. The period and split affect the SO2 removal apparently as a result of limits in the minimum flushing time combined with the rate of oxygen transfer to the catalyst. Increasing the period at a fixed split has almost the same effect as decreasing the split with a fixed period. The liquid Bow sate has no significant effect on the catalytic activity within the range of experimental conditions studied.