Oxidation of sulfur dioxide to sulfur trioxide and absorption on aluminum oxide pellet as a mean of removing sulfur dioxide from flue gas was studied in a packed bed reactor at various temperatures, residence times, SO₂ inlet concentrations (ppm level), and particle sizes. Three different experiments were conducted: (i) sulfation with oxygen/ozone, (ii) sulfation with oxygen only in the presence of UV radiation ( 254 nm or 366 nm ), (iii) sulfation with oxygen only. In all the experiments substantial absorption of sulfur dioxide by alumina pellet was observed. Sulfation with oxygen/ozone give the highest absorption of SO₂, followed by sulfation with oxygen in the presence of UV radiation, while sulfation with oxygen only had the lowest absorption. In all these experiments, the absorption of SO₂ decreases with increasing SO₂ concentration, increases with increasing residence time, and increases with decreasing particle size. At SO₂ concentration of 8,352 ppm, residence time of 0.018 sec., and particle size of 0.3175 cm, sulfation with oxygen/ozone and sulfation with oxygen only in the presence of UV radiation attain maximum absorption at about 275°C, whereas sulfation with oxygen only attains maximum absorption at about 640°C.