Abstract:Absorption solution with low concentration of SO2 was applied as object to study generation rate of sulfate radical and side effects of oxidation under different temperature, citrate total concentration, and pH value. Oxidation mechanisms and its inhibition method were explored. The results show that reaction order of oxidation rate on citric acid concentration, pH value, and oxygen is 0.5, 0.8 and 0 respectively. The minimum secondary oxidation reaction is obtained under the conditions of absorption and desorption including concentration of citric acid of 1.5 mol/L, pH value of 4.5, and reaction temperature of 95 ℃.