Response Characteristics Of Sulfate Radicals In Water Treatment

The strong oxidizing application of sulfate radical on degradation of organic compounds in water is an emerging advanced oxidation technology in recent years. Similar to the known hydroxyl radical, sulfate radical has extremely strong standard Oxidation-Reduction Potential. In theory, it can oxidize most of the organic pollutants. Currently, sulfate radical reaction mechanism with organic compounds in water is generally considered as hydrogen abstraction, electron transfer and addition reaction. But if different structure types of organic compounds exist in water, sulfate radical reaction modes and reaction ability have not been fully discussed. In water treatment, the general processing environment is relatively complicated. The amount of ions around sulfate radical on the impact of oxidizing organic compounds is also need to investigate.In this paper, by measuring the absorbance change of acid methyl orange at510nm and calculating the decolorization rate are to become the mainly indicator of sulfate radical treatment effect. Containing the alpha-H, aromatic and non-aromatic π electron representative substances are introduced into the same system, and observe the degradation ability and the reaction order of sulfate radical when there are different concentrations of organic compounds. Compare with the degradation effect of UV/Fe2+combined activation producing sulfate radical and in hydroxyl radical system. The experiment results show that the reaction sequence of sulfate radical in water:Containing non-aromatic π electron organic compounds> Containing aromatic π electron organic compounds> Containing alpha-H organic compounds> Containing non-alpha-H organic compounds. The reaction sequence of sulfate radical stay the same as UV/Fe2+combined activation condition, and organic compounds degradation efficiency improve doubled. Sulfate radical and hydroxyl radical have the similar reaction process with organic compounds, but the selectivity of sulfate radical is better.Also, explore the impact of sulfate radical treatment, when different oxyacid ions exist in water. Compared with hydroxyl radical, oxyacid ions have less effect on the sulfate radical. In the reaction, sulfate radicals have a high probability of collision with the surrounding water molecules, and hydrogen abstraction, generating hydroxyl radical. So there is a speculation that sulfate radical and hydroxyl radical in some solution can be transformed each other, and degrade organic pollutants together.