[Photoxidation reaction of Tl(I) in surface water]

The valence state of thallium affecting its toxicity, distribution and mobility, photoxidation reaction of Tl(I) was studied under the radiation from high-pressure arc mercury light or solar light. The results show that the low pH, the strong light intensity and UVB and VUC region are in favor of the photoxidation of Tl(I). In the case of pH = 2, only less than 1% Tl(I) remained in the solution after 10 min of irradiation, while pH = 9, with about 83% Tl(I) in the solution after 1 h of irradiation. After 5 min of irradiation, if the distance between the light source and the surface of solution is 20cm, just 4% Tl(I) remained in the solution, while the distance is 36 cm, still remained about 50%. 90% Tl(I) remained in filtered light, while less than 1% Tl(I) still remained in non-filtered light. The microorganic effect is not obvious comparing with photoxidation effect in this experiment, the remained Tl(I) in excluding microorganic and microorganic experiment are all about 70%.