地表水中Tl(Ⅰ)的光致化学氧化

铊的价态影响铊的毒性以及铊的迁移特性,本工作研究了光照对Tl(Ⅰ)的氧化作用.结果表明,pH值低、光照强度大以及UVB和UVC区有利于Tl(Ⅰ)的氧化.pH=2时,汞弧灯照射10 min后,原溶液中所剩的Tl(Ⅰ)不到1%;而pH=9时,光照1h后溶液中的Tl(Ⅰ)还剩83%;汞弧灯照射5min后,灯-液距离为20cm的实验,溶液中Tl(Ⅰ)仅剩4%,而灯-液距离为36cm时,溶液中的Tl(Ⅰ)还剩50%左右;经滤光后的汞弧灯照射后,溶液中所剩的Tl(Ⅰ)还剩90%左右,而未经滤光的汞弧灯照射后,溶液中所剩的Tl(Ⅰ)不足1%;微生物作用在本实验条件下,相对于光氧化作用并不明显,除去微生物和未除去微生物的水样,经日光照射后,所剩的Tl(Ⅰ)均为70%左右.

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%.