论文部分内容阅读
光敏剂亚甲兰、核黄素及玫瑰红 B可加速氯氰菊酯 (CPM)的光解作用。这些物质的敏化作用主要通过激发基态氧为单线态氧来实现。光敏剂和氧均是敏化光降解不可缺少的条件。 1 / Kexptl与 [A]的关系证实了单线态氧氧化机理。在亚甲兰、核黄素存在下氯氰菊酯 KA 分别为 6.49× 1 0 6L·mol-1· s-1和 2 .2 7× 1 0 6L· mol-1· s-1。氯氰菊酯的光解速率在一定范围内 ,随光敏剂浓度的增加而增加 ,过量的光敏剂将减少体系的透光率而导致氯氰菊酯光解速率降低。单线态氧探针性物质即竞争反应的引入将明显降低氯氰菊酯的光解速率 ,同时 ,不同极性溶剂因其对单线态氧猝灭能力的不同也会明显改变氯氰菊酯的光解速率
Photosensitizers methylene blue, riboflavin and rose B can accelerate photolysis of cypermethrin (CPM). The sensitization of these substances is mainly achieved by exciting the ground state oxygen to singlet oxygen. Photosensitizers and oxygen are indispensable conditions for sensitized photodegradation. The relationship between 1 / Kexptl and [A] confirms the singlet oxygen oxidation mechanism. In methylene blue, the cypermethrin KA in the presence of riboflavin was 6.49 × 10 6 L · mol -1 · s -1 and 2.27 × 10 6 L · mol -1 · s -1, respectively. The rate of photodegradation of cypermethrin within a certain range, with the increase of photosensitizer concentration increases, the excess photosensitizer will reduce the transmittance of the system and lead to lower photodegradation rate of cypermethrin. The introduction of singlet oxygen probe material, ie, competitive reaction, will obviously reduce the rate of photodegradation of cypermethrin. At the same time, different polar solvents can significantly change the photodegradation rate of cypermethrin due to their different singlet oxygen quenching ability