水中普萘洛尔的紫外光降解机制及其产物毒性

以高压汞灯为光源,研究了紫外光照条件下水中普萘洛尔(PRO)的光解行为、机制及安全性.PRO光解机制通过活性氧物种(ROS)猝灭实验来确定,光解产物安全性通过发光菌毒性实验来评价.结果表明,PRO的光解速率常数(k)随初始浓度的增加而下降,两者呈显著负相关关系(r2>0.95).随着溶液初始pH的升高,PRO的光解加快,pH 5~9的PRO溶液的k值为0.0953~0.267 min-1.ROS猝灭实验表明,PRO的紫外光解过程包括了激发三重态PRO(3PRO*)参与的直接光解,以及羟基自由基(·OH)和单线态氧(1O2)参与的自敏化光解,直接光解速率常数大于自敏化光解速率常数.采用FFA探针方法测定了不同实验条件下1O2的浓度,其总体变化规律与猝灭实验所得结论一致.发光菌毒性实验表明,PRO光解生成了比母体化合物毒性更强的中间产物.

UV Photolysis of Propranolol in Aqueous Solution: Mechanism and Toxicity of Photoproducts

This paper studied the phtodegradation behavior, mechanism and security of propranolol (PRO) in water under ultraviolet irradiation using the high pressure mercury lamp. The photodegradation mechanism was verified by reactive oxygen species (ROS) quenching method, and the photoproducts security was evaluated by luminescent bacteria toxicity test. The results showed that the rate of photolysis (k) of PRO decreased with increasing initial concentration, and showed a significant negative correlation (r²>0.95). The increasing k value was also accompanied with higher pH of the solution, and the k values were 0.0953-0.267 min^-1 under pH 5-9. ROS quenching experiments showed that the PRO UV photolysis process included a triplet PRO (³PRO^*) direct photolysis participation, and self-sensitized photolysis participation caused by hydroxyl radical (·OH) and singlet oxygen (¹O₂). Direct photolysis rate was greater than the rate of self-sensitized photolysis. The result of ¹O₂ steady concentration measured by FFA as the probe was consistent with the quenching method. The toxicity evaluation illustrated the formation of some intermediate photoproducts, which were more toxic than PRO.