天然水体溶解性物质对5种抗生素光解的影响

Influence of dissolved substances in natural water on the photolysis of five antibiotics

建立了分析水体溶解性物质对抗生素光解影响的方法,对比研究了8种典型天然水体成分对3类5种抗生素光解的影响及其作用机制.结果表明,不同水体成分对不同抗生素光解影响呈现很大的差异性.甲砜霉素主要发生间接光解,纯水中光解速率只有1.33×10^(–5)min^(–1),而其他抗生素则同时发生直接光解和间接光解.水体成分中NO_3~–,Fe^(2+)和Cl~–主要通过光致活性物种(·OH和~1O_2)影响抗生素光解,DOM主要通过滤光作用影响抗生素光解.另外Ca^(2+)和Mg^(2+)对不同抗生素的光解影响主要通过其与抗生素分子的络合作用实现,Ca^(2+)和Mg^(2+)分别促进了恩氟沙星光解(0.3933min^(–1)和0.2314min^(–1)),但一定程度上抑制了沙拉沙星的光解(0.0447min^(–1)和0.0289min^(–1)).

A method was established for analyzing the effects of dissolved substances on the photolysis of antibiotics and the differential effects and possible mechanisms of eight typical dissolved substances in natural water on the photolysis of five antibiotics were investigated comparatively.The results demonstrated that the effects of various dissolved substances were much different on the photolysis of these antibiotics.For thiamphenicol,the photolysis rate in pure water was only1.33×10–5min–1 and indirect photolysis was the main photodegradation pathway.However,for other antibiotics,indirect photolysis co-occurred with direct photolysis.The dissolved substances（e.g.,NO3–,Fe2＋and Cl–）affected the photolysis of antibiotics mainly through photogeneration of·OH and 1O2.Dissolved organic matter decreased the photolysis of antibiotics through light attenuation.In addition,Ca2＋and Mg2＋could influence the photolysis of antibiotics through their complexation with antibiotics.It was observed that Ca2＋and Mg2＋promoted the photolysis of enrofloxacin（0.3933min–1and 0.2314min–1,respectively）,but inhibited the photolysis of sarafloxacin（0.0447min–1 and 0.0289min–1,respectively）.