铁活化过硫酸盐降解抗生素的动力学、降解产物和毒性评估

Kinetics,Degradation Products and Toxicity Assessment of Iron-Activated Persulfate Degradation of Antibiotics

近年来,我国城市地下水中多种抗生素已被广泛检出,对生态环境和人类健康都会产生一定风险。以磺胺甲噁唑、磺胺二甲嘧啶、左氧氟沙星、环丙沙星和罗红霉素5种抗生素为研究对象,采用超高效液相色谱-四极杆-静电场轨道阱高分辨质谱(UPLC-Q-Orbitrap)测定了上述5种抗生素混合污染物在Fe^(2+)/过硫酸盐高级氧化反应体系中的降解动力学,鉴别其降解产物,推测了降解路径,并利用ECOSAR模型对母体化合物以及降解产物的生态毒性进行了评估。结果表明,Fe^(2+)活化过硫酸钠体系在3360 min内可以实现抗生素的高效去除。5种抗生素降解速率常数呈现磺胺二甲嘧啶>左氧氟沙星>环丙沙星>磺胺甲噁唑>罗红霉素的趋势。5种抗生素共鉴定出33种可能存在的降解产物,降解产物峰面积随时间一般呈现先上升后下降的趋势,其中一些降解产物可能比母体具有更强的生态毒性。本研究表明高级氧化反应体系中,除了需要关注母体化合物的降解,还需关注毒性降解产物的变化,以降低地下水中抗生素的生态毒性影响。

In recent years,a variety of antibiotics have been widely detected in urban groundwater in China,which can pose risks to ecological environment and human health.In this paper,five antibiotics including sulfamethoxazole,sulfamethazine,levofloxacin,ciprofloxacin and roxithromycin were studied.The degradation kinetics of the mixed pollution of the above five antibiotics in the Fe^(2+)/persulfate advanced oxidation reaction system was determined by ultra high performance liquid chromatography-quadrupole-electrostatic field orbitrap high resolution mass spectrometry(UPLC-Q-Orbitrap).The degradation products in the degradation process were identified,and the possible degradation pathways were proposed.The ECOSAR model was used to evaluate the ecotoxicity of the degradation products.The results showed that the Fe^(2+)activated sodium persulfate system could achieve efficient removal of antibiotics within 3360 min,and the degradation rate constant showed the trend of sulfamethazine>levofloxacin>ciprofloxacin>sulfamethoxazole>roxithromycin.A total of 33 possible degradation products were i dentified for the five antibiotics,some of which may have stronger ecotoxicity than their parent compounds,and the peak area of degradation products generally increased first and then decreased with time.This study shows that in the advanced oxidation reaction system,in addition to paying attention to the degradation of parent compounds,it is also necessary to pay attention to the changes of toxic degradation products to reduce the ecological toxicity of antibiotic in groundwater.