紫外光降解硝酸盐体系中四环素

Tetracycline degradation under UVA irradiation in nitrate system

为了考察紫外光照射下四环素(tetracycline,TC)在硝酸盐(NO3-)体系中的降解过程,研究了初始pH、TC初始浓度、NO3-浓度、腐殖酸以及磷酸盐等环境因子对TC光降解的影响,利用ESR检测和自由基猝灭实验,量化分析体系中不同氧化途径对TC去除的贡献率。结果表明:TC在NO3-体系中的光降解受pH影响显著;腐殖酸和磷酸盐对TC的降解表现出不同程度的抑制作用;TC通过直接光解、HO·、1O2和O2·-氧化4种途径降解,当TC浓度为10.0 mg·L-1,NO3-浓度为1.0 mmol·L-1,pH为7.0时光照150 min后,不同途径的贡献率分别为60.4%、25.6%、8.9%和5.1%。结果有助于了解TC的环境化学行为,为TC治理提供参考。

In order to investigate tetracycline(TC)degradation in nitrate system under the UVA-irradiation,the influences of initial pH,initial TC concentration,nitrate concentration,humic acid dosage and phosphate concentration on TC photodegradation process were studied.The contribution efficiencies of different oxidative pathways to TC removal were also quantified by using the electron spin resonance(ESR)detection and radicalquenching experiments.Results showed that the photodegradation of TC in nitrate solution was strongly affected by pH,humic acid and phosphate showed different degrees of inhibition against this process.The four pathways for TC degradation were identified as the direct photolysis,HO·,1O2 and O2·-oxidations.After 150 min irradiation treatment of 10.0 mg·L-1 TC in 1.0 mmol·L-1 nitrate system at pH 7.0,the contribution efficiencies of direct photolysis,HO·oxidation,1O2 oxidation and O2·-oxidation were 60.4%,25.6%,8.9%and 5.1%,respectively.Results can help to gain insight into the environmental behavior of TC and offer reference to TC-contamination treatment.