Degradation of 5-FU by means of advanced (photo)oxidation processes: UV/H2O2, UV/Fe2+/H2O2 and UV/TiO2--Comparison of transformation products, ready biodegradability and toxicity.
Degradation of 5-FU by means of advanced (photo)oxidation processes: UV/H2O2, UV/Fe2+/H2O2 and UV/TiO2--Comparison of transformation products, ready biodegradability and toxicity.
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DOI：
10.1016/j.scitotenv.2015.04.111
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发表时间：
2015-09
期刊：
影响因子：
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通讯作者：
C. Lutterbeck;M. Wilde;E. Bagińska;C. Leder;Ê. L. Machado;K. Kümmerer
中科院分区：
文献类型：
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作者：
C. Lutterbeck;M. Wilde;E. Bagińska;C. Leder;Ê. L. Machado;K. Kümmerer
研究了UV/H2O2、UV/Fe2 +/H2O2和UV/TiO2三种不同的高级光氧化工艺对抗代谢药5-氟尿嘧啶（5-FU）的降解。在UV/H2O2和UV/TiO2实验中进行了不同H2O2和TiO2浓度的预筛选实验以确定最佳催化剂浓度，而UV/Fe2 +/H2O2过程通过Box-Behnken设计（BBD）通过改变pH、Fe2+和H2O2浓度进行了优化。在所有的照射实验中，5-FU被迅速去除。UV/Fe2 +/H2O2和UV/TiO2处理的矿化度最高，而UV/H2O2处理的矿化度最低。在高级（光）氧化过程中形成了六种转化产物，并使用低分辨率和高分辨率质谱进行了鉴定。它们中的大多数在反应过程中形成并进一步消除。5-FU的母体化合物不被生物降解，而UV/H2O2处理256 min后形成的光解混合物在闭瓶试验（CBT）中显示出明显的生物降解性改善，并且对费氏弧菌无毒。计算机模拟预测显示5-FU的致突变和遗传毒性效应为阳性警报。相反，沿着工艺产生的几种转化产物（TP）未提供致突变或遗传毒性活性的指示。一个例外是m/z 146的TP，在几种细菌致突变性模型中具有阳性警报，可能需要进一步的实验检测。结果表明，深度处理可以消除母体化合物及其毒性。然而，形成的转化产物仍然是有毒的。因此，晚期治疗后的毒性筛查是可行的。
The present study investigates the degradation of the antimetabolite 5-fluorouracil (5-FU) by three different advanced photo oxidation processes: UV/H2O2, UV/Fe2 +/H2O2and UV/TiO2. Prescreening experiments varying the H2O2and TiO2concentrations were performed in order to set the best catalyst concentrations in the UV/H2O2and UV/TiO2experiments, whereas the UV/Fe2 +/H2O2process was optimized varying the pH, Fe2 +and H2O2concentrations by means of the Box–Behnken design (BBD). 5-FU was quickly removed in all the irradiation experiments. The UV/Fe2 +/H2O2and UV/TiO2processes achieved the highest degree of mineralization, whereas the lowest one resulted from the UV/H2O2treatment. Six transformation products were formed during the advanced (photo)oxidation processes and identified using low and high resolution mass spectrometry. Most of them were formed and further eliminated during the reactions. The parent compound of 5-FU was not biodegraded, whereas the photolytic mixture formed in the UV/H2O2treatment after 256 min showed a noticeable improvement of the biodegradability in the closed bottle test (CBT) and was nontoxic towardsVibrio fischeri. In silico predictions showed positive alerts for mutagenic and genotoxic effects of 5-FU. In contrast, several of the transformation products (TPs) generated along the processes did not provide indications for mutagenic or genotoxic activity. One exception was TP with m/z 146 with positive alerts in several models of bacterial mutagenicity which could demand further experimental testing. Results demonstrate that advanced treatment can eliminate parent compounds and its toxicity. However, transformation products formed can still be toxic. Therefore toxicity screening after advanced treatment is recommendable.