Tetracycline degradation by ozonation in the aqueous phase: Proposed degradation intermediates and pathway
Tetracycline degradation by ozonation in the aqueous phase: Proposed degradation intermediates and pathway
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DOI：
10.1016/j.jhazmat.2010.05.063
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发表时间：
2010-09-15
影响因子：
13.6
通讯作者：
Jung, Jin-Young
中科院分区：
文献类型：
--
作者：
Khan, M. Hammad;Bae, Hyokwan;Jung, Jin-Young
研究了四环素（TC）在pH值为2.2和7.0的水溶液中臭氧化的过程，考察了pH变化、官能团的质子化和解离以及自由基暴露变化对其转化途径的影响。液相色谱-三重四极杆质谱法检测了大约15种臭氧化产物，并揭示了它们的产生和随后的降解模式。在pH为2.2的臭氧化过程中，根据TC的结构、臭氧化化学和质谱数据，提出了TC的降解途径。在C11a-C12和C2-C3双键、芳香环和氨基上臭氧化TC分别生成m/z 461、477、509和416。在上述地点进一步臭氧化得到m/z 432、480、448、525和496。在两个ph值下，TOC的去除率在2 h后达到最高约40%，而TC在4 ~ 6 min内被完全去除。TOC去除率低可能是由于产生难降解产物和高TC浓度时臭氧供应不足所致。臭氧化对TC急性毒性的降低在pH 7.0比pH 2.2更快，但臭氧化2 h后，两种pH值的最大降幅均仅为40%左右。本研究试图了解转化产物、途径、急性毒性与溶液中残留有机物的数量之间的关系。总的来说，臭氧化是一种很有前途的去除TC和初始产物的方法。(C) 2010 Elsevier B.V.版权所有
During the ozonation of tetracycline (TC) in aqueous media at pHs 2.2 and 7.0, the effects of pH variations, protonation and dissociation of functional groups and variation in free radical exposure were investigated to elucidate the transformation pathway. Liquid chromatography-triple quadrupole mass spectrometry detected around 15 ozonation products, and uncovered their production and subsequent degradation patterns. During ozonation at pH 2.2, the TC degradation pathway was proposed on the basis of the structure, ozonation chemistry and mass spectrometry data of TC. Ozonation of TC at the C11a-C12 and C2-C3 double bonds, aromatic ring and amino group generated products of m/z 461, 477, 509 and 416, respectively. Further ozonation at the above mentioned sites gave products of m/z 432, 480, 448, 525 and 496. The removal of TOC reached a maximum of approximate to 40% after 2 h of ozonation, while TC was completely removed within 4-6 min at both pHs. The low TOC removal efficiency might be due to the generation of recalcitrant products and the low ozone supply for high TC concentration. zonation decreased the acute toxicity of TC faster at pH 7.0 than pH 2.2, but the maximum decrease was only about 40% at both pHs after 2 h of ozonation. In this study, attempts were made to understand the correlation between the transformation products, pathway, acute toxicity and quantity of residual organics in solution. Overall, ozonation was found to be a promising process for removing TC and the products initially generated. (C) 2010 Elsevier B.V. All rights reserved.