高铁酸钾氧化降解氧氟沙星的机理

以喹诺酮类抗生素氧氟沙星（OFL）为目标物质，研究高铁酸钾（Fe （VI））对OFL的去除及氧化机理.采用高效液相色谱仪（HPLC）、液相色谱-质谱联用仪（UPLC-QTOF-MS）等方法，考察Fe （VI）投加量、pH值、温度和共存物质等因素对OFL降解效果的影响，分析反应动力学，计算过程中Fe （VI）的贡献率，识别Fe （VI）氧化OFL的产物并推测主要反应路径.结果表明：当Fe （VI）与OFL的物质的量比为40：1、pH值为8、温度为25℃时，反应30min后OFL的降解率达到92.38%，前5min快速反应阶段，OFL的降解符合伪二级反应动力学.反应过程的活化能为28.17kJ/mol.反应中Fe （VI）及中间高价态铁的贡献率为70.34%，且腐殖酸会显著抑制该反应.通过对氧化产物进行分析提出了Fe （VI）氧化OFL的3条主要路径.OFL经脱羧、去甲基、脱羰、羟基化等反应，实现其分子上喹诺酮取代基、哌嗪基环及恶嗪基环的开环.

Oxidation and degradation mechanisms of ofloxacin by potassium ferrate

The oxidation and degradation mechanisms of quinolone antibiotic ofloxacin (OFL) by potassium ferrate (Fe (VI)) were studied. High performance liquid chromatography(HPLC), liquid chromatograph mass spectrometer(UPLC-QTOF-MS) and other methods were used to investigate the effects of Fe (VI) dosage, pH, temperature and coexisting substances on OFL removal, analyze the reaction kinetics, calculate the contribution rate of Fe(VI) in the process of OFL oxidation, identify the products of Fe(VI) and predict the main reaction pathways.The results show that the degradation efficiency of OFL reached 92.38% after 30 minutes of oxidation, with the molar ratio of Fe (VI) to OFL of 40:1, pH of 8 and temperature of 25 ℃. In the first 5 minutes' rapid reaction stage, OFL degradation conformed to pseudo second-order reaction kinetics, and the activation energy was 28.17kJ/mol. The contribution of Fe (VI) and the high-valent intermediate iron species to OFL removal was 70.34%, and humic acid significantly inhibited the reaction. Three main oxidation pathways for OFL degradation by Fe (VI) were proposed based on the analysis of reaction products, and the ring cleavages of quinolone, piperazine and oxazine rings were mainly achieved through decarboxylation, demethylation, decarbonylation and hydroxylation.