电子束辐照降解水中氧氟沙星的研究

应用电子直线加速器初步探索了水体中氧氟沙星的辐照降解影响条件及降解机理.对初始浓度为20mg/L的氧氟沙星水溶液进行了辐照降解研究，分别选取了0.5kGy，1.0kGy，2.0kGy，3.0kGy，5.0kGy共5个剂量组，以研究辐照吸收剂量对降解效率的影响，同时分别对氧氟沙星水溶液进行空气饱和（水合电子清除剂）、氮气饱和、添加0.005mol/L及0.05mol/L氯化钠、添加0.05mol/L叔丁醇（羟基自由基清除剂）、添加0.005mol/L碳酸钠、添加0.005mol/L硫酸钠等方法进行处理，以探究降解过程中辐照水体产生自由基对氧氟沙星降解的贡献率.结果表明，以空气饱和进行处理，可提高氧氟沙星的降解率，辐照吸收剂量为2.0kGy时降解率可达99%.反之，加入氯化钠、叔丁醇和碳酸钠抑制了氧氟沙星的降解，加入硫酸钠则影响不大，表明羟基自由基在氧氟沙星降解中起关键作用.通过应用超高效液相色谱-质谱（UPLC-MS）对降解产物的分析鉴定，推测出了氧氟沙星的降解转化途径.

Studies on the degradation of ofloxacin by Electron Beam irradiation in aqueous solution

The influence factors and mechanism of the degradation of ofloxacin in water by electron linear accelerator was investigated. In order to study the role of radicals, ofloxacin solution with initial concentration of 20mg/L was used in degradation with the doses of 0.5, 1.0, 2.0, 3.0 and 5.0 kGy, respectively, for each of different conditions. The solution were saturated with air as a scavenger of hydrated electron, saturated with nitrogen, containing 0.005 mol/L sodium chloride, 0.05 mol/L sodium chloride, 0.05 mol/L tert-butanol as scavenger of hydroxyl radical, 0.005 mol/L sodium carbonate, and 0.005 mol/L sodium sulfate, respectively. It was found that the degradation rate was promoted under the condition of saturated air, and could reach 99% with irradiation dose of 2.0 kGy. The presence of sodium chloride, tert butyl alcohol and sodium carbonate significently inhibited the degradation rate of ofloxacin, however, sodium sulfate had little effect on the degradation. This fact indicates that hydroxyl radicals play a key role in the degradation of loxacin. Based on the product analysis in irradiation by ultra performance liquid chromatography-mass spectrometry (UPLC-MS), the degradation pathway has be deduced as well.