泰乐菌素的超声波降解效果及机制

为研究超声波对水体中大环内酯类抗生素的去除效果,以典型的专用兽药抗生素泰乐菌素(TYL)为研究对象,考察初始浓度、溶液pH值、超声波功率、超声波处理时间对超声波降解效果的影响。在此基础上进一步考察H_2O_2和蒙脱石分别与超声波联合降解TYL的效果,并对TYL的超声波降解机制进行了探讨。结果表明:超声波对TYL有一定的降解效果,在初始浓度10 mg·L~(-1)、pH值11、超声波功率280 W、超声波处理时间90 min的条件下,TYL的降解率为72%。自由基清除剂正丁醇的添加显著抑制了TYL的降解,而且不同超声波功率、超声波处理时间和不同初始浓度及pH值条件下羟基自由基的浓度变化与TYL降解率呈正相关,表明TYL超声波的降解机制可能主要是羟基自由基的氧化。溶液中添加H_2O_2或蒙脱石均对TYL超声波降解产生协同作用,TYL的去除率可分别提高至80.9%和93.9%。H_2O_2可直接氧化TYL、促进·OH生成;蒙脱石的吸附性能及其中少量的铁均可影响溶液中·OH含量。H_2O_2或蒙脱石联合超声波降解TYL的降解效果和降解机制与添加物质的性质密切相关,不能简单归因于羟基自由基的氧化。研究表明,合适的超声波处理方法对大环内酯类抗生素有很好的去除效果,可以考虑将超声波法用于含抗生素废水处理的工艺中。

The efficiency and mechanism of ultrasonic tylosin degradation

In order to study the effect of ultrasonic waves on the removal of macrolide antibiotics from a water body, the influences of the initial concentration, pH value of the solution, ultrasonic power, and ultrasonic treatment time on ultrasonic degradation were investigated using the common veterinary antibiotic, tylosin(TYL). Moreover, combining H₂O₂ or montmorillonite with ultrasonic treatment was carried out in order to investigate the combined function of TYL degradation. On this basis, an ultrasonic degradation mechanism of TYL was also proposed in this paper. The results showed that ultrasonic treatment could degrade TYL effectively. The TYL degradation rate was 72% with an initial concentration of 10 mg·L^-1 TYL, pH of 11, ultrasonic power of 280 W, and ultrasonic treatment time of 90 min. The ultrasonic degradation of TYL was noticeably inhibited by the addition of the free radical scavenger. Moreover, the concentration of free radicals was positively correlated with the degradation rate of TYL under experimental conditions. These results indicated that the free radical played an important role in the ultrasonic degradation of TYL, and the oxidation of a hydroxyl radical may be the main mechanism of ultrasonic degradation. A synergistic phenomenon for the ultrasonic degradation of TYL was observed after an appropriate amount of H₂O₂/montmorillonite was added to the solution. The degradation efficiency of TYL was enhanced under both conditions. The ultrasonic degradation rate of TYL reached 80.9% and 93.9% when H₂O₂ or montmorillonite were combined with ultrasonic treatment, respectively. Direct oxidation and promotion of ·OH occurred in the process of combining H₂O₂ with ultrasonic treatment. For montmorillonite, the synergism mechanism might be due to the effect on ·OH concentration by adsorption characteristics and Fe₂O₃ in montmorillonite. The synergy of combined ultrasound degradation for antibiotics cannot be attributed solely to the oxidation of hydroxyl radicals, and it is closely related to the characteristics of any added substances. The results indicated that macrolide antibiotics could be removed efficiently by an appropriate ultrasound method. The application of ultrasound in the treatment of antibiotics wastewater should be considered.