崔延瑞,闫晓鹏,吴青,皮运清,鲍林林,马凯丽,康威.超声/K2S2O8体系降解左氧氟沙星过程中活性自由基产生机制[J].环境科学学报,2020,40(9):3241-3249
超声/K2S2O8体系降解左氧氟沙星过程中活性自由基产生机制
- Generation mechanism of active free radicals in the processes of levofloxacin degradation in US/K2S2O8 system
- 基金项目：河南省自然科学基金（No.182300410154）；河南省高等学校重点科研项目（No.17A610009，18B610003）；河南省科技厅重点科技攻关项目（No.172102310698）
- 崔延瑞
- 河南师范大学环境学院, 黄淮水环境与污染防治教育部重点实验室, 河南省环境污染控制重点实验室, 河南省水处理关键技术国际联合实验室, 新乡 453007
- 闫晓鹏
- 河南师范大学环境学院, 黄淮水环境与污染防治教育部重点实验室, 河南省环境污染控制重点实验室, 河南省水处理关键技术国际联合实验室, 新乡 453007
- 吴青
- 河南师范大学环境学院, 黄淮水环境与污染防治教育部重点实验室, 河南省环境污染控制重点实验室, 河南省水处理关键技术国际联合实验室, 新乡 453007
- 皮运清
- 河南师范大学环境学院, 黄淮水环境与污染防治教育部重点实验室, 河南省环境污染控制重点实验室, 河南省水处理关键技术国际联合实验室, 新乡 453007
- 鲍林林
- 河南师范大学环境学院, 黄淮水环境与污染防治教育部重点实验室, 河南省环境污染控制重点实验室, 河南省水处理关键技术国际联合实验室, 新乡 453007
- 马凯丽
- 河南师范大学环境学院, 黄淮水环境与污染防治教育部重点实验室, 河南省环境污染控制重点实验室, 河南省水处理关键技术国际联合实验室, 新乡 453007
- 康威
- 河南师范大学环境学院, 黄淮水环境与污染防治教育部重点实验室, 河南省环境污染控制重点实验室, 河南省水处理关键技术国际联合实验室, 新乡 453007
- 摘要：以左氧氟沙星水溶液为实验材料，比较了超声、K2S2O8和超声/K2S2O8 3种体系对左氧氟沙星的去除效果，并通过K2S2O8浓度、超声功率、pH值及添加异丙醇或叔丁醇的对照实验，分析了超声/K2S2O8体系去除左氧氟沙星过程中活性自由基产生机制及变化规律.结果表明：在左氧氟沙星浓度30 mg·L-1、过硫酸盐浓度20 mmol·L-1、超声功率360 W、pH=9的条件下，反应180 min，超声/K2S2O8体系中左氧氟沙星的去除率达到90%，超声体系为13.89%，K2S2O8体系只有5.82%；超声/K2S2O8体系存在协同作用，产生了更多的SO4-·和·OH；超声/K2S2O8体系中·OH的产生有超声和链式反应两种途径，其中，链式反应的贡献较大，K2S2O8的存在是·OH产生的必要条件，链式反应在自由基浓度较高条件下会发生猝灭，K2S2O8浓度对SO4-·的产生有重要影响，但K2S2O8浓度过高对SO4-·的产生无益；超声/K2S2O8体系降解左氧氟沙星过程中SO4-·与·OH是通过链式反应共同增减的，·OH在反应中占主导地位；反应初期·OH作用较大，随反应时间延长逐渐减小，SO4-·作用在反应初期较小，随着反应进行作用逐渐增大.
- Abstract：In this study, the degradation of levofloxacin in aqueous solution with Ultrasonic (US), K2S2O8 and US/K2S2O8 were investigated. Production of active free radicals in US/K2S2O8 system were studied based on the variation of K2S2O8 concentration, ultrasonic power, pH value and the addition of isopropanol or tert butanol. The results showed that under the conditions of levofloxacin concentration 30 mg·L-1, the ultrasonic power 360 W, K2S2O8 concentration 20 mmol·L-1 and pH=9, the removal rate of levofloxacin in US/K2S2O8, K2S2O8 and US system after 180 min was 90%, 5.82% and 13.89%, respectively. The synergistic effect in US/K2S2O8 system facilitated the production of more SO4-·and·OH free radicals. Moreover, both ultrasonic and chain reaction were capable to produce·OH in US/K2S2O8 system, and the chain reaction was the major contributor. The existence of K2S2O8 was also the necessary condition for·OH production. The chain reaction would be quenched when the concentration of free radicals at high level. The concentration of K2S2O8 had a significant effect on the production of SO4-·, but the high concentration of K2S2O8 would not benefit the production of SO4-·. In the processes of levofloxacin degradation in US/K2S2O8 system SO4-·and·OH free radicals were increasing and decreasing together by chain reaction, and·OH played a dominant role in the reaction. It shows that·OH plays a major role in the early stage of the reaction, and gradually weakens with the extension of the reaction time. SO4-·has little contribution in the early stage of the reaction, and gradually increases with the proceeding of the reaction.
