生物炭持久性自由基诱导产生ROS修复洞庭湖表层底泥抗生素污染的行为与机理研究

The long-term rapid development of intensive livestock farming has led to serious antibiotic pollution in Dongting Lake Wetland. Biochar amendment is an important in-situ remediation method for the remediation of refractory organic compounds contaminated soil or sediment. However, the research is focus on the immobilization/stabilization function of biochar and the reaction activity of persistent free radicals is ignored. Existing studies have confirmed that biochar persistent free radicals can induce reactive oxygen species (ROS) to degrade refractory organic compounds. But the involved mechanism of using biochar persistent free radicals induced ROS to repair antibiotics polluted surface sediment has not yet been elucidated. This project selects East Dongting Lake livestock breeding area as the research area. Firstly, the optimized preparation conditions are investigated and the prepared biochar, which is suitable for the remediation of antibiotics polluted surface sediment, is selected for the in-depth analysis of the biochar persistent free radicals’ reaction activity and formation mechanism. Further, the behavior mechanism of biochar persistent free radicals induced ROS for remediation of antibiotics polluted surface sediment is studied. Finally, the effect of the environmental aging on the physical and chemical properties of biochar and the repair behaviors are studied. This project comprehensively studied the behavior and mechanism of biochar persistent free radicals induced ROS for remediation of antibiotics polluted surface sediment. The purpose of this project is to provide practical reference and theoretical basis for the remediation of antibiotics polluted surface sediment of Dongting Lake.

集约化养殖业的长期迅速发展致使洞庭湖湿地受到严重的抗生素污染。生物炭应用于修复难降解有机物污染土壤或底泥是重要的原位修复方法，但研究重点长期集中在生物炭的固定/稳定化功能而忽视了其持久性自由基的反应活性。现有研究证实生物炭持久性自由基能够诱导产生活性氧自由基（ROS）修复难降解有机物污染，但利用生物炭持久性自由基诱导产生ROS修复表层底泥抗生素污染的有关机理尚未得到阐明。本项目拟以东洞庭湖禽畜养殖区为研究区域，优化制备条件得到适用于表层底泥修复的生物炭，并深入分析生物炭持久性自由基的反应活性与形成机理；进而研究生物炭持久性自由基诱导产生ROS修复湖泊表层底泥抗生素污染的行为与机理；最后研究环境老化作用对生物炭理化特性及其修复表层底泥抗生素污染行为的影响，综合探讨生物炭持久性自由基诱导产生ROS修复表层底泥抗生素污染的行为与机理。以期为洞庭湖表层底泥抗生素污染的修复提供实践参考与理论依据。

集约化养殖业的长期迅速发展导致洞庭湖及其周边湿地水体和底泥受到严重的抗生素污染，危害生态环境和人类健康。生物炭应用于修复难降解有机物污染水体或底泥具有广阔的应用前景，且生物炭持久性自由基诱导产生的活性自由基能够降解湿地环境介质中的抗生素等有机污染物。本项目首先研究了生物炭持久性自由基的反应活性与形成机理，利用电子顺磁共振技术研究了不同生物质类型及其组分对生物炭中持久性自由基形成的影响，发现生物炭中持久性自由基的含量随着生物炭中初始金属和酚类化合物含量的降低而急剧下降，且金属含量对持久性自由基形成的影响远大于酚类化合物；并进一步研究了异质金属对生物炭中持久性自由基形成的影响，在生物质引入铁元素的基础上，通过浸渍和共沉淀的方法引入异质金属，其中异质金属镍对生物炭持久性自由基的强度提升最为明显，为生物炭的调控制备提供了技术支撑。其次，本项目构建了生物炭/过氧化氢反应体系和生物炭负载双金属氧化物/过硫酸盐反应体系，研究了其对典型抗生素的降解行为与机理，其中生物炭/过氧化氢反应体系30min内对磺胺二甲基嘧啶的降解率可达85%，羟基自由基为主要的活性自由基，且生物炭以氧为中心的持久性自由基起主要诱导作用；生物炭负载双金属氧化物/过硫酸盐反应体系在30min内对磺胺二甲基嘧啶去除率高达99%，矿化率接近80%，展现出了高效、快速的污染修复潜力。本研究为开发基于生物炭反应活性的高级氧化技术修复湿地水体或底泥中的抗生素等有机物污染提供理论依据与技术支持。