纳米零价铁降解PCBs污染土壤过程中的氧化作用及机制

项目名称： 纳米零价铁降解PCBs污染土壤过程中的氧化作用及机制

项目编号： No.21307141

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 环境科学、安全科学

项目作者： 汪玉

作者单位： 中国科学院南京土壤研究所

项目金额： 25万元

中文摘要： 多氯联苯（PCBs）是目前备受关注的持久性有机污染物之一，研究已发现纳米零价铁对PCBs有很好的降解作用，但过去研究主要着重于其还原脱氯过程，而实际环境中由于很难存在绝对的厌氧条件导致纳米零价铁在氧气存在时会传递电子生成超氧自由基，从而诱发类Fenton反应，改变反应路径。本项目针对纳米零价铁修复PCBs污染土壤过程中的氧化作用开展深入研究，拟考察氧气存在下纳米零价铁降解PCBs污染土壤洗脱液中PCBs的氧化作用及其机制，其中，利用电子顺磁共振技术（EPR）检测降解过程中的自由基种类，通过气相色谱-质谱联用仪（GC-MS）鉴定降解产物，并考察自由基对纳米零价铁修复PCBs过程中的氧化贡献比例；同时，模拟实际环境考察不同环境因子对该氧化过程的影响。以期为纳米零价铁修复PCBs污染土壤的应用研究领域提供新的理论和实践。

中文关键词： 多氯联苯；纳米零价铁；pH自动控制；氧化作用；羟基自由基

英文摘要： Polychlorinated biphenyls (PCBs) are one group of persistent organic pollutants (POPs) that are of international concern. In the past, the degradation of PCBs using nanoscale zero valent iron (NZVI) mainly focused on its reductive dechlorination effect. However, the field environment is difficult to be controlled under anaerobic conditions completely. The corrosion of NZVI by oxygen (O2) can produce strong oxidants capable of transforming recalcitrant contaminants, providing a new approach for the oxidative treatment of contaminated soil. The mechanism through which the NZVI/O2 system produces oxidants involves the two-electron oxidation of NZVI followed by the Fenton reactions. Therefore, the main objective of this study will focus on the oxidation in the process of the degadation of PCBs contaminated soils extracted solutions by solvent in the NZVI/O2 system, and elucidate the role of reactive oxygen species (ROS) generated by NZVI in this process.The related mechanism of oOH generated by NZVI will be studied by investigating the formation of H2O2, Fe(II) and O2o? in this process. The degradation products of PCBs are determined by gas chromatography-mass spectrometry (GC-MS) with different reaction conditions. Electron Paramagnetic Resonance (EPR) technique is used to identify the radical species generated in

英文关键词： PCBs；NZVI；pH automatic control；Oxidation；hydroxyl radical