粘土矿物负载纳米零价铁/类芬顿体系对土壤中多溴联苯醚的联合降解机制研究

The accumulation of polybrominated diphenyl ethers (PBDEs) in soil has become increasingly severe which seriously threatens the ecological environment. Developing efficient removal method to eliminate PBDEs has become an important task to protect soil environmental. Based on the principles of nanoscale zero-valent iron (nZVI) based materials reduction and Fenton-like oxidation, this project aims to synthesize clay-supported nZVI materials with high catalytic activity and build a clay-supported nZVI reductive debromination/Fenton-like oxidation system for degrading PBDEs efficiently. The reaction type of removing higher brominated BDEs in soil by the clay-supported nZVI/Fenton-like system will be confirmed. And the coupled and cooperative relationship between reductive debromination and oxidative degradation will be also established. The degradation dynamic characteristics of PBDEs in soil by the clay-supported nZVI/Fenton-like system will be investigated through the kinetics experiments. Combined with the identification of PBDEs degradation products by LC-MS/MS and GC-MS, the reductive/oxidative degradation mechanism of PBDEs in soil and the debromination pathways will be elucidated. The influence of materials properties and typical soil environmental factors on the degradation performance will be discussed. These results can provide a theoretical basis for the rapid and efficient remediation of PBDEs contaminated soils.

多溴联苯醚（PBDEs）在土壤中污染累积日趋严重，威胁生态环境安全，寻求高效的PBDEs去除方法已成为土壤环境领域面临的重要课题。基于纳米零价铁基材料的还原和类芬顿氧化技术原理，本项目拟在高催化活性粘土矿物负载纳米零价铁的制备与表征基础上，构建粘土矿物负载纳米零价铁还原脱溴/类芬顿强化氧化联合降解体系，探明其对土壤中高溴代BDEs的降解反应类型，确立还原脱溴和氧化降解双重过程的耦合与协作关系。通过动力学实验探讨粘土矿物负载纳米零价铁/类芬顿体系联合降解土壤中PBDEs的动力学特征。结合LC-MS/MS和GC-MS对PBDEs降解产物的鉴定结果，揭示粘土矿物负载纳米零价铁还原/类芬顿氧化联合降解土壤中PBDEs的机理和PBDEs的脱溴路径，并考察材料性质与典型环境因素对粘土矿物纳米零价铁/类芬顿体系降解性能的影响机制。本项目的开展旨在为PBDEs污染土壤的快速、高效修复提供理论基础。

多溴联苯醚（PBDEs）是一类代表性持久性有机污染物，在土壤中普遍检出且污染累积日趋严重，对生态环境安全和人体健康存在一定的威胁。纳米零价铁基材料对卤代POPs具有良好的还原脱溴性能，然而通过还原脱溴并不能实现对PBDEs的高效矿化。本项目基于纳米零价铁基材料的还原脱溴和类芬顿氧化技术原理，制备并筛选出了具有高催化活性的粘土矿物负载纳米零价铁基材料，并构建了粘土矿物负载纳米零价铁基材料还原脱溴/类芬顿强化氧化联合降解体系。通过降解动力学实验，探讨了粘土矿物负载纳米零价铁基材料/类芬顿体系联合降解溶液和土壤中PBDEs的动力学特征和主要影响因素。项目结合PBDEs降解产物的鉴定结果，揭示了粘土矿物负载纳米零价铁还原/类芬顿氧化联合降解土壤中代表性PBDEs的机理和PBDEs的脱溴路径，确立了反应体系中还原脱溴和氧化降解双重过程的耦合与协作关系。本项目研究成果可为纳米零价铁基材料用于PBDEs污染土壤的快速、高效修复提供技术支撑。