腐殖酸对土壤中有机污染物化学氧化降解的影响及分子机制

Iron-bearing minerals-based in situ chemical oxidation remediation technology in soil has attracted wide attention. Humic acids (HA) in soil inevitably have an important impact on the oxidative degradation of organic pollutants, but the mechanism is not yet clear. In this project, homogeneous and easily tailored HA model substances will be constructed using an oriented synthesis strategy then its molecular structure will be modified. So, a series of HA with different redox activity, complexing/chelating ability and hydrophobic/hydrophilic property will be obtained. Various techniques including three-dimensional excitation emission matrix fluorescence spectrum, Fourier transform infrared spectrum, synchrotron radiation techniques, in situ attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectrum and two-dimensional correlation analysis will be used to investigate the reaction of HA at the interface of iron-bearing minerals, track in situ and real-time changes in the molecular microstructure of iron-bearing minerals interface and dynamically monitor the direction and process of the reaction. As a consequence, the coupling mechanism of the complex/chelate and redox reaction of HA at the molecular level and influence of HA on adsorption-desorption of organic pollutants will be revealed. In addition, the kinetics of chemical oxidation degradation of organic pollutants will be studied, aiming to elucidate the regulating effect of HA and carry out the correlation analysis of chemical oxidation degradation of organic pollutants with the structure and properties of HA. Finally the molecular mechanism for the effects of HA will be elucidated. The results are expected to lay a theoretical foundation for developing a highly efficient in situ chemical oxidation remediation technology for organic contaminated soil.

基于土壤中含铁矿物的土壤原位化学氧化修复技术引起人们的广泛关注。土壤中的腐殖酸（HA）不可避免的对有机污染物的化学氧化降解产生重要影响，但影响机制尚不清楚。本项目拟采用导向性合成策略构建均质性和易调控的HA模型化合物，并对其分子结构进行修饰，合成一系列具有不同氧化还原活性、络合/螯合能力和亲水/疏水性能的HA；采用三维荧光光谱、红外光谱、同步辐射、在线ATR-FTIR及二维相关谱等技术，研究HA在含铁矿物界面的反应，原位、实时跟踪含铁矿物界面分子微观结构变化，实现对反应方向和进程的动态监控；在分子水平上阐明HA的络合/螯合反应、氧化还原反应的耦联作用机制，明确HA对有机污染物吸附-解吸的影响；开展有机污染物化学氧化降解动力学研究，分析HA的调控作用，对有机污染物化学氧化降解与HA分子结构、性能进行关联分析，最终阐明HA影响的分子机制；为建立高效的有机污染土壤原位氧化修复技术奠定理论基础。

基于土壤中含铁矿物的土壤原位化学氧化修复技术引起人们的广泛关注。土壤中的腐殖酸不可避免的对有机污染物的化学氧化降解产生重要影响，本项目以土壤中常见的含铁矿物针铁矿和磁铁矿作为研究对象，系统研究了其催化过硫酸盐氧化降解有机污染物的性能，重点研究其晶面结构的调控以及不同暴露晶面对有机污染物吸附、催化降解的影响机制；特别是，土壤中的腐殖酸对该体系氧化降解有机物的影响因素及机制进行深入系统的研究；系统研究了催化剂活化过硫酸盐的性能、影响有机污染物降解因素、有机污染物降解动力学、自由基形成动力学以及降解机理等内容；此外，运用插层阴离子调控、缺陷工程、形貌工程、原子调节、表面修饰等调控策略对镍铁类水滑石（LDHs）基催化剂进行改性，以其作为催化剂活化过硫酸盐降解水中有机污染物；采用“种子内嵌外延生长”和“模板牺牲”的策略合成了一种LDHs基催化模块，并配套设计“填充柱”装置连续处理有机废水。本项目执行期间发表标注本基金的SCI收录论文17篇，申请国家发明专利4项，提交会议论文3篇，培养研究生8人（已毕业4人）。