缺氧系统中铁氧化物的归趋及其促进吡啶生物降解的机制

In this project, in order to overcome the low degradation efficiency of N-heterocyclic compounds such as pyridine under anaerobic or anoxic conditions, a biological regulation technology based on the addition of iron oxides is proposed to enhance pyridine degradation under anoxic condition. The type and size of iron oxides will be controlled, and the stimulative role of iron oxides with different type and size in anoxic degradation of pyridine will be investigated. The improvement in terms of pyridine degradation kinetics and metabolic pathways at the presence of iron oxides will be studied. The release of iron ions, transformation products and slow-release mechanism, the formation of surface-bound iron compounds will be investigated, in order to reveal the occurrence state of iron oxides, the stimulative role of transformation products of iron oxides and micro-interface between solid phase and liquid phase in pyridine anoxic degradation system. The effect of iron oxides on microbial community structure will be clarified based on clone library and FISH-CLSM analysis, with the dynamic change after the addition of iron oxides revealed as also. Based on the above investigation, Anaerobic Digestion Model No 1 (ADM1) and denitrification model will be used to develop the mechanism model for the coupling interaction between iron oxides and pyridine anoxic degradation. The main mechanism involved in the enhanced pyridine anoxic degradation at the presence of iron oxides will be revealed systematically at theoretical level.

针对吡啶等含氮杂环化合物在厌氧/缺氧条件下降解效率低下的问题，本项目提出了基于铁氧化物的生物调控技术，强化缺氧降解系统中的吡啶降解效率。对铁氧化物的类型和尺寸进行调控，探讨不同类型和尺寸的铁氧化物对吡啶缺氧降解过程的促进作用，探讨铁氧化物存在条件下吡啶降解动力学和代谢途径的变化；考察吡啶缺氧降解系统中铁离子的释放、铁氧化物的转化产物和缓释机理、表面结合铁复合物的形成，揭示吡啶缺氧降解系统中铁氧化物的赋存状态、铁氧化物转化产物的促进作用以及固液微界面对吡啶降解的意义；采用基因克隆文库和FISH-CLSM技术探究铁氧化物对生物群落结构的影响，探究铁氧化物作用过程中菌群的动态变化；在上述研究的基础上，以厌氧消化和反硝化模型为基础，构建铁氧化物与吡啶缺氧降解耦合作用的机理模型，从理论上系统地阐述铁氧化物强化吡啶缺氧生物降解的主要作用机制。

针对吡啶、氯酚等典型难降解污染物在厌氧/缺氧条件下降解效率低下的问题，本项目提出了基于铁氧化物强化的难降解污染物厌氧/缺氧生物降解的技术，显著提高了难降解污染物的降解效率。首先探讨了不同类型铁氧化物对难降解污染物降解过程的促进作用，研究发现相比Fe3O4和FeOOH，Fe2O3具有显著的促进作用；Fe2O3耦合厌氧系统具有更高的乙酸产生量、更高的甲烷产量以及更低的氧化还原电位和反应pH；考察了铁氧化物耦合厌氧系统中铁离子的释放、铁氧化物的转化产物以及铁氧化物在污泥中的赋存状态；揭示了铁氧化物对生物系统中微生物的多样性以及群落结构的影响，结果表明还原脱氯、发酵、电子转移和产甲烷功能菌属可得到有效富集；通过对生物系统中电子传递相关酶和蛋白的分析，发现了铁氧化物对难降解污染物生物降解的促进作用模式，阐明了铁氧化物与厌氧生物反应的耦合机理。此外，本项目重点探讨了铁氧化物投加量、污染物浓度、外加电子供体投加量等关键参数对污染物降解的影响，探究了厌氧生物系统的长期运行稳定性，研究结果可为铁氧化物生物强化技术在高毒性、难降解化工废水处理领域的应用提供技术基础。围绕课题研究，累计发表SCI论文9篇，授权国家发明专利2件，获得中国石油和化学工业联合会科技进步奖1项，培养博士研究生1名、硕士研究生5名。