铁氧化物介导厌氧生物强化还原硝基芳香族化合物的调控机制

As one kind of typical pollution in industrial wastewater, nitroaromatic compounds (NACs) pose a seriously threat to human health and ecological environmental. Thus, there are significant needs of appropriate methods for the remediation of the sites contaminated by NACs. Considering the conventional anaerobic bioprocess is usually limited by low removal rate and poor stability, (semi) conductive iron oxides, which can act as the efficient electron transfer mediator, will be added into the anaerobic system for the efficient reduction of NACs in this project. To obtain the key control strategies of this coupled system, the extracellular electron transfer ability and pollution reduction performance will be analyzed under different iron oxides characteristics, including type, particle size and dosage. In addition, the effects of iron oxides on degradation kinetics, metabolic pathways and the microbial community structure succession will be characterized to reveal synergistic effect of iron oxides and anaerobic microorganism for pollutant removal. In order to be further from the theoretical clarity the main functional and the regulation mechanism between the iron oxides and anaerobic microorganism, a mechanism model will be established. Furthermore, the stability and practical application potential of coupled system for the treatment of NACs containing wastewater will be evaluated under complex water quality conditions. Technical basises for the industrialized application of iron oxides coupled anaerobic system in NACs containing wastewater treatment will be provided through the exploration of the above key scientific problems.

硝基芳香族化合物（NACs）作为工业废水中一种典型污染物，对人类健康和生态环境造成了严重的威胁，有必要对其引起的污染进行针对性的处理。针对传统厌氧生物技术在处理NACs过程中存在效率低、稳定性差等问题，本项目拟向厌氧生物体系内引入（半）导电性铁氧化物，利用其良好的电子传递介导能力实现NACs的高效还原转化。考察不同类型、粒径、投加量的铁氧化物对污染物还原性能及胞外电子传递能力的影响，掌控耦合系统的关键调控策略；研究铁氧化物对降解动力学、代谢途径及群落结构等的影响规律，揭示铁氧化物与厌氧生物之间的协同作用机制；构建铁氧化物与厌氧生物的机理模型，从理论上进一步阐明两者的主要作用机理及调控机制；探讨在复杂水质条件下耦合体系处理NACs废水的性能，评估耦合系统的稳定性及其实际应用的潜能。通过上述关键科学问题的探索，可望为铁氧化物-厌氧生物耦合系统在处理含NACs实际废水的工业化应用提供技术储备。

对硝基芳香族化合物（NACs）进行厌氧降解是一种经济有效的预处理方法，但普遍存在还原效率低、系统稳定性差等问题。本项目采用水热法，成功制备了形貌可控，形态均一的纳米四氧化三铁纳米颗粒，并成功构建了铁氧化物-耦合厌氧生物系统。实验结果显示，初始浓度为45 mg/L的对硝基氯苯（4-CNB）在耦合系统内经反应58 h后去除率达到了68.95±1.42%，显著高于厌氧生物对照系统的57.11±4.08%和非生物对照系统内的7.44±1.10%，表明铁氧化物与厌氧生物在降解硝基芳香族化合物方面具有显著的耦合作用。同时，铁氧化物可显著降低厌氧生物系统内的氧化还原电位，提高电子传递效率和电导率，并可以维持较稳定的pH，这些均有利于NACs的还原降解。在铁氧化物刺激下，与异化铁还原和污染物生物降解相关的功能物种的相对丰度也增加。在长期连续流实验中，添加铁氧化物不仅提高了厌氧系统对环境胁迫（如高污染物浓度、低水力停留时间和低基质浓度的抵抗能力），而且加速了污泥的颗粒化。在以厌氧消化1号模型（ADM1）的基础上，成功构建了铁氧化物介导的厌氧生物模型。模拟结果与实验结果的充分验证，进一步表明了铁氧化物对厌氧生物的强化作用。综上所述，该耦合技术在处理含NACs废水中具有广泛的应用潜力