基于金属有机骨架纳米复合材料的生物-光-电体系强化有机微污染物降解效能与机制

Organic micro-pollutants in water have the effects of permanence and bioaccumulation, which will destroy the biological metabolism cycle and the stability of the ecosystem. In this research topic, the key problems of the typical organic micro-pollutants removal in refractory wastewater are discussed, such as the low efficiency of degradation and mineralization, the ambiguity of degradation mechanism and the unclear transformation pathway. A nanomaterial based on metal-organic framework as a photoelectric catalyst for the electrode materials is prepared by surface in-situ self-assembly technology. The related mechanism between preparation, microstructure and photocatalytic activity of the photocatalytic materials is studied to determine the optimal preparation method that suitable for oxidation and reduction of typical micro-pollutants. On this basis, an integrated bio-photo-electrocatalytic system is developed, and the mechanisms of photocatalytic oxidation of bioanode and photocatalytic reduction of biocathode on the removal of micro-pollutants are clarified. Furthermore, the degradation mechanism and electron transfer mechanism of micro-pollutants in the system are explored to analyze the synergistic mechanism of microorganisms, photocatalysis, and electrocatalysis. In addition, the micro-photo-electro integrated system is built by integrating bioelectrochemical technology with the existing biological wastewater treatment processes to achieve the degradation and mineralization of refractory organic micro-pollutants, and to establish a comprehensive evaluation system for processes stability. It provides a theoretical basis and technical basis for the removal of organic micro-pollutants in the water/wastewater.

水体中有机微污染物具有持久性和生物累积效应，会破坏生物代谢循环和生态系统稳定性。本课题针对难降解废水中典型有机微污染物的降解矿化效能低、降解机制和转化途径不明确等关键问题，开发一种利用表面原位自组装技术制备的金属有机框架纳米材料作为光电催化剂，研究制备、微观结构、光电催化效能三者间的关联机制，确定适用于典型微污染物氧化还原的光催化材料制备方法；构建生物-光-电协同作用体系，阐明体系中光催化氧化生物阳极和光催化还原生物阴极对微污染物去除的作用机理，解析该技术体系中微污染物的降解机制及电子传递机制，揭示生物、光、电三者的协同作用机制；构建生物-光-电一体式耦合体系，将生物电化学技术与现有废水生物处理工艺结合，以实现难降解有机微污染物降解及矿化，并建立生物-光-电一体式工艺稳定性的综合评价体系。为推动水体中新兴有机微污染物的去除提供理论依据和技术基础。

生物电化学技术能够将微生物的电化学活性和降解功能结合，在难降解污染物方面具有重要潜力和开发价值，并逐渐成为一种处理难降解废水中有毒有机化合物的新型废水处理技术。针对污染物降解矿化效能低、降解机制和转化途径不明确等问题，本课题首先制备并优化了一种MOF复合材料UiO-66-NH2x@Mg/Al-LDHy，对材料的性能进行了优化表征，强化了污染物的催化去除达98%。其次构建生物电化学耦合体系，优化关键调控参数外加电压为0.7 V，溶解氧浓度3-4 mg L-1，生物填料填充率为40%时，效果最好，污染物去除率95%，COD去除率87%。进而解析污染物的降解途径及转化机制，揭示电极在污染物降解中的预处理和附着微生物的深度处理。最后建立了一体式耦合工艺，优化和调控一体式反应器对混合污染物去除的主控运行参数，解析污染物的降解转化规律，建立体系耦合及匹配机制，使得污染物去除率为95.2%，COD去除率为93.6%，总氮去除率为30%，氨氮去除为75%，并达到稳定运行效果及出水水质。这对于废水中难降解有机污染物的高效去除具有良好的应用价值。