人工湿地型微生物燃料电池研究进展述评

湿地型微生物燃料电池(Constructed Wetland-Microbial Fuel Cell,CW-MFC)由人工湿地和微生物燃料电池耦合而成,因其具有丰富的微生物种群和较强的电极催化活性,在水质净化和生物产电领域有着良好的应用前景。从CWMFC反应器结构、电极材料及电极布置、填充材料、湿地植物、微生物和运行参数等几个方面对其研究和应用现状进行述评。总体上,大多数CW-MFC系统的产电效果并不理想,普遍净能量回收率小于0.050(kW·h)/kg COD,但在污染物处理去除方面效果显著,COD去除率基本可以达到80%以上。目前,上流式的垂直流运行模式是最合理且常用的运行模式,颗粒状的石墨或者活性炭与金属集电器的组合则是理想的电极材料,较小电极间距、多电极和扩大阴极的电极布置可有效提高系统产电性能,脱水明矾污泥是最具有研究价值的填料。此外,湿地植物会明显提高CW-MFC产电性能,其影响因素包括根际微生物活性、根际分泌物、根际沉积物、径向泌氧、光合作用;湿地植物和电系统还会促进微生物种群增长从而提高系统性能。CW-MFC中的污染物负荷、HRT(大多为3 d)、运行温度(20~40℃)和pH值(7~9)也是提高系统性能的关键因素。总结了未来CW-MFC所面临的挑战及研究方向,包括如何提高产电效率补充能源消耗、新兴污染物的降解及降解机理的研究,以及与其他工艺的联合应用。

Review and commentary on the constructed wetland-microbial fuel cells

This paper intends to make a review on the relevant studies of the application of constructed wetland(CW)and microbial fuel cell(MFC)as well as the influential factors concerned,including the system structure,the electrode materials,the electrode arrangements,packing materials,wetland plants,the microorganism species and the operational parameters,etc.As is well-known,the constructed wetland-microbial fuel cell(CW-MFC)is the result of the combination and integration of the constructed wetland(CW)and the microbial fuel cell(MFC).It has the advantages of higher micro-organic diversity and stronger catalyst activity of the electrodes so as to create a promising technical means in water purification and bio-electrogenesis,though,in general,CW-MFC does not work well to produce electricity with a generation rate at only 0.05(kW·h)/kg COD.Nevertheless,CW-MFC has a nice performance in decontamination,with their COD removal rate higher than 80%,and remarkable removal effect.Currently,the continuous up-flow is a more reasonable and commonly used operation mode.The optimal material for electrode is the granular graphite or activated carbon with metal collector.In addition,dewatered alum sludge is the most valuable packing material for the research.Besides,the existence of wetland plants in CWMFC could obviously increase its electricity generation via the plant roots,the rhizosphere secretion,the rhizosphere precipitants,the radial oxygen loss,as well as the photosynthesis.On the other hand,the wetland plants and the electrodes could also make contributions to the microorganism growth,so as to enhance the decontamination and electric generation.However,reasonable pollutant load,suitable HRT(mostly for 3 d),suitable operating temperature(20-40℃)and pH value(7-9)in the CW-MFC also serve as the key factors to improve the system performance.Thus,it can be concluded that,based on the literature,the paper has also defined the challenges and the perspectives for the future studies on the CW-MFC,including the improvement prosperity of the electric generation efficiency,the treatment of PPCP(persistent personal care products)and the corresponding mechanism,in addition to the combination of CW-MFC with other technologies concerned.