HA@Fe3O4修饰阳极增强微生物燃料电池降解雌激素

HA@Fe3O4 modified anode to enhance degradation of estrogen in microbial fuel cells

摘要:

类固醇雌激素(SEs)是一类广受关注且危害性较大的新污染物,常规的污水处理工艺难以将其完全去除。腐殖酸(HA)作为一种电子传递中介体,可大幅提高微生物代谢过程中胞外呼吸的电子传递效率。鉴于HA的这种特殊电化学性质,将其应用于微生物燃料电池(MFC)系统,将有望实现在低能耗的前提下对SEs的高效降解。本研究选取17α-乙炔基雌二醇(EE2)作为代表性SEs,利用HA与较强电容性的纳米Fe3O4颗粒形成的金属化合物(HA@Fe3O4)修饰MFC阳极,探究含有EE2的模拟废水在MFC阳极的降解特性。结果表明HA的存在不仅能提高微生物与阳极板之间的电子传递效率,还可显著增加阳极板的电容性进而提高产电性能,其最大功率密度可达522.32 mW/m2。此外,HA@Fe3O4修饰的阳极可显著提高MFC对EE2的降解效率,研究还发现EE2在低浓度范围内可提升MFC的性能,但高浓度时会抑制微生物的活性并降低MFC产电效率。本研究为微生物燃料电池在实际废水中有效应用提供了一定的研究基础。

Abstract:

Steroid estrogens (SEs) are a kind of emerging and harmful pollutants that have garnered worldwide attention. Traditional wastewater treating methods generally fail to eliminate them entirely. Humic acid (HA), as an electron transport mediator, can significantly improve the electron transport efficiency of extracellular respiration during microbial metabolism. In view of the special electrochemical properties of HA, its application to microbial fuel cell (MFC) systems is expected to achieve efficient degradation of SEs with low energy consumption. In this study, the MFC anode was modified with a metal compound (HA@Fe3O4) formed by HA and strong capacitive nano-Fe3O4 particles. 17α-ethynylestradiol (EE2) was selected as the representative SEs to evaluate the degradation performance of the modified MFC anode. The results showed that the presence of HA not only increased electron transfer efficiency between microorganisms and the anode, but also enhanced the electric production performance by improving the anode"s capacitance. The maximum power density in the MFC system increased to 522.32 mW/m2 after the combination of HA. Also, the anode modified with HA@Fe3O4 could significantly improve the degradation efficiency of EE2 by MFC. Additionally, EE2 at low concentrations promoted the performance of MFC, but inhibited the activity of microorganisms and reduced the electricity generation efficiency of MFC at high concentrations. This study provided a certain research basis for the effective application of MFC in actual wastewater.