底物对微生物燃料电池产电性能及微生物群落结构的影响研究

发布时间：2018-11-02 15:49

【摘要】：微生物燃料电池（Microbial Fuel Cell, MFC）是以微生物为催化剂氧化分解有机物，将有机物中的化学能转换为电能的生物反应器，能够实现废水处理和产生电能的双重效果，在环境保护和能源再生方面有非常大的发展前景。大多数有机物都能够用作微生物燃料电池的底物燃料，但是在实际应用中，MFC处理的有机废水种类繁多、成分复杂，因此研究MFC处理不同底物的产电效能以及MFC对更换底物的响应机制，对于MFC在实际应用中处理生产生活废水具有重要的指导意义。实验构建了单室空气阴极微生物燃料电池，以乳酸为底物运行反应器，待稳定后将底物更换为葡萄糖(Glucose)、乙酸(Acetate)和丙酸(Propionate)，稳定运行四个周期后，底物换回乳酸。三个阶段中，进水底物的COD均为500mg/L，在MFC运行过程中分别监测电化学参数，并通过分析阳极生物膜附着形态和微生物群落结构解析阳极微生物在MFC利用有机物产电过程中的作用机制。结果表明，在乳酸为底物的MFC最高产电电压为0.231V，功率密度为2.33W/m3，此时电池内阻为16Ω，COD去除率达到72.27%，库伦效率9.08%。将底物更换为葡萄糖、乙酸、丙酸后，MFC分别需要500、330和550h的适应时间达到稳定产电，最高电压分别是0.125、0.153和0.189V，周期为120、64、70h，对应的功率密度为0.77、1.43和1.65W/m3，库伦效率较之前有很大提高，分别达到17.85%、17.91%和29.16%。将底物继续更换为乳酸后，反应器仍需要一定的适应时间才达到稳定，适应时间分别是193、259、373h，稳定后的电压分别是0.121、0.110和0.188V，低于最初乳酸底物时的运行电压。同样，各MFC的功率密度也降低，Glu、Ace和Pro MFC分别为0.74、0.97和1.33W/m3，因而底物变化后微生物燃料电池的产电能力有所降低。通过DGGE图谱分析，Ace反应器将底物更换为乙酸后，阳极微生物结构发生明显变化，多样性指数由2.48增加至2.80。而Glu反应器的阳极微生物群落在三个阶段的条带相似性比较高。同样，Pro反应器三个阶段的条带也比较相似，可能是因为乳酸和丙酸结构相似，在被降解利用过程中的富集的微生物种类也比较相似。本实验表明，底物对微生物燃料电池的产电性能和阳极微生物群落结构有一定的影响，底物改变后，，MFC需要一定的适应时间才能恢复正常产电；反复更换底物，可能会导致MFC的产电性能降低。在实际应用中，应注意减小底物对于微生物燃料电池产电能力的影响。
[Abstract]:Microbial fuel cell (Microbial Fuel Cell, MFC) is a bioreactor that uses microorganism as catalyst to oxidize and decompose organic matter and convert the chemical energy of organic material into electric energy. It can realize the dual effect of wastewater treatment and power generation. In environmental protection and energy regeneration has a very large development prospects. Most organic compounds can be used as substrate fuel for microbial fuel cells, but in practical applications, organic wastewater treated by MFC has a variety of types and complex composition. Therefore, the study of the power generation efficiency of MFC for different substrates and the response mechanism of MFC to the replacement of substrates have important guiding significance for the practical application of MFC in the treatment of domestic wastewater. A single chamber air cathode microbial fuel cell was constructed. The substrate was changed to glucose (Glucose), acetate (Acetate) and propionate (Propionate), after four cycles of stable operation, and the substrate was replaced with lactic acid. In the three stages, the COD of the influent substrate was 500mg / L, and the electrochemical parameters were monitored during the operation of MFC. The mechanism of anodic biofilm adhesion and microbial community structure in the process of producing electricity by using organic compounds in MFC was analyzed by analyzing the mechanism of anodic biofilm attachment and microbial community structure. The results showed that the most high voltage of MFC with lactic acid as substrate was 0.231 V, the power density was 2.33 W / m ~ (3), the internal resistance of the battery was 16 惟, the removal rate of COD was 72.27%, and the Coulomb efficiency was 9.08%. After the substrates were replaced with glucose, acetic acid and propionic acid, the adaptation time of MFC was 500330 h and 550 h, respectively. The maximum voltage was 0.125 渭 g 0.153 and 0.189V, and the period was 120,6470h. The corresponding power density is 0.77 ~ 1.43 and 1.65 W / m ~ (3), and the efficiency of Coulomb is much higher than that before, reaching 17.85% 17.91% and 29.16% respectively. After the substrate was replaced with lactic acid, the reactor still needed a certain adaptation time to achieve stability, the adaptation time was 1925 9373 h, and the stable voltage was 0.121 渭 g 0.110 and 0.188 Vrespectively, which was lower than the operating voltage of the initial lactate substrate. In the same way, the power density of each MFC was also decreased, the Glu,Ace and Pro MFC were 0.74 and 1.33 W / m ~ (3), respectively, so the power production capacity of microbial fuel cells decreased after the substrate changed. By DGGE pattern analysis, when the substrate was replaced with acetic acid in Ace reactor, the microbial structure of anode changed obviously, and the diversity index increased from 2.48 to 2.80. The anodic microorganism community of Glu reactor was similar in the three stages. Similarly, the bands in the three stages of Pro reactor are similar, probably because the structure of lactic acid and propionic acid is similar, and the species of microorganism enriched in the process of degradation and utilization are similar. The results showed that the substrate had a certain effect on the electrical properties and the microbial community structure of the microbial fuel cell. After the substrate changed, the MFC needed a certain adaptation time to restore the normal electricity production. Repeated replacement of the substrate may lead to a decrease in the electrical performance of MFC. In practical application, attention should be paid to reducing the influence of substrate on the electricity production capacity of microbial fuel cells.
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM911.45

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