无介体双室微生物燃料电池产电性能初步研究

本文对无介体双室微生物燃料电池的产电性能进行了初步研究，并根据不同运行阶段产电性能的优劣，对其中微生物的差异性进行了比较分析。全文分为两个部分： 第一部分：以乙酸钠为阳极原料构建双室微生物燃料电池（MFC），研究不同阴极受体、外接电阻、乙酸钠浓度和pH等因素对电池产电性能的影响，研究结果表明：在500mL的阴阳极反应体系中，选用乙酸钠作为阳极底物，质量浓度为6.46 g/L， pH 7.0，接入500Ω外电阻，阴极电子受体选择高锰酸钾的情况下，微生物燃料电池产电性能最好，最大电功率密度达到294.72 mW/m2，库伦效率能达到25.87%。在确定最适外接电阻阻值的同时对MFC内阻进行测定，阻值为871.87Ω。 第二部分：微生物燃料电池运行中，比较以厌氧污泥作为接种源的第一阶段和只接入附着有大量微生物电极的第二阶段的产电性能，得出第二阶段产电性能优于第一阶段，最大电功率密度达到353.57mW/m2，比第一阶段提高58.85 mW/m2；库伦效率为39.35%，增幅达52％左右；针对微生物燃料电池运行过程中，底物CH3COONa可能存在其它的代谢途径，本实验进行了第二阶段产电性能与CH3COONa消耗率关系以及阳极液面上方气体成分和含量的研究，发现第二阶段50h前CH3COONa的大量消耗主要用于微生物的生长，在整个运行过程中，阳极液面上方含有CH4和CO2；对气体测定的同时还发现，振荡能增强电功率密度的输出；通过对电极上和污泥中微生物差异性分析得出，δ-变形菌纲、β-变形菌纲和拟杆菌门的菌种更适应微生物燃料电池的运行环境，能在电极上大量富集，提高电池的产电性能，只接入附着有大量微生物的电极能有效降低热袍菌纲的菌种数量，降低了CH3COONa的无为消耗，有效提高了电池的库伦效率。 Electricity production in the mediator-less two-chambered microbial fuel cell(MFC) was researched. Based on the result in the different operation phase in the MFC, the microbial diversity was analysed. The paper involved two parts: Part 1: A two-chambered microbial fuel cell (MFC) was constructed with high-concentration sodium acetate as fuel in the anode. The influence of different electron acceptors in the cathode, external resistance value, pH value and concentration of sodium acetate on electricity generation in MFC was investigated. The result showed that the maximum power density of 294.72 mW/m2 and the coulombic efficiency of 25.87% was achieved at sodium acetate concentration of 6.46 g/L, pH 7.0, external resistance 500Ωin the anode and when using potassium permanganate as electron acceptor in the cathode. While decided the value of resistor, we found that shaking has effect on electricity production in the MFC. Part 2: Comparing the electricity production in different operation phases when using anaerobic sludge as inoculum in the first phase and microbes in the anodic electrode as inoculum in the second phase, the result showed that electricity production in the second phase was more than that in the first phase, the maximum power density of 353.57 mW/m2 and the coulombic efficiency of 39.35% was achieved, 58.85 mW/m2 and 52％ more than that in the first phase, respectively. According to the fact that CH3COONa might be metabolized in other pathway in the running process in the MFC, we determining the relationship between electricity production and CH3COONa consumption, and the gas content in the anode, we found that CH3COONa was mainly used for microbe growth before 50h, and the anode contained CH4 and CO2. At the same time, we found that shaking could improve power density. The analysis on diversity of microbe in the anodic electrode and anaerobic sludge showed that δ-proteobacterium, β-proteobacterium and Bacteroidetes adapted themselves to the running environment of MFC. The anode could enrich them to improve the electricity production while reduced the quantity of Thermotogales, which were obligately anaerobic organotrophs with a fermentative metabolism, to increase the coulombic efficiency effectively.