石墨烯修饰阳极微生物燃料电池抗菌性及产电性能研究

发布时间：2018-04-17 05:07

本文选题：抗菌性 + 生物膜　；参考：《华南理工大学》2015年硕士论文

【摘要】：微生物燃料电池(Microbial fuel cell,简称MFC)能同时进行废水处理和产电,是近年来环境保护和能源领域的一项新兴技术。目前,限制MFC应用的瓶颈主要是产电低和造价高,而电极材料是决定MFC产电性能和成本的关键因素。研究表明,新兴材料石墨烯具有优异的物理化学特性,将其用于修饰MFC的电极能显著提升产电性能并降低制备成本。然而,石墨烯的抗菌性已被研究所证实,其修饰电极在MFC中必然会对电化学活性菌产生影响。为此,本研究探索了石墨烯修饰阳极(GMAs)与阳极电化学活性菌的相互作用关系,探明了GMAs对阳极电化学活性菌的抗菌性,并进一步考察了GMAs抗菌性对MFC产电性能的影响,为发展石墨烯修饰电极MFC奠定基础。本研究采用improved Hummers法制备了氧化石墨烯,XRD,Raman,TEM和AFM分析结果显示所制备的氧化石墨烯氧化程度高,是具有少量褶皱的少层片状结构。采用循环伏安电沉积法还原方法制备三种不同石墨烯负载量的电极:5-G,20-G和40-G。Raman和FESEM测试分析表明氧化石墨烯成功还原为石墨烯并均匀沉积在电极表面。电化学测试结果表明,GMAs的极化阻抗(Rct)明显比空白电极降低,电子传递性能显著增强。CV测试结果表明,接种Shewanella oneidensis MR-1 5h后,GMAs的电化学活性低于空白电极,运行时间增加至18h,GMAs电化学活性逐渐上升,并于30d后明显高于空白电极。CLSM测试结果表明,随运行进程,电极表面生物膜厚度逐渐增大。在接种5h后,GMAs表面生物膜活菌比低于空白电极,18h后,生物膜活菌比显著增大并明显超过空白电极。GMAs电化学活性和生物膜活菌比随时间变化的原因是由于生物膜成熟后,包裹在胞外聚合物内的细菌可大量避免石墨烯的抗菌性影响,且生物膜内部的细菌可以通过胞外聚合物或者纳米导线进行远距离电子传递。为进一步考察GMAs抗菌性对MFC产电性能的影响,研究了GMAs-MFC的产电性能。相比于空白电极,GMAs可显著降低阳极极化损失,提高MFC电压输出和功率密度,产电稳定时间缩短了27%。在运行初期GMAs对微生物的抗菌性并未对MFC产电性能造成负面影响,阳极石墨烯负载量越大,MFC的最大功率密度越高。
[Abstract]:Microbial fuel cell (MFCs), which can treat wastewater and produce electricity simultaneously, is a new technology in the field of environmental protection and energy in recent years.At present, the bottleneck to restrict the application of MFC is mainly low power generation and high cost, and electrode material is the key factor to determine the electrical performance and cost of MFC.The results show that graphene has excellent physical and chemical properties, and the electrode used to modify MFC can significantly improve the electrical properties and reduce the preparation cost.However, the antibacterial activity of graphene has been confirmed by the research, and its modified electrode must have an effect on the electrochemically active bacteria in MFC.Therefore, the interaction between graphene modified anode (GMas) and anode electrochemically active bacteria (AECs) was investigated, and the antibacterial activity of GMAs to AECO was investigated, and the effect of GMAs on the electrical properties of MFC was also investigated.It lays a foundation for the development of graphene modified electrode MFC.In this study, improved Hummers method was used to prepare graphene oxide. The results of TEM and AFM analysis showed that the oxidation degree of graphene oxide was high, and the graphene oxide had a small lamellar structure with a small number of folds.Three kinds of graphene loaded electrodes with different amounts of graphene were prepared by cyclic voltammetry electrodeposition. The results of 40-G.Raman and FESEM measurements showed that graphene oxide was successfully reduced to graphene and deposited uniformly on the electrode surface.The results of electrochemical measurement showed that the polarization impedance of GMAs was significantly lower than that of the blank electrode, and the electron transfer property was significantly enhanced. CV test showed that the electrochemical activity of GMAs was lower than that of the blank electrode after 5 h inoculation with Shewanella oneidensis MR-1.The electrochemical activity of GMAs increased gradually when the running time was increased to 18 h, and the results showed that the biofilm thickness on the electrode surface increased with the running process, and was obviously higher than that of the blank electrode after 30 days.After inoculation for 5 h, the ratio of biofilm viable bacteria on the surface of GMAs was lower than that of the blank electrode for 18 h, the ratio of biofilm viable bacteria increased significantly and exceeded the electrochemical activity of blank electrode. GMAs and the ratio of biofilm viable bacteria changed with time because of the maturation of biofilm.Bacteria encapsulated in extracellular polymers can largely avoid the antibacterial effect of graphene, and bacteria in biofilms can be transported through extracellular polymers or nanowires for long distance electron transport.In order to investigate the effect of GMAs antibacterial properties on the electrical properties of MFC, the electrical properties of GMAs-MFC were studied.Compared with the blank electrode, GMAs can significantly reduce the loss of anode polarization, increase the voltage output and power density of MFC, and shorten the power stability time by 27%.The antimicrobial activity of GMAs to microorganism did not have a negative effect on the electrical properties of MFC at the early stage of operation, and the higher the load of anode graphene was, the higher the maximum power density of MFC was.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703;TM911.45

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