石墨烯在强化微生物燃料电池阳极产电能力中的应用

发布时间：2018-11-18 10:04

【摘要】：微生物燃料电池(Microbial fuel cell,MFC)是一种能够利用微生物作催化剂,将有机质储存的化学能转化为电能的装置,具有发电与废弃物处置的双重功效。MFC具有操作条件温和、生物相容性强,安全、高效、连续等优点,在微生物传感器、生物修复、污水处理等方面具有广阔的应用前景。然而,输出功率密度低仍然是限制其进行实际应用的重要因素。阳极的结构与性质是影响其表面微生物生长和产电活性的主要因素,并最终影响MFC体系的产电性能。因此,本课题通过简易方法制备了具有较大比表面积的多孔石墨烯阳极,表面亲水且荷正电的石墨烯-CTAB阳极以及石墨烯掺杂生物膜阳极,并运行了单室空气阴极MFC,考察了这三种石墨烯修饰阳极对MFC体系产电性能的影响。主要研究内容和结果如下:(1)制备了多孔石墨烯阳极(N/G 50和N/G 100),并考察了其对空气阴极单室MFC运行性能的影响。与采用传统方法制备的石墨烯修饰阳极相比,多孔石墨烯阳极具有较大比表面积,更有利于微生物的附着生长和生物膜内电子的传递。MFC运行稳定后,多孔石墨烯阳极显示出更高的电化学活性和较低的电荷转移内阻(Rct),并且N/G 100阳极的性能最优异,N/G 100阳极MFC体系的输出电压,最大功率密度(Pmax)和库伦效率(CE)分别为~0.60 V,1000 mW·m-2和49.34%,分别是传统石墨烯阳极MFC体系的1.88倍,1.99倍和2.36倍。(2)通过简单真空过滤的方法制备了无粘结剂,低石墨烯负载量的石墨烯-十六烷基三甲基溴化铵(CTAB)阳极(G-CTAB-2.5,G-CTAB-5和G-CTAB-10),并考察了其对空气阴极单室MFC运行性能的影响。G-CTAB阳极具有亲水性荷正电表面,有利于微生物的附着和生长。几个G-CTAB阳极中G-CTAB-5阳极亲水性最好,Zeta电位最高,G-CTAB-5阳极MFC体系的输出电压,Pmax和CE最高,分别为0.57 V,731.3 mW·m-2和45.74%。(3)采用简单的方法制备了石墨烯掺杂生物膜阳极(G-0.75,G-1.5和G-3),并考察了其对空气阴极单室MFC运行性能的影响。在阳极生物膜中掺杂石墨烯大大提高了生物膜的导电率,促进了生物膜内电子转移过程。与纯生物膜阳极相比,石墨烯掺杂生物膜阳极具有更高的电化学活性和较低的Rct,几个石墨烯掺杂生物膜阳极中G-3阳极性能最佳。石墨烯掺杂生物膜阳极MFCs的启动时间明显缩短,其中G-3阳极MFC在接通外电路后立即开始产电,体系的输出电压和Pmax分别是~0.53 V和588 mW·m-2,是纯生物膜阳极MFC体系的2.41倍和4.98倍。并且,G-3阳极MFC体系的CE由纯生物膜阳极MFC体系的50.03%提高到73.97%。
[Abstract]:Microbial fuel cell (Microbial fuel cell,MFC) is a device that can convert the chemical energy stored in organic matter into electric energy by using microorganism as catalyst, which has the dual function of generating electricity and disposing of waste. MFC has mild operating conditions. Because of its strong biocompatibility, safety, high efficiency and continuity, it has a broad application prospect in microbial sensors, bioremediation, sewage treatment and so on. However, low output power density is still an important factor limiting its practical application. The structure and properties of the anode are the main factors affecting the surface microbial growth and electrical activity, and ultimately affect the electrical properties of the MFC system. Therefore, a porous graphene anode with a large specific surface area, a hydrophilic and positively charged graphene CTAB anode and graphene doped biofilm anode have been prepared by a simple method in this paper. The single chamber air cathode MFC, has been run. The effects of three graphene modified anodes on the electrical properties of MFC system were investigated. The main contents and results are as follows: (1) porous graphene anodes (N / G _ (50) and N _ (r / G _ 100) were prepared and their effects on the performance of single-cell MFC were investigated. Compared with the graphene modified anode prepared by traditional method, the porous graphene anode has a larger specific surface area, which is more conducive to the growth of microorganism and electron transfer in biofilm. The porous graphene anode exhibits higher electrochemical activity and lower charge transfer resistance (Rct),) and the best performance of the N / G100 anode is the output voltage of the N / G100 anode MFC system. The maximum power density (Pmax) and the Coulomb efficiency (CE) are ~ 0.60 V ~ (1 000) mW m ~ (-2) and 49.34 mW m ~ (-2), respectively, which are 1.88 times of those of the traditional graphene anodic MFC system, respectively. 1.99 times and 2.36 times. (2) Non-binder, low graphene supported graphene cetyltrimethylammonium bromide (CTAB) anode (G-CTAB-2.5) was prepared by simple vacuum filtration. G-CTAB-5 and G-CTAB-10), and their effects on the performance of MFC in single cell of air cathode were investigated. The positive surface of hydrophilic charge on G-CTAB anode is favorable to the adhesion and growth of microorganism. Among several G-CTAB anodes, G-CTAB-5 anode has the best hydrophilicity, Zeta potential is the highest, G-CTAB-5 anode MFC system has the highest output voltage, Pmax and CE are 0.57V, respectively. (3) the graphene doped biofilm anode (G-0.75G -1.5 and G-3) was prepared by a simple method and its effect on the performance of MFC in air cathode single cell was investigated. Doping graphene into anodic biofilm greatly increases the conductivity of biofilm and accelerates the electron transfer process in biofilm. Compared with pure biofilm anode, graphene doped biofilm anode has higher electrochemical activity and lower Rct,. G-3 anode has the best performance among several graphene doped biofilm anodes. The start-up time of graphene doped biofilm anode MFCs was shortened obviously, in which G-3 anode MFC began to produce electricity immediately after the external circuit was switched on, the output voltage and Pmax of the system were ~ 0.53 V and 588 mW m-2, respectively. It is 2.41 times and 4.98 times of pure biofilm anode MFC system. The CE of G-3 anode MFC system increased from 50.03% to 73.97% of the pure biofilm anode MFC system.
【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM911.45

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