氮修饰石墨毡用于微生物燃料电池阳极材料的研究

发布时间：2018-09-04 11:16

【摘要】：微生物燃料电池(MFC)作为近几年来发展起来的新可再生能源装置,具有条件温和、环境友好和在有效回收能源的同时可实现废水处理等优点,有望解决由于全球化石能源短缺以及化石能源在使用和开采中对环境的危害等问题,成为本世纪能源和环境领域的研究热点。微生物燃料电池利用微生物作为催化剂,氧化有机物质,直接将化学能转化为电能。影响MFC输出功率的最大限制因素是电子的转移过程。从MFC的结构来看,阳极作为电子转移的载体,对阳极的研究显得很重要,本文采用三种不同类型的含氮化合物修饰石墨毡作为微生物燃料电池的阳极,研究改性阳极材料对MFC产电性能的影响,并根据等温吸附法(BET)、扫描电子显微镜(SEM)、光电子能谱(XPS)等分析方法来进一步探索了氮修饰阳极对MFC的产电性能产生影响的原因。首先使用过硫酸铵通过浸渍和电化学氧化法修饰石墨毡作为阳极材料。实验结果表明：没有修饰过的石墨毡(GF)电压为0.5-0.52V,最大功率密度为283mW/m2；而浸渍法修饰的石墨毡(GF-A)和电化学氧化法修饰的石墨毡(GF-A1)所获得的最大输出功率密度分别为510mW/m2和609mW/m2,经过XPS的分析表明,MFCs输出功率随着阳极表面N/C比增加而增加。然后采用经过乙二胺和甘氨酸修饰过后的石墨毡作为阳极材料。实验结果表明：获得的最大输出功率为355mW/m2和500mW/m2,分别比GF增加了25%和77%。SEM图分析表明经过修饰过后的石墨毡吸附的微生物比较多,主要是由于经过乙二胺和甘氨酸修饰过后的石墨毡表面变得更粗糙,比表面积比较大,从而更多的细菌吸附在电极上,使得电子能够更容易的从微生物传递到阳极上。最后采用聚苯胺和聚氮氮二甲基苯胺修饰石墨毡作为阳极材料。实验结果表明：获得的最大输出功率密度分别为366mW/m2和333mW/m2。聚苯胺上N的孤对电子成为共轭主链的一部分,与醌式结构单元的N结合,形成了具有电荷传输作用的极化孤子,因此增加了电极的导电性。通过SEM和其他电化学测量手段,观察了材料表面的形态并进一步证明电池性能的改变。阳极表面积从未修饰的50.24m2/g增加到96.12m2/g和83.15m2/g,同时内阻也降低。增加的表面积和减少的内阻都可能是MFCs产电性能提高的重要原因,导电聚合物能够帮助阳极材料提高导电性和生物兼容性,从而提高MFC的输出功率。
[Abstract]:As a new renewable energy device developed in recent years, microbial fuel cell (MFC) has the advantages of mild conditions, friendly environment and efficient energy recovery and wastewater treatment. Due to the shortage of fossil energy in the world and the harm to the environment caused by the use and exploitation of fossil energy, it is expected to become a research hotspot in the field of energy and environment in this century. Microbial fuel cell uses microorganism as catalyst to oxidize organic matter and directly convert chemical energy into electric energy. The most limiting factor affecting the output power of MFC is the electron transfer process. From the point of view of the structure of MFC, it is very important to study the anode as the carrier of electron transfer. In this paper, three kinds of nitrogen-containing compounds modified graphite felt are used as the anode of microbial fuel cell. The effect of modified anode materials on the electrical properties of MFC was studied. The influence of nitrogen modified anode on the electrical properties of MFC was further explored by means of isothermal adsorption (BET), scanning electron microscope (BET),) (SEM), photoelectron spectroscopy (SEM),) and so on. First, ammonium persulfate was used as anode material to modify graphite felt by impregnation and electrochemical oxidation. The experimental results show that the (GF) voltage of unmodified graphite felt is 0.5-0.52V and the maximum power density is 283mW / m2; The maximum output power densities obtained by impregnation modified graphite felt (GF-A) and electrochemical oxidation modified graphite felt (GF-A1) are 510mW/m2 and 609mW / m2, respectively. The results of XPS analysis show that the output power increases with the increase of N / C ratio on the anode surface. Then graphite felt modified by ethylenediamine and glycine was used as anode material. The experimental results show that the maximum output power is 355mW/m2 and 500MW / m2, which is 25% higher than that of GF, respectively. The results of 77%.SEM diagram show that the modified graphite felt adsorbs more microorganisms than the modified graphite felt. The main reason is that the surface of graphite felt modified by ethylenediamine and glycine becomes rougher and the specific surface area is larger, so that more bacteria are adsorbed on the electrode, so that the electron can be transferred from microorganism to anode more easily. Finally, Polyaniline and polyazo-dimethylaniline were used as anode materials. The experimental results show that the maximum output power density obtained is 366mW/m2 and 333mW / m2, respectively. The solitary-pair electrons of N on Polyaniline form part of the conjugate main chain and combine with the N of the quinone structure unit to form a polarimetric soliton with charge transport effect which increases the conductivity of the electrode. The morphology of the material surface was observed by SEM and other electrochemical measurements. The surface area of the anode has never been modified to increase to 96.12m2/g and 83.15 m2 / g, while the internal resistance is also reduced. The increase of surface area and the decrease of internal resistance may be the important reasons for the improvement of the electrical properties of MFCs. Conductive polymers can help anode materials to improve their electrical conductivity and biological compatibility and thus increase the output power of MFC.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM911.4

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