微生物燃料电池阴极电子受体与结构的研究进展

从工程应用的角度分析了微生物燃料电池的结构变化趋势;从电化学角度介绍了几种两室微生物燃料电池中阴极室采用不同电子受体对提高电池输出功率的影响和单室空气阴极微生物燃料电池的研究现状及应用前景;分析了电池组在电池放大过程中可能存在的串挠和电压反转等问题,为微生物燃料电池的工程应用提供了理论参考。     

微生物燃料电池运行影响因素的研究

研究自行设计的微生物燃料电池在常温常压下,以厌氧污泥为接种源,以葡萄糖为底物原料,以不同溶液作为电子受体的条件下测试其稳定运行的影响因素与工艺条件。实验结果表明:该微生物燃料电池可稳定运行约30d,并在注入新的底物后,电压又快速回升至稳定电压。以铁氰化钾溶液作为电子受体,输出电压可达0.75V,输出功率为2100mW/m~2;以高锰酸钾溶液作为电子受体,输出电压为1.023V,输出功率为2638mW/m~2。     

单室空气阴极微生物燃料电池处理模拟生活废水同步产电研究

以某生活污水处理站厌氧池活性污泥为混合菌种,以葡萄糖为模拟生活废水,构建单室微生物燃料电池.利用微生物燃料电池实验生活废水降解与同步产电.实验结果表明:当葡萄糖浓度控制10mmol·L-1,pH值为7,温度控制在35℃时,其输出电压最大为0.486V,COD去除率最高为46.11％.微生物燃料电池(MFC)具有最佳的电化学性能.     

微生物燃料电池产电性能试验研究

以双室微生物燃料电池为研究对象,考察了电极间距、电极面积比和阳极室填充活性炭颗粒,阳极室填充液浓度、pH值、流通速度对微生物燃料电池输出电压和功率密度的影响,通过分析建立最优双室微生物燃料电池模型。研究结果表明,微生物燃料电池的最大输出电压为544.3 mV,最大功率密度为341.38 mW/m2,在微生物燃料电池运行1 500 min后,利用极化曲线法测定电池的内阻为375Ω。     

泡沫镍空气阴极微生物燃料电池的产电特性

研究了泡沫镍阴极的制备和对单室微生物燃料电池产电性能的影响。研究发现,当阴极PTFE扩散层超过4+1层时,MFC的功率密度随扩散层数增加而逐渐下降;当阴极扩散层为五层(4+1层)时,微生物燃料电池最大功率密度最大,达到31.3 W/m3,电池的库仑效率为25%;当使用7+1层PTFE扩散层时,电池功率下降到25.6 W/m3;泡沫镍阴极厚度对阴极性能影响不大;研究发现,滚压后再涂一层扩散层能够抑制泡沫镍阴极的长期运行的析盐。     

碳粉催化剂镍基体空气阴极微生物燃料电池特性研究

试验以泡沫镍材料作为空气阴极MFC的电极材料,并利用碳粉作为催化剂,在1.24 A/m2的电流密度下获得了214 mW/m2的最大功率密度输出。电位分析结果表明,阴极开路电位为+12 mV,阳极开路电位为-466 mV。采用改变外阻的调节方式,获得了18.6%~57.8%的库伦效率。试验结果表明,碳粉可以作为催化剂材料在泡沫镍基体空气阴极MFC系统中使用。     

超声预处理对单室空气阴极污泥微生物燃料电池性能的影响

为了提高污泥微生物燃料电池(MFC)产电性能和污泥处理效果,基于超声波破壁预处理技术,构建了以超声预处理污泥为底物的单室空气阴极污泥MFC,以污泥MFC的输出电压、最大功率密度、内电阻、污泥浓度和TCOD浓度为考察指标,探究不同声能密度预处理对污泥MFC产电性能及污泥降解效能的影响,结果表明,随着预处理超声密度的增加,MFC的产电性能和污泥处理效果得到有效提升。与未经预处理的污泥MFC相比,预处理声能密度为1.5 W/m L时,MFC稳定输出电压提高90.19%,最大输出功率密度提高135.43%,污泥减量效果提升68.8%,TCOD去除效果提高76.17%。本研究实验结果证明采用超声波对污泥进行预处理,能够有效提高污泥MFC的产电性能和污泥降解效率。     

活性炭与TiO_2混合催化镍基体生物阴极微生物燃料电池性能研究

以发泡镍为基体,柱状活性炭颗粒和Ti O2粉末均匀混合后作为催化剂涂覆在电极表面。将此复合电极作为双室生物阴极型MFC的电极,研究MFC的产电性能。结果表明:在运行周期内,系统最大输出电压可达到698.1 m V,稳定在500 m V以上的高电压输出时间为18 d;单位质子膜面积上可获得最大功率密度为183.33W/m4,质子膜的使用量明显减少,从而大大降低了MFC的产电成本。同时,阳极室对原生活污水COD去除率可达到74%,而库伦效率也可达到68.9%。试验结果表明,活性炭和Ti O2混合涂覆镍基体电极对双室生物阴极型MFC产电的催化效果良好。     

阳极材料对微生物燃料电池性能影响的研究

以石墨、碳纸、碳布和碳毡为阳极材料,研究不同材料在微生物燃料电池中的产电性能,并利用循环伏安法比较不同材料的电化学活性。结果表明:在电池性能方面,以石墨为阳极微生物燃料电池电压可达0.678V,输出功率为250mW/m2;碳毡电压达0.656V,输出功率204mW/m2,碳纸0.649V,输出功率156mW/m2;碳布最差,电压不稳定,输出功率56mW/m2。循环伏安曲线和电极材料表观吸附量:碳毡作为阳极材料,具有明显的氧化峰和还原峰,对导电微生物具有显著的吸附量,其次是石墨,碳纸次之,最差的是碳布。     

单室微生物燃料电池产电特性研究

采用石墨板为阴极构建了单室空气阴极微生物燃料电池(MFC),以混合菌种接种,并以乙酸钠和碳酸氢钠为碳源,研究了该MFC在间歇运行条件下的产电性能、电池内阻情况和COD去除率。结果表明,最高输出电压随着周期数增加而增加,由0.075 9 V上升到0.200 6 V,最大输出功率密度为34.80 mW/m2;在一个运行周期内,电池内阻随着时间的延长而逐渐增大,由376.6Ω上升到682.0Ω,电池内阻的增大将导致输出电压降低。COD去除率由起始的49.23%达到最大值86.99%,说明此单室空气阴极微生物燃料电池在产电的同时处理污水的效果也较好。     

Persulfate: A self-activated cathodic electron acceptor for microbial fuel cells

Potassium persulfate aqueous solution without pH adjustment is used as the cathodic electron acceptor in a two-chamber microbial fuel cell (MFC) in the present study. The performance of the MFC with K₂S₂O₈ solution is evaluated and compared with that of K₃Fe(CN)₆ solution. The results show that the maximum power density of the K₃Fe(CN)₆ used MFC doubled that with K₂S₂O₈ solution when fresh aqueous solution is used. However, a significant increase in electrical power generation is observed in the case of the MFC with K₂S₂O₈ solution after 2-day operation under an external resistance of 1000 Ω. This improvement can be attributed mainly to the increased cathode performance as a result of the hydrolysis of the persulfate ion in aqueous solution. It is demonstrated that persulfate can be used as an effective cathodic electron acceptor due to its unique capability of self pH adjustment.     

Effect of cathode electron-receiver on the performance of microbial fuel cells

Performance of cathode electron receivers has direct effect on the voltage and power density of MFC. This paper explored the electrical performance of MFC with potassium permanganate, ferricyanide solution and dissolved oxygen (DO) as cathode electron receivers. The results showed that the internal resistance of MFC with DO depends on catalyst and is higher than that of MFC with potassium permanganate and potassium ferricyanide solution. The maximum volume power density is 4.35 W/m³, and the smallest internal resistance is only about 54 Ω. In case of DO, the internal resistance and power density is different depending on the catalyst and is not too much related to the membranes.     

Power generation using polyaniline/multi‐walled carbon nanotubes as an alternative cathode catalyst in microbial fuel cells

Optimization of the cathode catalyst is critical to the study of microbial fuel cells (MFCs). By using the open circuit voltage and power density as evaluation standards, this study focused on the use of polyaniline (PANI)/multi‐walled carbon nanotube (MWNT) composites as cathode catalysts for the replacement of platinum (Pt) in an air‐cathode MFC, which was fed with synthetic wastewater. Scanning electron microscopy and linear scan voltammogram methods were used to evaluate the morphology and electrocatalytic activity of cathodes. A maximum power density of 476 mW/m² was obtained with a 75% wt PANI/MWNT composite cathode, which was higher than the maximum power density of 367 mW/m² obtained with a pure MWNT cathode but lower than the maximum power density of 541 mW/m² obtained with a Pt/C cathode. Thus, the use of PANI/MWNT composites may be a suitable alternative to a Pt/C catalyst in MFCs. PANI/MWNT composites were initially used as cathodic catalysts to replace Pt/C catalysts, which enhanced the power generation of MFCs and substantially reduced their cost. Copyright © 2014 John Wiley & Sons, Ltd.     

集胞藻PCC-6803催化的光合微生物燃料电池性能研究

以集胞藻PCC-6803(Synechocystis PCC-6803)为阳极催化剂搭建直接利用太阳能的双室H-型光合微生物燃料电池(PMFC),通过极化曲线法、交流阻抗法、循环伏安法等电化学方法,开展电极面积比、质子交换膜、内阻等因素对光合微生物燃料电池产电的影响研究。试验结果显示:在PMFC运转过程中,其输出功率稳定,且达到的最大功率密度为72.3 mW/m2;阴阳极面积大小对PMFC产电性能没有显著影响,说明双室光合微生物燃料电池中,质子交换膜传递质子的速率较慢,限制了PMFC发电效能的提高。PMFC启动后,随着生物膜的增长,其欧姆内阻、极化内阻、总内阻都呈现下降的趋势,且欧姆内阻下降的速率小于极化内阻,从而使欧姆内阻占总内阻的比率变大,进一步说明质子交换膜传递质子的速率是限制PMFC发电的关键因素。     

Effect of an anode modified with nitrogenous compounds on the performance of a microbial fuel cell

Three kinds of nitrogenous compounds (ammonium peroxydisulfate, ethylenediamine, methylene blue) were applied to modify graphite felt anodes in microbial fuel cells. All of the performances were greatly improved by modifying the anode surface. The maximum power density of the microbial fuel cell with modified anode was 355, 545, and 510 mW/m², respectively, which was larger than the ungroomed control (283 mW/m²). The power density of microbial fuel cell with ethylenediamine-treated electrode was highest among the four microbial fuel cells. The increase of power density was correlated with the changes of N/C and O/C ratios on the anode according to the X-ray photoelectron spectrometry analysis.     

Evaluating the performance of microbial fuel cells powering electronic devices

A microbial fuel cell (MFC) is capable of powering an electronic device if we store the energy in an external storage device, such as a capacitor, and dispense that energy intermittently in bursts of high-power when needed. Therefore its performance needs to be evaluated using an energy-storing device such as a capacitor which can be charged and discharged rather than other evaluation techniques, such as continuous energy dissipation through a resistor. In this study, we develop a method of testing microbial fuel cell performance based on storing energy in a capacitor. When a capacitor is connected to a MFC it acts like a variable resistor and stores energy from the MFC at a variable rate. In practice the application of this method to testing microbial fuel cells is very challenging and time consuming; therefore we have custom-designed a microbial fuel cell tester (MFCT). The MFCT evaluates the performance of a MFC as a power source. It uses a capacitor as an energy storing device and waits until a desired amount of energy is stored then discharges the capacitor. The entire process is controlled using an analog-to-digital converter (ADC) board controlled by a custom-written computer program. The utility of our method and the MFCT is demonstrated using a laboratory microbial fuel cell (LMFC) and a sediment microbial fuel cell (SMFC). We determine (1) how frequently a MFC can charge a capacitor, (2) which electrode is current-limiting, (3) what capacitor value will allow the maximum harvested energy from a MFC, which is called the “optimum charging capacitor value,” and (4) what capacitor charging potential will harvest the maximum energy from a MFC, which is called the “optimum charging potential.” Using a LMFC we find that (1) the time needed to charge a 3-F capacitor from 0 to 500 mV is 108 min, (2) the optimum charging capacitor value is 3 F, and (3) the optimum charging potential is 300 mV. Using a SMFC we find that (1) the time needed to charge a 3-F capacitor from 0 to 500 mV is 5 min, (2) the optimum charging capacitor value is 3 F, and (3) the optimum charging potential is 500 mV. Our results demonstrate that the developed method and the MFCT can be used to evaluate and optimize energy harvesting when a MFC is used with a capacitor to power wireless sensors monitoring the environment.     

Treatment of seafood industrial wastewater coupled with electricity production using air cathode microbial fuel cell under saline condition

The present study investigated seafood industrial wastewater treatment with corresponding power generation in air cathode microbial fuel cell under saline condition (40 g/L). The results recorded total chemical oxygen demand) removal of 52 ± 1.8%, 64 ± 1.1%, 85 ± 1.2%, 89 ± 1.4%, and 76 ± 1.2% to the corresponding organic load (OL) of 0.5, 0.75, 1, 1.25, and 1.5 gCOD/L under saline condition. Soluble chemical oxygen demand reduction was in the range of 46% to 78% at OL of 0.5 to 1.5 gCOD/L. The maximum power density (530 ± 15 mW/m²) and coulombic efficiency (52 ± 2.4%) was procured at the OL of 1.25 and 0.5 gCOD/L, respectively. Total suspended solids removal was 74 ± 1.5% at OL of 1.25 gCOD/L and 64 ± 1.3% at OL 1.5 gCOD/L. Bacterial community analysis for anode region samples for OL 0.5 and 1 gCOD/L was extensively dominated by Bacillus (MN880233) with 75.8% and 55.8%, respectively. Interestingly at 1.25 gCOD/L OL, Rhodococcus (MN880237) was predominant (42.3%) strain in the anode region and recorded high power production under saline condition. Sludge samples subjected to phylogenetic analysis explored the dominance of Clostridium, Turicibacter, and Marinobacter at different OL from 0.5 to 1.5 gCOD/L. Bacterial community results at 1.25 gCOD/L of OL sludge samples revealed completely different strains of dominancy in the community. Marinobacter (53.3%), Ochrobactrum (19.3%), and Bacillus (8.1%). Thus, the phylogenetic analysis of the anodic and sludge samples clearly detailed the presence of halophilic bacterial strains with high potential to treat seafood processing industrial wastewater and excellent exoelectrogenic activity for power production.     

Power generation using an activated carbon fiber felt cathode in an upflow microbial fuel cell

An activated carbon fiber felt (ACFF) cathode lacking metal catalysts is used in an upflow microbial fuel cell (UMFC). The maximum power density with the ACFF cathode is 315 mW m⁻², compared to lower values with cathodes made of plain carbon paper (67 mW m⁻²), carbon felt (77 mW m⁻²), or platinum-coated carbon paper (124 mW m⁻², 0.2 mg-Pt cm⁻²). The addition of platinum to the ACFF cathode (0.2 mg-Pt cm⁻²) increases the maximum power density to 391 mW m⁻². Power production is further increased to 784 mW m⁻² by increasing the cathode surface area and shaping it into a tubular form. With ACFF cutting into granules, the maximum power is 481 mW m⁻² (0.5 cm granules), and 667 mW m⁻² (1.0 cm granules). These results show that ACFF cathodes lacking metal catalysts can be used to substantially increase power production in UMFC compared to traditional materials lacking a precious metal catalyst.     

Relation of anodic and cathodic performance to pH variations in membraneless microbial fuel cells

One-compartment (membraneless) microbial fuel cells (MFCs) are effective tools to test new bio-technology at a laboratory level. More efforts in MFC design and materials are necessary to move from laboratory tests to real applications.