Identification of the Electricity-Producing Bacteria in Wastewater for Microbial Fuel Cells （MFCs）

A microbial fuel cell （MFC） is a device that converts chemical energy to electrical energy during substrate oxidation by microorganisms. The characterization and identification of these microbial communities will allow better control of this electricity generation with simultaneous removal of carbon and nitrogen. This study aims to investigate the role of natural bacteria in electricity generation by studying three different sources of wastewater： the raw wastewater （RW）, wastewater from an aeration tank （AEW） and returned activated sludge （RAS） from an activated sludge treatment plant. The result showed that after the MFC treatment, the number of bacterial strains was reduced from twenty strains to eight strains. Microscopic observation further showed that fifteen isolate before the treatment were gram-positive, and five were gram-negative whereas all isolates after the treatment were gram-positive rods or cocci The four strains isolated from the RAS inoculums, β-Comamonas sp., γ-Enterobacter sp., Bacillus cereus sp. and Clostridium sp. produced the highest power density of 67.57 mW/m^2 which made them potential candidates for electrochemically active bacteria in MFCs. However, the level of chemical oxygen demand （COD） removal was 20% and the total kjeldahl nitrogen （TKN） removal was 66.7%. Key words：

A Comprehensive Review on Oxygen Reduction Reaction in Microbial Fuel Cells

The focus of microbial fuel cell research in recent years has been on the development of materials,microbes,and transfer of charges in the system,resulting in a substantial improvement in current density and improved power generation.The cathode is generally recognized as the limiting factor due to its high-distance proton transfer,slow oxygen reduction reaction(ORR),and expensive materials.The heterogeneous reaction determines power gen-eration in MFC.This comprehensive review describes-recent advancements in the development of cathode mate-rials and catalysts associated with ORR.The recent studies indicated the utilization of different metal oxides,the ferrite-based catalyst to overcome this bottleneck.These studies conclude that some cathode materials,in parti-cular,graphene-based conductive polymer composites with non-precious metal catalysts provide substantial ben-efits for sustainable development in the field of MFCs.Furthermore,it also highlights the potentiality to replace the conventional platinum air cathode for the large-scale production of the next generation of MFCs.It was evi-dent from the experiments that cathode catalyst needs to be blended with conductive carbon materials to make cathode conductive and efficient for ORR.This review discusses various antifouling strategies for cathode biofoul-ing and its effect on the MFC performance.Moreover,it also depicts cost estimations of various catalysts essential for further scale-up of MFC technology.

Simultaneous Denitrification and Carbon Removal in Microbial Fuel Cells

In this article,microbial fuel cell( MFC) was used for simultaneous denitrification and carbon removal to ascertain their electricity generation performance. The results showed that strengthening domestication and enrichment of electrogenic bacteria had the best start-up effect. An increase in volumetric loading reduced the rate of pollutant removal but promoted the output voltage. The changes of working conditions such as influent concentration,sludge concentration and temperature had a great influence on the electricity generation performance of MFC,and their optimum values were 500 mg/L,2 000 mg/L and 35℃,respectively.

Utilization of Nanomaterials as Anode Modifiers for Improving Microbial Fuel Cells Performance

Microbial fuel cells(MFCs)are an attractive innovation at the nexus of energy and water security for the future.MFC utilizes electrochemically active microorganisms to oxidize biodegradable substrates and generate bioelectricity in a single step.The material of the anode plays a vital role in increasing the MFC’s power output.The anode in MFC can be upgraded using nanomaterials providing benefits of exceptional physicochemical properties.The nanomaterials in anode gives a high surface area,improved electron transfer promotes electroactive biofilm.Enhanced power output in terms of Direct current(DC)can be obtained as the consequence of improved microbe-electrode interaction.However,several limitations like complex synthesis and degeneration of property do exist in the development of nanomaterial-based anode.The present review discusses different renewable nanomaterial applied in the anode to recover bioelectricity in MFC.Carbon nanomaterials have emerged in the past decade as promising materials for anode construction.Composite materials have also demonstrated the capacity to become potential anode materials of choice.Application of a few transition metal oxides have been explored for efficient extracellular electron transport(EET)from microbes to the anode.

The Cellulolytic Bacteria <i>R. albus</i>for Improving the Efficiency of Microbial Fuel Cell

The current study has been undertaken to examine the beneficial effect in the power output of a microbial fuel cell (MFC) by adding cellulolytic bacteria Ruminococcus albus (R. albus) into the anodic chamber. Mediator-less H-type MFCs were set up where the anode chamber contained anaerobic digester microorganisms as inocula on finely ground pine tree (Avicel) at 2% (w/v) and the cathode chamber of 10mM phosphate buffered saline conductive solution, both separated by a cation exchange membrane. The functioning of the MFCs for generation of electrical power and the amounts of gaseous byproducts was monitored over a 9-day period. The addition of cellulolytic bacteria caused an increase of average power density from 7.9 m W/m2 to19.5 m W/m2, about 245% increase over a 9-day period. For both groups of MFCs;with R. albus and the control, the head space gases collected were methane and CO2. While the methane: CO2 ratios were found unchanged at 1.7:1 throughout the 9 days of operation, the total gas production increased from 248 mL to 319 mL due to the presence of R. albus addition. This study confirms that whereas the biocatalytic activity of anode microbial population determines the energy production, the addition of external cellulolytic bacteria into anode microbial population can improve and extend the biomass utilization.

Development of a Consolidated Anaerobic Digester and Microbial Fuel Cell to Produce Biomethane and Electricity from Cellulosic Biomass Using Bovine Rumen Microorganisms

Microbial fuel cells (MFCs) are bioelectrochemical systems that convert chemical energy contained in organic matter into electrical energy by using the catalytic (metabolic) activity of living microorganisms. Mediator-less two chamber H-type MFCs were constructed in the current study, using dairy digester microbial population as anode inocula to convert finely ground pine tree (Avicel) at 2% (w/v) to electricity. MFCs were placed at 37&deg;C and after the circuit voltage was stabilized on d9, bovine rumen microorganisms cultured anaerobically for 48 hrs in cellulose broth media were added to treatment group of MFC at 1% v/v dosage. MFC power and current across an external resistor were measured daily for 10 d. At the end of incubation on d19 head space gas and anode chamber liquid solutions were collected and analyzed for total gas volume and composition, and volatile fatty acids, respectively. Addition of enriched rumen microorganisms to anaerobic anode chamber increased cellulose digestibility and increased both CO2 and methane production;however, it decreased the methane to CO2 ratio. Over the experimental period, electricity generation was increased with rumen microorganism addition, and power density normalized to anode surface area was 17.6 to 67.2 mW/m2 with average of 36.0 mW/m2 in treatment, while control group had 3.6 to 21.6 (AVE 12.0) mW/m2. These observations imply that biocatalysis in MFCs requires additional cellulolytic activities to utilize structural biomass in bioenergy production.

Electricity Generation Performance of Microbial Fuel Cell Embedded in Anaerobic-Anoxic-Oxic Wastewater Treatment Process

Microbial fuel cell (MFC) embedded in anaerobic-anoxic-oxic (A2/O) process has positive effects on wastewater treatment, which can enhance the efficiencies of pollutants’ removal, along with electricity production. But the electricity generation performance and its optimization of MFC embedded in A2O process still needs to be further investigated. In this study, in order to optimize the contaminants removal and electricity production of the MFC-A2/O reactor, a lab-scale corridor-style MFC-A2/O reactor, which could simulate the practical A2/O biological reactor better, was designed and operated. The removal efficiencies of chemical oxygen demand, total nitrogen and total phosphorus were continuously monitored so as the electricity generation. In addition, the influences of the structural parameters’ changes of MFC on the output voltage, including electrode material, the directly connected area and the distance between electrodes, were also studied. The results elucidated that the effluent quality of A2/O reactor could be improved when MFC was embedded, and all the investigated structural factors were closely related to the electricity generation performance of MFC to some extent.

量子点碳修饰生物阴极提高BC-MFC系统脱氮及产电性能

为提高生物阴极微生物燃料电池系统脱氮及产电性能,提出采用量子点碳对生物阴极微生物燃料电池系统(BC-MFC)的生物阴极(BC)进行修饰,以增加阴极附着面积提高微生物附着量。以脱氮作为首要目标,产电作为次要目标,设计了4组不同类型生物阴极的BC-MFC系统进行实验。结果表明,利用量子点碳对生物阴极进行修饰,能提高系统的脱氮能力,氨氮和总氮去除率最高可达到80%和77%,相比于对照组均提升约10%;系统微生物群落形成更快,启动时间缩短,且系统内阻最高下降24.19Ω,平均下降约23Ω,功率密度最高提升9.42 mW·m^(-3),平均提升6.76 mW·m^(-3);增加了系统的不稳定因素,采用微生物提前挂膜培养和在阴极区域栽种湿地植物的方法可提高系统稳定性。

LDH改性电极强化CW-MFC耦合系统深度处理污水研究

构建了人工湿地-微生物燃料电池(CW-MFC)耦合系统,探究了层状双氢氧化物(LDH)材料改性电极对CW-MFC系统运行性能及其微生物群落结构的影响。结果表明,LDH材料的结构及其中的Fe、Ni元素显著影响电极生物膜中的微生物群落结构及与脱碳除氮相关的功能微生物数量,聚苯胺(PANI)的添加增强了LDH的电导率,这些因素共同作用改善了系统的污染物去除性能和产电性能。其中,阴阳极均用FeNi-LDH/PANI改性的反应器的性能最好,其COD、NO_(3)^(-)-N和NH_(4)^(+)-N的去除率分别为95.68%、96.72%和95.32%,出水水质可达到地表水Ⅱ类标准;该系统稳定运行期间的平均输出电压为108.96 mV,最大功率密度可达到1.99 W/m^(3)。

某垃圾填埋场渗滤液反渗透浓缩液的MFC处理研究

垃圾渗滤液反渗透浓缩液含盐、高浓度有机物和营养物质。该文开展单室空气阴极式的微生物燃料电池(Microbial Fuel Cell,MFC)处理广西某垃圾填埋场不同盐度的垃圾渗滤液反渗透浓缩液的处理研究。结果表明,盐度越低,处理效果越好,当以低盐度浓缩液混合乙酸钠作为处理对象时,效果最佳,浓缩液中COD、NH_(3)-N和TN的去除率分别达到90.91%、46.54%、64.89%。MFC处理垃圾渗滤液反渗透浓缩液为高效低能耗处理提供新途径。

底物浓度和缓冲液浓度对MFC性能影响研究

实验研究了阳极室进口底物浓度和缓冲溶液浓度对碳刷阳极微生物燃料电池产电性能的影响,并利用循环伏安法考察了不同条件下阳极生物膜的电化学活性。结果表明,电池的功率密度随进口底物浓度的增加而增大;在进口底物浓度为500 mg COD/L时,其达到饱和。随着缓冲液浓度的增加,电池的功率密度增大,这是由于缓冲液不仅维持了阳极室及阳极生物膜的p H,而且增强了阳极电解液的离子强度。循环伏安测试结果进一步证实了不同条件下电池的产电性能。

pH对微藻型MFCs处理养猪源分离废水影响研究

实验构建了以微藻为阴极的双室微生物燃料电池(MFCs),以养猪源分离废水为阳极底物,考察在稳定运行的基础上,阳极初始pH对微藻型MFCs的产电性能和养猪源分离废水处理效果的影响。结果表明,微藻型MFCs中阳极液在碱性环境中有利于提高系统的性能,当pH从6增加到10时,微藻型MFCs的产电性能随之提高。当pH=10时,系统的产电性能达到最佳,功率密度为534.8 mW/m^3,是pH=6时的2.12倍。pH对COD的去除率影响不大,均在90%以上;NH_4^+-N的去除率随着pH的升高而提高,当pH=10时,NH_4^+-N去除率达93.54%。

进水COD浓度对基于MFC的UASB生物传感器反馈性能的影响

考察MFC生物传感器在不同COD负荷条件下电信号的反馈情况.通过对比不同进水COD条件下的反馈时间,研究pH对MFC传感器反馈性能的影响.实验结果表明：MFC电信号与进水COD质量浓度具有良好的线性关系;在1000-3000mg/L的进水条件下,MFC稳定电压与进水COD质量浓度呈y=3.83×10^-5x＋0.25的线性增长关系,传感器的反馈时间为4h;随着进水COD质量浓度提升至4000-6000mg/L,MFC稳定电压与进水COD质量浓度呈y=-5.95×10^-5x＋0.54的线性下降关系,系统内挥发性脂肪酸大量积累导致pH降至4.6,反馈时间延缓至8.6h,系统长期处于酸化状态,产电微生物活性降低,电子传递速率受到抑制,传感器反馈时间延迟.

无介体MFC微生物催化剂的“独立驯化”与“在线驯化”结合研究

采用独立驯化和在线驯化相结合的新颖方式,以碳毡、碳布和碳纸为阳极挂膜材料,考察驯化方式和阳极材料对无介体微生物燃料电池(MFC)产电性能和有机物去除效果的影响。结果表明,独立驯化期阳极材料特性对微生物挂膜的影响较大,扫描电镜结果表明挂膜效果最好的是碳毡,碳布次之,碳纸较差;在线驯化约10 h后,微生物催化剂的电化学活性显著升高,第2个周期电压达到峰值(碳毡、碳布、碳纸的峰电压分别为0.803、0.604和0.574 V),第3个周期MFC能长时间稳定运行,其中,碳毡MFC电压平台维持在0.78 V左右长达180 h;比较MFCs的产电能力优劣顺序为:碳毡(1 339.6 mW/m3)>碳纸(96.8 mW/m3)>碳布(80 mW/m3);COD去除率为:碳毡(89.5%)>碳纸(79%)>碳布(74.7%)。

以铁氰化钾为电子受体的MSBR-MFC集成系统响应机理研究

将双室微生物燃料电池(MFC)的阴极区改造成膜序批式生物反应器(MSBR),从产能和净化的双重角度构建了MSBR-MFC集成系统,以铁氰化钾作电子受体、碳毡作生物阴极和固定填料,采取"厌氧、好氧"交替运行方式处理城市生活污水,考察MSBR-MFC系统的产电能力及污染物去除效果。结果表明,系统在厌氧段投加铁氰化钾后,电能输出将大幅提高,最适投加量为30 mmol.L-1;该条件下好氧段系统最大输出功率密度为893.1 mW.m-3,输出峰电压为570.4 mV,电池内阻约300Ω,1个HRT(8 h)内累积产电量13.6 C;阴极区COD、氨氮、TP去除率分别为90.5%、99%和96.2%,阴阳两极室累积有机物去除容积负荷约2.125 kg.m-.3d-1,比传统双室MFC提高了约80.8%。

喹啉为MFC阳极燃料的微生物群落结构演化分析

通过构建填料型微生物燃料电池(MFC),首次对以喹啉为燃料时的MFC阳极表面的微生物群落进行了分析.PCR-DGGE的试验结果表明,随着燃料的改变,微生物群落也发生改变.当以喹啉和葡萄糖的混合溶液稳定地作为燃料时,由于受到喹啉毒性的抑制,微生物多样性降低,优势菌也发生明显的改变.与葡萄糖共基质相比,以单一喹啉为燃料时的阳极微生物优势菌落发生明显改变.新增加一类菌,这类菌与Pseudomonas sp.DIC5RS的同源性为100%,推测该菌在单一喹啉为MFC燃料时喹啉的降解过程中起到关键作用.

MFC技术处理铜、银重金属废水的研究

将具有氧化性的有机废水池作为电池的阳极,具有还原性的重金属废水池作为电池的阴极,利用微生物燃料电池(MFC)同时处理有机废水和重金属废水.结果表明,利用铜离子溶液作阴极,MFC最大电压可达到0.277 V,最大功率密度为33.49 mW/m2,COD的去除率为31.6%,铜的去除率可达42%;利用银离子溶液作阴极,MFC最大电压可达到0.311 V,最大功率密度为42.21 mW/m2,COD的去除率为64.6%,银的去除率可达78%.即不管是从产电角度还是从废水处理角度考虑,都是以银离子废水作阴极优于铜离子.

Progress in enhancing the remediation performance of microbial fuel cells for contaminated groundwater

Microbial fuel cells(MFCs)have become more prevalent in groundwater remediation due to their capacity for power generation,removal of pollution,ease of assembly,and low secondary contamination.It is currently being evaluated for practical application in an effort to eliminate groundwater pollution.However,a considerable majority of research was conducted in laboratories.But the operational circumstances including anaerobic characteristics,pH,and temperature vary at different sites.In addition,the complexity of contaminants and the positioning of MFCs significantly affect remediation performance.Taking the aforementioned factors into consideration,this reviewsummarizes a bibliography on the application of MFCs for the remediation of groundwater contamination during the last ten decades and assesses the impact of environmental conditions on the treatment performance.The design of the reactor,including configuration,dimensions,electrodes,membranes,separators,and target contaminants are discussed.This review aims to provide practical guidance for the future application of MFCs in groundwater remediation.

NG-MFCs协同FCDI处理含盐废水应用研究

以氮掺杂石墨烯(NG)催化微生物燃料电池(MFCs)的阴极,同时多级串并联方式连接MFCs与流动电极电容去离子(FCDI)装置,用以处理含盐废水。结果表明,NG-MFCs的产电脱氮性能明显提升,其最大输出电压为523 m V,NH_4^+-N的去除率达到92.7%;并联方式下的MFCs产电输出更加稳定,处理Na Cl质量浓度2 g/L的盐溶液,MFCs-FCDI装置的除盐率达到30%。因此,NG-MFCs以其输出能量FCDI进行除盐,可达到能源利用与污水处理的双重效果。

梧桐叶浸泡液对CW-MFC降解活性艳红的影响

在自行构建的人工湿地(CW)-微生物燃料电池(MFC)系统中,以葡萄糖为对照,系统研究了梧桐叶浸泡液对活性艳红X-3B脱色效果的影响及机理。结果表明,当实验进水X-3B的质量浓度不高于50 mg/L时,系统的脱色率近乎达到100%;当X-3B的质量浓度升高至100 mg/L和150 mg/L时,出水X-3B含量出现明显波动。葡萄糖组脱色主要发生在底部和阳极区域,脱色率分别为78.13%和14.96%,而梧桐叶浸泡组脱色主要发生在底部和阴极区域,脱色率分别为68.28%和16.78%。葡萄糖组X-3B的偶氮结构、萘环结构、三嗪结构和苯环结构在系统中逐步得到降解,而梧桐组缺少苯环和萘环结构的特征峰。不同碳源对不同区域微生物群落结构产生影响,使得X-3B的脱色降解呈现不同的规律。