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.

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.

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。

Microalgae Scenedesmus obliquus as renewable biomass feedstock for electricity generation in microbial fuel cells （MFCs）

Renewable algae biomass, Scenedesmus obliquus, was used as substrate for generating electricity in two chamber microbial fuel cells （MFCs）. From polarization test, maximum power density with pretreated algal biomass was 102mW·m^2 （951mW·m^3） at current generation of 276mA·m^-2. The individual electrode potential as a function of current generation suggested that anodic oxidation process of algae substrate had limitation for high current generation in MFC. Total chemical oxygen demand （TCOD） reduction of 74% was obtained when initial TCOD concentration was 534mg · L^-1 for 150 h of operation. The main organic compounds of algae oriented biomass were lactate and acetate, which were mainly used for electricity generation. Other byproducts such as propionate and butyrate were formed at a negligible amount. Electrochemical Impedance Spectroscopy （EIS） analysis pinpointed the charge transfer resistance （112Ω ） of anode electrode, and the exchange current density of anode electrode was 1214 nA·cm^-2.

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%。

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。

硫氮比对MFC生物脱氮脱硫和产电的影响

文章以硫化钠(Na 2S)溶液为阳极模拟废水,以硝酸钾(KNO 3)溶液为阴极模拟废水,在阴、阳极室分别接种活性污泥菌群,构建双室微生物燃料电池(microbial fuel cell,MFC),考察不同硫元素与氮元素的质量比(简称“硫氮比”)对生物脱氮除硫与产电性能的影响。实验结果表明:当硫氮比为5∶5时,系统中脱氮、除硫与产电性能最佳,阴极室的硝酸盐出口液质量浓度从100.00 mg/L降至8.68 mg/L,转化率为91.32%,运行周期为90 h,平均转化速率为24.35 mg/(L·d);硫化物的转化率为98.84%,脱氮脱硫的效率最高,同时MFC的电流密度和功率密度均达到最大值,分别为16875 mA/m^(3)、1560.56 mW/m^(3)。16S rRNA测序结果表明,MFC阳极富集的优势菌属为Chlorobaculum、Desulfobacterium和Longilinea等,而阴极反硝化优势菌属为Acidovorax、Thermomonas和Nitrospira等,且硫氮比影响优势菌属的菌群丰度。

填料对电极氨氧化型CW-MFC耦合系统运行性能的影响

在基于电极氨氧化作用的人工湿地-微生物燃料电池(CW-MFC)耦合系统中设置阳极层,探究了阳极层中不同种类填料对系统运行性能及其微生物学特征的影响.结果表明,利用电极氨氧化型CW-MFC处理生活污水时,阳极层中填料的理化特性可显著影响电活性氨氧化生物膜中的微生物群落结构及功能微生物数量,进而会造成装置脱氮产电性能的差异.相较于石英砂和沸石,当选用废砖块作为阳极层填料时,其较大的比表面积、较高的EC值及Fe含量提高了参与电极氨氧化反应的功能微生物(尤其是Nitrosomonas、Geobacter、Empodebacter和Candidutus Brocadia)的丰度及活性,CW-MFC中的电极氨氧化作用随之得以强化,其运行性能亦较理想,此时系统的COD、TP、TN和NH_(4)^(+)-N去除率分别可达(87.29±2.06)%、(92.52±3.20)%、(87.10±2.27)%和(96.49±0.76)%,其输出功率密度峰值为0.60W/m^(3),出水水质满足《城镇污水处理厂污染物排放标准》(GB 18918-2002)一级A标准.

微生物燃料电池工作原理及产电性能提升策略

微生物燃料电池(MFC)是一种解决其他能源在环境方面不足的新技术,目前低能量输出是MFC实际应用的关键瓶颈。基于MFC工作原理,提出微生物活性差、电子迁移阻力、质子传输阻力及阴极还原反应缓慢是MFC能量输出的限制因素,并从以下5个方面综述了提升MFC产电性能策略:调节pH和选择最佳盐度,加强微生物代谢活性;改性阳极材料,降低电子迁移阻力;增强电解液电导率、优化隔膜材料及缩短电极间距减小质子传输阻力;制备高效阴极催化剂和选择优异电子受体加快阴极还原反应速率;改进MFC反应器构型,提高整体产电性能。未来,可在合成新型阴极催化剂、降低膜污染、优化微生物生长环境、制备优异的电极材料和改进MFC反应器配置5个方面开展重点研究。

Nitrogen recovery from wastewater using microbial fuel cells

Nitrogen is one of major contaminants in wastewater; however, nitrogen, as bio-elements for crop growth, is the indispensable fertilizer in agriculture. In this study, two-chamber microbial fuel cells （MFCs） were first operated with microorganisms in anode chamber and potassium ferricyanide as catholyte. After being success- fully startup, the two-chamber MFCs were re-constructed to three-chamber MFCs which were used to recover the NO-3 -N and NH＋4 -N of synthetic wastewater into value- added nitrogenous fertilizer from cathode chamber and anode chamber, respectively. Ferric nitrate was used as the sole electron acceptor in cathode, which also was used to evaluate the NO-3 -N recover efficiency in the case major anion of NO3 in cathode. The output voltage of these MFCs was about 600-700 mVat an external load of 500 Ω. About 47% NH＋4 -N in anode chamber and 83% NO-3 -N in cathode chamber could be recovered. Higher current density can selectively improve the recovery efficiency of both NH＋4-N and NO3 -N. The study demonstrated a nitrogen recovery process from synthetic wastewater using three-chamber MFCs.

Comparative Study of Electrochemical Performance and Microbial Flora in Microbial Fuel Cells by Using Three Kinds of Substrates

This work aimed to investigate the distinct electrochemical performance and microbial flora of microbial fuel cells(MFCs)in relation to different single hazardous fed fuels.Three replicate MFCs were inoculated with the same microbial consortium from a coking wastewater treatment plants wherein ammonium chloride(ammoniiim chlo-ride-fed MFC,N-MFC),phenol(phenol-fed MFC,P-MFC)and potassium sulphide(potassium sulphide-fed MFC,S-MFC)were the sole substrates and main components of real coking wastewater.With initial concentrations of am-monium chloride,phenol and potassium sulphide of 0.75,0.60 and 0.55 g/L,the removal efficiencies reached 95.6%,90.6%and 99.9%,respectively,whereas the peak output power densities totalled 697,324 and 1215 mW/m^2.Micro-bial community analysis showed that the respective addition of substrate substantially altered the microbial community structure of anode biofllm,resulting in changes in relative abundance and emergence of new strains and further affecting the electrochemical properties of MFCs.The chemical oxygen demand(COD)removal efficiency of real coking wastewater,in which,the inoculum was the combined biomass from the three MFCs,reached 82.3%.

On the use of ferroelectric material LiNbO3 as novel photocatalyst in wastewater-fed microbial fuel cells

In this work, the use of lithium niobate （LiNbO3）, a ferroelectric and photocatalyst material, is investi- gated as a new type of cathode catalyst for wastewater-fed single-chamber microbial fuel cells （MFCs）. Carbon cloth electrodes coated with LiNbO3 were studied with and without UV-vis irradiation to assess its photocatalytic behavior in these devices. The synthesized phase of LiNbO3 was characterized by X- ray diffraction, differential scanning calorimetry, particle size distribution, and transmission electron microscopy analyses. The MFC containing a LiNbO3-based cathode exhibited a maximum open circuit potential and power output of 400 mV and 131 mW/m^3, respectively, under irradiation. This cathode configuration also achieved the maximum chemical oxygen demand removal of 84% after 120 h of MFC operation. These results show that ferroelectric materials such as LiNbO3 could be used as cathode cat- alysts in MFC devices. As a complementary analysis, the removal of the heavy metals detected in the wastewater was also monitored.

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。

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.

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%。