[object Object], [object Object], [object Object] et al.

Biosensors and Bioelectronics • 2016

[object Object], [object Object], [object Object] et al.

Physical Chemistry Chemical Physics • 2014

The integration of Microbial Fuel Cells (MFCs) in a microfluidic geometry can significantly enhance the power density of these cells, which would have more active bacteria per unit volume. Moreover, microfluidic MFCs can be operated in a continuous mode as opposed to the traditional batch-fed mode. Here we investigate the effect of fluid flow on the performance of microfluidic MFCs. The growth and the structure of the bacterial biofilm depend to a large extent on the shear stress of the flow. We report the existence of a range of flow rates for which MFCs can achieve maximum voltage output. When operated under these optimal conditions, the power density of our microfluidic MFC is about 15 times that of a similar-size batch MFC. Furthermore, this optimum suggests a correlation between the behaviour of bacteria and fluid flow.

[object Object], [object Object], [object Object] et al.

Electrochimica Acta • 2022

Carlo Santoro, Alexey Serov, Lydia Stariha et al.

Energy & Environmental Science • 2020

Development of low-cost iron-based catalysts for MFC cathodes.

Bradley R. Ringeisen, Emily Henderson, Peter K. Wu et al.

Environmental Science & Technology • 2006

Miniature MFC achieves high power density with Shewanella oneidensis.

Shaoan Cheng, Hong Liu, Bruce E. Logan

Environmental Science & Technology • 2006

Improved cathode design increases power density in single-chamber MFCs.

Doo Hyun Park, J. Gregory Zeikus

Applied and Environmental Microbiology • 2000

ABSTRACT Neutral red (NR) was utilized as an electron mediator in microbial fuel cells consuming glucose to study both its efficiency during electricity generation and its role in altering anaerobic growth and metabolism of Escherichia coli and Actinobacillus succinogenes . A study of chemical fuel cells in which NADH, NR, and ferricyanide were the electron donor, the electronophore, and the electron acceptor, respectively, showed that electrical current produced from NADH was proportional to the concentration of NADH. Fourfold more current was produced from NADH in chemical fuel cells when NR was the electron mediator than when thionin was the electron mediator. In microbial fuel cells in which E. coli resting cells were used the amount of current produced from glucose when NR was the electron mediator (3.5 mA) was 10-fold more than the amount produced when thionin was the electron mediator (0.4 mA). The amount of electrical energy generated (expressed in joules per mole of substrate) and the amount of current produced from glucose (expressed in milliamperes) in NR-mediated microbial fuel cells containing either E. coli or A. succinogenes were about 10- and 2-fold greater, respectively, when resting cells were used than when growing cells were used. Cell growth was inhibited substantially when these microbial fuel cells were making current, and more oxidized end products were formed under these conditions. When sewage sludge (i.e., a mixed culture of anaerobic bacteria) was used in the fuel cell, stable (for 120 h) and equivalent levels of current were obtained with glucose, as observed in the pure-culture experiments. These results suggest that NR is better than other electron mediators used in microbial fuel cells and that sludge production can be decreased while electricity is produced in fuel cells. Our results are discussed in relation to factors that may improve the relatively low electrical efficiencies (1.2 kJ/mol) obtained with microbial fuel cells.

Min-soo Hyun, Sang-Kyung Kim, Doohwan Jung et al.

Journal of Power Sources • 2006

Hyung Joo Kim, Hyung Soo Park, Moon Sik Hyun et al.

Enzyme and Microbial Technology • 2002

Shaoan Cheng, Bruce E. Logan

Electrochemistry Communications • 2007

César I. Torres, Andrew Kato Marcus, Hyung-Sool Lee et al.

FEMS Microbiology Reviews • 2010

Johnson Sarah M., Chen Liu, Rodriguez Carlos et al.

Nature Communications • 2024

This breakthrough study presents a revolutionary flow-based microbial fuel cell design that eliminates biofilm limitations through redox mediator technology. Using planktonic Shewanella bacteria with artificial redox mediators, the system achieves extraordinary current densities exceeding 40 mA/cm². The flow configuration enables continuous operation with superior mass transfer, resulting in unprecedented power performance compared to traditional biofilm-based systems.

Zhang Wei, Liu Chen, Wang Xiaoming et al.

Scientific Reports • 2025

This study presents novel nickel silicide nanowire anodes that significantly enhance microbial fuel cell performance. The 3D nickel foam substrate decorated with nanowires achieves unprecedented power densities of 323 mW/m² and current densities of 2.24 A/m². The nanowire architecture provides superior biocompatibility with E. coli bacteria, resulting in enhanced electron transfer kinetics and improved biofilm formation. The electrode demonstrates a 2.5x power increase and 4x current boost compared to bare nickel electrodes, while maintaining excellent long-term stability.

Shengyu Shi, Pengfei Cui, Shasha Wang et al.

Water • 2025

This study investigated the nitrogen removal performance of a three-stage AO reactor for refractory TN and the changes in microbial community structure within the activated sludge system under varying sodium chloride concentration conditions. Under an influent sodium chloride concentration of 0 g/L with sufficient carbon source, the removal rates of Total Nitrogen (TN), Chemical Oxygen Demand (CODcr), and Ammonium (NH4+-N) remained stable at 98%, 99.7%, and 99.9%, respectively. When the sodium chloride concentration increased to 20 g/L, the activity of AOB was significantly inhibited, with removal efficiency rates dropping to 83%, 89%, and 70%, respectively, and the NAR increasing to 91.97%. Analytical results demonstrated that both ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) exhibited inhibited metabolic activities, with NOB experiencing earlier functional impairment. Under NaCl concentrations ≤ 10 g/L, conventional nitrogen removal via nitrification–denitrification (ND) remained dominant. When NaCl concentrations exceeded 10 g/L, due to the accumulation of NO2−-N, the phyla Planctomycetota and Proteobacteria maintained dominance in the microbial community, while partial nitrification (PN) and denitrification pathways gradually replaced ND. Extracellular polymeric substance (EPS) secretion emerged as the primary microbial defense mechanism against salinity stress. Experimental findings informed proposed strategies including phased acclimatization for salt-tolerance enhancement, EPS production regulation, and targeted enrichment of functional consortia, which collectively improved the denitrification efficiency by 18.7–22.3% under salinity levels ≤ 20 g/L. This study provides theoretical foundations and technical references for process optimization in hypersaline industrial wastewater treatment systems.

M. Kim, C. Kim, Y. Sohn

Fuel Cells • 2018

Abstract The channel/rib structure, commonly used in proton‐exchange membrane fuel cells (PEMFC), has disadvantages of uneven pressure distribution, gas supply, and produced‐water management under “rib” portion. In recent years, porous metal foam has been studied as an alternative flow field. We determined that the application of porous metal foams improved the PEMFC performance by compensating for the drawback of the channel/rib‐type flow field owing to the unique properties of metal foams (e.g., high conductivity, high porosity, and ease‐of‐deformation). Thus, this study confirmed the difference in the PEMFC performance with metal foams depending on cell configurations. Furthermore, the actual 500 W class PEMFC stack was fabricated to confirm the possibility of the metal foam application in the stack scale.

Taewoo Yi, Willie F. Harper

Water Environment Research • 2009

Microbial fuel cells (MFCs) simultaneously provide waste treatment while capturing energy in the form of electricity. Although these devices are being used in engineered and natural environments where nitrate or sulfate may inhibit power production, the effects of these electron acceptors have not been fully explored. This research investigated the effect of nitrate and sulfate on MFC power production when these chemicals are present at the anode. Nitrate decreased the maximum current and power density by 15 and 17%, respectively, when present at 20 mg/L, and sulfate caused the maximum current and power density to decrease by 4 and 7%, respectively (also at 20 mg/L). Stronger inhibition was observed at higher nitrate and sulfate concentrations, but power production persisted. Coulombic efficiency decreased as nitrate and sulfate levels increased, although this was not primarily due to the biochemical reduction of nitrate or sulfate; rather, it was probably because of the inhibition of exoelectrogens.

P. Pusomjit, O. Chailapakul, H. Y. Ng et al.

Water Science and Technology • 2018

Abstract Microbial fuel cells (MFCs) are an ecologically friendly technology that can recover electricity and simultaneously treat wastewater. Among all the influential factors, cathode material and catalyst play a crucial role in electricity production and oxygen reduction. In this study, Pt nanocatalysts deposited on single-walled carbon nanotubes (Pt/SWCNTs) were synthesized by the deposition-precipitation (DP) method under optimal conditions. The results show that DP might be a promising method for the preparation of Pt/SWCNTs due to its simple, cost-effective and time-saving procedure, in addition to being highly efficient at creating small Pt particles (0.9 nm) that were very uniformly distributed. The synthesized Pt/SWCNTs suspension was spray-coated on to carbon cloth and then used as a cathode for MFCs. The electricity generation of MFCs equipped with a Pt/SWCNTs cathode was evaluated in terms of open circuit voltage (0.6954 V), internal resistance (63.3 Ω•m2) and maximum power density (2,022 mW/m2). The chemical oxygen demand removal, biological oxygen demand removal, total dissolved solids removal, total suspended solids removal and silver recovery was satisfactory at 84.5%, 74.0%, 45.7%, 60.0% and 99.0%, respectively. Therefore, Pt/SWCNTs from the DP method was identified as a potential candidate to replace commercial Pt-carbon cloth for MFC cathodes.

Daichi Yoshizu, Atsushi Kouzuma, Kazuya Watanabe

Microorganisms • 2023

One of practical challenges in anaerobic-digestion (AD) technology is the cost-effective treatment of residue effluents containing high concentrations of organics, nitrogen and phosphorus (CNP). In order to evaluate the utility of microbial fuel cells (MFCs) for treating anaerobic-digester effluents (ADEs) and generating power from them, laboratory-scale single-chamber MFCs were filled with ADE obtained from a commercial AD plant treating food wastes and thereafter operated by routinely supplying ADE at different hydraulic residence times (HRTs, 5 to 20 days). It is shown that MFCs were able to reduce not only organics in ADE but also nitrogen and phosphorus. For instance, data demonstrated that over 50% of CNP was removed in MFCs operated at an HRT of 10 days, at which the maximum power density reached over 200 mW m−2 (based on the projected area of anode). Metabarcoding of 16S rRNA genes showed that some bacteria were specifically enriched in anode biofilms, suggesting their involvement in power generation. Our study suggests that MFCs are applicable to reducing CNP in ADEs at reasonable rates, and provides subsequent work with fundamental data useful for setting targets for further developments.

Matteo Grattieri, Sofia Babanova, Carlo Santoro et al.

ECS Meeting Abstracts • 2014

Microbial fuel cell (MFC) is an innovative electrochemical biotechnology capable to produce electricity directly from wet marginal biomass and various wastes. Several interests related to this area of science are progressively increasing worldwide [1, 2]. The Single Chamber Microbial Fuel Cell (SCMFC), or rather a membraneless air-cathode MFC configuration, is the most studied MFC system due to simple design and the higher performance. The membrane removal leads to positive effects such as costs reduction, decrease of the MFCs ohmic resistance and as a result enhance the MFC output. Unfortunately, the membrane removal allows the oxygen transport and diffusion into the solution (electrolyte) and it thus lower the anodic performance, which are optimized for strictly anaerobic conditions. In fact, the presence of oxygen in the SCMFC solution affects the biofilm formation and development and disturb severely the biofilm settlement on the electrode. Generally, biofilm action is not limited in a monolayer of bacteria directly in contact with the electrodes, but it needs to be considered as a 3D structure next to the surface, of hundred micrometer thickness. The biofilm is involved (completely or partially) in the electrochemical and chemical processes carring out an effective electron transfer (EET) to/from the electrodes in this three dimensional space [3]. Consequently, the determination of oxygen profiles close to the anode and cathode electrode becomes of fundamental importance. Until now, to the best of our knowledge, no exhaustive studies have been focused on the determination of oxygen profile into the electrolyte of a SCMFC and how the presence of oxygen affects the MFC output. This work aimed to measure the oxygen presence/absence in the different zones inside the SCMFC solution and particularly close to the electrodes surfaces. Accordingly, a “home made” enzymatic oxygen micro-probe based on Bilirubin Oxidase (BOx) enzyme has been designed. The main advantage of utilizing an enzyme is its selectivity towards a specific reaction and in this case BOx is able to catalyze oxygen reduction reaction to water [4]. The advantage of utilizing a micro-probe is the possibility of obtain a precise oxygen measurment inside the SCMFC solution that would permit the optimization of this technology, allowing further cell configuration development for future on-field application. The probe was prepared by immobilization of BOx on modified carbon fiber embaded in plastic body and sealed with epoxy resin (Fig. 2A). The diameter of the sensor, exposed to the electrolyte, was approximatelly 100 μm. This micro-probe was calibrated via Cyclic Voltammetry (CV) using phosphate buffer 50 mM with additional indifferent electrolyte (KCl 100 mM) in different aeration conditions using a typical three electrode electrochemical cell. The reference electrode was an Ag|AgCl electrode and a Pt wire was used as counter electrode. The calibration curve was created by plotting the current at -0.4 V vs Ag|AgCl as a function of the oxygen concentration (Figure 1). The oxygen concentration in the electrolyte during the voltammetry measurements was monitored via DO probe and used for the calibration plot. In order to precisely measure the oxygen content inside the MFCs` electrolyte for localized analysis, a computer controlled stage (Newark System Inc.) was used. The analysis setup is shown at Figure 2B. A Luggin capillary was used during the analysis in order to reduce the ohmic drop. The oxygen concentration was studied both for the anode and cathode biofilm. [1] C. Santoro, Y. Lei, Li, P. Cristiani, Biochemical Engineering J. 2012; 62:8–16 [2] W. Li, G. Sheng, X. Liu, H. Yu. Bioresource Technology . 2011; 102: 244–252 [3] L. Huang, J.M. Regan, X. Quan, Bioresource Technology , (2011), 102: 316-323 [4] S. Brocato, C. Lau, P. Atanassov, Electrochimica Acta . 2012; 61: 44-49

Xiangfeng Xie, Jijing Hu, Xian Cao et al.

Sustainability • 2024

In this study, a constructed wetland was coupled with a microbial fuel cell to establish a coupled system known as the constructed wetland–microbial fuel cell (CW–MFC), utilized for the treatment of X-3B azo dye wastewater at varying concentrations. Experimental results indicated that the anodic region made the primary contributions to the discoloration of azo dyes and COD removal, with a contribution rate of 60.9–75.8% for COD removal and 57.8–83.0% for the effectiveness of discoloration. Additionally, the role of plants in the constructed wetland area could achieve the removal of small molecular substances and further discoloration. In comparison to open-circuit conditions, under closed-circuit conditions the CW–MFC effectively degraded X-3B azo dye wastewater. Under an external resistance of 2000 Ω, a maximum COD removal rate of 60.0% and a maximum discoloration rate of 85.8% were achieved for X-3B azo dye at a concentration of 100 mg/L. Improvements in the treatment efficiency of X-3B dye wastewater were achieved by altering the external resistance. Under an external resistance of 100 Ω and an influent concentration of X-3B of 800 mg/L, the COD removal rate reached 78.6%, and the decolorization rate reached 85.2%. At this point, the CW–MFC exhibited a maximum power density of 0.024 W/m3 and an internal resistance of 99.5 Ω. Spectral analysis and GC–MS results demonstrated the effective degradation of azo dyes within the system, indicating azo bond cleavage and the generation of numerous small molecular substances. Microbial analysis revealed the enrichment of electrogenic microorganisms under low external resistance conditions, where Geobacter and Trichococcus were dominant bacterial genera under an external resistance of 100 Ω, playing crucial roles in power generation and azo dye degradation within the system.

Aleksandr Kiessling, Julie C. Fornaciari, Grace Anderson et al.

Journal of The Electrochemical Society • 2021

Hydroxide-exchange-membrane water electrolysis (HEMWE) is an emerging hydrogen-production pathway that combines many advantages of incumbent alkaline water electrolysis (AWE) and proton-exchange-membrane water electrolysis (PEMWE). Advancement in HEMWE has been accelerated with the development of stable and conductive hydroxide exchange membranes (HEMs) and a more comprehensive understanding of alkaline gas-evolving kinetics. However, performance and durability without supporting electrolytes (SELs) remain inferior to PEMWE and AWE and little is known about the role and impact of the SELs. This study investigates the effects of SELs used as anolyte solutions in HEMWEs including cation-type, anion-type, SEL conductivity and pH, presence of carbonates and increased cation/OH − ratios on cell voltage and stability. We report our findings that (i) cell potential and high-frequency resistance did not correlate with anolyte SEL conductivity, (ii) cation-type influences cell voltage at low current densities (<50 mA cm −2 ) as predicted by half-cell measurements, (iii) increased cation/OH − ratio causes increased overpotentials, and (iv) carbonates are exchanged in the HEM but removed via self-purging at high current density. Overall, this study concludes that concentrated KOH is still the best SEL.

Muhammad Nihal Naseer, Asad A. Zaidi, Kingshuk Dutta et al.

Journal of The Electrochemical Society • 2023

Microbial fuel cell (MFC) is attractive for research community as a promising bioelectricity production technology using organic waste. However, due to low performance and erroneous reproducibility and replicability, MFC lacks industrial application. Additionally, the nonlinear dynamic behavior of MFC, along with the involvement of electrochemistry and biology in mathematical models, makes it difficult to comprehend and simulate. To overcome these barriers, this study provides a simulation platform for conducting theoretical studies using a fundamental mathematical model of MFC. This novel Simulink/MATLAB model is based on mass balance across both compartments of MFC, and provides power density as a function of a wide range of performance-affecting parameters. Model validation depicts only 2%–10% error. This model can provide a stepping stone to perform theoretical optimization and industrial application studies in future. By varying the values of different parameters; studies may be performed to spot optimum values of the most sensitive parameters. Therefore, using the proposed tool paves the path for further improvements in design, cost effectiveness and performance efficiency that ultimately promises up-scaling of MFCs as a renewable and alternative energy resource.

Kumar Gaurav, Ram Singh, Brajesh Kumar Tiwari et al.

Journal of Polymer Engineering • 2019

Abstract Proton exchange membranes (PEMs), used as separators, are one of the important components in microbial fuel cells (MFCs). The efficiency of MFC is greatly influenced by PEM. Nafion, which is a commonly used membrane, has several disadvantages in addition to its high cost. The aim of the present work was to develop low-cost PEMs with higher conductivity. In the current work, membranes were prepared using comparatively cheaper material polyvinyl chloride with different concentrations of silica (SiO 2 ), citric acid and phosphotungstic acid (PWA) by the solution casting method. Different membrane properties such as surface morphology, water uptake capacity, ion exchange capacity (IEC), tensile strength, leaching test and potential applications in MFCs were investigated. The results showed that the prepared membrane with 10% silica has the highest water uptake of 55.8%. The IEC of prepared membranes was found to vary from 0.024 to 0.875 meq/g. The membranes showing better IEC were applied to the MFC. The maximum power density obtained was 43.91 m W/cm 2 in the case of a membrane with both 5% PWA and 5% silica. The results obtained make this membrane a promising and economically viable new material in MFC applications.

Chamindu Jayathilake, Gayani P. Dilangani, Sampath Bandara et al.

bioRxiv (Cold Spring Harbor Laboratory) • 2022

Abstract Methanogenesis conducted by archaea acts as a competing metabolic pathway that diverts available carbon and electrons away from exo-electrogenic metabolism in mixed culture inoculated microbial fuel cells (MFCs). Statin-class compounds are known to selectively inhibit eukaryotic and archaeal versions of HMG Co-A reductase (class-I) enzyme and the bacterial version of the same enzyme (class-II) is known to be unresponsive to statins. The results of this study demonstrated that the two model statin compounds Simvastatin and Atorvastatin were effective in suppressing methanogenesis in MFCs when applied in moderate concentrations (5 mg/L and 40 mg/L respectively) in MFC anodes. Power densities increased 2 fold compared to control (to 63 ± 1.8 mW/m 2 ) and 2.5 fold (to 69.5 ± 1.8 mW/m 2 ) with Simvastatin and Atorvastatin addition respectively. There was an almost complete suppression of CH 4 production with the addition of both statins into MFC anodes as shown by gas composition analysis. Quantitative FISH (qFISH) analysis showed that methanogens Methanosarcina, Metanobacteria and Methanomicrobiales together with all archaea were almost completely suppressed when statins were supplemented into MFC anodes. This study demonstrated that the statins addition can be used to boost power densities in MFCs.

Tabbi Wilberforce, Abdul Ghani Olabi

Sustainability • 2020

The investigation conducted is aimed at establishing the best operational conditions to obtain the best output of a 5-cell stack Proton Exchange Membrane fuel cell (PEMFC) with three different bipolar plate geometries. The work further explores the best input parameters that will yield the maximum voltage, current power as well as fuel efficiency from each of the three designs under investigation. A polarization curve was generated for each of the three designs and a surface response plot developed for each experiment. The work concluded that the spiral design performed very well compared to the other designs under investigation and even existing on the fuel cell market.

L. Fan, A. Knott, I. Jørgensen

RE&PQJ • 2024

State-of-the-art switched-capacitor DC-DC power converters mainly focus on low voltage and/or high power applications. However, at high voltage and low power levels, new designs are anticipated to emerge and a power converter that has both high efficiency and high power density is highly desirable. This paper presents such a high voltage low power switched-capacitor DC-DC converter with an input voltage up to 380 V (compatible with rectified European mains) and an output power experimentally validated up to 21.3 W. The wide band gap semiconductor devices of GaN switches and SiC diodes are combined to compose the proposed power stage. Their switching and loss characteristics are analyzed with transient waveforms and thermal images. Different isolated driving circuits are compared and a compact isolated half bridge driving circuit is proposed. The full-load efficiencies of 98.3% and 97.6% are achieved for the power stage and the complete power converter, without heatsink or airflow. The corresponding power densities are 7.9 W/cm3 and 2.7 W/cm3, based on boxed volumes, respectively.

Indrasis Das, Sovik Das, Swati Das et al.

Journal of The Electrochemical Society • 2021

For successful field-scale application of microbial fuel cell (MFC), the power recovery from field-scale MFC needs to be improved considerably with simultaneous reduction in its fabrication cost. These problems can be addressed by applying low-cost and efficient cathode catalyst in MFCs. In this regard, Cu 0.5 Mn 0.5 Fe 2 O 4 (CuMnFe) was synthesized and applied as cathode catalyst in lab and field-scale MFCs with capacity of 150 ml and 25 l, respectively. Lab-scale MFC having CuMnFe as cathode catalyst demonstrated power density of 176.0 ± 8.2 mW m −2 , which was competitive with MFC having Pt as cathode catalyst (183.0 ± 12.6 mW m −2 ) and it was about seven times higher than control MFC (25.5 ± 4.5 mW m −2 ) having no catalyst. Application of CuMnFe as cathode catalyst in field-scale MFC produced power density of 7.74 mW m −2 , which was three-times higher than the power produced by the field-scale MFC operated without any cathode catalyst (2.58 mW m −2 ). The cathode catalyst CuMnFe also demonstrated excellent anti-biofouling properties, which in turn improved the power production of field-scale MFC. Therefore, low-cost CuMnFe can be anticipated as an efficacious cathode catalyst for application in MFCs that would produce long term stable higher power, while offering simultaneous treatment to wastewater.

Qiao Yang, Zhenxing Wu, Lifen Liu et al.

Materials • 2016

Conventional oil sewage treatment methods can achieve satisfactory removal efficiency, but energy consumption problems during the process of oil sewage treatment are worth attention. The integration of a constructed wetland reactor and a microbial fuel cell reactor (CW-MFC) to treat oil-contaminated wastewater, compared with a microbial fuel cell reactor (MFC) alone and a constructed wetland reactor (CW) alone, was explored in this research. Performances of the three reactors including chemical oxygen demand (COD), oil removal, and output voltage generation were continuously monitored. The COD removals of three reactors were between 73% and 75%, and oil removals were over 95.7%. Compared with MFC, the CW-MFC with a MnO2 modified cathode produced higher power density and output voltage. Maximum power densities of CW-MFC and MFC were 3868 mW/m3 (102 mW/m2) and 3044 mW/m3 (80 mW/m2), respectively. The plants in CW-MFC play a positive role for reactor cathode potential. Both plants and cathode modification can improve reactor performance of electricity generation.

Rakib Parvez, Narayan Roy, Mohammad Shariar Shovon et al.

Water Practice & Technology • 2024

ABSTRACT Methylene blue (MB) is a textile dye that can be fatal to aquatic life, plants, and human health when discharged into the environment without treatment. A cheese whey-microbial fuel cell (CW-MFC) is a device that generates electricity from the degradation of cheese whey by microbial activity. The microbial activity of the CW-MFC during electricity production was able to decolorize MB. In this study, 50 ppm of MB was used to evaluate the decolorization capability of bacteria of the CW-MFC. A bacterial consortium present in the bioanode of the CW-MFC showed good MB decolorization in both the ex situ and in situ operations. Ex situ operation performed outside the CW-MFC reactor showed 92.2% MB decolorization within 18 h, while the in situ operation conducted inside the CW-MFC reactor showed 97.1% MB decolorization within the same timeframe. The maximum decolorization performance was achieved at pH 4 and 37 °C. The treated MB exhibited very little or no toxicity in the germination, rooting, and shooting of Oryza sativa compared to the untreated MB. Thus, the CW-MFC can be used as a promising technique to decolorize and remove the toxic effects of MB-contaminated wastewater, and the treated wastewater can be applicable for irrigation purposes.

Rodrigo Oliveira Goncalves, Ali Salehi, Marlon Publico et al.

The Scientific World Journal • 2022

Sustained bioenergy production from organisms that thrive in high salinity, low oxygen, and low nutrition levels is useful in monitoring hypersaline polluted environments. Microbial fuel cell (MFC) studies utilizing single species halophiles under salt concentrations higher than 1 M and as a closed microbial system are limited. The current study aimed to establish baseline voltage, current, and power density from a dual-chambered MFC utilizing the halophile Halobacterium salinarum NRC-1. MFC performance was determined with two different electrode sizes (5 cm2 and 10 cm2), under oscillating and nonoscillating conditions, as well as in a stacked series. A closed dual-chamber MFC system of 100 mL capacity was devised with Halobacterium media (4.3 M salt concentration) as both anolyte and catholyte, with H. salinarum NRC-1 being the anodic organism. The MFC measured electrical output over 7, 14, 28, and 42 days. MFC output increased with 5 cm2 sized electrodes under nonoscillating ( p < 0.0001 ) relative to oscillating conditions. However, under oscillating conditions, doubling the electrode size increased MFC output significantly ( p = 0.01 ). The stacked series MFC, with an electrode size of 10 cm2, produced the highest power density (1.2672 mW/m2) over 14 days under oscillation. Our results highlight the potentiality of H. salinarum as a viable anodic organism to produce sustained voltage in a closed-MFC system.

Jung-Chieh Su, Szu-Ching Tang, Po-Jui Su et al.

Energies • 2019

The pattern of micro-electricity production of simple two-chamber microbial fuel cells (MFC) was monitored in this study. Piggery wastewater and anaerobic sludge served as fuel and inocula for the MFC, respectively. The output power, including voltage and current generation, of triplicate MFCs was measured using an on-line monitoring system. The maximum voltage obtained among the triplicates was 0.663 V. We also found that removal efficiency of chemical oxygen demand (COD) and biochemical oxygen demand (BOD) in the piggery wastewater was 94.99 and 98.63%, respectively. Moreover, analytical results of Fast Fourier Transform (FFT) demonstrated that the output current comprised alternating current (AC) and direct current (DC) components, ranging from mA to μA.

Liang Zhu, Xiong Peng, Shun‐Li Shang et al.

Advanced Functional Materials • 2019

Abstract Although the peak power density of anion exchange membrane fuel cells (AEMFCs) has been raised from ≈0.1 to ≈1.4 W cm −2 over the last decade, a majority of AEMFCs reported in the literature have not been demonstrated to achieve consistently high performance and steady‐state operation. Poly(olefin)‐based AEMs with fluorine substitution on the aromatic comonomer show considerably higher dimensional stability compared to samples that do not contain fluorine. More importantly, fluorinated poly(olefin)‐based AEMs exhibit high hydroxide conductivity without excessive hydration due to a new proposed mechanism where the fluorinated dipolar monomer facilitates increased hydroxide dissociation and transport. Using this new generation of AEMs, a stable, high‐performance AEMFC is operated for 120 h. When the fuel cell configuration is subjected to a constant current density of 600 mA cm −2 under H 2 /O 2 flow, the cell voltage declines only 11% (from 0.75 to 0.67 V) for the first 20 h during break‐in and the cell voltage loss is low (0.2 mV h −1 ) over the subsequent 100 h of cell testing. The ease of synthesis, potential for low‐cost commercialization, and remarkable ex situ properties and in situ performance of fluoropoly(olefin)‐based AEM renders this material a benchmark membrane for practical AEMFC applications.

K. Gérardin, S. Raël, C. Bonnet et al.

Fuel Cells • 2018

Abstract A single polymer electrolyte fuel cell has been directly hybridized to a stack of three supercapacitors: the system formed has been investigated in operation in the fuel cell dynamic load cycle, which emulates the energy demand in transported applications. Comparison with regular, non‐hybridized fuel cell operation was analyzed in terms of hydrogen consumption in the case that the gas flow rates are directly controlled by cell current during the cycles with constant gas stoichiometric factors: the smoothening effect of the supercapacitors in the overall circuit leads to more even profiles of the cell current and voltage in the cycle, which allows safer and better hydrogen consumption management in this regime: the average H 2 consumption per cycle could be reduced by 16% without change of the overall energy produced. Besides, the runs were conducted over more than 1,300 hours with evaluation of the fuel cell performance and capacity at regular intervals, with or without hybridization. A moderate positive effect of hybridization was observed in the time variations of the voltage‐current curves and the fuel crossover. However, the resistances for ohmic, charge transfer and diffusion phenomena, were not so much improved by the hybridization, in spite of less sharp voltage.

Meltem Yavuz Çelikdemir

IET Renewable Power Generation • 2024

ABSTRACT The reliable and efficient operation of polymer electrolyte membrane fuel cells (PEMFCs) necessitates the implementation of preventive strategies and maintenance protocols to minimize the likelihood of failures. To address this, the study identifies effective diagnostic techniques for detecting faults in PEMFCs. A data‐driven approach leveraging machine learning methods is proposed to enhance the detection of flooding faults under varying operational conditions. This approach enables the automatic extraction of fault‐related features directly from raw data. Experimental data obtained from an 80 W PEMFC, widely used in the literature for comparability, was utilized in the study. Various machine learning classification algorithms were applied, and their performance metrics were analysed. Among these, the random subspace k‐nearest neighbor algorithm demonstrated superior accuracy and the shortest training time, leading to the development of a novel model. The study evaluated 22 variables associated with PEMFCs, performed fault diagnosis, and assessed fault severity. Furthermore, a risk analysis was conducted using the proposed model, enabling the prediction of both the risk level and the probability of fault occurrence as percentages. Key performance metrics, including accuracy, sensitivity, precision, and specificity, were calculated as 99.97%, 99.98%, 99.90%, and 99.98%, respectively, during model validation. During testing, these metrics were recorded as 99.45%, 100%, 98.42%, and 99.16%, respectively.

Roger E. Anderson, Scott MacAdam, Fermin Viteri et al.

Volume 2: Controls, Diagnostics and Instrumentation; Cycle Innovations; Electric Power • 2007

Future power plants will require some type of carbon capture and storage (CCS) system to mitigate carbon dioxide (CO2) emissions. The most promising technologies for CCS are: oxy-fuel (O-F) combustion, pre-combustion capture, and post-combustion capture. This paper discusses the recent work conducted by Siemens Power Generation, Florida Turbine Technologies, Inc. (FTT) and Clean Energy Systems, Inc. (CES) in adapting high temperature gas turbines to use CES’s drive gases in high-efficiency O-F zero emission power plants (ZEPPs). CES’s O-F cycle features high-pressure combustion of fuel with oxygen (O2) in the presence of recycled coolant (water, steam or CO2) to produce drive gases composed predominantly of steam and CO2. This cycle provides the unique capability to capture nearly pure CO2 and trace by-products by simple condensation of the steam. An attractive O-F power cycle uses high, intermediate and low pressure turbines (HPT, IPT and LPT, respectively). The HPT may be based on either current commercial or advanced steam turbine technology. Low pressure steam turbine technology is readily applicable to the LPT. To achieve high efficiencies, an IPT is necessary and efficiency increases with inlet temperature. The high-temperature IPT’s necessitate advanced turbine materials and cooling technology. O-F plants have an abundance of water, cool steam ∼200°C (400°F) and CO2 that can be used as cooling fluids within the combustor and IPT systems. For the “First Generation” ZEPP, a General Electric J79 turbine, minus the compressor, to be driven directly by CES’s 170 MWt high-pressure oxy-fuel combustor (gas generator), has been adapted. A modest inlet gas temperature of 760°C (1400°F) was selected to eliminate the need for turbine cooling. The J79 turbine operating on natural gas delivers 32 MWe and incorporates a single-stage free-turbine that generates an additional 11 MWe. When an HPT and an LPT are added, the net output power (accounting for losses) becomes 60 MWe at 30% efficiency based on lower heating value (LHV), including the parasitic loads for O2 separation and compression and for CO2 capture and compression to 151.5 bar (2200 psia). For an inlet temperature of 927°C (1700°F), the nominal value, the net output power is 70 MWe at 34% efficiency (LHV). FTT and CES are evaluating a “Second Generation” IPT with a gas inlet temperature of 1260°C (2300°F). Predicted performance values for these plants incorporating the HPT, IPT and the LPT are: output power of approximately 100–200 MWe with an efficiency of 40 to 45%. The “Third Generation” IPT for 2015+ power plants will be based on the development of very high temperature turbines having an inlet temperature goal of 1760°C (3200°F). Recent DOE/CES studies project such plants will have LHV efficiencies in the 50% range for natural gas and HHV efficiencies near 40% for gasified coal.

J. D. Sole, M. W. Ellis, D. A. Dillard

Journal of Fuel Cell Science and Technology • 2009

A promising type of proton exchange membrane fuel cell (PEMFC) architecture, the ribbon fuel cell, relies on the gas diffusion layer (GDL) to conduct electrical current in-plane to adjacent cells or collector terminals. The potential advantages of the fuel cell ribbon architecture with respect to conventional fuel cell stacks include reduced manufacturing costs, reduced weight, reduced volume, and reduced component cost. This work addresses the critical component of fuel cell ribbon assemblies, which is the GDL. The materials and treatments necessary to fabricate GDLs for fuel cell ribbon assemblies are presented along with experimental results for various candidate gas diffusion materials. An experimentally validated analytical model, which focuses on the electrical losses within the GDL of the ribbon fuel cell, was developed and used to guide design and testing. Low in-plane resistance is extremely important for the ribbon architecture because high in-plane GDL resistance can cause significant variation in current density over the catalyzed area. To reduce the current variation the new GDLs are fabricated with materials that have reduced in-plane resistance. Properties and performance for a common gas diffusion media, ELAT® LT-1200W (BASF Fuel Cell), were measured as a reference for the new gas diffusion layers. The widely used ELAT material exhibited an in-plane resistance of 0.39 Ω/sq, whereas the new diffusion materials exhibited in-plane resistances in the range of 0.18−0.06 Ω/sq. The performance of a ribbon fuel cell was predicted using a two-dimensional model that combines the polarization curve for a conventional bipolar plate type PEMFC and the resistive properties of the GDL material of interest. Experiments were performed to validate the analytical model and to prove the feasibility of the ribbon fuel cell concept. Results show that when the novel GDLs were adhered to a catalyzed membrane and tested in a ribbon fuel cell test assembly utilizing serpentine flow channels and in-plane current collection, a range of performance was achieved between 0.28 A/cm2 and 0.48 A/cm2 at a cell potential of 0.5 V. The agreement between the experimental data and the model predictions was very good for the ELAT and the B1/B polyacrylonitrile (PAN)-based carbon cloth. Differences between predicted and measured performance for a pitch-based GDL material were more significant and likely due to mass transport limitations.

Zhenyu Guo, Lei Wang, Changyuan Yu

Biology Open • 2023

ABSTRACT The microbial fuel cell (MFC), which converts biomass energy into electricity through microbial metabolism, is one of the important devices for generating new bioenergy. However, low power production efficiency limits the development of MFCs. One possible method to solve this problem is to genetically modify the microbial metabolism pathways to enhance the efficiency of MFCs. In this study, we over-expressed the nicotinamide adenine dinucleotide A quinolinate synthase gene (nadA) in order to increase the NADH/+ level in Escherichia coli and obtain a new electrochemically active bacteria strain. The following experiments showed an enhanced performance of the MFC, including increased peak voltage output (70.81 mV) and power density (0.29 μW/cm2), which increased by 361% and 20.83% compared to the control group, respectively. These data suggest that genetic modification of electricity producing microbes could be a potential way to improve MFC performance.

Authors to be extracted

Applied and Environmental Microbiology • 2003

This research investigates bioelectrochemical system technologywith emphasis on electrode material engineering. Results contribute to the development of sustainable bioelectrochemical technologies.

Sudeep C. Popat, Dongwon Ki, Bruce E. Rittmann et al.

ChemSusChem • 2012

Abstract Cathodic limitation in microbial fuel cells (MFCs) is considered an important hurdle towards practical application as a bioenergy technology. The oxygen reduction reaction (ORR) needs to occur in MFCs under significantly different conditions compared to chemical fuel cells, including a neutral pH. The common reason cited for cathodic limitation is the difficulty in providing protons to the catalyst sites. Here, we show that it is not the availability of protons, but the transport of OH − from the catalyst layer to the bulk liquid that largely governs cathodic potential losses. OH − is a product of an ORR mechanism that has not been considered dominant before. The accumulation of OH − at the catalyst sites results in an increase in the local cathode pH, resulting in Nernstian concentration losses. For Pt‐based gas‐diffusion cathodes, using polarization curves developed in unbuffered and buffered solutions, we quantified this loss to be >0.3 V at a current density of 10 A m −2 . We show that this loss can be partially overcome by replacing the Nafion binder used in the cathode catalyst layer with an anion‐conducting binder and by providing additional buffer to the cathode catalyst directly in the form of CO 2 , which results in enhanced OH − transport. Our results provide a comprehensive analysis of cathodic limitations in MFCs and should allow researchers to develop and select materials for the construction of MFC cathodes and identify operational conditions that will help minimize Nernstian concentration losses due to pH gradients.

Liping Huang, Irini Angelidaki

Biotechnology and Bioengineering • 2008

Abstract Pentose and humic acids (HA) are the main components of hydrolysates, the liquid fraction produced during thermohydrolysis of lignocellulosic material. Electricity generation integrated with xylose (typical pentose) degradation as well as the effect of HA on electricity production in microbial fuel cells (MFCs) was examined. Without HA addition the maximum power density increased from 39.5 mW/m 2 to 83 mW/m 2 when initial xylose concentrations increased from 1.5 to 30 mM, while coulombic efficiency ranged from 13.5% to 52.4% for xylose concentrations of 15 and 0.5 mM, respectively. Compared to controls where HAs were not added, addition of commercial HA resulted in increase of power density and coulombic efficiency, which ranged from 7.5% to 67.4% and 24% to 92.6%, respectively. Digested manure wastewater (DMW) was tested as potential mediator for power generation due to its content of natural HA, and although it could produce higher coulombic efficiency namely 32.2% than the control of 18.3%, showed lower power density which was approx. 57 mW/m 2 in comparison to power density of the control which was 69 mW/m 2 . Presence of commercial HA or DMW in the anode chamber resulted in faster xylose degradation and formation of more oxidized products (acetate and formate) as well as less reduced products (lactate and ethanol) compared to the controls. The reduced power generation in the presence of DMW was attributed to the presence of bacterial inhibitors such as phenolic compounds. Therefore, new feedstocks for MFCs, containing both mediators and substrates, such as lignocellulose hydrolysates should be considered for their applicability in MFCs. Biotechnol. Bioeng. 2008;100: 413–422. © 2008 Wiley Periodicals, Inc.