Kartik S Aiyer

FEMS Microbiology Letters • 2020

ABSTRACT Microbial fuel cells (MFCs) offer a promising solution towards recovery and treatment of heavy metal pollutants. In this study, two-chambered MFCs were employed for recovery of chromium, copper and vanadium (Cr (VI), Cu (II) and V (V)). One g/L concentrations of K2Cr2O7, CuCl2 and NaVO3 served as catholytes, while a mixed culture was used as anolyte. Cr (VI), Cu (II) and V (V) were reduced biologically into less toxic forms of Cr (III), Cu and V (IV) respectively. Power density and cathodic efficiency were calculated for each of the catholytes. Cr (VI) gave the maximum power density and cathodic efficiency due to its high redox potential. Current produced depended on the concentration of the catholyte. Over a period of time, biological reduction of catholytes lead to decrease in the metal concentrations, which demonstrated the application of MFC technology towards heavy metal treatment and recovery in a reasonably cost-effective manner.

A. J. Majewski, U. Bossel, R. Steinberger‐Wilckens

Fuel Cells • 2018

Abstract The paper describes operation and optimization of an onboard reforming system for an auxiliary power unit solid oxide fuel cell (SOFC APU) system for trucks that use liquid natural gas as fuel. The reformer system is based on partial oxidation and produces a reformate gas flow sufficient for a 100 W fuel cell. The ALMUS AG concept and configuration of the SOFC APU unit is described. The paper presents analyses of the efficiency of the partial oxidation reformer. The selected catalyst AB10 is analyzed under various reaction temperatures and molar ratios of CH 4 :air. Two reforming reactor configurations are tested; both with 5 g of the catalyst. The optimal operating conditions for the reactor are proposed. The reformer is currently operated in an electric furnace that simulates the actual system and condition in a combustion chamber. The main focus is to obtain stable operation with high hydrogen yield and low coke deposition. The paper presents analyses of a 1,000 h partial oxidation stability test. The demonstration of the performance of the CPOX reformer confirms the system applicability. The observed slow catalyst deactivation is attributed to the detected coke deposition. The change to the structure of deposited coke along the reactor is explained.

Seokwon Cho, Stephen Busch, Angela Wu et al.

SAE International Journal of Advances and Current Practices in Mobility • 2022

<div class="section abstract"><div class="htmlview paragraph">To comply with increasingly stringent pollutant emissions regulations, diesel engine operation in a catalyst-heating mode is critical to achieve rapid light-off of exhaust aftertreatment catalysts during the first minutes of cold starting. Current approaches to catalyst-heating operation typically involve one or more late post injections to retard combustion phasing and increase exhaust temperatures. The ability to retard post injection timing(s) while maintaining acceptable pollutant emissions levels is pivotal for improved catalyst-heating calibrations. Higher fuel cetane number has been reported to enable later post injections with increased exhaust heat and decreased pollutant emissions, but the mechanism is not well understood. The purpose of this experimental and numerical simulation study is to provide further insight into the ways in which fuel cetane number affects combustion and pollutant formation in a medium-duty diesel engine.</div><div class="htmlview paragraph">Three full boiling-range diesel fuels with cetane numbers of approximately 45, 50, and 55 are employed in this study with a well-controlled set of calibrations employing a five-injection strategy. The two post injections are block-shifted to increasingly retarded timings, and the effects on exhaust heat and pollutant emissions are quantified for each fuel. For a given injection strategy calibration, increasing cetane number enables increased exhaust temperature and decreased hydrocarbon and carbon monoxide emissions for a fixed load. The increase in exhaust temperature is attributed to an increased fueling requirement to compensate for additional wall heat losses caused by earlier, more robust pilot combustion with the more reactive fuels. Formaldehyde is predicted to form in the fuel-lean periphery of the first pilot injection spray and can persist until exhaust valve opening in the absence of direct interactions with subsequent injections. Unreacted fuel-air mixture in the fuel-rich interior of the first-pilot spray is likely too cool for any significant reactions, and can persist until exhaust valve opening in the absence of turbulence/chemistry interactions and/or direct heating through interactions with subsequent injections.</div></div>

Antanas Zinovicius, Juste Rozene, Timas Merkelis et al.

Sensors • 2022

Electrically conductive polymers are promising materials for charge transfer from living cells to the anodes of electrochemical biosensors and biofuel cells. The modification of living cells by polypyrrole (PPy) causes shortened cell lifespan, burdens the replication process, and diminishes renewability in the long term. In this paper, the viability and morphology non-modified, inactivated, and PPy-modified yeasts were evaluated. The results displayed a reduction in cell size, an incremental increase in roughness parameters, and the formation of small structural clusters of polymers on the yeast cells with the increase in the pyrrole concentration used for modification. Yeast modified with the lowest pyrrole concentration showed minimal change; thus, a microbial fuel cell (MFC) was designed using yeast modified by a solution containing 0.05 M pyrrole and compared with the characteristics of an MFC based on non-modified yeast. The maximal generated power of the modified system was 47.12 mW/m2, which is 8.32 mW/m2 higher than that of the system based on non-modified yeast. The open-circuit potentials of the non-modified and PPy-modified yeast-based cells were 335 mV and 390 mV, respectively. Even though applying a PPy layer to yeast increases the charge-transfer efficiency towards the electrode, the damage done to the cells due to modification with a higher concentration of PPy diminishes the amount of charge transferred, as the current density drops by 846 μA/cm2. This decrease suggests that modification by PPy may have a cytotoxic effect that greatly hinders the metabolic activity of yeast.

Mark Yunovich

CORROSION 2004 • 2004

Abstract Magnesium anodes are provided to the corrosion control industry by a number of domestic and international manufacturers and distributors. Due to the difficulty and time involved in performance testing, anode composition is commonly the only criterion used for quality control by the end users. Many of the anodes, however, have been shown to meet the compositional and potential specifications, and yet have had measured efficiencies as low as 7%. The paper analyzes multiple ‘high potential’ anodes obtained from a variety of sources (manufacturers, distributors, and end users). The primary focus of the analysis was to establish whether any of the parameters could be used as a reliable predictor of the anode efficiency. The scope of the analysis included such characteristics as anode source, manufacturing process, macrostructure, chemical composition, and microstructure. The tested anodes exhibited efficiency range between 7 and 61 percent based on the ASTM G97 Standard Test Method. It was shown that compliance with the ASTM B843 can not serve as a predictor of the anode performance in the laboratory tests or field trial; electrochemical potentials are not an accurate predictor of the efficiency values. The primary finding of the study was that the efficiency of the high potential anodes is controlled by the presence of the iron-rich secondary phases in the grain boundaries. A correlation was determined between the extent to which the grain boundaries are decorated and the resulting ASTM G97 Standard Test Method efficiency.

Ting Zhu, Liu Feng, Chengwei Cao

Journal of Chemical Technology & Biotechnology • 2022

Abstract Background Hydrocarbon production is a potential emission source of arsenic. Sites contaminated by arsenic and hydrocarbons are common but have received little attention. This study selects soil polluted by petroleum hydrocarbons and arsenic as a matrix to construct soil microbial fuel cells (SMFCs), investigates the effect of arsenic on the performance of the SMFCs, so as to provide basic data for the remediation design of such sites, and thus provides a new technical option for the remediation of organic–inorganic‐contaminated sites. Results Five groups of SMFCs were tested under different soil arsenic concentrations. When soil arsenic concentration increased from 4.72 to 842.12 mg kg −1 , the maximum power density of the SMFCs decreased from 11.3 to 1.8 mW m −2 , while the internal resistance increased from 871.4 to 1322.1 Ω. The anode microbial community of the SMFCs aggregated arsenic‐resistant and electric adaptive microbes due to increased arsenic stress, resulting in a decrease in community abundance but an increase in community evenness, which accordingly contributed to the observed change in bioelectricity output. SMFCs did drive the migration of arsenic in soil to the cathode, and this effect decreased with increasing soil arsenic concentration. Conclusions With an increase of arsenic, the bioelectricity output of SMFCs was significantly inhibited and the abundance of anode microbial communities decreased. SMFCs did have a cathodic driving effect on arsenic in the soil. This study has practical significance for improving SMFCs in metal/metalloid‐polluted sites, which can provide an optional process for the remediation of organic–metal/metalloid‐polluted sites. © 2022 Society of Chemical Industry (SCI).

Jonathan Teik Ean Goh, Ainul Rasyidah Abdul Rahim, Mohd Shahbudin Masdar et al.

Membranes • 2021

The polymer electrolyte membrane (PEM) is a key component in the PEM fuel cell (PEMFC) system. This study highlights the latest development of PEM technology by combining Nafion® and ionic liquids, namely 2–Hydroxyethylammonium Formate (2–HEAF) and Propylammonium Nitrate (PAN). Test membranes were prepared using the casting technique. The impact of functional groups in grafting, morphology, thermal stability, ion exchange capacity, water absorption, swelling and proton conductivity for the prepared membranes is discussed. Both hybrid membranes showed higher values in ion exchange capacity, water uptake and swelling rate as compared to the recast pure Nafion® membrane. The results also show that the proton conductivity of Nafion®/2–HEAF and Nafion®/PAN membranes increased with increasing ionic liquid concentrations. The maximum values of proton conductivity for Nafion®/2–HEAF and Nafion®/PAN membranes were 2.87 and 4.55 mScm−1, respectively, equivalent to 2.2 and 3.5 times that of the pure recast Nafion® membrane.

Marcelinus Christwardana, J. Joelianingsih, Linda Aliffia Yoshi

Journal of Electrochemical Science and Engineering • 2023

The microbial fuel cell (MFC) is an ecologically friendly alternative energy source. Due to the typically limited electron transfer in MFC systems, co-biocatalysts are necessary to enhance their performance. Enzymes are used as co-biocatalysts due to their superior ability to generate energy, and the system is known as an enzymatic microbial fuel cell (EMFC). One of the substrates that may be used is bagasse waste extracted from sugarcane. Saccharo­myces cerevisiae and the enzyme glucose oxidase (GOx) serve as co-biocatalysts in the breakdown of sugarcane bagasse waste in this study, which uses single-chamber EMFCs. In EMFC using sugarcane bagasse waste extract employing S. cerevisiae biocatalyst and glucose oxidase enzyme co-biocatalyst, the open circuit voltage was 0.56 V and the maximum power density was 146.65 mW m-2, an increase of 10.4 times to MFCs that solely employed only yeast biocatalyst. In addition, the chemical oxygen demand (COD) reduction achieved by this technology is 75 %. In addition, the pH of sugarcane bagasse waste extract samples treated with Saccharomyces cerevisiae yeast and GOx enzyme decreased from 4.6 to 4.2. This research demonstrates that adding the co-biocatalyst GOx enzyme may boost the performance of the traditional yeast MFC.

I. P. Sahu, M. K. Das, M. K. Soni et al.

Journal of Applied Research and Technology • 2024

In the present study, the flow field in the bi-polar plate and Gas diffusion layer (GDL) of 1.2 kW Nexa fuel cell (FC) training system having a serpentine flow field has been examined. The channel dimension and shape in the flow field of the bipolar/end plates have been examined. Pressure drop with hydrogen flow rate and channel length. For enormous hydrogen inputs, The optimal measurement is around 1.5, 1.5,, and 0.5 mm for the values of channel width, channel depth, and width of land, corresponding Research on the effect of channel designs revealed that semi-circular, rectangle and triangular-shaped and found The land width for triangular and semicircular-shaped are almost zero millimeters which increase the water vapor accumulation, due to which the losses increase. However there are very few losses in the polarization curve seen in the square cross-section because there is very l water vapor buildup. A GDL is an essential component of an FC. The three-dimensional model of the GDL is simulated using COMSOL metaphysics 4.2 and observed that increased porosity facilitated the entry of more reactants into the reaction side, resulting in increased current density. Low membrane thickness resulted from excessive current density in the membrane. Thicker GDL provides reactant species that raise the rate of consumption at the point where the catalytic layer and GDL interface. The outcomes of the simulation are contrasted with experimental data found in published works. The comparison demonstrates that the modeling outcomes and the experimental data agree quite well.

S. Bégot, F. Harel, J. M. Kauffmann

Fuel Cells • 2008

Abstract In this paper, experimental investigations on the influence of operational parameters on PEM fuel cell cold start are presented. The effect of current density, stack impedance at 1 kHz prior to start, as well as gas flow rate, gas pressure, coolant flow rate and surrounding subfreezing temperature are studied. The experimental apparatus is briefly described. It includes a main unit at room temperature and a smaller separate unit in a climatic chamber. Low current density, high impedance prior to start, moderate subfreezing temperature (–5 °C), high gas flow rate, low gas pressure and low coolant flow rate are found to have a positive impact on the cold start performance. Combining these parameters, self start‐up of the fuel cell without additional energy is achieved at –5 °C in 30 min. The whole set of observations leads to the following hypotheses on freeze mechanism: in the first phase, dry membranes and low current lead to a transient phase of membrane humidification. Then, in the second phase, ice clogging of the active layers occurs. In the third phase, a variable quantity of the produced water reaches the gas diffusion layers and channels.

Ignacio Araneda, Natalia F. Tapia, Katherine Lizama Allende et al.

Water • 2018

Greywater reuse through decentralized and low-cost treatment systems emerges as an opportunity to tackle the existing demand for water. In recent years, constructed wetlands (CW) systems and microbial fuel cells (MFCs) have emerged as attractive technologies for sustainable wastewater treatment. In this study, constructed wetland microbial fuel cells (CW-MFCs) planted with Phragmites australis were tested to evaluate the potential of combining these two systems for synthetic greywater treatment and energy recovery. Open (CW) and closed circuit (CW-MFCs) reactors were operated for 152 days to evaluate the effect of energy recovery on the removal of soluble chemical oxygen demand (sCOD), nutrients and total suspended solids (TSS). Results indicate no significant differences for sCOD and phosphate removal efficiencies. CW-MFCs and CW reactors presented sCOD removal efficiency of 91.7 ± 5.1% and 90 ± 10% and phosphate removal efficiencies of 56.3 ± 4.4% and 61.5 ± 3.5%, respectively. Nitrate removal efficiencies were higher in CW: 99.5 ± 1% versus 86.5 ± 7.1% in CW-MFCs, respectively. Energy generation reached a maximum power density of 33.52 ± 7.87 mW m−3 and 719.57 ± 67.67 mW m−3 at a poised anode potential of −150 mV vs. Ag/AgCl. Thus, our results suggest that the incorporation of MFC systems into constructed wetlands does allow energy recovery while providing effective greywater treatment.

Aruna Mohanty, Young Eun Song, Jung Rae Kim et al.

Membranes • 2021

A class of phenolphthalein anilide (PA)-based poly(ether sulfone) multiblock copolymers containing pendant quaternary ammonium (QA) and imidazolium (IM) groups were synthesized and evaluated as anion exchange membrane (AEM) materials. The AEMs were flexible and mechanically strong with good thermal stability. The ionomeric multiblock copolymer AEMs exhibited well-defined hydrophobic/hydrophilic phase-separated morphology in small-angle X-ray scattering and atomic force microscopy. The distinct nanophase separated membrane morphology in the AEMs resulted in higher conductivity (IECw = 1.3–1.5 mequiv./g, σ(OH−) = 30–38 mS/cm at 20 °C), lower water uptake and swelling. Finally, the membranes were compared in terms of microbial fuel cell performances with the commercial cation and anion exchange membranes. The membranes showed a maximum power density of ~310 mW/m2 (at 0.82 A/m2); 1.7 and 2.8 times higher than the Nafion 117 and FAB-PK-130 membranes, respectively. These results demonstrated that the synthesized AEMs were superior to Nafion 117 and FAB-PK-130 membranes.

Guangyi Zhang, Zhongchen Wang, Mengshuo Liu et al.

Journal of The Electrochemical Society • 2023

Green and sustainable techniques are in great demand for the remediation of heavy metal-contaminated soil. Cadmium ion (Cd 2+ ) in soil could be extracted under the internal electric field and participating on the surface of the electrode. Here, we proposed a sediment microbial fuel cell (SMFC) for the electrokinetic remediation of cadmium (Cd) contamination soil. Within the 7 weeks of SMFC operation, the removal efficiency for total Cd could be up to 70.04 ± 0.45%, which was significantly higher than that obtained by open circuit SMFC. The maximum output power density was 71.00 ± 0.82 mW m −2 with a current density of 0.60 ± 0.03 A m −2 . Results obtained by electrochemical impedance showed that the inter resistance of SMFC was 944 ± 14 Ω. High-throughput sequencing revealed that the Alpha-, Beta- and Gammaproteobacteria increased to 67.85%–80.99% in the SMFC. The relative abundance of Cd 2+ /Zn 2+ -exporting ATPase, participating in Cd 2+ reduction, in SMFC varied from 25.83% to 30.68%, which were significantly higher than that of control (11.21% to 19.94%). Our findings have presented an effective energy-saving method for the remediation of heavy metal-contaminated soils.

Yuhong Zhou, Simeng Zhao, Lu Yin et al.

Electroanalysis • 2018

Abstract A novel membrane‐less microbial fuel cell (ML‐MFC) which used the baffles instead of the ion exchange membrane (IEM) was developed for ammonium‐containing wastewater treatment and electricity generation. By means of installing an ideal nitrifying unit between the anodic and cathodic chamber, the novel ML‐MFC accomplished organics degradation and nitrogen removal without additional loop. The removal efficiencies of COD, NH 4 + −N and TN achieved 97.07±0.47 %, 91.76±3.32 % and 87.66±1.59 %, respectively. Meanwhile, the effluent pH was near neutral and turbidity was quite low. In addition, the maximum power density of 1.007±0.032 W/m 3 was obtained. Combined with the analysis of microbial community, electroactive bacteria (EAB) Desulfovibrio , Comamonas and Thiobacillus were enriched in biofilm. Considering the superior effluent quality and the promising energy potential, the novel ML‐MFC has good application prospects in efficient and sustainable wastewater treatment.

Yatin Patil, Sunil Kulkarni, Kenneth A. Mauritz

Journal of Applied Polymer Science • 2011

Abstract Nafion® membranes were modified via in situ , catalyzed sol–gel reactions of titanium isopropoxide to form titania particles in the polar acid domains. FTIR spectroscopy showed successful intraparticle chemical bond formation with incomplete condensation of TiOH groups. Although such modification can lower membrane fuel cell performance, this study was aimed at reducing membrane degradation without significantly altering performance in the sense of material optimization. These incorporated particles did not change membrane equivalent weight and the water uptake was similar to that of the unmodified Nafion® membrane. Membrane dimensional stability, mechanical properties, and ability to withstand contractile stresses associated with humidity change at 80°C and 100% RH were improved. An open circuit voltage (OCV) accelerated degradation test showed the titania modification held voltage better than the unmodified membrane. Performance deterioration of Nafion® after the OCV test was much higher than that of the modified membrane and the fluoride emission of the latter was lower. The degraded Nafion® membrane failed when subjected to creep, whereas the modified membrane remained intact with significantly low deformation. This inorganic modification offers a simple way to enhance membrane durability by reducing both physical and chemical degradation. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Sandy L. Calderon, Pilar García Avelino, Angélica María Baena-Moncada et al.

Sustainable Environment Research • 2020

Abstract This study is focused on electrical energy generation in a double-compartment microbial fuel cell. Carbon felt impregnated with multi-walled carbon nanotubes was used as an anode, which contained gold nanoparticles and Shewanella spp. grown under aerobic conditions was used as a biocatalyst. The electrodes, used before and after biofilm growth, were characterized by scanning electron microscopy and cyclic voltammetry. The results revealed the formation of Shewanella spp. colonies on the electrode surface and electrochemical activity under aerobic and anaerobic conditions. During biofilm growth in Luria Bertani medium, a stabilized average power density of 281 mW m − 2 was recorded. Subsequently, the cell reached a maximum current density of 0.11 mA cm − 2 after 72 h of operation and a coulombic efficiency of 65% under anaerobic conditions.

Omar José Duarte-Urbina, F. Fernández-Luqueño, G. Vargas-Gutiérrez et al.

ECS Meeting Abstracts • 2018

Microbial fuel cells (MFCs) represent a sustainable alternative to generate energy from wastewater treatment, reducing the consumption and pollution of fossil fuels, which are used in traditional technologies. An effective way to improve the performance of MFCs is the use metal-free carbon-based anode catalysts, which have shown high catalytic activity with significantly lower cost than noble metals. In this study, the synthesis and characterization of methanol-functionalized carbon catalysts is reported. Onion waste has been thermochemically treated via carbonization, chemical activation with ZnCl 2 and pyrolysis at 400, 600 and 800 ºC (named CCA4, CCA6 and CCA8, respectively). Graphite flakes have been ball milled in the presence of thiourea and ZnCl 2 , followed by pyrolysis at a 500 ºC in order to obtain the graphene catalyst (named GNS). Subsequently, the carbons have been submitted to surface functionalization with methanol using the intermittent microwave heating technique to produce the CCA4f, CCA6f, CCA8f and GNSf catalysts. Anodes have been fabricated by depositing catalytic layers (separately) of CCA4f, CCA6f, CCA8f and GNSf on gas diffusion electrodes. The catalytic activity of the anodes has been evaluated by cyclic voltammetry (VC) in a three electrodes half-cell, using Pharmaceutical Wastewater (PWW) as electrolyte, and compared to that of a gas diffusion electrode without catalyst. The results show that the mechanochemical treatment of graphite in the presence of thiourea modifies its crystalline structure producing the heteroatoms-doped GNS. Meanwhile, CCA4, CCA6 and CCA8 have an amorphous structure self-doped with the N and S heteroatoms. The catalysts are thermally stable at 700 ºC and exhibit a highly heterogeneous morphology. Nitrogen adsorption-desorption and BET analyses indicate that the activation with ZnCl 2 promotes the formation of mesoporous structures with average pore size ranging from 11.38 (GNSf) to around 2 nm (CCA4f, CCA6f and CCA8f). Moreover, the specific surface areas of CCA4f, CCA6f and CCA8f (1468, 1611 and 1269 m 2 g -1 , respectively) are approximately 20 times higher than that of GNSf (69.7 m 2 g -1 ). The electrochemical characterization demonstrates that the increase in activation temperature improves the catalytic activity of the CCAf series of catalysts for the oxidation of organic matter in the PWW electrolyte. The current density (j) decreases in the order CCA8f>CCA6f>CCA4f. On the other hand, the catalytic activity of GNSf is less than those of CCA8f and CCA6f, but similar to CCA4f. The results show that the metal-free CCAf carbons have the potential to be used as anode catalysts in MFCs.

Qing Wu, Jieqiong Liu, Qiannan Li et al.

International Journal of Environmental Research and Public Health • 2022

Efficient and sustainable technologies for cleaning of contaminated water and sediments are in urgent demand. In this study, a new type of sediment microbial fuel cell coupled floating bed (FB-SMFC) was developed to repair eutrophic water and sediment in a cleaner way. The effect of electrode spacing on the power generation capacity and the synchronous remediation of pollutants from eutrophic water and sediment were studied. When the electrode distance was 60 cm, the maximum power generation and pollutant removal effects were obtained. At the end of the experiment, the maximum output voltage was 0.4 V, and the chemical oxygen demand (CODCr, potassium dichromate method), total nitrogen (TN), and total phosphorus (TP) contents in the overlying water were 8 mg/L, 0.7 mg/L, and 0.39 mg/L. The corresponding removal rates were 88.2%, 78.8%, and 59.0%, respectively. The removal rates of organic matter and TN in the sediment were 12.8% and 86.4%, respectively, and the fixation rate of TP was 29.2%. Proteobacteria was the dominant phylum of bacteria in the sediment and anode. Many anaerobic bacteria were found in the overlying water, which facilitated denitrification. Overall, the results of this research revealed a highly efficient and reliable strategy for eutrophic water and sediment remediation, aquatic ecosystems restoration, and human health protection.

Topal Leyla, Carolina Nunes Kirchner, Wiebke Germer et al.

International Journal of Renewable Energy Development • 2014

The effects of different temperatures (55, 65, 75 and 85 °C) and cathode gas compositions (O2, synthetic air, air and 90% synthetic air+10% CO2) on alkaline anion exchange membrane fuel cell (AAEMFC) were evaluated. Membrane electrode assemblies (MEA) were fabricated using commercial anion exchange membrane (AEM) in OH- form and Pt catalyst. Polarization curves and voltage responses during constant current were performed in order to describe the influences of temperature and gas composition on the AAEMFC performance. The experimental results showed that the fuel cell performance increases with elevating temperatures for all applied gas compositions. Highest power density of 34.7 mW cm-2 was achieved for pure O2 as cathode feed. A decrease to 20.3 mW cm-2 was observed when cathode gas composition was changed to synthetic air due to reduction of the O2 partial pressure. The presence of CO2 in atmospheric air applied to the cathode stream caused a further drop of the maximum power density to 15.2 mW cm-2 driven by neutralization of OH- ions with CO2.

Licheng Zhang, Xiao Chen, Chi Zhang et al.

Journal of Chemical Technology & Biotechnology • 2025

Abstract Background The continuous flow double‐sludge anaerobic/aerobic/anoxic process is a good choice for removing nitrogen (N) and phosphorus (P) simultaneously, although these are difficult to remove efficiently. Microbial fuel cells (MFCs) can extract energy from wastewater and use electrons to remove pollutants. This study proposes a novel integration of MFCs with the continuous flow double‐sludge AOA process, investigating the system's performance across different carbon (C)/N ratios (2, 3.5, 5 and 6.5) in terms of pollutant removal, electricity generation and microbial community structure. Result When the influent C/N ratio was 3.5, the average removal rates of chemical oxygen demand, ammonium (NH 4 + )‐N, and phosphate (PO 4 3− )‐P were 92.01%, 79.68% and 92.91%, respectively, and the average simultaneous nitrification and denitrification (SND) and SND P removal (SNDPR) rates of nitrogen oxide (NO x − )‐N were 53.30% and 42.09%, respectively. The diversity and abundance of microbial community were at a good level, and the relative abundance of Dechloromonas , Pseudomonas and Candidatus_Competibacter reached 4.16%, 2.16% and 4.61%, respectively, at C/N = 3.5. Conclusions Significant differences in pollutant removal were observed under different C/N conditions, with electron acceptors emerging as the biggest factor affecting power generation. According to the microbiological results, the combination of lower C/N ratios and higher PO 4 3− ‐P contributed to the enrichment of key functional microorganisms. © 2025 Society of Chemical Industry (SCI).

S. Wernick

Transactions of The Electrochemical Society • 1931

The electrodeposition of Cd from CdSO 4 solutions was studied, with the object of determining the effect of variation of pH of the solution, current density and temperature of the electrolyte on the crystal structure and grain size of the deposit; and on the anode and cathode efficiencies and the electrode efficiency ratio. The pH of a simple solution of CdSO 4 rises rapidly with progressive deposition, and requires to be buffered in order to maintain a uniform pH. At the same time, the crystal structure of the deposit becomes progressively less granular, but subsequently (at a pH above 6), more crystalline, dark and less adherent. An optimum range of pH is approximately 5 to 5.7. The effect of aluminum sulfate, sodium acetate, boric acid and sodium chloride as buffering agents was examined. The best buffer within the desired range of pH was a mixture of boric acid and sodium chloride. CdSO 4 solution with this buffer was adopted as a standard electrolyte. Increasing c.d. has only a small effect on anode and cathode efficiency, the variation being 1.6 per cent and 1.4 per cent respectively, and the electrical efficiency ratio is also little affected. There is however a marked effect on the grain size of the deposit, which consists of large crystal aggregates at low c.d. and is relatively fine grained and also more adherent at higher c.d. “Treeing” occurs when the c.d. exceeds 4.5 amp./s. dm. Increasing temperature has a relatively more marked effect on the electrode efficiencies than c.d. The anode efficiency rises notably at the higher temperatures examined, and the cathode efficiency decreases somewhat, resulting in a progressive increase in the electrical efficiency ratio. The effect on the deposit is at first in the direction of refinement of the grain size, but at higher temperatures, a coarser, crystalline structure develops. It is concluded that temperatures in excess of 40° to 50° C. are undesirable in depositing Cd from CdSO 4 solutions. The “structureless” type of deposit obtainable from cadmium cyanide solutions is unobtainable from CdSO 4 solutions in the absence of an “addition agent.”

Sofia Boulmrharj, Mohammed Khaidar, Mohamed Bakhouya et al.

Sustainability • 2020

The search for new fuels to supersede fossil fuels has been intensified these recent decades. Among these fuels, hydrogen has attracted much interest due to its advantages, mainly cleanliness and availability. It can be produced from various raw materials (e.g., water, biomass) using many resources, mainly water electrolysis and natural gas reforming. However, water electrolysis combined with renewable energy sources is the cleanest way to produce hydrogen while reducing greenhouse gases. Besides, hydrogen can be used by fuel cells for producing both electrical and thermal energy. The aim of this work was towards efficient integration of this system into energy efficient buildings. The system is comprised of a photovoltaic system, hydrogen electrolyzer, and proton exchange membrane fuel cell operating as a cogeneration system to provide the building with both electricity and thermal energy. The system’s modeling, simulations, and experimentations were first conducted over a short-run period to assess the system’s performance. Reported results show the models’ accuracy in analyzing the system’s performance. We then used the developed models for long-run testing of the hybrid system. Accordingly, the system’s electrical efficiency was almost 32%. Its overall efficiency reached 64.5% when taking into account both produced electricity and thermal energy.

Daouda Fofana, Sadesh Kumar Natarajan, Pierre Bénard et al.

ISRN Electrochemistry • 2013

Platinum cluster formations have been investigated as a way to reduce the amount of Pt at the cathode of polymer electrolyte membrane fuel cells. One, two, and three layers of Pt (0.05 mg/cm 2 ) sputtered directly on microporous layers of gas diffusion layers with and without interfacial carbon-Nafion layers and carbon-polytetrafluoroethylene (CPTFE) layers have been used as a cathode. Comparison with experimental results had showed that the best performance was obtained with three layers of Pt sputtered on carbon-Nafion containing 34.8 wt.% of Nafion and sputtered carbon-polytetrafluoroethylene containing 16.9 wt.% of polytetrafluoroethylene. High limiting current densities (>1.1 A/cm 2 ) have been reached with cathode Pt loading as low as 0.05 mg/cm 2 . SEM imagery and cyclic voltammetry characterization have been performed to consolidate this study. High Pt utilization can be showed by this method. The factor influencing Pt utilisation in the oxygen reduction reaction is intrinsically related to Pt clusters formation and helps in enhancing the PEMFC performance with low Pt loading.

Chin‐Tsan Wang, Aristotle T. Ubando, Vimal Katiyar et al.

International Journal of Energy Research • 2020

Summary Microbial fuel cells (MFCs) are considered as power generation devices for sustainable energy. However, the power generated is insignificant compared to other energy production devices. In this study, a mini autonomous biosensor (MAB) based on MFCs has been designed for detecting hazardous hexavalent chromium in wastewater. Hexavalent chromium has been classified as a human carcinogen causing serious birth defects due to its mutagenic and teratogenic properties. The power generated by the MAB has been investigated to study the feasibility of providing power to itself. In addition, electrochemical analyses of conductive silver paste and carbon cloth as the anode were conducted in the MAB for detecting hexavalent chromium in the anode chamber. Results show that a maximum voltage of 518.17 mV and a power density of 1.075 mW/cm 2 could be achieved using carbon cloth with an external resistance of 1000 Ω, while a higher limiting current density of 0.015 mA/cm 2 could be achieved with conductive silver glue as the anode electrode. Besides, the voltage output of the MAB decreased rapidly with the addition of hexavalent chromium into the wastewater. Also, the recovery time for the MAB was much shorter than found in previous studies. The MAB demonstrated potential for simultaneous production of electricity and detection of hexavalent chromium, which would open up avenues for autosensing applications in the environment as well as smart powering devices. Results indicate that the MAB with conductive silver glue as anode electrode is feasible for detecting hexavalent chromium in wastewater.

Syarifah Noor Syakiylla Sayed Daud, Muhammad Noorul Anam Mohd Norddin, Juhana Jaafar et al.

High Performance Polymers • 2019

Sulfonated poly(ether ether ketone) (sPEEK) membrane is a promising proton-conducting membrane for fuel cell. However, the performance and lifetime of sPEEK membrane depend on the degree of sulfonation (DS). High DS of sPEEK increases the performance, but the mechanical properties could deteriorate progressively which affect its lifetime. Thus, this study investigated the effect of adding polyvinylidene fluoride (PVDF) into high DS (80%) of sPEEK through solution blending method toward its physicochemical properties and morphology structures. The PVDF concentration was varied to 5, 10, 15, and 20 wt% relative to the sPEEK content. The existence of hydrophobic PVDF in 80% sPEEK improved the mechanical properties where the water uptake and swelling degree of membrane decreased, whereas the tensile strength increased. The sPEEK/PVDF 15 exhibited the highest proton conductivity (46.23 mS cm −1 ) at 80°C. Incorporating PVDF into high DS of sPEEK enhanced the mechanical properties which can be used as a proton-conducting membrane for fuel cell that may improve the performance and prolong the lifetime of the cell.

Kayoung Park, Magnus So, Masaki Goto et al.

ECS Meeting Abstracts • 2020

In order to improve the cell performance of polymer electrolyte fuel cells (PEFCs), it is essential to design the cathode catalyst layers (CLs) with the optimal morphology considering the mass transport such as electron, proton, and oxygen as well as an electrochemical reaction. As designing the cathode CLs, it is required to consider the fabrication method, compositions of catalyst ink, ionomer loading, resulting in effect of the cell performance. Particularly, ionomer as the pathway for proton conduction strongly influences proton transfer resistance and oxygen diffusion resistance. Too much ionomer included to CLs obstructs oxygen diffusion, and decreases the porosity and average void size in the CLs. Also, the thickness of the ionomer on Pt particles is increased, leading to an increase in the overvoltage. These results in performance loss. Thus, it is needed to reduce ionomer loading in the CLs. However, low ionomer loading reduces the ability of proton conductions, resulting in lower performance by an increase in proton transfer resistance. In our previous study, we introduced silica-coated Pt catalysts in order to control ionomer loading [1]. Silica-coated Pt catalysts, developed by Takenaka et al. have maintained a high activity for the oxygen reduction reaction during the durability tests because silica coating has merits of suppression of Pt particle agglomeration and diffusion of Pt cations in the catalyst, and easy control of surface characteristics like hydrophobicity or hydrophilicity [2]. In our previous study, we experimentally examined the effects of silica coating in the CLs on the catalyst ink, morphology of CLs, cell performance. As these results, catalyst ink for silica-coated Pt catalyst maintained good dispersion and high stability compared to that of non-coated Pt catalysts. In addition, the performance at 0.6 V for the silica-coated Pt catalysts with low ionomer loading showed higher than that of non-coated Pt catalysts at all the relatively humidity (RH). In particular, at low humidity conditions (20% RH), the silica-coated Pt catalysts showed significantly enhanced performance compared with non-coated Pt catalysts. These results suggest that the hydrophilic groups included in silica layers contribute to the improvement of proton conductivity. In this present study, we examined the numerical analysis of silica-coated Pt catalysts in order to understand the effect of silica coating on the performance in detail, such as current density distribution, overvoltage. In our research group, in order to understand the effect of nano and mesoscale structure of Pt/Carbon catalyst layer on cell performance and internal phenomena, various simulation models which included the effect of the structure of carbon aggregate, ionomer coverage, and formation of agglomerate, have already been developed with some experimental knowledge such as FIB-SEM observation, the actual pore size distribution of CLs, relative oxygen diffusion coefficient, agglomerate size distribution measurement in CL ink [3-5]. These simulation models were applied to the numerical analysis of the silica-coated Pt catalysts in the CLs. In our presentation, we will discuss the effect of silica coating on Pt catalysts in CLs on the cell performance analyzed numerically. Acknowledgment This work was partially supported by the New Energy and Industrial Technology Development Organization (NEDO), Japan. References [1] K. Park et al., Int. J. Hydrogen Energy, 45, 1867–1877 (2019). [2] S. Takenaka, M. Goto, Y. Masuda, S. Emura, and M. Kishida, Int. J. Hydrogen Energy, 43, 7473–7482 (2018). [3] G. Inoue et al., J. Power Sources, 439, 227060 (2019). [4] M. So et al., Int. J. Hydrogen Energy, 44, 28984–28995 (2019). [5] T. Terao et al., J. Power Sources, 347, 108–113 (2017).

Angelo Esposito, Pierpaolo Polverino, Cesare Pianese et al.

ASME 2010 8th International Fuel Cell Science, Engineering and Technology Conference: Volume 1 • 2009

Proton Exchange Membrane Fuel Cell performance significantly depends on electrode water content. Indeed, an excess of liquid water in the pores of the gas diffusion layer (GDL) and in the gas flow channel (GFC) can drastically bring down the output power. Depending on the operating conditions, liquid water emerging from the GDL micro-channels can form droplets, films or slugs in the GFC. In the regime of droplets formation, the interaction with the gas crossing-flow leads to an oscillating mechanisms that is fundamental to studying the detachment from the GDL surface, as the authors have shown in a previous publication. In this work, a numerical model of a droplet growing on the GDL surface is developed to describe the interaction between droplet cross-flowing gas stream. The droplet shape and its deformation are reconstructed assuming a known geometry. Therefore, a lumped force balance is enforced to determine the center of mass motion law. Oscillation frequencies during growth and at detachment are found as a function of droplet size. The model is also exploited to find the relationship between droplet critical detachment size and gas velocity. The numerical results are compared with the droplet frequency-size and detachment size-gas velocity experimental results previously presented by the authors. The matching between the numerical and experimental data is very good and is a mean of validation for the model. The low computational burden and the conciseness of the results make the model suitable for applications such as control and optimization strategies development to enhance PEMFC performance. Additionally, the model can be exploited to implement monitoring and diagnostic algorithm.

Christopher Leon Schreiber, Anna Kapulwa, Junji Inukai

ECS Meeting Abstracts • 2024

Introduction: Despite the high potential and expected major impact of PEFCs on the economy of the future, there are still challenges to overcome, before commercialized. PEFCs operated at temperatures higher than 100°C are expected to be used especially in the heavy-duty vehicle department due to their use of smaller and lighter radiators and lower susceptibility to catalyst poisoning. To achieve this goal however, PEFCs operated above 100°C need higher performance, stability, and durability, while reducing the cost at the same time. The performance, durability and stability of a fuel cell are related to the distribution of physical and chemical parameters, e.g. oxygen partial pressure ( p (O 2 )). During the operation of the fuel cell, the distribution of those parameters is inhomogeneous. [1] Therefore, we used an in-house developed 2-dimensional non-destructive real-time/space visualization system to achieve an understanding of the inside the fuel cell during operation at higher temperatures. Experimental: The PEFCs used for this experiment have an active area of 4 cm 2 with 10 straight gas flow channels. To visualize the oxygen partial pressure, an oxygen sensitive dye (PtTFPP) was used. PtTFPP has absorption peaks at 407, 530 and 540 nm and an emission peak at 650 nm. The emission peak is quenched by oxygen partial pressure, and the emission intensity decreases monotonically with increasing oxygen partial pressure (Fig.1). The oxygen sensitive dye was applied on the surface of the cathode side GDL. For the excitation, a laser with a wavelength of 532 nm was used and the emitted light was captured by a CCD camera. [2] The laser light was first diffused and then guided by mirrors into the cell. In order for the laser light to enter the fuel cell the cathode side endplate, which was usually made of metal, was exchanged with a transparent quartz glass endplate. Visualizations were carried out at 90, 100, and 110 o C at a constant water vapor pressure of 37.97 kPa, which equaled 53.6, 36.8, and 25.9% RH, respectively. Prior to the visualization, calibrations at 15, 18, 21, and 24% O 2 concentration, and performance tests in form of IV and CV were carried out for each temperature. The gas flow rate during the experiments was set to 100 mL min -1 Air/H 2 (parallel flow) at cathode and anode, respectively. For the oxygen concentration of 24% diluted (with N 2 ) oxygen with a total flowrate of 100 mL min -1 was used. Results and Discussion: The IV performance tests showed decreasing cell performance with increasing temperatures, which was expected because of the increasing resistance due to drying out of the membrane. Furthermore, a decrease of the ECSA was observed with increasing temperatures. The 2D-Visualization showed that oxygen partial pressure on the surface of the GDL beneath the gas flow channels was much higher than theoretically calculated. Furthermore, at lower current densities the oxygen partial pressure was higher in the outlet than at the inlet of the cell, which was unexpected (Fig. 2). It was previously shown (Kakizawa et al.) that liquid water accumulates near the outlet of the cell. The accumulated liquid water as well as the water vapor at elevated temperatures is expected to hinder the diffusion of O 2´ to the catalyst layer which could explain the increased oxygen partial pressure near the outlet and the decreased oxygen partial pressure near the inlet. However, power is generated, and oxygen was consumed elsewhere in the cell, namely inside the GDL close to the catalyst layer. This model will be researched using a 3-dimensional visualization system in the future. [1] Y. Kakizawa, C. L. Schreiber, S. Takamuku, M. Uchida, A. Iiyama, J. Inukai, Visualization of the oxygen partial pressure in a proton exchange membrane fuel cell during cell operation with low oxygen concentrations, J. Power Sources, 483, 229193 (2021). [2] Y. Kakizawa, T. Kobayashi, M. Uchida, T. Ohno, T. Suga, M. Teranishi, M. Yoneda, T. Saiki, H. Nishide, M. Watanabe, A. Iiyama, J. Inukai, Oscillation mechanism in polymer electrolyte membrane fuel cell studied by operando monitoring of oxygen partial pressure using optical probes, J. Surf. Finish. Soc. Jpn, 72, 230 (2021). Figure 1

Takao Watanabe, Yoshiyuki Izaki, Yoshihiro Mugikura et al.

Electrical Engineering in Japan • 1993

Abstract The molten carbonate fuel cell (MCFC) power plant is expected to be one of the most promising future power generation systems for the electric utilities because of its high efficiency, environmental suitability and capability of using coal as fuel. To obtain such attractive performance, it is necessary for the plant to adopt the gas‐recycling operation system. The authors tested a 6‐kW class MCFC stack with three types of gas recyclings, i.e., cathode, anode and carbon dioxide ones, including pressurized conditions. This paper describes the test results and the effects of the gas‐recycling operations. Cathode gas recycling is proved to be able to control the stack temperature and give the flexibility for setting oxygen utilization. Anode gas recycling is proved to be able to suppress the methane formation and decrease the deviation of the stacked cell voltages. Including the starting‐up process, it is proved that the electricity can be generated from the stack without supplying carbon dioxide from outside the system by carbon dioxide gas recycling. In such a process using a burner for carbon dioxide gas recycling, burner temperature must be controlled to a certain value. It is important to adjust the fuel supplying rate, load current and cathode gas‐recycling ratio to each other. At the load change process, constant gas utilization operation is not effective in changing the burner temperature.

Rustiana Yuliasni, Nur Zen, Nanik Indah Setianingsih

Jurnal Riset Teknologi Pencegahan Pencemaran Industri • 2020

This study aimed to identify the effect of substrate concentration on the performance of A Three chambers Microbial Salinity Cell (a three chambers MSC). In this study, 3 three chambers MSC was made of plexy glass with total volume of 200 ml. Alumunium wrapped with with platinum on vulcan carbon cloth were used as electrodes,with each working area 63 cm2. The results showed that a Three chambers Microbial Salinity Cell was able to generate electricity and at the same time removed salinity. The degree of electricity deneration and salinity removal were influenced by initial substrate concentration in the anode chamber. The higher substrate concentration, the better performance of MSC. The best performance of MSC achieved when COD was 2034 mg/L, resulted in maximum voltage of 0. 44 V, and maximum current density of 0.29 mA/m2. With % CE was 5.4%. The maximum conductivity increase in salinity chamber was from 11.2 µS/cm to 1027 µS/cm (salinity 0.57% ppt).

Guo-Yao Leow, Sze-Mun Lam, Jin-Chung Sin et al.

E3S Web of Conferences • 2024

In this study, an innovative and efficient carbide lime-assisted plant-microbial fuel cell (Ca-P-MFC) system was developed for treating dyestuff effluent and generating electricity. This system featured a carbon brush anode and a cupric oxide/carbon (CuO/C) cathode. The Ca-P-MFC system revealed outstanding performance compared to both the P-MFC and CW systems. At a carbide lime loading of 200 mg L −1 , the Ca-P-MFC system achieved an impressive methylene blue decomposition efficiency of 86.6% and a maximum power density ( P ) of 60.2 mW m −2 . The improved performance can be attributed to the incorporation of carbide lime, which promoted microbial reactions extending from the electrode surfaces throughout the operational area of the system. Furthermore, carbide lime served as an effective electron carrier, facilitating electron transfer across the system. The optimal loading of carbide lime was systematically evaluated in the developed Ca-P-MFC system, providing comprehensive insights into the mechanism of P-MFC.

Tatsuya Hatanaka, Kenji Kudo, Takamasa Nonaka et al.

ECS Meeting Abstracts • 2017

Polymer electrolyte fuel cells (PEFCs) are already put into the market as the power source for hydrogen fuel cell vehicles (FCVs), but further technical advancement is necessary to achieve both higher cell performance and lower cost required for wider distribution. Regarding the latter requirement, a precious metal-free cathode is an attractive alternative and various candidates have been examined such as nonprecious metal-containing or metal-free carbon-based catalysts, metal oxides, oxynitrides, and metal chalcogenides [1]. In spite of extensive researches, however, the cell performances and stabilities using those materials are still significant lower than conventional Pt-based cells. Another approach for a precious metal-free cathode is to flow a catholyte containing oxidized-state redox mediator through porous carbon electrode. The system is similar to a redox flow battery, and the reduced-state mediator is oxidized with air in another compartment (we call this system as "redox flow fuel cell"; RFFC). ACAL Energy Inc. has reported comparable cell performance to Pt-based one by this concept and also excellent durability in a potential cycle test [2]. In this paper, a molybdovanado phosphoric heteropoly acid, a kind of polyoxometalate (POM) is mentioned as a mediator; however, the characteristics of the catholyte were not described in detail. For better system efficiency, high cell performance must be achieved at high catholyte utilization, which is required to minimize the external pump energy consumption. High catholyte utilization, however, means low mediator oxidation states (i.e. state of charge; SOC) at the outlet. Therefore, the high cell performance even with low SOC catholyte is necessary. In this study, we examined the cell performances of RFFCs as functions of SOC using a molybdovanado phosphoric heteropoly acid as the mediator, and conducted ex-situ catholyte analysis using XAS, 31 P-NMR, 51 V-NMR and pH measurements to clarify the reactions in the catholyte of RFFCs. Membrane electrode assemblies (MEAs) were constructed using NR212 perfluorinated membrane (DuPont), a precious metal-free carbon cloth for the cathode and a Pt/C catalyst layer coated MPL/GDL for the anode. The electrode area was 1cm 2 and the interdigitated carbon flow field was used for the cathode. The catholyte, 140 cc of 0.3 M aqueous solution of H 6 PMo 9 V 3 O 40 (V3-POM) powder purchased from Nippon Inorganic Colour & Chemical Co., was circulated to the cathode with a tube pump at the flow rate of 14 cc/min. Fully humidified hydrogen gas was supplied to the anode at the flow rate of 100 cc/min. The cell performance was measured at the temperature maintained at 40˚C. The SOC of the catholyte was controlled by the time of period of constant current (0.3 A/cm 2 ) discharge. Small amount of catholyte (~1 cc) was sampled at each SOC and used for analysis, XAS, 31 P-NMR, 51 V-NMR and pH measurements. The obtained cell performance was shown in below. OCV exceeded 1.0V at SOC=100%, and iR-corrected cell voltage at 0.3A/cm 2 was about 0.86V. This performance is excellent as a precious metal-free cathode cell and comparable to a typical conventional Pt-based cathode cell. This result indicates that the RFFC has a good potential for a high energy conversion FC system. The ohmic resistance was found to be about 500mΩcm 2 by high frequency impedance measurements, five times as large as a typical conventional PEFC with a similar structure. The post analysis of MEA by cross-sectional EPMA revealed that membrane contained vanadium, but no molybdenum nor phosphor, suggesting decomposition of V3-POM. The dependence of OCV on SOC was found to be significantly larger than expected from the Nernst equation ( E = E 0 + RT / nF ln(x ox /(1-x ox ); where x ox is the concentration of the oxidized mediator). This discrepancy indicates that the redox reaction of the catholyte is not simple and that V3-POM is not suitable for a high utilization operation because the OCV at low SOC is too low to obtain a high cell voltage. The redox species was confirmed as vanadium by ex-situ XAS measurements conducted at BL33XU in SPring-8, Japan. The detail of reaction mechanism of V3-POM revealed by NMR and pH measurements will be discussed in the presentation. Reference: [1] M. Shao, Q. Chang, J. Dodelet, and R. Chenitz; Chem. Rev., (2016), 116, 3594–3657. [2] A. Creeth; Fuel Cells Bulletin (2011) 12–15.

Sari Tasa, Teppo Aapro

Journal of Fuel Cell Science and Technology • 2006

Mobile device manufacturers would like to provide totally wireless solutions—including charging. Future multimedia devices need to have longer operation times as simultaneously they require more power. Device miniaturization leaves less volumetric space available also for the energy source. The energy density of the Li-ion batteries is high, and continuously developed, but not at the same speed as the demand from devices. Fuel cells can be one possible solution to power mobile devices without connection to the mains grid, but they will not fit to all use cases. The fuel cell system includes a core unit, fuel system, controls, and battery to level out peaks. The total energy efficiency is the sum of the performance of the whole system. The environmental performance of the fuel cell system cannot be determined yet. Regulatory and standardization work is on-going and driving the fuel cell technology development. The main target is in safety, which is very important aspect for energy technologies. The outcomes will also have an effect on efficiency, cost, design, and environmental performance. Proper water, thermal, airflow, and fuel management of the fuel cell system combined with mechanical durability and reliability are the crucial enablers for stable operation required from the integrated power source of a mobile device. Reliability must be on the same level as the reliability of the device the energy source is powering; this means years of continuous operation time. Typically, the end-users are not interested of the enabling technologies nor understand the usage limits. They are looking for easy to use devices to enhance their daily life. Fuel cell technology looks promising but there are many practical issues to be solved.

Subhendu Bhandari, Soumya Pandit, Chetan Pandit et al.

Research Square • 2024

Abstract In the present study, Polyaniline (PANI)/ Carbon Felt (CF) composite electrodes were developed to be used as an anode in a Microbial Fuel Cell (MFC) for the enrichment of specific electroactive organisms on the anode. Comparative analysis of two approaches of Phenol degradation namely adsorption & biodegradation and for simultaneous generation of bio-electricity. Sulfuric acid-doped PANI was electrochemically synthesized in aqueous medium and deposited in-situ on the carbon felt anode followed by its characterization using SEM, XRD, and CV. To use these in MFC, different concentrations of PANI ranging from 0.25 mg/cm 2 to 1.25 mg/cm 2 , was deposited onto CF via potentiostatic electrodeposition technique and compared. The morphological analysis using FESEM of the anode revealed homogenous deposition of nanostructured PANI onto the surface of CF. Further characterization of PANI/CF composite shows that PANI has improved the surface area of the anode, thereby, increasing the conductivity of the anode and promoting biofilm attachment to the anode. The PANI/ CF composite anode with loading rate of 1.0 mg/cm 2 showed the best results with maximum power density of 584.2 mW m -2 and lowest charge transfer resistance of 49.6 Ω. The reduction of COD and total phenol of wastewater were 73% and 88% respectively. The obtained results from this study show that the power production and efficiency of the MFCs can be improved greatly by using Sulphate containing PANI/ CF composite as an anode material. The CLSM results indicated that PANI facilitates in promoting EAB biofilm which in turn helps in achieving enhanced power output.

Kyoung‐Yeol Kim, Euntae Yang, Mi‐Young Lee et al.

Journal of Chemical Technology & Biotechnology • 2013

Abstract BACKGROUND An ultrafiltration microbial fuel cell ( UF‐MFC ) is a novel technology that can simultaneously produce high‐quality effluent and electricity during wastewater treatment. To increase the power density and mitigate the inevitable biofouling phenomena in UF‐MFCs , the anode direct contact ( ADC ) method was tested. ADC application in UF‐MFCs improves the power densities by reducing the distance between the anode electrode and UF membrane (lowering the internal resistance), and mitigates biofouling on the UF membrane surface due to the direct contact of the porous anode electrode with the membrane surface. RESULTS The maximum power density increased from 76.6 ± 2.5 mW m −2 to 129.4 ± 13.9 mW m −2 after applying the ADC , with the internal resistance decreasing from 0.49 Ω m 2 to 0.23 Ω m 2 . The concentrations of extracellular polymeric substances ( EPS ) and total cell number were also analyzed as indicators for measuring biofouling on the UF membrane surface. EPS proteins and total cell numbers were reduced (62.8% and 64.9% each) with ADC application after 70 h operation, though no differences were observed in the specific permeate flux. CONCLUSION ADC application is simple and its use can enhance the power densities and mitigate the biofouling phenomena of UF‐MFCs . © 2013 Society of Chemical Industry

Rojas-Flores Segundo, Cabanillas-Chirinos Luis, Nélida Milly Otiniano et al.

Sustainability • 2025

The intensification of agricultural production due to high global demand has led to uncontrolled waste production from this industry, creating an environmental imbalance due to inadequate waste management. In developing regions, the lack of access to electricity has become a critical problem, affecting people’s health, education, and economy. To address this issue, alternative and sustainable ways of generating electricity have been explored. This research focuses on the potential of using asparagus waste in single-chamber microbial fuel cells (MFCs) at different pH levels (4, 4.7—target, 7, and 9) to achieve optimal performance. It has been demonstrated that using this substrate, the MFC at pH 7 obtained the best results on the seventh day, generating an electric current of 4.859 mA and a maximum voltage of 0.965 V. The substrate showed an oxidation-reduction potential of 312.821 mV, a chemical oxygen demand reduction of 76.47%, and an electrical conductivity of 254.854 mS/cm. Additionally, it managed to generate a power density of 2.149 mW/cm2 at a current density of 5.979 mA/cm2. MFCs at different pH levels (4, 4.7—target, 7, and 9) demonstrated their potential to generate electrical energy by powering an LED light when connected in series. This research holds promise in promoting sustainable energy solutions for the future.

B. Passmore, J. Hornberger, B. McPherson et al.

Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) • 2011

A high temperature, high performance power module was developed for extreme environment systems and applications to exploit the advantages of wide bandgap semiconductors. These power modules are rated > 1200V, > 100A, > 250 °C, and are designed to house any SiC or GaN device. Characterization data of this power module housing trench MOSFETs is presented which demonstrates an on-state current of 1500 A for a full-bridge switch position. In addition, switching waveforms are presented that exhibit fast transition times.

Dina Koltysheva, Kateryna Shchurska, Yevhenii Kuzminskyi

Innovative Biosystems and Bioengineering • 2024

Background. The possibility of converting organic compounds into electrical energy in microbial fuel cells (MFCs) makes MFCs a promising eco-friendly technology. However, the use of platinum or hexacyanoferrates may increase costs or lead to secondary environmental pollution. The use of microalgae in the cathode chamber is a promising solution to these problems. Objective. We aimed to establish the dependence of electrical energy generation and the efficiency of the appli­cation of a specific type of algae on the type and mode of lighting. Methods. In the study, two-chamber H-type MFC with salt bridge was used. Fermented residue after methanogenesis was used as inoculum in the anode chamber, and microalgae cultures Chlorella vulgaris, Desmodesmus armatus, and Parachlorella kessleri were used as inoculum in the cathode chamber. Results. MFCs with microalgae demonstrate the ability to generate current under different light sources. The maximum voltage for the MFC with an anode biofilm and with microalgae in the cathode chamber is 13–15% lower compared to the MFC with an abiotic cathode (840 ± 42 mV). The maximum current is 2–6% lower than the control (480 ± 24 mA) for the MFC with Chlorella vulgaris and the MFC with Parachlorella kessleri, and 8% higher for the MFC with Desmodesmus armatus compared to the MFC with an abiotic cathode. The MFCs with microalgae are capable of generating electrical energy for an extended period. Conclusions. With a pre-grown anodic biofilm, both the current and voltage maintain relative stability when the light source is changed. The potential use of solar lighting broadens the applicability of the MFCs with microalgae, as it eliminates the need for additional costs associated with artificial light sources.

Irene Merino-Jimenez, Carlo Santoro, Santiago Rojas-Carbonell et al.

Catalysts • 2016

A comparison between different carbon-based gas-diffusion air-breathing cathodes for microbial fuel cells (MFCs) is presented in this work. A micro-porous layer (MPL) based on carbon black (CB) and an activated carbon (AC) layer were used as catalysts and applied on different supporting materials, including carbon cloth (CC), carbon felt (CF), and stainless steel (SS) forming cathode electrodes for MFCs treating urine. Rotating ring disk electrode (RRDE) analyses were done on CB and AC to: (i) understand the kinetics of the carbonaceous catalysts; (ii) evaluate the hydrogen peroxide production; and (iii) estimate the electron transfer. CB and AC were then used to fabricate electrodes. Half-cell electrochemical analysis, as well as MFCs continuous power performance, have been monitored. Generally, the current generated was higher from the MFCs with AC electrodes compared to the MPL electrodes, showing an increase between 34% and 61% in power with the AC layer comparing to the MPL. When the MPL was used, the supporting material showed a slight effect in the power performance, being that the CF is more powerful than the CC and the SS. These differences also agree with the electrochemical analysis performed. However, the different supporting materials showed a bigger effect in the power density when the AC layer was used, being the SS the most efficient, with a power generation of 65.6 mW·m−2, followed by the CC (54 mW·m−2) and the CF (44 mW·m−2).

Mostafa Ghasemi, Mehdi Sedighi, Yie Hua Tan

Sustainability • 2021

In this paper, we reported the fabrication, characterization, and application of carbon nanotube (CNT)-platinum nanocomposite as a novel generation of cathode catalyst in microbial fuel cells (MFCs) for sustainable energy production and wastewater treatment. The efficiency of the carbon nanocomposites was compared by platinum (Pt), which is the most effective and common cathode catalyst. This nanocomposite is utilized to benefit from the catalytic properties of CNTs and reduce the amount of required Pt, as it is an expensive catalyst. The CNT/Pt nanocomposites were synthesized via a chemical reduction technique and the electrodes were characterized by field emission scanning electron microscopy, electronic dispersive X-Ray analysis, and transmission electron microscopy. The nanocomposites were applied as cathode catalysts in the MFC to obtain polarization curve and coulombic efficiency (CE) results. The catalytic properties of electrodes were tested by linear sweep voltammetry. The CNT/Pt at the concentration of 0.3 mg/cm2 had the highest performance in terms of CE (47.16%), internal resistance (551 Ω), COD removal (88.9%), and power generation (143 mW/m2). In contrast, for the electrode with 0.5 mg/L of Pt catalyst, CE, internal resistance, COD removal, and power generation were 19%, 810 Ω, 96%, and 84.1 mW/m2, respectively. So, it has been found that carbon nanocomposite cathode electrodes had better performance for sustainable clean energy production and COD removal by MFC.