Doo Hyun Park, J. Gregory Zeikus

Biotechnology and Bioengineering • 2002

Abstract A new one‐compartment fuel cell was composed of a rubber bunged bottle with a center‐inserted anode and a window‐mounted cathode containing an internal, proton‐permeable porcelain layer. This fuel cell design was less expensive and more practical than the conventional two‐compartment system, which requires aeration and a ferricyanide solution in the cathode compartment. Three new electrodes containing bound electron mediators including a Mn 4+ ‐graphite anode, a neutral red (NR) covalently linked woven graphite anode, and an Fe 3+ ‐graphite cathode were developed that greatly enhanced electrical energy production (i.e., microbial electron transfer) over conventional graphite electrodes. The potentials of these electrodes measured by cyclic voltametry at pH 7.0 were (in volts): +0.493 (Fe 3+ ‐graphite); +0.15 (Mn 4+ ‐graphite); and −0.53 (NR‐woven graphite). The maximal electrical productivities obtained with sewage sludge as the biocatalyst and using a Mn 4+ ‐graphite anode and a Fe 3+ ‐graphite cathode were 14 mA current, 0.45 V potential, 1,750 mA/m 2 current density, and 788 mW/m 2 of power density. With Escherichia coli as the biocatalyst and using a Mn 4+ ‐graphite anode and a Fe 3+ ‐graphite cathode, the maximal electrical productivities obtained were 2.6 mA current, 0.28 V potential, 325 mA/m 2 current density, and 91 mW/m 2 of power density. These results show that the amount of electrical energy produced by microbial fuel cells can be increased 1,000‐fold by incorporating electron mediators into graphite electrodes. These results also imply that sewage sludge may contain unique electrophilic microbes that transfer electrons more readily than E. coli and that microbial fuel cells using the new Mn 4+ ‐graphite anode and Fe 3+ ‐graphite cathode may have commercial utility for producing low amounts of electrical power needed in remote locations. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 348–355, 2003.

Eda Sonmez, Burcak Avci, Nourhan Mohamed et al.

The European Chemistry and Biotechnology Journal • 2024

The effect of platinum (Pt) loadings of air-cathodes in the 0-0.5 mg cm-2 range on single chamber microbial fuel cell (MFC) performance and cathode impedance was evaluated. In MFC tests, reducing benchmarking Pt loading of 0.5 mg cm-2 to 0.1-0 mg cm-2 decreased maximum power density by between 38% and 84%. The decrease in cathode open circuit potential with reduced loadings was small down to a catalyst loading of 0.03 mg cm-2, but was significant when the loading was further reduced to 0.01 or 0 mg cm-2. Impedance measurements of cathodes revealed that both charge-transfer and diffusion resistance increase with decreasing catalyst loadings on cathodes. Charge-transfer resistance of benchmarking cathode increased to a small extent when loadings were reduced to 0.1-0.03 mg cm-2. Below 0.03 mg cm-2, dramatic increase of charge-transfer resistance suggested that 0.03 mg cm-2 can be considered as the minimum Pt loading for which kinetic limitations are not of great concern and can be overcome to a large extent compared to lower loadings. In comparison to charge-transfer resistance, diffusion resistance differed more significantly between the loadings of 0.03 and 0.5 mg cm-2; and it was therefore the main component that changed the internal resistance of these cathodes.

Yong Juan Zhang, Min Zhang, Xin Yao et al.

Advanced Materials Research • 2010

Microbial fuel cell (MFC) was used to treat organic wastewater and heavy metal waste water treatment in this test. At the same time, organic waste water tank with the oxidation is taken as the battery anode; heavy metal waste water tank with reduction is taken as the cathode of the battery. The results showed that under the same conditions, with copper ion solution as a cathode liquid solution of MFC, the maximum voltage was 61.6mV, the maximum electric power density was 147.4 mW / cm2, and COD removal rate was relatively stable, and reached 68.67%; but when copper ion solution was taken as cathode solution, the maximum voltage was 36.9mV, the maximum electric power density was 43.7 mW / cm2, and COD removal rate changed heavily and reached 58.62%. The results shows that from the point of produce electricity and wastewater treatment, silver ions are better than copper.

Reuben Yao Tamakloe, Michael Kweku Edem Donkor, Keshaw Singh

European Scientific Journal, ESJ • 2017

The main challenges in the construction of microbial fuel cells (MFCs) are the identification of materials, designs, and architectures that may maximize power generation efficiency and fabrication cost. In view of these facts, an attempt was made to design and fabricate Multi – Chamber MFCs of different configuration using locally available Mfensi clay as ionexchange partitions. The performance of each micro-cell, combined effect of the total system as one cell, and the overall performance were studied. The volume of each chamber of these cells was approximately 130 cm3 . It was found that the wastewater of chemical oxygen demand (COD) that was 6340 gm/L used in the MFCs yielded a maximum open circuit voltage (OCV) of 1421 ± 30 mV. The peak power density of 33.30 mW/cm2 (0.037 mA/cm2 ) at 1000 Ω was normalized to the anode surface area

Pierangela Cristiani, Paolo Bonelli, Alessandro Liberale et al.

ECS Meeting Abstracts • 2018

Microbial Fuel Cells (MFCs) are a promising technology to harvest energy from aquatic environments and act as sensing devices at the same time. Several prototypes of sediment MFCs have been tested in the past and more recently floating systems have been investigated as well, with encouraging results both in terms of energy harvesting and sensing. The challenge is now to scale up laboratory MFC designs for self-powering water quality sensors and implement these in real environments, where electricity sources may not be available. In this work, the performances of floating MFCs, suitably designed for aerobic and anaerobic water environments, were studied in long-term experiments. Several designs of flat and tubular cells were tested, using low-cost materials, such as plastic lunch boxes, and polystyrene or wood to keep the system afloat. Untreated carbon cloth, free of any chemical catalyst, was used for the electrodes. Flat MFCs were able to generate up to 15 mW/m 2 , depending on nutrient availability in the water. The electric performance of cathodes and anodes were differently correlated to chemical and physical water parameters (day/night cycle, chemical oxygen demand, total carbon content, nitrates and temperature among others). The Total Organic Carbon and Total Inorganic Carbon in the tank were continuously monitored with Sievers 820 Portable Total Organic Carbon Analyzer and compared to the current production of the cells. Different types of power management systems had to be suitably designed, depending of the range of power produced by the MFC prototypes. A new generation of low-energy remote system (LORA) was integrated in an electronic circuit to harvest the power generated from MFCs and to transmit signals over long distance. The experimentation was carried out in the wastewater plant site at Carimate (Figure 1), Como (Italy) and in the pool of the city garden “Orto Botanico Città Studi” at Milan (Italy). Figure 1

Jiqiang Zhang, Zaiwang Zhang, Kun Rong et al.

Processes • 2022

In this study, a microbial fuel cell (MFC) that can achieve simultaneous anode anaerobic ammonium oxidation (anammox) and electricity generation (anode anammox MFC) by high-effective anammox bacteria fed with purely inorganic nitrogen media was constructed. As the influent concentrations of ammonium (NH4+-N) and nitrite (NO2−-N) gradually increased from 25 to 250 mg/L and 33–330 mg/L, the removal efficiencies of NH4+-N, NO2−-N and TN were over 90%, 90% and 80%, respectively, and the maximum volumetric nitrogen removal rate reached 3.01 ± 0.27 kgN/(m3·d). The maximum voltage and maximum power density were 225.48 ± 10.71 mV and 1308.23 ± 40.38 mW/m3, respectively. Substrate inhibition took place at high nitrogen concentrations (NH4+-N = 300 mg/L, NO2−-N = 396 mg/L). Electricity production performance significantly depended upon the nitrogen removal rate under different nitrogen concentrations. The reported low coulombic efficiency (CE, 4.09–5.99%) may be due to severe anodic polarization. The anode charge transfer resistance accounted for about 90% of the anode resistance. The anode process was the bottleneck for energy recovery and should be further optimized in anode anammox MFCs. The high nitrogen removal efficiency with certain electricity recovery potential in the MFCs suggested that anode anammox MFCs may be used in energy sustainable nitrogen-containing wastewater treatment.

S. E. Oh, J. R. Kim, J.-H. Joo et al.

Water Science and Technology • 2009

Oxygen intrusion into the anode chamber through proton exchange membrane can result in positive redox conditions in fed-batch, two chamber MFCs at the end of a cycle when the substrate is depleted. A slight increase in dissolved oxygen to 0.3 mg/L during MFC operation was not found to adversely affect power generation over subsequent cycles if sufficient substrate (acetate) was provided. Purging the anode chamber with air or pure oxygen for up to 10 days and 10 hrs also did not affect power generation, as power rapidly returned to previous levels when the chamber was sparged with nitrogen gas. When MFCs are connected in series, voltage reversal can occur resulting in a positive voltage applied to the anode biofilm. To investigate if this adversely affected the bacteria, voltages of 1, 2, 3, 4, and 9 V, were applied for 1 hr to the MFC before reconnecting it back to a fixed external load (1,000 Ω). A voltage of <2 V did not affect power generation. However, applying 3 V resulted in a 15 h lag phase before recovery, and 9 V produced a 60 h lag phase suggesting substantial damage to the bacteria that required re-growth of bacteria in the biofilm. These results indicate that charge reversal will be a more serious problem than oxygen intrusion into the anode chamber for sustained performance of MFCs.

Wilgince Apollon, Alejandro Isabel Luna-Maldonado, Juan Antonio Vidales-Contreras et al.

Journal of Experimental Biology and Agricultural Sciences • 2022

Plant microbial fuel cell (Plant-MFC) is an emerging technology that uses the metabolic activity of electrochemically active bacteria (EABs) to continue the production of bioelectricity. Since its invention and to date, great efforts have been made for its application both in real-time and large-scale. However, the construction of platforms or systems for automatic voltage monitoring has been insufficiently studied. Therefore, this study aimed to develop an automatic real-time voltage data acquisition system, which was coupled with an ATMEGA2560 connected to a personal computer. Before the system operation started it was calibrated to obtain accurate data. During this experiment, the power generation performance of two types of reactors i.e. (i) Plant-MFC and (ii) control microbial fuel cell (C-MFC), was evaluated for 15 days. The Plant-MFC was planted with an herbaceous perennial plant (Stevia rebaudiana), electrode system was placed close to the plant roots at the depth of 20 cm. The results of the study have indicated that the Plant-MFC, was more effective and achieved higher bioelectricity generation than C-MFC. The maximum voltage reached with Plant-MFC was 850 mV (0.85 V), whereas C-MFC achieved a maximum voltage of 762 mV (0.772 V). Furthermore, the same reactor demonstrated a maximum power generation of 66 mW m¯2 on 10 min of polarization, while a power density with C-MFC was equal to 13.64 mW m¯2. S.rebaudiana showed a great alternative for power generation. In addition, the monitoring acquisition system was suitable for obtaining data in real-time. However, more studies are recommended to enhance this type of system.

L. Woodward, M. Perrier, B. Srinivasan et al.

AIChE Journal • 2010

Abstract Microbial fuel cells (MFCs) constitute a novel power generation technology that converts organic waste to electrical energy using microbially catalyzed electrochemical reactions. Since the power output of MFCs changes considerably with varying operating conditions, the online optimization of electrical load (i.e., external resistance) is extremely important for maintaining a stable MFC performance. The application of several real‐time optimization methods is presented, such as the perturbation and observation method, the gradient method, and the recently proposed multiunit method, for maximizing power output of MFCs by varying the external resistance. Experiments were carried out in two similar MFCs fed with acetate. Variations in substrate concentration and temperature were introduced to study the performance of each optimization method in the face of disturbances unknown to the algorithms. Experimental results were used to discuss advantages and limitations of each optimization method. © 2010 American Institute of Chemical Engineers AIChE J, 2010

Muhammad Nihal Naseer, Asad A. Zaidi, Hamdullah Khan et al.

Catalysts • 2021

Microbial fuel cell, as a promising technology for simultaneous power production and waste treatment, has received a great deal of attention in recent years; however, generation of a relatively low power density is the main limitation towards its commercial application. This study contributes toward the optimization, in terms of maximization, of the power density of a microbial fuel cell by employing response surface methodology, coupled with central composite design. For this optimization study, the interactive effect of three independent parameters, namely (i) acetate concentration in the influent of anodic chamber; (ii) fuel feed flow rate in anodic chamber; and (iii) oxygen concentration in the influent of cathodic chamber, have been analyzed for a two-chamber microbial fuel cell, and the optimum conditions have been identified. The optimum value of power density was observed at an acetate concentration, a fuel feed flow rate, and an oxygen concentration value of 2.60 mol m−3, 0.0 m3, and 1.00 mol m−3, respectively. The results show the achievement of a power density of 3.425 W m−2, which is significant considering the available literature. Additionally, a statistical model has also been developed that correlates the three independent factors to the power density. For this model, R2, adjusted R2, and predicted R2 were 0.839, 0.807, and 0.703, respectively. The fact that there is only a 3.8% error in the actual and adjusted R2 demonstrates that the proposed model is statistically significant.

Mahnaz Izadi, Ali Mosallanejad, Alireza Lahooti Eshkevari

IET Power Electronics • 2022

Abstract This paper presents and comprehensively investigates a non‐isolated quadratic boost dc–dc converter (QBC), designed based on integrating a triple winding coupled inductor into the basic quadratic impedance network. The topology only contains ten components. It provides a high boost factor as well as high efficiency. Unlike most previous step‐up dc–dc converters, the employed improving method does not change the converter input current from continuous mode to pulsating or discontinuous shapes, making it suitable for connecting to the current sensitive resources. Thanks to this improvement, the voltage stress across the power switch is low, especially for higher winding coefficient values. A 20/240 V/240 W prototype has been designed and fabricated to evaluate the operating principle and performance of this QBC. Experimental results show the converter produces high gain (12 times as tested) and operate with high efficiency (up to 94%). Also, the voltage stress on the power switch is one‐third of the output voltage.

Jhonathan Prieto Rojas, Wejdan Alqarni, Muhammad Mustafa Hussain

Energy Technology • 2014

Abstract We have developed a sustainable, single feeding, microsized, air‐cathode and membrane‐free microbial fuel cells with a volume of 40 μL each, which we have used for rapid evaluation of power generation and viability of a series array of three cells seeking higher voltage levels. Contrary to expectations, the achieved power density was modest (45 mW m −3 ), limited due to non‐uniformities in assembly and the single‐channel feeding system.

Guang Yu Zhou, Yuichiro Yoshino, Takahiro Yamashita et al.

Applied Mechanics and Materials • 2012

Using wastewater as substrate, taking anaerobic sludge as inoculant, microbial fuel cells (MFCs) have emerged in recent years, which can generate electricity and accomplish wastewater treatment simultaneously. Based on the evaluation indexes of output voltage, coulombic efficiency, power density and TOC removal rate, three abiotic factors, anode size, membrane and membrane size, affecting MFC performance were investigated with an orthogonal experiment (L 4 (2 3 )). The results show that the impact order of factors through analyzing the value “R” was “anode size > membrane > membrane size”. The optimal set with these three factors for the performance of MFCs was big size anode, Naf-117 and big size membrane. Meanwhile, the high TOC removal rate (more than 90%) and high acetates consumed rate (100%) show the MFCs have strong ability of wastewater treatment. Cation exchange membrane Yumi-28 has compared ability of wastewater treatment and energy-production potential in MFC work.

Chin-Tsan Wang, I-Ting Li, Jer-Huan Jang

ECS Meeting Abstracts • 2024

Hexavalent chromium is considered as a human carcinogen due to its mutagenic and teratogenic properties, which can cause severe birth defects. Microbial Fuel Cell (MFC) is a promising power generation device for sustainable energy. The application of MFC is limited due to low power generation. In the present study, a miniature biosensor based on microbial fuel cell has been designed and assembled for detecting hexavalent chromium in wastewater. The miniature biosensor can generate power for sustaining operation. The power provided by the biosensor has been studied in the present investigation. Besides, both conductive silver glue and carbon cloth are employed as the anode for the biosensor. Electrochemical analyses for the above materials are conducted for the biosensor in detecting hexavalent chromium in the anode chamber. It is found that the maximum voltage can reach up to 518.17 mV and the power density of 1,075 mW/cm 2 can be achieved with carbon cloth as the anode electrode using an external resistance of 1000W. It is also measured that a higher limiting current density can reach up to 0.015 mA/cm 2 with conductive silver glue as the anode electrode. Furthermore, the voltage output of the biosensor decreased severely with the addition of hexavalent chromium into the wastewater. In addition, the recovery time for the biosensor is much shorter than those in previous studies. It is concluded that the biosensor possesses the potential of simultaneous detection of hexavalent chromium and electricity generation, leading to a new era of autosensing applications in the environment as well as smart powering devices.

HADI WISA NUGRAHA, GUNAWAN DJAJAKIRANA, SYAIFUL ANWAR et al.

Biodiversitas Journal of Biological Diversity • 2020

Abstract. Nugraha HW, Djajakirana G, Anwar S, Santosa DA. 2020. Producing renewable electric energy through a microbial fuel cell in the rice field. Biodiversitas 21: 4139-4146. Microbial Fuel Cell (MFC) is an alternative technology that converts chemical energy into electrical energy using microbes. This study aimed to apply MFC technology in the rice field to produce renewable electricity by utilizing microbes that have been previously isolated. The study was conducted in two experiments. The first experiment was carried out to select MFC prototypes with different in the oxygen circulation system (anode and cathode holes) that capable of producing the highest Voltage. The second experiment was performed to test the selected MFC prototype for electricity production in 12 combination treatments of microbes, organic matter, and fertilization (mixed NPK fertilizer) with three replications on rice cultivation in a greenhouse. The results showed that the best MFC prototype was a prototype that has two holes, each at anode and cathode (MFC 2). The highest electrical Voltage was generated by the treatment with microbes and organic matter, without fertilizer. The treatments produced the highest electrical current was the addition of microbes, organic matter, without and with 50% fertilizer. The highest power density was generated by the treatment with microbes and organic matter, without fertilization. The addition of ex-situ isolated microbes significantly increased the production of electricity.

Mojdeh Lotfi, Habibollah Younesi, Bita Roshanravan et al.

Water and Environment Journal • 2023

Abstract This study confirmed the efficacy of modified electrode microbial fuel cells (MFCs) in removing chemical oxygen demand (COD) and generating electricity using wastewater from industrial meat processing. The findings of linear sweep voltammetry (LSV) and cyclic voltammetry (CV) demonstrated that applying CuO particles to carbon cloth (CC) significantly reduced the charge transfer resistance, resulting in improved electrochemical performance. In the batch experiment, the MFCs were conducted by applying different electrodes and Nafion‐117 as a proton exchange membrane (PEM). X‐ray powder diffraction (XRD), energy‐dispersive X‐ray analysis (EDAX) and scanning electron microscope (SEM) analyses were performed to study the development of metal oxide on the electrode surface. The MFC operating with the CC/CuO electrode achieved a maximum COD removal (74.6%), which was attained at the peak power output of 82.56 mW/m 2 and the greatest current density of 213.33 mA/m 2 , as indicated by the polarization curve data. In light of these findings, coating CuO on the CC anode promotes electron transfer, enhances the electrode's conductivity and increases its electrochemical surface area. In summary, the findings of this study hold significant implications for sustainable electricity production and remarkable effects on environmental quality, highlighting the strategic importance of the research approach and outputs in addressing global energy and environmental challenges.

Jincheng Wei, Peng Liang, Kuichang Zuo et al.

ChemSusChem • 2012

Abstract A simple and low‐cost modification method was developed to improve the power generation performance of inexpensive semicoke electrode in microbial fuel cells (MFCs). After carbonization and activation with water vapor at 800–850 °C, the MFC with the activated coke (modified semicoke) anode produced a maximum power density of 74 W m −3 , 17 W m −3 , and 681 mW m −2 (normalized to anodic liquid volume, total reactor volume, and projected membrane surface area, respectively), which was 124 % higher than MFCs using a semicoke anode (33 W m −3 , 8 W m −3 , and 304 mW m −2 ). When they were used as biocathode materials, activated coke produced a maximum power density of 177 W m −3 , 41 W m −3 , and 1628 mW m −2 (normalized to cathodic liquid volume, total reactor volume, and projected membrane surface area, respectively), which was 211 % higher than that achieved by MFCs using a semicoke cathode (57 W m −3 , 13 W m −3 , and 524 mW m −2 ). A substantial increase was also noted in the conductivity, C/O mass ratio, and specific area for activated coke, which reduced the ohmic resistance, increased biomass density, and promoted electron transfer between bacteria and electrode surface. The activated coke anode also produced a higher Coulombic efficiency and chemical oxygen demand removal rate than the semicoke anode.

Priyadharshini Mani, Vallam Thodi Fidal Kumar, Taj Keshavarz et al.

Energies • 2018

Redox mediators could be used to improve the efficiency of microbial fuel cells (MFCs) by enhancing electron transfer rates and decreasing charge transfer resistance at electrodes. However, many artificial redox mediators are expensive and/or toxic. In this study, laccase enzyme was employed as a biocathode of MFCs in the presence of two natural redox mediators (syringaldehyde (Syr) and acetosyringone (As)), and for comparison, a commonly-used artificial mediator 2,2′-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) was used to investigate their influence on azo dye decolorization and power production. The redox properties of the mediator-laccase systems were studied by cyclic voltammetry. The presence of ABTS and As increased power density from 54.7 ± 3.5 mW m−2 (control) to 77.2 ± 4.2 mW m−2 and 62.5 ± 3.7 mW m−2 respectively. The power decreased to 23.2 ± 2.1 mW m−2 for laccase with Syr. The cathodic decolorization of Acid orange 7 (AO7) by laccase indicated a 12–16% increase in decolorization efficiency with addition of mediators; and the Laccase-Acetosyringone system was the fastest, with 94% of original dye (100 mgL−1) decolorized within 24 h. Electrochemical analysis to determine the redox properties of the mediators revealed that syringaldehyde did not produce any redox peaks, inferring that it was oxidized by laccase to other products, making it unavailable as a mediator, while acetosyringone and ABTS revealed two redox couples demonstrating the redox mediator properties of these compounds. Thus, acetosyringone served as an efficient natural redox mediator for laccase, aiding in increasing the rate of dye decolorization and power production in MFCs. Taken together, the results suggest that natural laccase redox mediators could have the potential to improve dye decolorization and power density in microbial fuel cells.

, Nurul Shahzira Hazri, Sahriah Basri et al.

Jurnal Kejuruteraan • 2025

Magnesium-air fuel cell (MAFC) is a hybrid system that combines the design of a fuel cell and a battery, requiring a constant replacement of anode and electrolyte to operate. MAFC application is limited for short-term high-power applications like emergency and portable power supplies because of severe corrosion problems impairing the performance of MAFC. Hence, this study focuses on performance by investigating the effect of electrolyte volume, electrodes position, and electrolyte concentration on performance of Mg–air fuel cell. Three sets of experiments were conducted starting with variation in volume of electrolyte. Then, it is applied in the cell configuration to test the MAFC performance with different electrode position. Lastly, the best electrode position is applied to the new modified MAFC together with the chosen electrolyte to investigate the effect of electrolyte concentration on MAFC performance. Finding shows that electrolyte volume not really significant to the performance while higher NaCl concentration can increase the performance of MAFC significantly. 10 wt% of NaCl produce the highest power density of 38.95 mW.cm<sup>-2</sup> and operating voltage of 1.67 V. Unfortunately, higher corrosion rate was observed in higher NaCl concentration. Finally, adding sodium phosphate act as corrosion inhibitor manage to suppress the corrosion reaction and lowers the corrosion rate.

Mosammat Mustari Khanaum, Shafiqur Rahman, Md. Saidul Borhan et al.

Water SA • 2024

Microbial fuel cells (MFCs) represent a promising technology to generate bio-electricity and synchronously reduce wastewater pollutants. The presence of exoelectrogens in wastewater is critical for bio-electricity and pollutant reduction, but the performance of exoelectrogens at different pH levels remains unknown. This study aims to bridge this gap by offering an integrated approach to understanding the performance of exoelectrogens under varying substrate pH, particularly in bio-electricity generation and pollutant reduction in sugarbeet processing wastewater (SBWW). Three pH levels (ranging from acidic to alkaline) were studied and MFC's electricity output was measured. Later, current density, power density, and coulombic efficiency (CE) were calculated. Both pre- and post-experiment substrate samples were analysed with inductively coupled plasma (ICP). Furthermore, 16S rRNA gene analysis, DNA amplification, sequencing library preparation, and bioinformatics workflows on post-experiment samples of the substrate and anode samples were conducted. A diverse community of microorganisms was identified, especially Alphaproteobacteria, Gammaproteobacteria, and Deltaproteobacteria (Geobacter). Bacteroidetes and Desulfovibrio were the major exoelectrogens responsible for electricity generation. Among the three pH levels tested, the most alkaline pH level (9.5±0.1) outperformed the others, achieving a 54% higher power density, 21% greater current density, and a 40% higher CE compared to the acidic pH level (6.5±0.1). Around 50–99% of pollutants were removed from the SBWW. The study revealed that Gammaproteobacteria thrive and perform better in alkaline environment.

Chul Kyu Jin, Jae Hyun Kim, Bong‐Seop Lee et al.

Fuel Cells • 2023

Abstract Stainless steel bipolar plates (BPs) fabricated using innovative additive manufacturing techniques can improve fuel cell performance and reduce costs. A high current density can be obtained using a low‐cost membrane electrode assembly (MEA) with low platinum (Pt) loading at the anode, along with BPs with rectangular micro channels. Three types of BPs of serpentine flow field are designed after varying the width of the rectangular channel. Two types of MEAs are used. First is 0.12 mg cm −2 Pt loading at anode, and the second is 0.50 mg cm −2 . Wherein MEA with Pt loading at 0.12 mg cm −2 is used, a high current density is obtained as the channel width decreases. The BP with 300 µm channels has a current density of 1.205 A cm −2 , which is higher by 31.4% than that of BP with 500 µm channels and higher by 70.2% than that of the BP with 940 µm channels. However, when the MEA with Pt loading at 0.50 mg cm −2 is applied to the test, the opposite results are obtained: As the channel width becomes narrow, the current density decreases. In the long‐term operation, a similar trend in the current density as that of the short‐term operation is observed.

Shih-Hang CHANG, Yuan-Ting TSAO, Kuan-Wei TUNG

Materials Science • 2021

In this study, we investigate the effect of heat treatment on the surface properties of carbon cloth electrodes and on the power generation efficiencies of microbial fuel cells (MFCs) configured with the heat-treated carbon cloth electrodes. Water contact angle measurements show that the hydrophobic surfaces of the carbon cloth became super-hydrophilic after heat treatment at a temperature above 500 °C, making it suitable for bacterial propagation. X-ray photoelectron spectrometry revealed that the signal of the C-O functional group of the carbon cloth electrodes increased in intensity after heat treatment. The MFCs configured with heat-treated carbon cloth electrode exhibited high power density of 16.58 mW/m2, whereas that of the untreated MFCs was only 8.86 mW m2. Compared with other chemical modifications, heat treatment does not use any environmentally unsound acidic or toxic solutions during modification and are promising for manufacturing large-scale MFC stacks.

Hussain & Ismail

IRAQI JOURNAL OF AGRICULTURAL SCIENCES • 2020

Three identically designed microbial fuel cell-constructed wetland (MFC-CW) systems were constructed and setup in this study for simultaneous biotreatment of petroleum refinery wastewater (PRW) and bioelectricity generation. MFC-CW1 and MFC-CW2 were planted with Canna indica, and Phragmites australis, respectively. MFC-CW3 was unplanted and considered as the control. These three systems were operated simultaneously in a batch mode for two cycles to evaluate the effect of PRW biotreatment on the growth and development of the selected plants and the potential of generated bioelectricity as well. The operation period for each cycle was 8 days. Results demonstrated that maximum removal efficiency of the organic content represented as chemical oxygen demand (COD) were 98.75%, 97.67%, and 97.83% observed in MFC-CW1, MFC-CW2, and MFC-CW3, respectively, whereby, the highest power generation were 19.86, 19.04, and 18.7 mW/m2, respectively. On the other hand, both types of plants exhibited notable growth and new sprouts appearance. The potential convergence of the results in the three MFC-CWs, and the healthy growth of both types of plants clearly and potentially indicated that the dominant mechanism of organic pollutant removal was via biodegradation process by the anodic biofilm in the MFC rather than being removed by phytoremediation process.

Livinus A. Obasi, Cornelius O. Nevo

Academia Green Energy • 2024

This study provides a comparative evaluation of the ability of response surface methodology (RSM) and artificial neural network (ANN) to predict the performance of microbial fuel cell (MFC) driven by greywater-syrup substrate system as anolyte with respect to power generation and wastewater treatment. Fourier transform infrared instrumental analysis of the substrate shows the functional groups of compounds present. A 24 central composite design and a three-layered (4:n:1) feedforward ANN architecture trained by a backpropagation algorithm were used to study and predict the MFC process performance criteria. The ANN gave the best prediction with n = 10 neurons. The response variables (power density generation (mW/m2) and chemical oxygen demand (COD) removal efficiency (%)) were measured against four process input variables: mass of the clay component of the proton exchange membrane (PEM) (g), PEM preparation temperature (PPT), anolyte pH, and concentration. Optimal responses with respect to power density and COD removal of 88.3 mW/m2 and 95.2% were recorded at the values of 70 g, 300°C, 8.5, and 66.9 v/v for mass of clay, PPT, pH, and anolyte concentration, respectively. The power density and COD removal predictive abilities of the ANN and RSM models were evaluated in terms of error functions: root mean square error (RMSE) (0.512; 0.0557), chi-square (0.0510; 0.1240), model predictive error (MPE) (0.3326; 0.3526), and coefficient of determination (R2) (0.9954; 0.9051) and RMSE (0.0272; 0.0707), chi-square (0.0280; 0.181), MPE (0.08242; 0.1569), and R2 (0.9932; 0.9245), respectively. These results indicate the superiority of the ANN in predicting the performance of the MFC over the RSM.

Arthur Kerviel, Apostolos Pesyridis, Ahmed Mohammed et al.

Applied Sciences • 2018

Mass-produced, off-the-shelf automotive air compressors cannot be directly used for boosting a fuel cell vehicle (FCV) application in the same way that they are used in internal combustion engines, since the requirements are different. These include a high pressure ratio, a low mass flow rate, a high efficiency requirement, and a compact size. From the established fuel cell types, the most promising for application in passenger cars or light commercial vehicle applications is the proton exchange membrane fuel cell (PEMFC), operating at around 80 °C. In this case, an electric-assisted turbocharger (E-turbocharger) and electric supercharger (single or two-stage) are more suitable than screw and scroll compressors. In order to determine which type of these boosting options is the most suitable for FCV application and assess their individual merits, a co-simulation of FCV powertrains between GT-SUITE and MATLAB/SIMULINK is realised to compare vehicle performance on the Worldwide Harmonised Light Vehicle Test Procedure (WLTP) driving cycle. The results showed that the vehicle equipped with an E-turbocharger had higher performance than the vehicle equipped with a two-stage compressor in the aspects of electric system efficiency (+1.6%) and driving range (+3.7%); however, for the same maximal output power, the vehicle’s stack was 12.5% heavier and larger. Then, due to the existence of the turbine, the E-turbocharger led to higher performance than the single-stage compressor for the same stack size. The solid oxide fuel cell is also promising for transportation application, especially for a use as range extender. The results show that a 24-kWh electric vehicle can increase its driving range by 252% due to a 5 kW solid oxide fuel cell (SOFC) stack and a gas turbine recovery system. The WLTP driving range depends on the charge cycle, but with a pure hydrogen tank of 6.2 kg, the vehicle can reach more than 600 km.

Nur Syafira Khoirunnisa, SYAIFUL ANWAR, DWI ANDREAS SANTOSA

Biodiversitas Journal of Biological Diversity • 2020

Abstract. Khoirunnisa NS, Anwar S, Santosa DA. 2020. Isolation and selection of cellulolytic bacteria from rice straw for consortium of microbial fuel cell. Biodiversitas 21: 1686-1696. Cellulose such as in rice straw can be utilized as an organic substrate in Microbial Fuel Cell (MFC) to generate electricity by microorganisms as a biocatalyst. This research aimed to get cellulose-degrading bacteria with high capability to degrade rice straw and able to be used as consortium with exoelectrogen bacteria in Microbial Fuel Cell. The stages of research included: (i) isolation of the bacteria using carboxymethylcellulose (CMC) agar medium, (ii) selection of the isolates for that purpose, (iii) enzyme assay and MFC performance test, and (iv) identification of selected isolate. There were 125 isolates that were obtained. Selection based on the ability to degrade cellulose as indicated by clear zone on CMC medium resulted in 23 isolates. Ten isolates belong to anaerobic facultative bacteria were selected. Three of them were synergistic with exoelectrogen bacteria. The three isolates were tested for exoglucanase (Avicel) and total enzyme activity (Filter Paper) with the highest results were 6.21 U/mL (isolate J404) and 5.88 U/mL (isolate J401), respectively. The optimum MFC performance was achieved by one isolate, J401, which produced highest voltage of 40.8 mV and a power density of 0.33 mW/m2. The best isolate, J401, was identified as Xanthomonas translucens based on 16S rRNA method.

Yu J. Shen, Olivier Lefebvre, Zi Tan et al.

Water Science and Technology • 2012

Wastewater may contain various potential toxicants. A microbial fuel cell (MFC) is a device in which bacteria convert the chemical energy into electricity. If a toxic event occurs, microbial activity is inhibited and thus the power output of the MFC decreases. Therefore, an MFC could serve as an early toxicity warning device. A real-time biomonitoring system was developed using MFCs to detect the inflow of toxic substances into wastewater treatment systems. After the MFCs reached steady state, a toxic incident was created by adding HCl into the wastewater to alter its pH. Consequently, a rapid decrease in voltage was observed immediately, followed by a subsequent recovery. The optimal MFC design was a single-chamber air cathode MFC, where the anode and cathode were separated by a Selemion proton exchange membrane. Under an external resistance of 5 Ω, the maximum power averaged 0.23 ± 0.023 mW with domestic wastewater. The optimized MFC showed high sensitivity and fast recovery when exposed to the acidic toxic event. When the hydraulic retention time was decreased from 22 to 3.5 min, sensitivity of the MFC increased substantially. Finally, the extent of inhibition observed was found to be related to the toxicity level, suggesting that a dosage–response relationship exists.

Shaik Bajithun, Baranitharan Ethiraj

ECS Transactions • 2022

The main aim of this study is to compare the power generation of Klebsiella variicola and anaerobic sludge operated double chamber MFC (DMFC) using municipal wastewater. Materials and methods: The wastewater samples collected from MFC with Klebsiella variicola (N=32) and anaerobic sludge (N=32) operated for 10 days (G power 80%). Voltage was measured using a multimeter and current, power, and power density was calculated from it for both groups. Results: The power generation was found to be high in Klebsiella variicola (1230mW/m 2 ) operated MFC compared to anaerobic sludge (120mW/m 2 ) due to its ability to form efficient biofilm on the anode surface compared to anaerobic sludge. The Independent sample T test was done which showed that the Klebsiella variicola operated MFC power generation (p<0.001), found to be significantly higher compared to anaerobic sludge. Conclusion: The study shows that Klebsiella variicola operated MFC is able to achieve higher power generation compared to anaerobic sludge.

Ian D. Deninger, Ashna K. Sran, Jason J. Keleher

ECS Meeting Abstracts • 2022

Microbial fuel cells (MFCs) have emerged as a renewable energy source due to their ability for direct conversion of organic substrates into electrical energy. However, issues with low power density, limited long-term stability, and higher operational costs have slowed larger scale integration and adoption. One main factor impacting fuel cell performance is the bacterial interactions at the electrode interface and the associated electron transfer mechanisms which are being widely studied. To increase productive interactions between the microbes and anode, this work focused on the synthetic design of a conductive polysaccharide-based (i.e., agar, alginate, pectin) nanocomposite material. More specifically, metal-carboxyl (Fe 3+ or V 5+ )coordination chemistry was used to photoinitiate the polymerization of polyaniline (PANI) directly on the backbone of the biopolymer matrix increasing the overall uniformity. Results show that the n-doped conducting polymer nanocomposite has enhanced current flow when exposed to E. Coli. Additionally, the electrode surface was modified via non-covalent linkages of organic fuels, such as glucose, with TiO 2 nanoparticles to decrease bacteria-surface repulsions. Initial results show that the sugar functionalized electrodes demonstrated an increased electric response in conjunction with photochemical activity. This phenomenon was observed through decreased fluorescence intensity without a decrease in cell viability as well as increased open circuit potential in the presence of light. This ligand-metal charge transfer coupled with increased conductivity of a biomimetic bulk material has resulted in an overall improved MFC system.

M. Abu Mallouh, B. W. Surgenor, M. Salah et al.

Volume 1: Applied Mechanics; Automotive Systems; Biomedical Biotechnology Engineering; Computational Mechanics; Design; Digital Manufacturing; Education; Marine and Aerospace Applications • 2014

Power management systems are one of the most important components in modern hybrid vehicles. They are needed to optimize the operation of the hybrid system components. In this paper, a model for a fuel cell/battery vehicle is developed using PSAT and then tested with four power management control strategies utilizing the driving cycle of Amman city, the capital of Jordan. The main components of the hybrid vehicle are a PEM fuel cell, battery, and a brushless dc motor. PEM fuel cells are popular due to their good start up, high power density, and low operating temperature. The role of the battery in a hybrid system is to boost the system power during start-up and transient events in addition to storing the energy recovered from the braking process. The developed hybrid vehicle model is designed and configured so that it matches the power, acceleration, and maximum speed of a midsized vehicle powered by an internal combustion engine. The proposed control strategies are the thermostat strategy, fuel cell optimized strategy, load following strategy and fuzzy logic strategy. All four control strategies are implemented in simulation utilizing PSAT. The simulation results indicate that the best performance in terms of fuel economy is achieved by the load following control strategy.

Nannan Guo, Ming C. Leu

Journal of Fuel Cell Science and Technology • 2013

Selective laser sintering (SLS) was used to fabricate graphite composite plates for polymer electrolyte membrane fuel cells, which has the advantages of reducing time and cost associated with the research and development of bipolar plates. Graphite composite plates with three different designs, i.e., parallel in series, interdigitated, and bio-inspired, were fabricated using the SLS process. The performance of these SLS fabricated plates was studied experimentally within a fuel cell assembly under various operating conditions. The effect of temperature, relative humidity, and pressure on fuel cell performance was investigated. In the tests conducted in this study, the best fuel cell performance was achieved with a temperature of 65–75°C, relative humidity of 100%, and back pressure of 2 atm. The performance of fuel cell operating over an extended time was also studied, with the result showing that the SLS fabricated graphite composite plates provided a relatively steady fuel cell output power.

M. C. Nájera, L. Verea, O. Lastres et al.

Fuel Cells • 2020

Abstract This work presents the study of different electrical potentials applied to a carbon cloth material to develop biofilms for their application as bioelectrodes in a microbial fuel cell (MFC). The principal aim of this work was to develop bioanodes and biocathodes for their simultaneous operation in a MFC. The potentials applied were 0.1 V, 0.4 V, and –0.42 V vs . Ag/AgCl KCl reference electrode. Also, electrodes were studied, where a positive potential was applied and gold as the catalyst for oxygen reduction reaction (ORR) was used. The bioelectrodes were characterized with the cyclic voltammetry (CV) technique and the results determined the application of the bioelectrodes as bioanode or biocathode in the MFC. The biofilms formed were observed with the scanning electron microscopy (SEM) technique, and also a new type of electroactive bacteria (Sphingomonas paucimobilis) for biocathodes was identified with a molecular technique. The bioelectrodes developed were tested in a MFC and a maximum power density of 0.585 W m −2 was obtained.

Tunc Catal, Hong Liu, Burak Kilinc et al.

Letters in Applied Microbiology • 2024

Abstract In microbial electrochemical cells (MECs), electroactive microbial biofilms can transmit electrons from organic molecules to anodes. To further understand the production of anodic biofilms, it is essential to investigate the composition and distribution of extracellular polymeric substance (EPS) in the MECs. In this study, the structure of EPS was examined in microbial electrolysis cells from mixed cultures forming biofilm using carbon fiber fabric anode. EPS was extracted from the anode biofilm of microbial electrolysis cells inoculated with mixed microbial culture. The anode biofilm yielded 0.4 mg of EPS, of which 51.2% was humic substance, 16.2% was protein, 12.6% was carbohydrates, and 20% consisted of undetermined substances. Using epifluorescence microscopy, the composition of bacterial cells and their location inside EPS were studied, and the distribution of microbial communities was compared based on current density results in the presence of various carbohydrates. On the electrode surface, bacteria and EPS gathered or overlapped in various locations can affect microbial electrochemical performance. Our findings showed that EPS formation in electroactive biofilms would be important for enhanced efficiency of electricity- or hydrogen-producing microbial electrolysis cells.

Tianwen Zheng, Bin Xu, Yaliang Ji et al.

Research Square • 2020

Abstract Background: The global production of glycerol is increasing year by year since the demands of biodiesel is rising. It is benefit for high-yield succinate synthesis due to its high reducing property. A. succinogenes , a succinate-producing candidate, cannot grow on glycerol anaerobically, as it needs a terminal electron acceptor to maintain the balance of intracellular NADH and NAD + . Microbial fuel cell (MFC) has been widely used to release extra intracellular electrons. However, A. succinogenes is a non-electroactive strain which need the support of electron shuttle in MFC, and pervious research showed that acid tolerant A. succinogenes has higher content of unsaturated fatty acids, which may be beneficial for the transmembrane transport of lipophilic electron shuttle. Results: MFC assisted succinate production was evaluated using neutral red as an electron shuttle to recover the glycerol utilization. Firstly, an acid tolerant mutant JF1315 was selected by atmospheric and room temperature plasma (ARTP) mutagenesis aiming to improve transmembrane transport of neutral red (NR). Additionally, MFC was established to increase the ratio of oxidized NR to reduced NR. By combining these two strategies, ability of JF1315 for glycerol utilization was significantly enhanced, and 23.92 g/L succinate was accumulated with a yield of 0.88 g/g from around 30 g/L initial glycerol, along with an output voltage above 300 mV. Conclusions: A novel MFC-assisted system was established to improve glycerol utilization by A. succinogenes for succinate and electricity production, making this system as a platform for chemicals production and electrical supply simultaneously.

Guotao Sun, Anders Thygesen, Anne Meyer

Energies • 2016

Implementation of microbial fuel cells (MFCs) for electricity production requires effective current generation from waste products via robust cathode reduction. Three cathode types using dissolved oxygen cathodes (DOCs), ferricyanide cathodes (FeCs) and air cathodes (AiCs) were therefore assessed using bioethanol effluent, containing 20.5 g/L xylose, 1.8 g/L arabinose and 2.5 g/L propionic acid. In each set-up the anode and cathode had an electrode surface area of 88 cm2, which was used for calculation of the current density. Electricity generation was evaluated by quantifying current responses to substrate loading rates and external resistance. At the lowest external resistance of 27 Ω and highest substrate loading rate of 2 g chemical oxygen demand (COD) per L·day, FeC-MFC generated highest average current density (1630 mA/m2) followed by AiC-MFC (802 mA/m2) and DOC-MFC (184 mA/m2). Electrochemical impedance spectroscopy (EIS) was used to determine the impedance of the cathodes. It was thereby confirmed that the FeC-MFC produced the highest current density with the lowest internal resistance for the cathode. However, in a setup using bioethanol effluent, the AiC-MFC was concluded to be the most sustainable option since it does not require ferricyanide. The data offer a new add-on option to the straw biorefinery by using bioethanol effluent for microbial electricity production.

Leila Samiee, Sedigheh Sadegh Hassani

Current Nanoscience • 2020

Background: Porous carbon materials are promising candidate supports for various applications. In a number of these applications, doping of the carbon framework with heteroatoms provides a facile route to readily tune the carbon properties. The oxygen reduction reaction (ORR), where the reaction can be catalyzed without precious metals is one of the common applications for the heteroatom-doped carbons. Therefore, heteroatom doped catalysts might have a promising potential as a cathode in Microbial fuel cells (MFCs). MFCs have a good potential to produce electricity from biological oxidization of wastes at the anode and chemical reduction at the cathode. To the best of our knowledge, no studies have been yet reported on utilizing Sulfur trioxide pyridine (STP) and CMK-3 for the preparation of (N and S) doped ordered porous carbon materials. The presence of highly ordered mesostructured and the synergistic effect of N and S atoms with specific structures enhance the oxygen adsorption due to improving the electrocatalytic activity. So the optimal catalyst, with significant stability and excellent tolerance of methanol crossover can be a promising candidate for even other storage and conversion devices. Methods: The physico-chemical properties of the prepared samples were determined by Small Angle X-ray Diffraction (SAXRD), N2 sorption-desorption, Transmission Electron Microscopy (TEM), Field Emission Scanning Electron Microscopy (FESEM) and X-ray Photoelectron Spectroscopy (XPS). The prepared samples were further applied for oxygen reduction reaction (ORR) and the optimal cathode was tested with the Microbial Fuel Cell (MFC) system. Furthermore, according to structural analysis, The HRTEM, and SAXRD results confirmed the formation of well-ordered hexagonal (p6mm) arrays of mesopores in the direction of (100). The EDS and XPS approved that N and S were successfully doped into the CMK-3 carbon framework. Results: Among all the studied CMK-3 based catalysts, the catalyst prepared by STP precursor and pyrolysis at 900°C exhibited the highest ORR activity with the onset potential of 1.02 V vs. RHE and 4 electron transfer number per oxygen molecule in 0.1 M KOH. The high catalyst durability and fuel-crossover tolerance led to stable performance of the optimal cathode after 5000 s operation, while the Pt/C cathode-based was considerably degraded. Finally, the MFC system with the optimal cathode displayed 43.9 mW·m-2 peak power density showing even reasonable performance in comparison to a Pt/C 20 wt.%.cathode. Conclusions: The results revealed that the synergistic effect of nitrogen and sulfur co-doped on the carbon substrate structure leads to improvement in catalytic activity. Also, it was clearly observed that the porous structure and order level of the carbon substrate could considerably change the ORR performance.

Wahyu Rinaldi, Yudha Nurdin, Syahiddin Syahiddin et al.

Jurnal Rekayasa Kimia & Lingkungan • 2014

Penelitian ini mengusulkan sebuah prototipe reaktor microbial fuel cell (MFC) tanpa membran beraliran kontinyu. Dinding Reaktor dibuat dari pipa PVC dan elektroda dari serat karbon. Mikroba yang ditambatkan di anoda bersumber dari larutan FloTank®. Pada penelitian ini digunakan limbah organik artifisial yang dibuat dari glukosa monohidrat dengan konsentrasi 250 mg/L COD. Waktu tinggal limbah divariasikan pada 0,5; 1; 1,5; dan 2 hari. Nilai rata-rata daya listrik yang dihasilkan untuk waktu tinggal limbah 0,5; 1; 1,5; dan 2 hari berturut-turut adalah 38,02; 43,01; 45,35; 46,71 mW/m2, dan daya volumetrik yang dihasilkan adalah 111,25; 125,86; 132,71; dan 136,69 mW/m3. Persentase penurunan Chemical Oxygen Demand (COD) limbah paling tinggi diperoleh pada waktu tinggal 1,5 hari yaitu sebesar 32,26%.

Vinothkumar Veeramani, Kanimozhi Rajangam, Jaya Nagendran

Sustainable Environment Research • 2020

Abstract The use of non-noble metal catalyst as electrode for energy harvesting device have drawn great deal of attention owing to its distinct features. In this work, cobalt oxide has been directly fabricated on carbon cloth substrates using simple cost effective Successive Ionic Layer Adsorption and Reaction. Cobalt oxide synthesized from Co (II) nitrate and NaOH was used as the electrode for generation of electricity from dairy wastes using Microbial Fuel Cells (MFC). Electrochemical characteristics such as cyclic voltammetry have been carried out for the cobalt oxide/carbon cloth and the obtained results are found to be a good alternative for platinum catalyst. A current of 0.15 mA was obtained at an external resistance of 2 kΏ. A single cell prototype of double chamber MFC is designed and the performance analysis is carried out in this work.

Antonio Castellano-Hinojosa, Manuel J. Gallardo-Altamirano, Clementina Pozo et al.

bioRxiv (Cold Spring Harbor Laboratory) • 2023

Abstract The fish-canning industry generates large quantities of wastewater that typically contains high concentrations of organic matter and salts. However, little is known about the potential valorization of this type of industrial wastewater using the microbial fuel cell (MFC) technology operated in a continuous flow mode. This study investigated the impacts of three different hydraulic retention times (HRT) on the performance, energy production, and prokaryotic and eukaryotic anodic microbiome of an MFC inoculated with activated sludge from a seafood industry and fed with synthetic wastewater that mimics fish-canning effluents. Three consecutive HRTs were studied: 1 day (HRT1), 3 days (HRT3), and 6 days (HRT6) for 30 days, 21 days, and 21 days, respectively. Voltage, current density, and power density were significantly greater at HRT1 compared to HRT3 and HRT6, whereas no differences in coulombic efficiency (CE) were detected among HRTs. Decreases in the efficiency of removal of organic compounds and increases in the abundance of archaeal communities with increased HRT was related to limited energy production at greater HRT. The increased energy production at HRT1 was tightly linked to increased and decreased absolute abundances of bacterial and archaeal communities, respectively. Variations in the HRT significantly impacted the diversity and composition of the prokaryotic community with critical impacts on energy production. The proliferation of known and diverse electroactive microorganisms, such as those belonging to the genera Geobacter , Shewanella , Arcobacter , and Clostridium , was related to increased energy production at HRT1. However, HRT3 and HRT6 enhanced the growth of archaeal methanogens (mainly Methanosarcina sp.), which negatively impacted current production. The eukaryotic community showed less sensitivity to changes in HRT and no significant impact on current production. The carbon oxygen demand and organic matter removal % increased from approximately 20% at HRT1 to almost 60% at HRT6. This study shows there is a critical balance between the HRT and prokaryotic microorganisms contributing to organic removal rate and increases and decreases in energy production in an MFC treating wastewater from the fish-canning industry and operated in a continuous mode.

Pimprapa Chaijak, Alisa Kongthong

Communications in Science and Technology • 2024

This study investigates the effect of microbial configuration on the electrochemical performance of photosynthetic microbial fuel cells (PMFCs). The PMFC configuration incorporating both bacteria and microalgae exhibited the highest open-circuit voltage (OCV) of 397.95 ± 31.53 mV, significantly higher than that of the OCVs obtained in the sterile control (C1) and the microalgae-only configuration (C2), which were 32.47 ± 22.43 mV and 284.59 ± 12.63 mV, respectively. Furthermore, the PMFC containing only microalgae achieved a current density (CD) of 20.96 ± 0.18 mA/m³ and a power density (PD) of 0.40 ± 0.01 mW/m³ under room temperature conditions. Notably, the combined bacteria and microalgae configuration demonstrated a substantial performance improvement, yielding a significantly higher CD of 49.33 ± 0.36 mA/m³ and PD of 0.78 ± 0.01 mW/m³ at room temperature. This configuration also achieved a maximum decolorization of 93.57 ± 0.10% with a corresponding algal biomass recovery of 134.90 ± 2.69 mg/L. These findings highlighted the critical role of microbial composition in PMFC performance. The combination of bacteria and microalgae yielded superior results compared to other configurations under the investigated conditions.