Xiuwei Fu, Li Fu, Hashem Imani Marrani

Journal of New Materials for Electrochemical Systems • 2021

The microbial fuel cell is one of the most important tools in the supply of renewable energy and its controller plays an important role in improving the performance and stability of its output. Using the advantages of adaptive and sliding mode methods, this paper presents a combined technique to ensure the stability and output voltage stabilization of the fuel cell in the presence of parametric uncertainties and nonlinear terms. The proposed control method is compared with classical control approaches and the simulation results confirm its efficiency.

Victoria Marie Ehlinger, Ahmet Kusoglu, Adam Z. Weber

ECS Meeting Abstracts • 2019

Throughout the lifetime of a polymer-electrolyte fuel cell, the membrane undergoes chemical degradation that causes defects to form and grow, contributes to a loss of performance, and can lead to cell failure. A combination of accelerated stress tests (ASTs) 1-2 and modeling studies 3-4 have been performed on this topic to better understand membrane degradation mechanisms and how to mitigate them 5-6 . During fuel-cell operation, formed peroxide radicals due to reactant gas crossover attack the polymer backbone and end chains, leading to membrane thinning and formation and growth of defects such as cracks and pinholes. This study builds upon our previous modeling study on membrane degradation to analyze the addition of chemical scavengers into the fuel-cell membrane to mitigate the effects of chemical degradation via radical attack. The developed model is transient and 1D across the fuel-cell sandwich. The transport and concentration of cerium is modeled using an ion-transport model based on concentration solution theory, thereby allowing the evaluation of how water gradients also move cerium ions throughout the ionomer, resulting in nonintuitive distributions. The model results also show how drive-cycle testing impacts the performance of the cell and the location of cerium, where relaxation of the applied gradients help redistribute the cerium in the ionomer. The purpose of the study is to optimize the cerium amount in both the membrane and catalyst layers by balancing effects of mitigation of chemical degradation and performance due to the impact of cerium on the ionomer material properties. For the latter, a key feature is accounting for the nonlinearities induced by the impacts of cerium on membrane and catalyst-layer ionomer properties. Acknowledgements The authors would like to thank Hans Johansen for helpful discussions and Los Alamos National Laboratory for providing material property data. Funding support was supplied by the Fuel Cell Performance and Durability Consortium (FC-PAD), by the Fuel Cell Technologies Office (FCTO), Office of Energy Efficiency and Renewable Energy (EERE), of the U.S. Department of Energy under contract number DE-AC02-05CH11231. References R. Borup, et al., Chem. Rev. , 107 , 3904 (2007) F. A. de Bruijn, et al., Fuel Cells , 8 , 3 (2008). R. Singh, et al., J. Electrochem. Soc. , 165 , F3328 (2018) K. H. Wong and E. Kjeang, J. Electrochem. Soc. , 166 , F128 (2019). M. Zatón, et al., Sustainable Energy & Fuels , 1 , 409 (2017). F. D. Coms, et al., in The Chemistry of Membranes Used in Fuel Cells: Degradation and Stabilization , 1st ed., S. Schlick Editor, John Wiley & Sons, Inc. (2018).

Simona Di Micco, Pasquale De Falco, Mariagiovanna Minutillo et al.

E3S Web of Conferences • 2021

Microbial fuel cells (MFCs) are playing an important role in the context of sustainable energy development. They represent a sustainable approach to harvest electricity from biodegradable materials. However, harvesting energy from MFCs represents a critical issue because of the low output voltage and power produced. Realizing stacked configurations may involve an increase in MFCs performances in terms of output voltage, current and electric power. In this paper, two stacked configurations under different electrical connection modes have been designed, developed, modeled and tested. The stacked MFCs consist of 4 reactors (28 mL x4) that are connected in series, and parallel-series modes. Three different tests have been carried out, which involves: 1) performing the polarization and power curves by applying decreasing resistances; 2) assessment of the electric behavior of each reactor over time at a fixed resistance, 3) performing the polarization and power curves by applying increasing resistances. Moreover, a numerical model for predicting the transient behavior of the electrical quantities for one reactor, has been developed and validated by using the experimental data. As expected, the results highlighted that the parallel-series configuration assures the highest volumetric power density compared to the series configuration, reaching the maximum value of 1248.5 mW/m 3 (139.8 µW) at 0.291 mA. Eventually, by comparing the numerical and the experimental data, it has been demonstrated that the developed model is able to predict the reactor’s electrical trend with a good accuracy.

Atsushi Aoki, Akebono Tanaka

ECS Meeting Abstracts • 2018

Organic light emitting diodes (OLED) have been greatly investigated for application in flat panel display and light source. A different type of OLED is light emitting electrochemical cell (LEC), which consists of luminescent chromophore films with solid electrolyte such as ionic ruthenium complex film. Driving process of LEC is different from that of OLED. That is, upon applied voltage, the electric double layer is formed at the interface between the anode or cathode and ionic luminescent film and hole and electron are injected from both electrodes into the luminescent film and then light is emitted by charge recombination. Thus, LEC has attractive features which are single-layer device and no requirement to use low work function metal as a cathode. However, LEC has some drawback which is ill charge-injection balance between hole and electron caused by the difference in ion size between large ruthenium complex cation and small counter anion. To improve the charge-injection balance, incorporation of small cation into ionic luminescent layer will be expected. In this study, current efficiency for LEC was improved by introduction of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as additive electrolyte into the ruthenium complex film of LEC. LEC was prepared by spin-coating tris(2,2’-bipyridyl) ruthenium(II) complex TFSI 2 (Ru(bpy) 3 (TFSI) 2 ) and poly(methyl methacrylate) (PMMA) matrix in acetonitrile solution with LiTFSI solid electrolyte on ITO anodes. And then silver was vacuum-deposited onto the resulting ruthenium complex film with solid electrolyte on ITO anodes. The luminescent property of LEC was performed by applying constant current. The standard LEC without LiTFSI was not emitted and the lower voltage than 1 V was observed in the constant current of smaller than 1.5 mA whereas it was emitted and the voltage of around 2.5 V was observed in the constant current of larger than 1.5 mA. These results indicate that the only hole injection occurs and the electron injection does not occur until the applied current over 1.5 mA. It’s due to the thicker electric double layer of ruthenium complex at the cathode of LEC. As introduction of LiTFSI into the ionic luminescent layer, the emission starts at the smaller applied current with increasing amount of LiTFSI. The maximum current efficiency becomes 3.0 cd/A in the LEC containing 3 wt% LiTFSI. However, the addition of more than 3 wt% LiTFSI into LEC makes LEC performance worse because the distance between ruthenium complex become wide and the electron hopping rate becomes slow. Finally, addition of 10 wt% LiTFSI makes crystalize ionic luminescent layer and it does not function as LEC. Therefore, we found that the introduction of 3 wt% LiTFSI to LEC was the optimum condition.

Ignacio T. Vargas, Natalia Tapia, John M. Regan

Materials • 2022

During the last decade, bioprospecting for electrochemically active bacteria has included the search for new sources of inoculum for microbial fuel cells (MFCs). However, concerning power and current production, a Geobacter-dominated mixed microbial community derived from a wastewater inoculum remains the standard. On the other hand, cathode performance is still one of the main limitations for MFCs, and the enrichment of a beneficial cathodic biofilm emerges as an alternative to increase its performance. Glucose-fed air-cathode reactors inoculated with a rumen-fluid enrichment and wastewater showed higher power densities and soluble chemical oxygen demand (sCOD) removal (Pmax = 824.5 mWm−2; ΔsCOD = 96.1%) than reactors inoculated only with wastewater (Pmax = 634.1 mWm−2; ΔsCOD = 91.7%). Identical anode but different cathode potentials suggest that differences in performance were due to the cathode. Pyrosequencing analysis showed no significant differences between the anodic community structures derived from both inocula but increased relative abundances of Azoarcus and Victivallis species in the cathodic rumen enrichment. Results suggest that this rarely used inoculum for single-chamber MFCs contributed to cathodic biofilm improvements with no anodic biofilm effects.

Tejas Ambekar

International Journal for Research in Applied Science and Engineering Technology • 2022

Abstract: This work aims towards the simulation of Various proton exchange membrane fuel cell (PEMFC) models to investigate the effects of operating parameters such as temperature, pressure, anode flow levels and cathode reactants, component types, cooling temperatures in the performance of a modified fuel cell. The basic model and the tubular model are developed in modelling software based on the size of the parameter later simulated using the addon module in the Ansys software. The Addon module is specifically designed to mimic a different type of fuel cell. The simulated model of cell power output showed positive compliance with experimental results taken from the literature and revealed that the operating pressure, temperature, and flow rate of reactants positively affect the function of the Fuel cell. The results also showed that the cooling temperature of the coolant indicates higher concentrations of current congestion compared to the base model without cooling. Corrective results obtained from the effect of temperature on cell function showed that the fuel cell temperature favor both cell function and efficiency. It can therefore be assumed that the efficiency of the cell is strongly influenced by operating temperature, pressure, cooling temperature, fuel flow rate and oxidant. Keywords: PEM fuel cell, Current density, tubular fuel cell, addon-module.

Kalagbor IA

Open Access Journal of Waste Management & Xenobiotics • 2019

Green Chemistry is gaining prominence in environmental and technological processes. Generating electricity from agro wastes comprising of waste vegetables and fruits are new sources of clean energy. Scientists need to develop technological methods of converting these agro wastes to useful resources especially in developing countries. Fruit wastes are generated in large quantities globally from processing plants. Defective tomatoes rejected and damaged banana fruits as well as unusable pineapple fruits and peels constitute part of the agro waste biomass generated annually. Effective management of this biomass is still ongoing. This research focuses on the conversion of these agro wastes to bioelectricity (green energy) using single microbial fuel cells (SMFCs) technology. Fruits wastes of 5kg, 10kg, 15kg and 20k were used. Results showed that the higher the quantity of substrate, the higher the electricity produced. The maximum voltage outputs generated on day 1 were 4.2V, 3.1V and 3.0V from tomatoes, banana and pineapple (fruit and peel) wastes respectively. The values obtained for current readings were significantly proportional to the voltage readings. The physiochemical parameters; pH, Conductivity, BOD, COD and DO were consistent with those from similar studies. The conversion of tomatoes, banana and pineapple fruit waste to bioelectricity was achieved. Reduction of this biomass by biodegradation using the SMFC technology is one way of removing these agro wastes from the ecosystem to maintain a clean, healthy, pollution-free environment.

Mirella Di Lorenzo, Tom P. Curtis, Ian M. Head et al.

Water Science and Technology • 2009

This study reports an investigation of the effect of the anode surface area on the performance of a single chamber microbial fuel cell (SCMFC) based biosensor for measuring the organic content of wastewater. A packed bed of graphite granules was used as the anode. The surface area of the anode was changed by altering the granule bed thickness (0.3 cm and 1 cm). The anode surface area was found to play a role in the dynamic response of the system. For a granule bed thickness of 1 cm and with an external resistance of 500 Ω, the response time (defined as the time required to achieve 95% of the steady-state current) was reduced by approximately 65% in comparison to a SCMFC biosensor with a carbon cloth anode.

Subha Chandrasekarabarathi, Priya ArunKumar, Rajesh Banu Jeyakumar

Environmental Progress & Sustainable Energy • 2023

Abstract Microbial fuel cells (MFC) are recent advancements in treating wastewater and generating power simultaneously. In the present study, chocolaterie wastewater rich in organic content was the substrate in a dual‐chambered MFC. Activated Carbon Fiber Felt (ACFF) electrodes (anode and cathode) were separated by Nafion 117 proton exchange membrane in the dual‐chambered reactor. The primary goal was to investigate the impact of organic loading on MFC efficiency in treating chocolaterie wastewater and carrying out microbial analysis. 1, 2, 3, and 4 gCOD/L were the organic loadings of the reactor. MFC performance increased till the optimum value, and after that, it declined. A total of 2 gCOD/L was the optimum organic loading. At this optimum organic loading, dual‐chambered MFC removed 79% of total chemical oxygen demand (TCOD), 70% of soluble chemical oxygen demand (SCOD), and 67% of total suspended solids (TSS). At 2 gCOD/L organic loading, the maximum power density was 99 mW/m 2 . Coulombic efficiency was 58% at 1 gCOD/L and 30% at 2 gCOD/L organic loadings. Microbial analysis revealed the presence of Ochrobactrum and Pseudomonas sp. as dominant exoelectrogens in the anodic biofilm. These species were proven for the contaminant degradation efficiency and potential for power generation. Hence dual‐chambered MFCs can treat high‐strength chocolaterie wastewaters efficiently at optimum operating conditions.

Samindi Madhubha Jayawickrama, Tsuyohiko Fujigaya

ECS Meeting Abstracts • 2019

Polymer electrolyte membrane fuel cells (PEMFCs) have been receiving ample attention as an efficient and clean power source for stationary and automotive applications. 1 One of the challenges for commercialization of PEMFCs is to minimize the amount of Platinum (Pt) to lower the cost of PEMFC. Pt is the most stable and active catalyst for oxygen reduction reaction (ORR). 2 Incorporation of non-precious metals and decreasing the catalyst particle size are common methods to reduce the amount of Pt used in PEMFC. However, these methods involve dissolution of non-precious metals in acidic condition 3 and agglomeration of small sized Pt 4 , resulting in decreased Pt utilization. Therefore, improvement of Pt utilization efficiency is required. Optimizing catalyst structure by increasing number of reaction sites is a promising strategy to improve the Pt utilization efficiency. One approach is increasing mass diffusion (oxygen, proton) by selecting a non-porous carbon support like acetylene black (AB). 5 However, Pt durability and utilization are limited due to lack of anchoring sites for Pt particles in AB. 6 Another approach is optimizing ionomer/carbon ratio. However, recent high-resolution transmission electron microscopy studies suggest that the ionomer coverage in the electrode may be rather inhomogeneous. 7 In this study, we demonstrate a novel approach to improve Pt utilization efficiency in PEMFC by preventing deposition of Pt particles into interior pores of carbon support and simultaneously providing homogeneous ionomer; Nafion coverage. This approach involves polymer coating onto carbon blacks (CBs). Polybenzimidazole (PBI) is used as the surface coating material of CB where PBI interacts with CB via π-π and acid-base interactions. It is reported that PBI coating works as the micropore capping agent of CB. 8 Therefore, PBI coating can reduce number of Pt particles deposited into geometrically restricted areas of CB. Moreover, PBI coating may trigger a homogeneous Nafion coverage due to the acid-base interaction between Nafion and PBI concurrently. Three morphologically different CBs; Vulcan, Ketjen black (KB) and AB were used to investigate the Pt utilization efficiency in polymer coated CBs. The PBI coating onto CB was easily done by addition of CB into PBI dissolved N,N -dimethylacetamide and 1 hr sonication to the mixture to prepare Vulcan/PBI, KB/PBI and AB/PBI. Then Pt nano-particles were deposited via polyol reduction to prepare Vulcan/PBI/Pt, KB/PBI/Pt and AB/PBI/Pt and compared with their non-coated Vulcan/Pt, KB/Pt and AB/Pt. AB/PBI/Pt shows homogeneous Pt dispersion over AB/Pt due to the presence of binding sites through coordination of Pt with imidazole groups in PBI as an additional advantage. The micropore density of CBs is increasing in the order of AB < Vulcan < KB. Power density of CB/Pts was decreased in the following order; AB/Pt < Vulcan/Pt < KB/Pt, consistent with the order of increasing micropore density. The lower performance of KB/Pt is due to the decreased number of accessible Pts for the electrochemical reaction especially for ORR 5 . Interestingly, power densities of CB/PBI/Pts were higher than that of respective CB/Pts. The higher power density of CB/PBI/Pt can be attributed to the reduced inaccessible amount of Pt deposited into the micropores of CB and the reduced protonic resistance in the catalyst layer due to the homogeneous Nafion layer. 9 Furthermore, power densities of CB/PBI/Pts were increasing in the order of KB/PBI/Pt < Vulcan/PBI/Pt < AB/PBI/Pt. The highest performance of AB/PBI/Pt is believed to be due to lower mass transfer limitation in the catalyst layer which is caused by the lower pore density of AB/PBI along with the uniform Nafion coverage. References Kibsgaard, J.; Gorlin, Y.; Chen, Z.; Jaramillo, T. F., J. Am. Chem. Soc. 2012, 134 , 7758. Nørskov, J. K.; Rossmeisl, J.; Logadottir, A.; Lindqvist, L.; Kitchin, J. R.; Bligaard, T.; Jónsson, H., J. Phys. Chem. B 2004, 108 , 17886. Colón-Mercado, H. R.; Kim, H.; Popov, B. N., Electrochem. Commun . 2004 , 6 , 795. Tang, L.; Han, B.; Persson, K.; Friesen, C.; He, T.; Sieradzki, K.; Ceder, G., J. Am. Chem. Soc . 2010 , 132 , 596. Park, Y.-C.; Tokiwa, H.; Kakinuma, K.; Watanabe, M.; Uchida, M., J. Power Sources 2016 , 315 , 179. Badam, R.; Vedarajan, R.; Matsumi, N., Chem. Commun . 2015 , 51 , 9841. Lopez-Haro, M.; Guétaz, L.; Printemps, T.; Morin, A.; Escribano, S.; Jouneau, P. H.; Bayle-Guillemaud, P.; Chandezon, F.; Gebel, G., Nat. Commun . 2014 , 5 , 5229. Fujigaya, T.; Hirata, S.; Berber, M. R.; Nakashima, N., ACS Appl. Mater. Interfaces 2016 , 8 , 14494. Jayawickrama, S. M; Han, Z. et al ., in review.

Kristopher Ray Simbulan Pamintuan, Angelika Michelle C. Katipunan, Patricia Ann O. Palaganas et al.

International Journal of Renewable Energy Development • 2020

Plant-Microbial Fuel Cell (PMFC) technology is a promising bioelectrochemical system that can exploit natural plant rhizodeposition to generate electricity. PMFCs can be used to simultaneously generate electricity while growing edible plants, as illustrated in this study. However, the common problem encountered for soil PMFCs is the low power output. To solve this problem, the stacking behavior of PMFCs was examined to maximize the power output of several cells. A grid of 9 PMFCs (3x3) was constructed with stainless steel and carbon fiber electrodes growing green beans (V. ungiculata spp. sesquipedalis) for stacking purposes. Stacking results have shown that too many cells connected in series will result in voltage losses, while stacking in parallel conserves voltage between cells. Stacking a maximum of 3 cells in series is acceptable based on the results, since cumulative stacking revealed that voltage reversals can reduce the overall potential of the stack if there are too many connected cells. Stack combinations were also tested, resulting in an enhanced performance upon combining series and parallel connections allowing power to be amplified and power density to be conserved. The combination of three sets of three cells in series stacked in parallel (3S-P) generated the highest power and power density (160.86 μW/m2) amongst all combinations, showing that power amplification without losses to power density are possible in PMFC stacking. Overall, proper stacking combinations have been shown to greatly affect the performance of PMFCs. It is hoped that the results of this study will contribute to the efforts of applying PMFC technology on a larger scale.

Minling Shao, Muhammad Nadeem Zafar, Magnus Falk et al.

ChemPhysChem • 2013

Abstract After initial testing and optimization of anode biocatalysts, a membraneless glucose/oxygen enzymatic biofuel cell possessing high coulombic efficiency and power output was fabricated and characterized. Two sugar oxidizing enzymes, namely, pyranose dehydrogenase from Agaricus meleagris ( Am PDH) and flavodehydrogenase domains of various cellobiose dehydrogenases (DH CDH ) were tested during the pre‐screening. The enzymes were mixed, “wired” and entrapped in a low‐potential Os‐complex‐modified redox‐polymer hydrogel immobilized on graphite. This anode was used in combination with a cathode based on bilirubin oxidase from Myrothecium verrucaria adsorbed on graphite. Optimization showed that the current density for the mixed enzyme electrode could be further improved by using a genetically engineered variant of the non‐glycosylated flavodehydrogenase domain of cellobiose dehydrogenase from Corynascus thermophilus expressed in E. coli (ngDH Ct CDHC310Y ) with a high glucose‐turnover rate in combination with an Os‐complex‐modified redox polymer with a high concentration of Os complexes as well as a low‐density graphite electrode. The optimized biofuel cell with the Am PDH/ngDH Ct CDHC310Y anode showed not only a similar maximum voltage as with the biofuel cell based only on the ngDH Ct CDHC310Y anode (0.55 V) but also a substantially improved maximum power output (20 μW cm −2 ) at 300 mV cell voltage in air‐saturated physiological buffer. Most importantly, the estimated half‐life of the mixed biofuel cell can reach up to 12 h, which is apparently longer than that of a biofuel cell in which the bioanode is based on only one single enzyme.

Stephane Chevalier, Jean-Christophe Olivier, Christophe Josset et al.

ECS Meeting Abstracts • 2018

Polymer Electrolyte Membrane (PEM) fuel cells are considered as promising clean sources for automotive applications. A key challenge to reduce the cost of this technology is to increase the power density by operating PEM fuel cells at high current densities. Part of the research are focused in developing and designing new materials for this technology such as advanced catalyst layers (CL), new gas diffusion layers (GDL) structure, or innovative cell assembly conditions (clamping pressure, channel design…)[1]. To assess the performance of new materials, in situ characterisation techniques are required. Electrochemical impedance spectroscopy (EIS) is one of the most used technique to characterise the material impact onto the fuel cell mass/charge transfer, ohmic resistance and mass transport. However, due to the large number of parameters which has to be identified, inaccuracy in the identification process may arise leading to incorrect fuel cell material properties characterisation [2]. In authors’ recent work [3], it was shown that current density distributions can be used as a useful information to characterise fuel cell material properties. Thus, in this communication we will present a segmented cell designed and built to measure current density distribution along the channel while allowing optical access inside the channel to visualise the presence of liquid water. A range of fuel cell GDLs is characterised in situ in this cell for a range of operating conditions. The effective diffusivity of the GDLs is directly obtained from the current density distribution without any knowledge of the other fuel cell parameter (membrane ohmic resistance or CL kinetics). The values of effective diffusivity obtained using our methodology are compared to the ones obtained through EIS measurements, and their respective accuracy will be discussed. In addition, examples on the use of this characterisation cell to assess the performance of channel designs and fuel cell assembly conditions will be given. The results presented in this communication will introduce a novel fuel cell characterisation methodology which can strongly improve the development of more efficient fuel cell systems. References [1] T. Yoshida, K. Kojima, Toyota MIRAI Fuel Cell Vehicle and Progress Toward a Future Hydrogen Society , Interface Mag. 24 (2015) 45–49. [2] S. Chevalier, D. Trichet, B. Auvity, J.C. Olivier, C. Josset, M. Machmoum, Multiphysics DC and AC models of a PEMFC for the detection of degraded cell parameters , Int. J. Hydrogen Energy. 38 (2013) 11609–11618. [3] S. Chevalier, C. Josset, B. Auvity, Analytical solutions and dimensional analysis of pseudo 2D current density distribution model in PEM fuel cells , Renew. Energy. 125 (2018) 738–746.

Rebecca Isseroff, Benjamin Akhavan, Cheng Pan et al.

MRS Proceedings • 2013

ABSTRACT Obstructing commercialization of Proton Exchange Membrane Fuel Cells (PEMFC) is the soaring cost of platinum and other catalysts used to increase membrane efficiency. The goal of this investigation is to find a relatively inexpensive catalyst for coating the membrane and enhancing the efficiency of the PEMFC. Graphene oxide was reduced using NaBH 4 in the presence of metal salts, primarily KAuCl 4 and K 2 PtCl 4 , to synthesize metal-nanoparticle/reduced graphene oxide (RGO). FTIR indicated the successful synthesis of RGO, while Transmission Electron Microscopy displayed the presence of nanoparticles on RGO sheets. Nafion® membranes were coated with metal-nanoparticle/RGO and tested in an experimental PEMFC alongside bare Nafion®, Gold (Au) nanoparticles, and RGO. The metal-nanoparticle/RGO composites enhanced the PEMFC compared to bare Nafion®. Au-RGO, the best catalyst composite, increased the efficiency up to 150% better than nanoparticles or RGO alone while using only 1% of the concentration of Au nanoparticles. Theoretical power output of the Au-RGO synergy could increase fuel cell efficiency up to 18 times more than the Au-nanoparticles themselves by altering concentrations of Au nanoparticles in Au-RGO. The Au nanoparticles changed the structure and catalytic ability of graphene in the Au-RGO, offering a promising future for PEM fuel cell technology.

Mónica Mejía‐López, Laura Verea, Pathiyammattom Joseph Sebastian et al.

Fuel Cells • 2021

Abstract An experimental design was performed to study the combined effects of the parameters used for bacteria selective biofilm formation. The parameters were the potential applied, the time of the biofilm formation with electroactive bacteria or the biofilm formation, and the initial substrate concentration in the medium. The performance of the biofilms formed was compared by their kinetic parameter the apparent electron transfer rate constant ( K app ), which was obtained from cyclic voltammetry analysis. The results from the experimental design showed that the highest K app of 0.56 s −1 was with the potential applied of −0.45 V for 5 h and 12 mM of the initial substrate concentration in the medium. New values of these parameters were calculated from the statistical analysis of the experimental design results and successfully higher value of K app of 0.64 s −1 can be calculated and obtained. The electroactivity and capability of the biofilm for hydrogen production was also proved in a single chamber microbial electrolysis cell, and a hydrogen production yield of 0.24 m 3 H 2 /m 3 d was obtained. The biofilm formed with these last parameters was also identified with molecular techniques as Exiguobacterium which has barely been reported as electroactive bacteria and used for hydrogen production.

Mohamed Derbeli, Oscar Barambones, Jose Antonio Ramos-Hernanz et al.

Energies • 2019

Proton exchange membrane fuel cell (PEMFC) topology is becoming one of the most reliable and promising alternative resource of energy for a wide range of applications. However, efficiency improvement and lifespan extension are needed to overcome the limited market of fuel cell technologies. In this paper, an efficient approach based on a super-twising algorithm (STA) is proposed for the PEMFC system. The control objective is to lengthen the fuel cell lifetime by improving its power quality, as well as to keep the system operating at an optimal and efficient power point. The algorithm adjusts the PEMFC operating point to the optimum power by tuning the duty cycle of the boost converter. The closed-loop system includes the Heliocentris hy-ExpertTM PEMFC, DC–DC boost converter, DSPACE DS1104, dedicated PC, and a programmable electronic load. The practical implementation of the proposed STA on a hardware setup is performed using a dSPACE real-time digital control platform. The data acquisition and the control system are conducted together with the dSPACE 1104 controller board. To demonstrate the performance of the proposed algorithm, experimental results are compared with 1-order sliding mode control (SMC) under different load resistance. The obtained results demonstrate the validity of the proposed control scheme by ensuring at least 72% of the maximum power produced by PEMFC. In addition, it is proven that the STA ensures all the fundamental properties of the 1-order SMC, as well as providing chattering reduction of 91%, which will ameliorate as a consequence the fuel cell lifetime.

Edi Leksono, Justin Pradipta, Tua Agustinus Tamba

Journal of Mechatronics, Electrical Power, and Vehicular Technology • 2012

One essential parameter in fuel cell operation is oxygen excess ratio which describes comparison between reacted and supplied oxygen number in cathode. Oxygen excess ratio relates to fuel cell safety and lifetime. This paper explains development of air feed model and oxygen excess ratio calculation in commercial self-humidified PEM fuel cell system with 1 kW output power. This modelling was developed from measured data which was limited in open loop system. It was carried out to get relationship between oxygen excess ratio with stack output current and fan motor voltage. It generated fourth-order 56.26% best fit ARX linear polynomial model estimation (loss function = 0.0159, FPE = 0.0159) and second-order ARX nonlinear model estimation with 75 units of wavenet estimator with 84.95% best fit (loss function = 0.0139). The second-order ARX model linearization yielded 78.18% best fit (loss function = 0.0009, FPE = 0.0009).

Hsiu Lu Chiang, Teng Lang Feng, Ay Su et al.

Advanced Materials Research • 2014

Hydrogen is known to be an ideal fuel that provides zero-emission energy. Fuel cells have emerged as one of the most promising candidates for fuel-efficient and emission-free vehicle power generation. PEMFC stacks require liquid cooling which can be operated in an open-cathode mode with air supplied by one or several fans, thus reducing the overall complexity of the PEMFC system. In this study, an open cathode PEMFC is used as the dependable power source and experiments are carried out to investigate the temperature characteristic of open cathode PEMFC. Combined with the using of oxidant and cell stack cooling, the optimal air fan supply voltage is 9.0V, and the maximal power can be obtained is 355W.

Dong Tang, Hui Min Lv, Chang Yuan Li

Advanced Materials Research • 2012

A new tubular cathode support for Direct Ethanol Fuel Cell (DEFC) was prepared by the gelcasting process using mesocarbon microbead(MCMB) and graphite as the main raw materials. Through the tubular cathode electrical property test, the advantages and disadvantages of cathode tube performance are studied at different graphite proportion. The results showed that when the graphite is more than 30 percent, the charge transmission ability has become extremely close. When the graphite ratio is 40 and 50 percent, the electrical performance is the best. With the graphite doping ratio of 40 percent, the electrode electrochemical reaction will have been reinforced when the temperature is high. When the air flow is 100 ml/min, the electricity capacity is better.

Srinivasa Reddy Badduri, G. Naga Srinivasulu, S. Srinivasa Rao

Materials Science Forum • 2019

A 3-D computational model was developed to examine the proton exchange membrane fuel cell (PEMFC) performance using Bio inspired (Bio channel) flow channel design bipolar plate. The model was developed using ANSYS FLUENT-15.0 software and simulations were carried out at 100 % humidity conditions. The parameters such as pressure distribution, hydrogen and oxygen concentrations and proton conductivity were briefly presented. The simulation results of bio channel are presented in the form of polarization curves. The results of a Bio channel compare with the conventional flow channel and observed that the bio channel gives a less pressure drop, uniform distribution of reactants and high cell voltage at a particular current density. From the observation from the polarization data, the bio channel performance was 20% higher than triple serpentine flow channel.

Karishma Maheshwari, Monika Sogani, Kumar Sonu et al.

ChemistrySelect • 2025

Abstract The current study employs the microbial desalination cell (MDC) and uses cost‐effective bio‐based polymeric membranes. The membrane was developed using the flowering plant Delonix regia flower pod powder (DRF), which was then mixed with polyurethane (PU) (Control MDC). The addition of filler material, glass powder derived from waste (DRFG), to the DRF: PU (50:50 v/v) mixture in a ratio of 1:1 (Test MDC) was done due to the presence of silicates in the elemental composition of glass powder, which will lead to improved hydration, power densities, and ion exchange capabilities. The study revealed that the DRF and DRFG membranes had an ion exchange capacity of 0.078 and 0.098 mmol H + /g, respectively. The analysis revealed that adding recycled glass powder increased the ion exchange capability by 1.25 times as compared to the control MDC. The membranes developed for the MDC system were used to treat the RO‐reject water collected from a household RO system in Varanasi, India. The results showed that the power densities of control and test MDC systems were 55 and 230 mW/m 2 , respectively. Additionally, after 30 days of operation, the ion exchange capacity recorded was 0.040 and 0.095 mmol H + /g for control and test MDC systems, respectively.

Deborah J Myers

ECS Meeting Abstracts • 2018

Over the past decade, the intrinsic oxygen reduction reaction (ORR) activity of platinum-based nanoparticle catalysts for polymer electrolyte fuel cells (PEFCs) has been improved by over an order of magnitude, with numerous catalysts now exceeding the catalytic activity target (>0.44 A/mg-Pt) established for the automotive propulsion power application. 1-3 However, the majority of catalysts meeting the activity targets are unable to achieve the current densities at low catalyst loadings (cathode loading: 0.1 mg-Pt/cm²) necessary to meet the automotive performance and cost targets simultaneously. 2 Many of the high activity catalysts also rapidly lose activity during voltage cycling in the PEFC environment. 2,4 Research focus in recent years has broadened beyond catalyst activity improvement to the understanding the sources and mechanisms of activity and performance loss and using that knowledge to mitigate the losses. For example, the major source of electrochemically-active surface area (ECA) loss for platinum nanoparticles is dissolution of particles of <~4 nm, leading to the development of catalysts with larger as-prepared mean diameters . 5,6 It has also been determined that base metal is rapidly lost from platinum-base alloy nanoparticles during electrode preparation and during voltage cycling in the fuel cell environment, leading to development of catalysts with lower initial base metal content and “pre-leaching” of base metal. 4 In state-of-the-art catalysts, the platinum or platinum alloy nanoparticles are supported on high-surface-area carbon powders, such as Vulcan XC72R, Ketjen black, or graphitized carbon blacks. These inexpensive supports fulfill the necessary functions of electron conduction and dispersing and anchoring the catalyst particles. However, they are prone to oxidation and have weak interaction with the Pt nanoparticles. These shortcomings allow the nanoparticles to migrate and coalesce during fuel cell operation and to become disconnected from the support due to oxidation, leading to ECA loss, with support oxidation also causing loss of catalyst layer porosity. 7 There have been extensive alternative support development efforts aimed at addressing these issues while maintaining the electrical conductivity of carbon (~2 S/cm). 8 A wide array of alternative supports have been developed, including doped oxides, carbides, 9,10 and nitrides, to name a few, but most lack the requisite high surface area and/or high electrical conductivity. 8 While a improved materials are the ultimate solution to the carbon support instability issues, automotive fuel cell system developers have designed system-level mitigation strategies to allow the existing carbon supports to achieve the lifetime targets. A more recently-studied support issue is the impact of support structure on catalyst utilization. 11 While the higher surface area carbon supports are desirable in terms of their ability to disperse the catalyst nanoparticles, they contain internal porosity. A significant portion of the catalyst nanoparticles can be buried in the pores. 12 Limited proton conductivity in the pores leads to under-utilization of the buried catalyst particles at high current densities and, especially, under low humidity conditions. 11 To overcome this limitation, recent efforts focus on catalyst deposition methods or carbon supports that can limit catalyst deposition to the external surface of the support. 11,13 This presentation will give an overview of the current understanding of catalyst and catalyst support performance and performance stability and the interactions between catalyst, support, and ionomer that define these properties. The impact of catalyst and support degradation on the ionomer properties will also be discussed. Acknowledgements This work was supported by the U.S. Department of Energy (DOE), Energy Efficiency and Renewable Energy, Fuel Cell Technologies Office under the auspices of the Fuel Cell Performance and Durability (FC-PAD) Consortium. Argonne National Laboratory is managed for the U.S. DOE by the University of Chicago Argonne, LLC, under contract DE-AC-02-06CH11357. References U.S. DOE FCTO Multi-Year Research, Development, and Demonstration Plan, 2016. A. Kongkanand et al., J. Phys. Chem. Lett. , 7 (2016) 1127−1137. M. Debe , Nature , 486 (2012) 43–51. R. Mukundan, et al., 232 nd Electrochemical Society Meeting, National Harbor, MD, Oct., 2017, Abstract 1681. J.A. Gilbert, et al., Electrochimica Acta , 173 (2015) 223-234. K. Yu, et al., Chemistry of Materials , 2014. L. Castanheira, et al., ACS Catal. 5 (2015) 2184–2194. Y. Shao, et al., J. Mater. Chem. 19 (2009) 46–59. M. Nie, et al., J. Power Sources , 162 (2006) 173-176. H. Chhina, et al, J. Power Sources , 179 (2008) 50-59. K. Shinozaki, et al., J. Electrochem. Soc. , 158 (2011) B467-B475. K.L. More, “FC136 – FC-PAD: Components and Characterization”, 2017 DOE-FCTO Annual Merit Review and Peer Evaluation, June 6, 2017. https://www.hydrogen.energy.gov/pdfs/review17/fc136_more_2017_o.pdf A. Kongkanand, “FC144 – Highly-Accessible Catalysts for Durable High-Power Performance”, 2017 DOE-FCTO Annual Merit Review and Peer Evaluation, June 7, 2017. https://www.hydrogen.energy.gov/pdfs/review17/fc144_kongkanand_2017_o.pdf

M. L. Jiménez González, Carlos Hernández Benítez, Zabdiel Abisai Juarez et al.

Catalysts • 2020

In this paper, the effect of cathode configuration on the performance of a membrane-less microbial fuel cell (MFC) was evaluated using three different arrangements: an activated carbon bed exposed to air (MFCE), a wetland immersed in an activated carbon bed (MFCW) and a cathode connected to an aeration tower featuring a water recirculation device (MFCT). To evaluate the MFC performance, the efficiency of the organic matter removal, the generated voltage, the power density and the internal resistance of the systems were properly assessed. The experimental results showed that while the COD removal efficiency was in all cases over 60% (after 40 days), the MFCT arrangement showed the best performance since the average removal value was 82%, compared to close to 70% for MFCE and MFCW. Statistical analysis of the COD removal efficiency confirmed that the performance of MCFT is substantially better than that of MFCE and MFCW. In regard to the other parameters surveyed, no significant influence of the different cathode arrangements explored could be found.

Sheng-Hu Zhen, Yang-Yang Yu, Rong-Rong Xie et al.

Fermentation • 2023

Chitin is one of the most abundant polymers in nature, with chitinous biomass often discarded as food waste and marine debris. To explore an effective way to degrade chitin, in this work, anaerobic sludge was inoculated at the anode of a two-chamber microbial fuel cell (MFC), and chitin was degraded via anaerobic respiration and fermentation. The results showed that the anaerobic sludge could degrade chitin under both the anaerobic respiration and fermentation modes, with similar degradation rates (7.10 ± 0.96 and 6.96 ± 0.23 C-mg/L·d−1). The open-circuit voltage and output current density could roughly reflect the degradation of chitin in the MFC. The maximum current density generated through the anaerobic sludge degradation of chitin via anaerobic respiration was 160 mA/m2, and the maximum power density was 26.29 mW/m2. The microbial sequencing results revealed substantially different microbial community profiles, with electroactive bacteria (EAB) flora and fermentative bacteria (Longilinea) as the main microbial groups that degraded chitin via anaerobic respiration and fermentation, respectively. Therefore, anaerobic sludge may be a good choice for the treatment of refractory biomass due to its abundant electroactive and fermentative flora.

Ahmed H.Shallal, Ibtehal Kareem Shakir

Iraqi Journal of Chemical and Petroleum Engineering • 2022

Zinc-air fuel cells (ZAFCs) are a promising energy source that could compete with lithium-ion batteries and perhaps proton-exchange membrane fuel cells (PEMFCs) for next-generation electrified transportation and energy storage applications. In the present work, a flow-type ZAFC with mechanical rechargeable was adopted, combined with an auxiliary cell (electrolyzer) for zinc renewal and electrolyte recharge to the main cell. In this work a practical study was performed to calculate the cell capacity (Ah), as well as study the electrolysis cell efficiency by current efficiency, and study the effective parameters that have an influence on cell performance such as space velocity and current density. The best parameters were selected to obtain the best performance for cell operation. The obtained cell capacity was 2.4Ah. The best performance of the electrolyzer was obtained with 0.6min-1 space velocity. At the same time, the best performance of the electrolyzer was when the value of the current density was 200A/m2

Yoshiyuki Matsuda, Takahiro Shimizu, Daichi Imamura

ECS Meeting Abstracts • 2024

Introduction The allowable concentration of formic acid is defined as 0.2 ppm in Grade D of ISO 14687: 2019, which is the hydrogen quality specification for fuel cell vehicles. The effect of formic acid in hydrogen on polymer electrolyte fuel cell (PEFC) performance has been reported by some researchers [1-4], but the reaction mechanism of formic acid in the PEFC is not well understood. In this study, the reaction behavior of formic acid in the PEFC and its impact on voltage decrease were investigated. Experimental The effect of formic acid in hydrogen was evaluated using a single cell. A “JARI Cell 2” with a 25 cm 2 electrode area and double serpentine flow channels was used in the experiment. The anode and cathode catalysts were Pt/C (TEC10E50E, Tanaka Kikinzoku Kogyo). The platinum loadings on the anode and cathode were 0.05 mg cm -2 and 0.30 mg cm -2 , respectively. The electrolyte membrane was a fluorine-based material with a thickness of 12 μm. The 22BB (SGL Carbon) gas diffusion layers were used on both the anode and cathode. The single-cell tests were performed at a cell temperature of 60°C and without external humidification. This is because formic acid easily dissolves in water and is likely to be exhausted from the cell with water at high humidification, so no humidification is considered the most severe condition. Before formic acid addition, the preconditioning was conducted at 1.0 A cm -2 of current density using high-purity hydrogen as a fuel for more than 10 hours. Then, formic acid (15-300 ppm) was started to supply the anode. After a period of time, the supply of formic acid to the anode was stopped and the voltage recovery was evaluated. Results and discussion Figure 1 shows the voltage drop over time due to formic acid in hydrogen at a current density of 1.0 A cm -2 and cell temperature of 60˚C. The voltage dropped quickly after the start of the formic acid supply, but the amount was small even at high formic acid concentrations. The voltage drop due to formic acid was 14 mV after 25 hours at 60 ppm and 20 mV after 5 hours at 300 ppm. The voltage was recovered after stopping the formic acid addition. To understand the reaction behavior of formic acid during the fuel cell operation, the anode and cathode exhaust gas were analyzed by gas chromatograph-mass spectrometer. The result showed that no formic acid was detected from the anode or cathode while the fuel cell was operated at a current density of 1.0 A cm -2 with 15 ppm formic acid addition to the anode. Meanwhile, the amount of CO 2 equivalent to that supplied to the anode as formic acid was detected from the cathode exhaust gas. The results suggest that formic acid supplied to the anode permeated through the electrolyte membrane as shown in Fig. 2 and was oxidized at the cathode. Acknowledgment This work is based on results obtained from a project, JPNP18011, commissioned by the New Energy and Industrial Technology Development Organization (NEDO). References [1] Shogo Watanabe, Masahito Tatsumi, Motoaki Akai, .2004 Fuel Cell Seminar Abstracts, 248-251 (2004). [2] Jaana Viitakangas, Jari Ihonen, Pauli Koski, Matti Reinikainen, Thor Anders Aarhaug, J. Electrochem. Soc., 165 , F718 (2018). [3] Xiaoyu Zhang, Hugo M. Galindo, Hector F. Garces, Philip Baker, Xiaofeng Wang, Ugur Pasaogullari, Steven L. Suib, Trent Molter, J. Electrochem. Soc., 157 , B409-B414 (2010) [4] Takahiro Shimizu and Yoshiyuki Matsuda., JARI Research Journal, 20190201 (2019). Figure 1

Matilda Kpeli, Michael K. E. Donkor, Reuben Tamakloe

MOMENTO • 2023

Microbial fuel cell (MFC) technologies are making headway in developing and expanding renewable energy through the conversion of organic matter to electricity. Various substrates can be used in the MFCs technology to enable energy generation, either pure substances or complex mixtures of organic materials. This study aims to consider the feasibility of raw honey as a fuel for mediator-less double-chamber MFC. The cell voltage was monitored in mediator-less double-chamber H2O2 cathode microbial fuel cell. The Mfensi clay partition and the raw honey were analyzed using FTIR-ATR. The results show the highest open-circuit voltage of 1414 mV with a maximum current density of 0.6540 A/m2 and a maximum power density of 247.0 W/m2. These results demonstrate that raw honey can be used for power generation in MFCs and for practical applications.

Evelyn, Edy Saputra, Amun Amri et al.

MATEC Web of Conferences • 2018

Microbial fuel cell (MFC) is an emerging energy production technology which converts the chemical energy stored in biologically degradable compounds to electricity at high efficiency. MFC with added mediator can enhance the electron transfer from the microbes to the anode, and used to treat industrial waste gases. In this work, the rate of microbial-reduced mediator reaction at the surface of glassy carbon (GC) electrode in an ethanol-fed MFC was investigated using cyclic voltammetry (CV), and compared with linear sweep voltammetry (LSV). The CV method provided a better estimation of the kinetic parameters than the LSV method due to low concentrations of the mediators used (0.2-1.0 mM), affecting the Tafel behaviours. All of the voltammograms indicated a quasi-reversible process for the anode reaction. The highest exchange current density (i o ) of 0.14±0.01 mA/cm 2 and the highest power output of 0.008 mW/cm 2 were obtained using 0.2 mM N′,N′,N′,N′-TMPD as the mediator. The MFC power density of 0.03 mW/cm 2 was achieved for 1 mM N-TMPD. Further increase in the power density (0.16 mW/cm 2 ) was possible with carbon cloth electrode. The results of this study confirmed the advantage of a mediator for gaseous pollutant treatment and electricity production in a MFC.

Yuichiro Tabuchi, Norio Kubo

ASME 2008 6th International Conference on Fuel Cell Science, Engineering and Technology • 2007

Proton exchange membrane fuel cells (PEMFCs) are regarded as a promising alternative clean power source for automotive applications. Key to the acceptance of PEMFCs for automobiles are cost reduction and power density for compactness. In order to meet these requirements, further improvement of cell performance is required. In particular, under higher current density operation, water and heat transport in PEMFC have strong effects on cell performance. In this study, the impact of Rib/Channel dimensions, heat and water transport on cell performance under high current density is investigated using the multiphase mixture model (M2 model), and the limiting current density is evaluated using a uniform test cell with 10cm2 active area and 24 straight channels. Limiting current densities were measured under different oxygen concentrations at 70°C and 70% relative humidity at both sides. In order to neglect the effect of liquid water in channels and the distribution of oxygen and hydrogen concentrations along the flow channel, large flow rates were introduced at both sides. Experimental results show a nonlinear relation between oxygen concentration in the channel and limiting current density. Numerically it is found that this nonlinear trend is caused by liquid water in the Rib region. In addition, it is also found that not only liquid water, but also heat transport and water transport through the membrane significantly affect the limiting current density. Finally, it is concluded that the combination analysis using limiting current experiments of uniform cell system and M2 model is very useful for fundamental understanding and for fuel cell design optimization.

Lei Xu, Yaqian Zhao, Liam Doherty et al.

Scientific Reports • 2016

Abstract MFC centered hybrid technologies have attracted attention during the last few years due to their compatibility and dual advantages of energy recovery and wastewater treatment. In this study, a MFC was integrated into a dewatered alum sludge (DAS)- based vertical upflow constructed wetland (CW). Powder activate carbon (PAC) was used in the anode area in varied percentage with DAS to explore its influences on the performance of the CW-MFC system. The trial has demonstrated that the inclusion of PAC improved the removal efficiencies of COD, TN and RP. More significantly, increasing the proportion of PAC from 2% to 10% can significantly enhance the maximum power densities from 36.58 mW/m 2 to 87.79 mW/m 2 . The induced favorable environment for bio-cathode formation might be the main reason for this improvement since the content of total extracellular polymeric substances (TEPS) of the substrate in the cathode area almost doubled (from 44.59 μg/g wet sludge to 87.70 μg/g wet sludge) as the percentage of PAC increased to 10%. This work provides another potential usage of PAC in CW-MFCs with a higher wastewater treatment efficiency and energy recovery.

Dengping Hu, Guangyao Zhang, Juan Wang et al.

Australian Journal of Chemistry • 2014

The poor kinetics of oxygen reduction reaction (ORR) in neutral media and ambient temperature limit the performance of microbial fuel cells (MFCs). So higher-performing, low-cost oxygen reduction catalysts play a key role in power output. Through direct nanoparticle nucleation and growth on carbon black, a nanocomposite of manganese cobaltite and carbon black (in situ-MnCo2O4/C) was synthesized via a facile hydrothermal method. Subsequently, the in situ-MnCo2O4/C samples were characterized. The results show that the MnCo2O4 nanoparticles with a crystalline spinel structure are well dispersed on carbon black. Electrochemical measurements reveal that in situ-MnCo2O4/C demonstrates excellent ORR catalytic activity, which may account for the synergetic coupling effect between MnCo2O4 and carbon black. The ORR on as-prepared in situ-MnCo2O4/C hybrid mainly favours a direct 4-electron reaction pathway in alkaline solution. Moreover, in situ-MnCo2O4/C was used as an alternative catalyst for ORR in dual-chamber MFC. The obtained maximum power density is 545 mW m–2, which is far higher than that of the plain cathode (Pmax = 214 mW m–2) and slightly lower than that of commercial Pt/C catalyst (Pmax = 689 mW m–2). This study implies that in situ-MnCo2O4/C nanocomposite is an efficient and cost-effective cathode catalyst for practical MFC application.

Yong-juan Zhang, Cai-yu Sun, Xiao-ye Liu et al.

Water Science and Technology • 2013

Molasses wastewater contains large amounts of glucose, and it can provide enough energy for microbial decomposition. The microbial fuel cell (MFC) in this study was demonstrated to be able to treat real wastewater with the benefit of harvesting electricity energy. Efficient operation of this MFC requires a molasses wastewater and preferably an inexpensive anode electrolyte. The results from a batch of experiments showed that molasses wastewater could not only serve as the electron acceptor in anode, but also generate electricity stably. A maximum voltage output of 514.5 mV and a maximum power density of 65.82 mW/m2 were recorded at external resistance of 1,000 Ω. The MFC not only effectively dealt with the molasses wastewater, the chemical oxygen demand removal rate is 81.22%, but also had a significant effect in the processing of analog silver wastewater. At the end of the experiment, after disassembling the device, silver precipitation was found stacked on the cathode carbon paper electrode, and some black sediment was found at the side of the proton membrane anode.

Nabea Muneer Mahdi, Ahmed Hassoon Ali

Journal of Physics: Conference Series • 2021

Abstract In this work single chamber microbial fuel cell (SCMFC) incorporating agar salt bridge pipe were used to investigate the interaction mechanisms between bacterial growth, Congo red decolorization, and bioelectricity generation. After 20 days of SCMFC operation in a batch test using a mixture of Congo red (CR) and sucrose as fuel, graphite plates electrodes, temperature 32ºC and under anaerobic working condition results showed that 98% decoloraization at dye concentration 300 mg\l demonstrated at UV-Visible Spectrophotometer ( wavelength 500 nm) and maximum voltage output of approximately 263.9 mv. Microbial community analysis showed the high species of bacteria Shigella dysenteria and Salmonella sp. (23×109 and 19×109 Count CFU/mL respectively). The bacterial growth activates start to decrease due to substrate reduction for metabolic process and pH automatically dropping from 8.2 to 6.9 as a result of the reaction. This study offered a feasible option for the dye wastewater treatment and electricity generation by using single chamber microbial fuel cells.

Emmanuel Egbadon, Campbell O. Akujobi, Chris O. Nweke et al.

International Letters of Natural Sciences • 2016

This study aimed at the simultaneous treatment of wastewater obtained from swine and generation of bioenergy in form of electricity from the energy stored in the organic component of the wastewater. The Open circuit voltage, current, power density and microbiological and physicochemical parameters were monitored. An initial Open circuit voltage of 516mV, Current of 0.29mA, and Power density of 32.74mW/m 2 were recorded, which increased to give maximum Open Circuit Voltages of 836mV, Current of 0.49mA, and Power density of 88.45mW/m 2 . The results revealed that The Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), Organic carbon, Total Soluble solids (TSS), Ammonia, Ammonium and Ammonium-Nitrogen all showed percentage decrease of 85.92%, 51.74%, 78.16%, 98.87%, 55.87%, 55.79% and 55.90% respectively while parameters such as Total Dissolved Solids (TDS), Nitrate, Nitrate-Nitrogen, Phosphates, Phosphorus and Orthophosphates however increased after treatment to give a percentage increase of -273.60%, -131.65%, -134.85%, -168.77%, -159.26%, and -157.03% respectively. Bacteria isolates identified at the biofilms on the anode were Corynebacterium specie , Bacillus specie , Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Streptococcus faecalis . The results from this study further exacerbate the Bioelectricity production as well as wastewater treatment potentials of the Microbial Fuel Cell technology.

Iwona Gajda, John Greenman, Carlo Santoro et al.

ECS Meeting Abstracts • 2018

Bioelectrochemical systems are employing microbes as biocatalysts to convert waste into valuable resources. For example, a Microbial Fuel Cell (MFC) utilises chemical energy locked in human urine into direct electrical current and can be scaled-up to power practical applications [1]. It is therefore paramount to improve power output and study catalytic reactions in which wastes are converted to useful products. In this work, an iron based electrocatalyst incorporated into an air-breathing cathode was tested in order to verify the functionality of the MFC as a simple, trigenerative system for (i) improved electricity levels (ii) to efficiently treat waste (neat human urine) in the anode and (iii) to obtain electrochemically treated (cleaned) catholyte as a function of system performance. The novelty of this process is in the simplicity of the operation, chemical-free and self-sustaining recovery. Materials and Methods Small scale (50 mm height) terracotta cylinders were constructed as MFCs with an internal cathode chamber and an external anode [2]. Cathodes were based on activated carbon (control) and iron catalyst blended into activated carbon (catalyst). Anodes were made from carbon veil wrapped around the ceramic cylinder. Each reactor was placed in the plastic beaker and seeded with a concentrated mixed inoculum derived from activated sludge and fresh human urine. The following feeding cycles, neat human urine was used as substrate for the MFCs. Results and Discussion The power output data are consistent with the polarisation experiments and indicate that the catalyst is performing 37 % better than the control. The catalyst based MFCs were also most efficient in utilising organic content (COD removal) in the anode which can be linked to their electrical performance. Due to MFC operation, a continuous formation of clear liquid was observed on the cathode electrode which was initially empty. It was recovered as a catholyte liquid from the inner chamber of the MFC (Fig 1) as an electrochemically cleaned (bleached) catholyte. Due to the electric field generated by the microbial anode, the substrate (urine) is separated into two solutions: the anolyte and the catholyte showing pH and ion splitting. Ion concentration, pH and rate of catholyte production relationships showed a linear dependence with power generation which underlined the ability of ceramic MFC system to generate electric power and simultaneously clean human urine. Conclusions The study confirmed that current generation was a key factor to drive the water extraction, pH and ion splitting functioning similar to electrodialysis system bleaching urine. Acknowledgements This work has been supported by the Bill & Melinda Gates Foundation, grant no. OPP1094890 and OPP 1139954. References Ieropoulos, I. et al ., (2016). Pee power urinal – microbial fuel cell technology field trials in the context of sanitation. Environ. Sci.: Water Res. Technol., 2, 336-343. Gajda, I., et al ., (2015). Simultaneous electricity generation and microbially-assisted electrosynthesis in ceramic MFCs. Bioelectrochemistry 104, 58–64. Figure 1

Irnie Azlin Zakaria

Journal of Mechanical Engineering • 2023

Efficient thermal management is essential for the optimal performance and durability of the Proton Exchange Membrane Fuel Cell (PEMFC). However, the conventional passive cooling methods require a larger heat exchanger for better heat dissipation. Alternatively, nanofluids as a coolant have gained attention recently due to their enhanced heat transfer properties. This investigation aims to evaluate the thermal performance of hybrid nanofluids in a distributor type of PEMFC cooling plate. In this investigation, 0.5% volume concentration of mono Al2O3, mono SiO2 nanofluids, and hybrid Al2O3:SiO2 nanofluids with a mixture ratio of 10:90, 30:70, 50:50, and 70:30 in 60:40 W:EG were investigated. The cooling plate was modelled and a fixed heat flux of 6500 w/m2 was applied to replicate the actual working parameter of PEMFC. The study shows that the heat transfer coefficient was improved by 61% in 10:90 hybrid nanofluids of Al2O3:SiO2 in W:EG in comparison to the base fluid. Meanwhile, the accompanied pressure drops in 10:90 hybrid nanofluids of Al2O3:SiO2 in W:EG show a reduction up to 4.38 times lower as compared to single Al2O3 nanofluids at Re 1800. This is advantageous since it will reduce the parasitic loss related to the PEM fuel cell.

Do Yeon Hong, Yeon Woo Cha, Yoomin Ahn

Advanced Materials Technologies • 2024

Abstract In this study, textile‐based microbial photoelectrochemical solar cells are developed for flexible electronic device applications. Configuration of the self‐pumping microfluidic channel without a proton exchange membrane is adopted to miniaturize the biophotovoltaic device. The microchannel region of the miniature device is patterned by silk screen printing using a body‐friendly Ecoflex to maintain the flexibility of the fabric substrate. Gold nanoparticle biosynthesized Synechocystis sp. PCC 6803 biocatalyst, supercapacitive ternary nanocomposite anode, and solid‐state Ag 2 O oxidant are used to enhance the biosolar cell performance. A maximum current density of 135.1 µA cm −2 and peak power density of 14.1 µW cm −2 , which are higher than previous textile‐based microbial fuel cells, are achieved in the presence of light. The monolayer fabric‐based biosolar cell has a stable performance up to 100 and 20 cycles of stretching and twisting, respectively. The presented new platform of flexible microbial solar cells offers the development possibility of self‐sustaining wearable electronics.

, Songyot Mongkulphit, Petch Pengchai et al.

International Journal of Environmental Science and Development • 2020

Scaling-up microbial fuel cells for continuous-flow wastewater treatment is the conventional challenge for numbers of researchers. Here in this study, we constructed large volume biofilter-microbial fuel cells (BMFCs) by applying graphite electrodes to the low-cost biofilters. Very high flow rates of 625-2,667 mL/hr (15-35 L/day) were applied to the BMFCs to explore their influence on wastewater treatment and electricity generation. An effect of hydraulic retention time (HRT) was expunged from the experiment by using various chamber volumes under the same HRT of 5 hrs. The result revealed that 32-73 % of COD removal, 5-14% of TN removal, 13-18% of TP removal, and 16.2-53 mW/m2 of power output could be achieved by the BMFCs. Higher flow rates led to higher pollutant removal rates and higher power densities under the linear regression equations with determination coefficients (R2) of 0.81-0.99. As the power density was the linear function of the pollutant removal rates (R2 = 0.93-0.97), the increasing shear rate which accorded with the increasing flow rate was considered as the key factor to enrich biomass and provoke electrogenic activity in an anode chamber. Therefore, the highest pollutant removal rates and highest power density were observed at the highest flow rate.

Venkatesh Chaturvedi, Pradeep Verma

Journal of Waste Management • 2014

Keratinolytic potential of Pseudomonas aeruginosa strain SDS3 has been evaluated for the metabolism of chicken feathers. Results indicated that strain SDS3 showed complete metabolism of 0.1 and 0.5% (w/v) chicken feathers in minimal medium. Feathers were metabolized up to 80% at 1% (w/v) concentration. Maximum soluble protein ( 480.8 ± 17.1 μ g/mL) and keratinase ( 15.4 ± 0.25 U/mL) were observed in the presence of 1% chicken feathers after five days of incubation. The effect of carbon and nitrogen sources showed that feather degradation was stimulated by complex carbon/nitrogen sources such as starch, malt extract, tryptone, and beef extract and was inhibited by simple carbon and nitrogen sources. Electricity production by employing chicken feathers as a substrate in microbial fuel cell (MFC) was evaluated. It was observed that maximum voltage corresponding to 141 mV was observed after 14 days of incubation. Maximum power density of 1206.78 mW/m 2 and maximum current density of 8.6 mA/m 2 were observed. The results clearly indicate that chicken feathers can be successfully employed as a cheap substrate for electricity production in MFC. This is the first report showing employment of chicken feathers as substrate in MFC.

Berkay Eren, Mehmet Hakan Demir

Asia-Pacific Journal of Chemical Engineering • 2022

Abstract The output voltage of microbial fuel cells (MFCs) needs to be controlled effectively to improve the operating efficiency of MFC system against the load variations, disturbances, and uncertainties. The output voltage control is purposed to provide the MFC with an appropriate amount of fuel required to maintain the stability of output voltage. In the applications, the MFC output voltage can be requested to track the variable reference voltage or to track the constant output voltage under changing conditions such as load change. For this purpose, two adaptive fuzzy PID (FPID) controllers powered by optimization algorithms were designed in this study to keep the output voltage value of the MFC at the desired values. This study extends the previous works by using optimization algorithms, such as particle swarm optimization (PSO) and gray wolf optimization (GWO) algorithms, to adjust fuzzy logic parameters, which are used for tuning Proportional‐Integral‐Derivative (PID) controllers. The optimization‐based adaptive FPID controllers play an active role in efficient, fast, and robust tracking of the reference voltage value with its adaptive structure. The designed adaptive control algorithms were tested under different cases, which involve the variation of the reference voltage and load conditions. The results show that both of these controllers can effectively control the output voltage of a MFC by regulating the flow rate of the fuel. In addition, the performances of the designed controller strategies according to the results obtained vary according to the reference signal. While PSO‐based FPID gives more successful results for positive step changes, GWO‐based FPID gives more successful results for negative step changes. These two control strategies show more efficient, robust, successful, and faster performances compared to the traditional PID controller.