Muaz Mohd Zaini Makhtar, Husnul Azan Tajarudin, Mohd Dinie Muhaimin Samsudin et al.

AIP Advances • 2021

Dewatered sludge is redundantly found in a municipal wastewater treatment plant, and the amount is increasing every year. However, the dewatered sludge could be used to power the membrane-less microbial fuel cell (ML-MFC), which is operated electrochemically via incorporation of electricity producing micro-organisms. The dewatered sludge normally acts as an electron donating substrate. Results showed that the ML-MFC produced voltage at about 927.7 ± 11.24 mV whereby 178.7 mg/L of chemical oxygen demand (COD) was removed after 240 h of incubation period. Nonetheless, voltage and COD removal values obtained from the dewatered sludge in the ML-MFC might differ every time the study is repeated because the availability of maximum biomass of electrogenic bacteria (EB) will be different due to the heterogeneous properties and EB performance inside the ML-MFC. The parametric uncertainty analysis of COD removal was then assessed using Monte Carlo simulation (stochastic variable) to determine the distribution probability affected by the fluctuation and variation of kinetic model parameters. From the study of 100 000 samples tested (simulation), the results show that the substrate removal (S) value ranged from 172.58 to 185.02 mg/L. The impact of each kinetic parameter on the ML-MFC performance was evaluated via sensitivity analysis. It is found that the ML-MFC performance significantly relied on the growth of EB present.

Mohammad Amin Sadeghi, Jake Barralet, Tomislav Friscic et al.

ECS Meeting Abstracts • 2019

Polymer electrolyte fuel cells (PEFCs) have attracted special attention as a source of power for vehicles and stationary power generation systems, owing to features such as high energy density and fast refueling times. They are, however, still expensive and therefore their successful commercialization is contingent on continued reduction in their price. During the last decade according to U.S. Department of Energy, the cost power generated by fuel cell (FC) systems has been reduced from $124/kW in 2006 to $53/kW in 2015, with the ultimate goal set at $30/kW. Apart from reducing the manufacturing and material processing costs, maximizing their catalytic performance directly translates into cheaper FCs. This can be done in two ways: (1) coming up with new catalysts that are either cheaper or more durable (or both) than platinum, and (2) reducing the platinum loading without affecting performance. Here, we consider the latter by optimizing – via computer simulation – the internal structure of the PEFC catalyst layer (CL), which is host to platinum nanoparticles deposited on a carbon backbone for electron transport and a thin coating of an ionomer (e.g. Nafion) for ion transport. Optimizing the internal structure, by definition, requires that a pore-scale modeling strategy to be employed rather than volume-averaged continuum methods. This challenge has two parts: (1) digital reconstruction of the CL with high fidelity such that it is representative of an actual CL, and (2) multiphysics simulation of coupled nonlinear equations associated with different transport mechanisms in different locations, i.e. electron transport in the solid phase, ion transport in the ionomer phase, and gas (oxygen) transport in the void phase together coupled with interfacial phenomena such as gas partitioning and electrochemical reaction at void-ionomer and ionomer-platinum interfaces, respectively. The length scales at which different transport mechanisms occur vary from only a few nanometers through the ionomer film up to a few tenths of a micron in inter-agglomerate pores. Such disparate length scales make it difficult to perform – in reasonable time – direct numerical simulation (DNS) on a large-enough section of the entire CL such that it is statistically representative. We propose pore-scale strategy based on a hybrid of DNS and pore network modeling (PNM). PNM is a pore-scale modeling technique in which a porous domain is mapped onto an equivalent graph such that each node represents a single pore. Such simplification reduces the computational complexity of PNMs up to 4-5 orders of magnitude, compared to an equivalent DNS. In this work, the void and the carbon backbone are each modeled by PNM, and the ionomer thin film and platinum nanoparticles are modeled by DNS. Briefly, the justification behind this decision is that transport of oxygen and protons, for the most part, are restricted by the diffusivity and ionic conductivity in the ionomer phase rather than in the void and carbon, respectively. For the digital reconstruction of the CL, we use “process-based” reconstruction in which the actual manufacturing process of the CL is mimicked. The reconstructed geometry is in the form of a three-dimensional (3D) image and consists of 4 distinct phases: carbon support, platinum, Nafion (as the ionomer), and void. Using a network extraction algorithm, the equivalent networks corresponding to the void and carbon phases are extracted. The entire digital reconstruction was performed using the open-source software OpenPNM and PoreSpy . We propose a simple algorithm to couple the two extracted networks with the remainder of the original 3D image, which now only consists of Nafion and platinum. Note that the computational bottleneck of the entire simulation is the DNS, which is only applied to the Nafion and platinum phases. Since the carbon backbone and the void usually contribute up to 80% of the total volume of the CL, the proposed hybrid scheme significantly reduces the computational time compared with the case where the entire domain is modeled using DNS. While the proposed hybrid model allows for simulating much larger sections of the CL – therefore obtaining more representative results – the DNS step still imposes a serious limitation. Ideally, one could apply PNM to model the Nafion film, eliminating the DNS step altogether. However, since the thickness of the Nafion film is very small compared to the largest length scale of the system, network extraction algorithms require ultrahigh-resolution 3D images to generate a reasonably-accurate network that represents the thin Nafion film. Therefore, this study can be regarded as the first step toward developing a full network model of the CL. We hope that this study will become a cornerstone for many future studies.

Fatima Zahra Belhaj, Hassan El Fadil, Zakariae El Idrissi et al.

Electronics • 2020

Based on full and rigorous study, this paper addresses the issue of ensuring a feasible association in practice between a Proton Exchange Membrane Fuel Cell (PEMFC) and DC-DC power converters including a buck and boost converter. This association is mathematically modeled, analyzed, and controlled by an optimal PID controller. Using absolute stability tools with a rigorous analytical approach that takes into consideration windup effects, in addition to the nonlinear behavior of the Proton Exchange Membrane Fuel Cell, sufficient conditions are provided to ensure that the closed-loop system is L2-stable. These conditions allow the optimal PID controller parameters to be chosen and ensure the closed-loop system stability, by tracking reference outputs, and an optimal performance against perturbations. Formal analysis, numerical simulations, and experimental validation were carried out to verify that the PID controller designed with an anti-windup action is robust and meets all of the pre-defined objectives. Moreover, this study demonstrates that the association between the PEMFC and the DC-DC converters is achieved if only certain conditions are met.

Eric Alexander Chadwick, Pranay Shrestha, Harsharaj Birendrasingh Parmar et al.

ECS Meeting Abstracts • 2024

The bipolar plate of polymer electrolyte membrane (PEM) fuel cells is responsible for reactant delivery, liquid product water removal, and mechanical stability of PEM fuel cell stacks. Bipolar plates account for 70-90% of the weight and volume and 18-28% of the production costof stacks [1]. Improving the function of the flow fields embedded in the bipolar plates can significantly impact the energy density of PEM fuel cells by improving liquid water management and reactant distribution. Researchers have modified conventional flow fields by adding baffles or partially narrowed channels as semi-obstructive structures in the channels, exploiting Forchheimer’s intertial effect to locally increase gas velocity, thereby increasing oxygen diffusion and water removal in the GDL [2,3]. However, adding obstructions such as baffles or narrowed channels inherently increases the overall pressure drop across the flow fields, thus increasing the power required to supply reactant gases. In other attempts, biomimetic channel architectures have been shown to enhance preferential water flow; however, these designs have not been tailored to control water accumulation for improved reactant distribution [4,5]. Therefore, there is still a need to investigate flow field land-channel architectures that both enhanced inertial gas diffusion to the catalyst layer reaction sites and efficiently remove excess liquid water. In this work, PEM fuel cell flow fields were laser-cut to enhance the liquid water removal and reactant distribution in the under-land region of the GDL. Operando synchrotron X-ray radiography revealed reduced GDL water accumulation when using our novel flow fields. The reduced mass transport overpotential and corresponding power density increase were attributed to enhanced liquid water removal and reactant distribution due to the flow field design. Ultimately, this work can be used to further optimize the design of bipolar plates for more efficient stacks and accelerate the commercialization of PEM fuel cells. References: Y. Wang, D. F. Ruiz Diaz, K. S. Chen, Z. Wang, and X. C. Adroher, Materials Today , 32 , 178–203 (2020). H. Guo, H. Chen, F. Ye, and C. F. Ma, Int J Energy Res , 43 , 2737–2755 (2019). H. Chen, H. Guo, F. Ye, and C. F. Ma, Int J Hydrogen Energy , 46 , 2990–3007 (2021). N. Guo, M. C. Leu, and U. O. Koylu, Int J Hydrogen Energy , 39 , 21185–21195 (2014). S. Feng et al., Science , 373 , 1344–1348 (2021).

Yuxian Yang, Jialuo Lin, Xin Li et al.

Physical Chemistry Chemical Physics • 2022

The cathode electrocatalyst Nano-Co@NC is synthesized from ZIF-67, exhibiting a high Co mass loading and enabling MFCs with a comparable initial power density to and better durability than that using Pt/C.

Chuan Yu Yen, Shu Hang Liao, Yu Feng Lin et al.

Key Engineering Materials • 2007

The thin polymer composite bipolar plates (the thickness < 1.5 mm) for use in polymer electrolyte membrane fuel cells (PEMFCs) containing vinyl ester resin, graphite powder, organoclay have been fabricated by bulk molding compound (BMC) process. Organoclay prepared by ionic exchange of montmorillonite (MMT) with three different Mw of diamine intercalating agents was used to reinforce the mechanical properties of the composite bipolar plates. Results indicate that the basal spacing and content of MMT varied with Mw of POP-diamines are critical in determining the resultant mechanical properties for bipolar plates. The flexural strength and the unnotched impact strength of the plate were ca. 38 % (from 30.21 MPa to 45.66 MPa) and ca. 30 % (from 58.11 J/m to 80.21 J/m) higher than the pristine graphite plate, respectively, as the basal spacing of MMT (2 phr) was increased from 1.71 to 5.43 nm. The limiting oxygen index (L.O.I.) and the UL-94 test revealed that the bipolar plate possesses excellent flame retardant with L.O.I. higher than 50 and UL-94-V0. In addition, the electrical conductivity of the bipolar plates with different MMT contents and basal spacing of MMT is higher than 100 S/cm.

Gustavo A. Andreasen, Silvina G. Ramos, Hernán A. Peretti et al.

Journal of Electrochemical Energy Conversion and Storage • 2016

The performance of a hydrogen storage prototype loaded with AB5H6 hydride, whose equilibrium pressure makes it suitable for both feeding a H2/air proton exchange membrane (PEM) fuel cell and being charged directly from a low-pressure water electrolyzer, interacting thermally with the fuel cell exhaust air, is reported. The nominal 70 L hydrogen storage capacity of the prototype suffices for hydrogen delivery at 0.5 L min−1, which allows a power supply of 50 W for 140 min from the H2/air fuel cell in the absence of thermal interaction. The storage prototype was characterized by monitoring the internal pressure and the temperatures of the external wall and at the center inside the container at different hydrogen discharge conditions. The responses of the integrated system after either immersing the metal hydride container in air or exposing it to the fuel cell hot exhaust air stream under forced convection were compared. The system shows the best performance when the heat generated at the fuel cell is used to increase the metal hydride container temperature, allowing the operation of the fuel cell at 280 W for 16 min at a high hydrogen flow rate of 4 L min−1.

Ahmet Erensoy, Nurettin Çek

ChemistrySelect • 2018

Abstract In this study, biofuel properties of poplar wood materials rich in organic materials were investigated for microbial fuel cells. Therefore, in this study, investigates the chemical, biochemical properties with electrochemical performance of single chamber microbial fuel cell manufactured using poplar biomass materials, natural soil, graphite anode electrode and graphite cathode electrode. With the increase in the weight of the poplar tree in the microbial fuel cells, the power density increased. SEM, EDS, FTIR analyses showed that bacillus and coccus type bacteria in the natural structure of the soil act as the catalyst in the anode electrode. Poplar wood, electrodes and bacteria have served in harmony. According to experimental results, the maximum power reaches to 16.88 mW and microbial fuel cell successfully displays a maximum power density of 8555 mW/m 2 . All these results indicate that poplar wood may be appropriate biofuel sources for electrical energy generation as an effective environmentally microbial fuel cell technology.

Giuseppe De Lorenzo, Francesco Piraino, Francesco Longo et al.

Energies • 2022

This paper describes the implementation of a hydrogen-based system for an autonomous surface vehicle in an effort to reduce environmental impact and increase driving range. In a suitable computational environment, the dynamic electrical model of the entire hybrid powertrain, consisting of a proton exchange membrane fuel cell, a hydrogen metal hydride storage system, a lithium battery, two brushless DC motors, and two control subsystems, is implemented. The developed calculation tool is used to perform the dynamic analysis of the hybrid propulsion system during four different operating journeys, investigating the performance achieved to examine the obtained performance, determine the feasibility of the work runs and highlight the critical points. During the trips, the engine shows fluctuating performance trends while the energy consumption reaches 1087 Wh for the fuel cell (corresponding to 71 g of hydrogen) and 370 Wh for the battery, consuming almost all the energy stored on board.

Radwan A. Almasri, Nasser AM Barakat, Osama M Irfan

Journal of Chemical Technology & Biotechnology • 2024

Abstract Background Recently, the concept of the membrane‐less microbial fuel cell (MFC) has gained traction to avoid the high internal resistance that is created upon utilizing conventional membranes. Nevertheless, an overlooked problem arises from the ingress of oxygen from the cathode side into the anolyte solution, fostering the formation of biofilms by aerobic microorganisms on the cathode surface. This biofilm layer poses a formidable impediment, leading to cell disconnection. Moreover, low surface area of conventional anodes is another important issue behind the low power density generation. In this research, a novel approach to circumvent biofilm formation and achieve stable and high‐power‐density output from MFCs by harnessing a commercial antibacterial spacer is introduced. Results Air‐cathode, sewage‐driven MFCs showed continuous power generation without the need for external microorganisms. Conversely, the absence of the innovative membrane resulted in a catastrophic power breakdown after 125 h of operation due to the formation of a dense biofilm layer on the cathode. Through the utilization of the proposed membrane strategy, stable power density output of 100 ± 8, 135 ± 11 and 142 ± 10 mW m −2 with carbon cloth, carbon paper and carbon felt anodes, respectively, was achieved. Moreover, a novel anode is introduced from graphitization of grape tree branches. The proposed anode could increase the generated power to 516 ± 17 mW m −2 from the sewage‐driven air‐cathode MFC, more than three times compared to the best conventional anode, carbon felt. Conclusion This study provides significant solutions for sustainability, low‐performance and high‐cost problems of microbial fuel cells. © 2024 Society of Chemical Industry (SCI).

Jaydev Chetan Zaveri, Shankar Raman Dhanushkodi, C. Ramesh Kumar et al.

Energies • 2023

Modern industries encourages the use of hydrogen as an energy carrier to decarbonize the electricity grid, Polymeric Electrolyte membrane fuel cell which uses hydrogen as a fuel to produce electricity, is an efficient and reliable ‘power to gas’ technology. However, a key issue obstructing the advancement of PEMFCs is the unpredictability of their performance and failure events caused by flooding and dehydration. The accurate prediction of these two events is required to avoid any catastrophic failure in the cell. A typical approach used to predict failure modes relies on modeling failure-induced performance losses and monitoring the voltage of a cell. Data-driven machine learning models must be developed to address these challenges. Herein, we present a machine learning model for the prediction of the failure modes of operating cells. The model predicted the relative humidity of a cell by considering the cell voltage and current density as the input parameters. Advanced regression techniques, such as support vector machine, decision tree regression, random forest regression and artificial neural network, were used to improve the predictions. Features related to the model were derived from cell polarization data. The model’s results were validated with real-time test data obtained from the cell. The statistical machine learning models accurately provided information on the flooding- and dehydration-induced failure events.

Kumar Krishnamurthy, Vippalapalli Lakshmi Devi

Recent Advances in Electrical & Electronic Engineering (Formerly Recent Patents on Electrical & Electronic Engineering) • 2024

Background: This study aims to evaluate the performance of a 1.26 kW Proton Exchange Membrane Fuel Cell (PEMFC) fed Electric Vehicle (EV) using an Enriched Switched Parameter Cuk (ESPC) converter and an Elman Back Propagation (EBP) maximum power point tracking algorithm (MPPT). The acceptance of fuel cell-fed EVs in modern society is critical to the development of a pollution-free environment. One of the significant contributors to excessive pollution is transportation on public roads using internal combustion engines powered by crude oil as their primary energy source. Objective: This study identifies suitable high voltage gain DC-DC converters with minimum duty cycle operation for fuel cell-fed electric vehicle systems and develops an intelligent MPPT controller for hybrid electric vehicle applications. Methods: In this study, MATLAB/Simulink environment is used to design a 1.26 kW PEMFC powered electric vehicle. To integrate PEMFC to BLDC motor, an Enriched Switched Parameter Cuk converter is built with a high static converter voltage gain. Results: The effectiveness and performance of the fuel cell-fed EV system are investigated using perturb and observe method and Elman Back Propagation MPPT approaches for various fuel cell input temperature conditions and intervals. Conclusion: This study discusses the use of low-voltage fuel cell sources with power electronic converters that are available for various high gains in the literature. The proposed ESPC is designed to reduce stress on power converter components and is intended for low-voltage FC-fed electric vehicle applications.

Min Wang, Grace Rome, Samantha Medina et al.

ECS Meeting Abstracts • 2020

Polymer electrolyte membrane fuel cells (PEMFC) have great potential for power generation in many applications, but to implement them on a larger scale, understanding of quality requirements, tolerances, and controls during manufacturing must improve. As part of this broad challenge, irregularities resulting from the membrane electrode assembly (MEA) production process must be studied to determine if they impact the performance of the cell. 1,2 One potential irregularity is a locally increased thickness of the coated or deposited electrode. In order to understand and provide insight into the impact of such irregularities, we intentionally created thick spots in the center of cathode electrodes, either by liquid casting or ultrasonic spraying of the additional catalyst ink. The thick spots fabricated by these two different approaches exhibited different sizes, morphologies, and Pt loading distributions, which were carefully characterized by optical microscopy, X-ray fluorescence spectroscopy (XRF), and scanning electron microscopy (SEM). Edge-protected MEAs were fabricated using both pristine electrodes and electrodes with thick spot irregularities. The effect of these irregularities on MEA structure were investigated by cross-sectional SEM. Electrochemical performance, including electrochemically active surface area (ECSA), H 2 /O 2 polarization curves, mass activity and H 2 /air polarization curves, was measured to study the impact of the electrode irregularities on catalyst utilization and PEMFC initial performance. NREL’s segmented cell was utilized to investigate the resulting spatial performance of a representative thick spot MEA. The results indicate that thick spot irregularities that are present in the center of the cathode electrode impact initial cell performance although the impact of the thick spots on ECSA and mass activity was minimal. The latter suggests that the number of active Pt sites and the kinetics were not significantly altered. However, the H 2 /air polarization curves indicated that liquid-cast thick spots and large sprayed thick spots decrease cell performance dramatically at current densities above 0.8 A/cm 2 . Based on cross-sectional SEM analysis, the likely causes of this performance drop may originate from (i) delamination between the GDL and CL, (ii) the presence of thin spots in the membrane due to deformation associated with the thick spot, (iii) additional compression of the GDL and/or (iv) thick catalyst layer sections inhibiting local mass transport. Spatial performance diagnostics confirmed that the performance loss of MEAs containing liquid-cast thick spots is more pronounced at high current density than at low current density. Moreover, the performance of the area surrounding the liquid-cast thick spot is impacted as well, likely due to the various morphological changes resulting from the irregularity. We expect that the morphological changes resulting from these irregularities could serve as seed points for premature cell failure in long-term PEMFC operation. Future work will focus on the impact of electrode thick spot irregularities on PEMFC performance-over-time and lifetime, for both reinforced and non-reinforced membranes. References: (1) Phillips, A.; Ulsh, M.; Porter, J.; Bender, G. Utilizing a Segmented Fuel Cell to Study the Effects of Electrode Coating Irregularities on PEM Fuel Cell Initial Performance. Fuel Cells 2017 , 17 (3), 288–298. https://doi.org/10.1002/fuce.201600214. (2) Phillips, A.; Ulsh, M.; Neyerlin, K. C.; Porter, J.; Bender, G. Impacts of Electrode Coating Irregularities on Polymer Electrolyte Membrane Fuel Cell Lifetime Using Quasi In-Situ Infrared Thermography and Accelerated Stress Testing. Int. J. Hydrogen Energy 2018 , 43 (12), 6390–6399. https://doi.org/https://doi.org/10.1016/j.ijhydene.2018.02.050. Figure 1

Kunpeng Li, Takatera Ryogo, Yohei Nagata et al.

ECS Meeting Abstracts • 2023

Protonic ceramic fuel cells (PCFCs) show relatively high performance at intermediate temperature range (400–600 °C) due to high proton conductivity in electrolyte. However, besides proton, other charges such as electron hole and oxygen vacancy can also be conductive in PCFCs. Especially, the hole conductivity will induce a hole current leakage so that current efficiency and power density will decrease. Besides the operating temperature, the conductivities of proton and hole are also strongly affected by the partial pressures of steam and oxygen in the PCFC [1,2]. Higher steam partial pressure leads higher proton conductivity, so that a higher power density can be expected. However, other influences such as concentration overpotential may be non-negligible. Furthermore, the proton and hole current density are affected by defect concentrations differences between two surfaces of the electrolyte membrane. Numerical simulation method is powerful tool for dealing with the complicated conditions in a PCFC mentioned above. In the present study, the influences of steam partial pressure on a BaZr 0.8 Yb 0.2 O 3− δ (BZYb20) electrolyte are investigated. Specifically, to reveal the currents induced by the electrostatic potential and gas concentrations, Nernst-Planck model is selected. To relatively obviously reveal the steam concentration influences on the PCFC performances, low (3%) and high (69%) humidification conditions of H 2 fuel gas are adopted. The results in Fig. 1(a) and 1(b) show the simulation and experimental current-voltage characteristics under 3% and 69% humidification conditions, respectively. The green solid and dotted lines are external and proton current densities considering concentration overpotential influence, respectively. The blue lines express external current density when no concentration overpotential in the numerical model. The red circles are the measured data. At low steam partial pressure, the simulation results well reproduced the experimental data without concentration overpotential consideration. However, an obvious deviation was found between simulation and experimental results when neglecting concentration overpotential in the simulation model. The performances such as open circuit voltage (OCV) and hole current leakage (difference between proton and external current density) are influenced by the steam partial pressure. References [1] K. Li et al ., Int. J. Hydrogen Energy, 45 (2020), 34139-149. [2] Y. Okuyama, et al ., J. Hydrogen Energy, 39 (2014), 20829-36. Figure 1

Dilan Akagunduz, Ozlem Aydin, Ebru Tuncay et al.

EUCHEMBIOJ Reviews • 2024

The global water pollution problem is becoming increasingly crucial. One of the major contributors to water pollution is the presence of heavy metals. Heavy metals pose significant threat to both humans and all ecosystems. Various factors influence the removal of heavy metals from wastewater, including pH, temperature, natural organic matter (NOM), and ionic strength, which vary based on the chemical properties of the pollutants. More effective and modern approaches receive attention and extensively researched to substitute traditional methods such as adsorption, membrane filtration, and chemical-based separation. Among these methods, Microbial fuel cells (MFCs) are particularly intriguing. This review article focuses on MFCs and their potential applications in various fields, including clean water production. MFCs represent an innovative technology that not only generates electricity, but also demonstrates significant potential for heavy metal removal from wastewater. Cathodic chamber of MFCs effectively reduces heavy metals, while organic substrates act as carbon and electron donors in the anodic chamber. Through various mechanisms, including direct and indirect metal reduction, biofilm formation (metal sequestering), electron shuttling, and synergistic interactions among microbial communities, microorganisms exhibit remarkable efficiency in removing metals. Studies showed that dual- and single-chamber MFCs could efficiently remove a range of heavy metals, including chromium, cobalt, copper, vanadium, mercury, gold, selenium, lead, magnesium, manganese, zinc, and sodium, while simultaneously generating electricity, achieving high removal efficiencies ranging from 25% to 99.95%. This range of efficiency varies depending on the specific contaminant being targeted, the concentration of the contaminant, as well as the operating conditions such as pH and temperature. Moreover, MFCs demonstrated a wide range of power outputs, typically ranging from 0.15 W/m² to 6.58 W/m², depending on the specific configuration and conditions. These findings underscore the potential of MFCs as a sustainable and efficient approach for both wastewater treatment and energy generation.

Nicholas Siefert, Gautam Ashok

ASME 2012 10th International Conference on Fuel Cell Science, Engineering and Technology • 2012

Generating electricity at wastewater treatment plants is a promising near-term application of fuel cell systems. The scale of most wastewater treatment plants is such that there is a good match with the scale of today’s fuel cell systems. This paper presents an exergy analysis and an economic comparison between two fuel cell systems that generate electricity at a wastewater treatment plant. The first process integrates an anaerobic digester (AD) with a solid oxide fuel cell (SOFC). The SOFC was modeled using publicly-available data from the tests on the Rolls-Royce pressurized SOFC. The second process has the wastewater sent directly to a microbial fuel cell (MFC). An MFC is an electrochemical cell in which bacteria convert acetate, sugars and/or other chemicals into protons, electrons and carbon dioxide at the anode electrode. The MFC was modeled as a PEM fuel cell as used for vehicle applications, but with a few changes: (a) anaerobic bacteria, such as geobacter, grow directly on the surface of the anode electrode, (b) there is no anode gas diffusion layer (GDL), (c) iron pyrophyrin, rather than platinum, is used as the catalyst material on the anode, in addition to the bacteria, and (d) the Nafion electrolyte is replaced with a bipolar membrane in order to minimize the transfer of non-proton cations, such as Na+, from the anode to the cathode. The rest of the equipment in the MFC is the same as those in commercial vehicle PEM fuel cells in order to use recent DOE cost estimates for PEM fuel cell systems. In both cases, we generated V-i curves of SOFC and MFC-PEM systems from data available on a) PEM & SOFC electrolyte conductivity and b) anode and cathode exchange current densities, including the effect of platinum levels on the cathode exchange current density of PEM fuel cells. A full exergy analysis was conducted for both systems modeled. The power per inlet exergy will be presented as a function of the current density and the pressure of the fuel cell. Using various Department of Eneregy (DOE) cost estimates for fuel cell systems, we perform parametric studies for both the MFC and AD-SOFC systems in order to maximize the internal rate of return on investment (IRR). In the MFC case, we varied the platinum loading on the cathode in order to maximize the IRR, and in the AD-SOFC case, we varied the current density of the SOFC in order to maximize the IRR. Finally, we compare the IRR of the two systems modeled above with the IRR of an anaerobic digester integrated with a piston engine capable of operating on biogas, such as the GE Jenbacher. Using an electricity sale price of $80/MWh, the IRR of the AD-SOFC, the microbial fuel cell and the AD-piston engine were 9%/yr, 10%/yr and 2%/yr, respectively. This economic analysis suggests that further experimental research should be conducted on both the microbial fuel cell and the pressurized SOFC because both systems were able to generate attractive values of IRR at an electricity sale price close to the average industrial price of electricity in the US.

Savita Rambabu Nemade, Purnima Swarup Khare

International Journal of Latest Technology in Engineering Management & Applied Science • 2025

Abstract: This study represents the important role of dye sensitizer selection for best photovoltaic response and the photo anode thickness of semiconducting layer for determining the efficiency of dye-sensitized solar cells (DSSCs). For obtaining these objectives we employ an ex-situ methodology to prepare the composite materials. So we prepare nanocomposite by adding 20 wt.% of ZnO nanoparticles into TiO2 nanoparticles (20TZ). We fabricate dye sensitized solar cell by using the doctor blade technique. Furthermore our key findings are to extends the duration of dye loading, highlighting its significant influence on DSSC performance. The research also encompasses variations in the thickness of the semiconducting layer, providing critical insights into DSSC efficiency. Significance of present research work represent , photoanode thickness of 300-micron 20TZ-based DSSC, sensitized with 3% of N749 dye for a 2-hour loading period, achieves an impressive power conversion efficiency of 15.1%. The stability of 20TZ-based DSSCs was evaluated under continuous light illumination, revealing a minimal decrease in power conversion efficiency of 1.61% over 240 hours. Significance of present study is that we achieve power conversion efficiency 15.1% for the assemble dye sensitized solar cell and its stability duration time.

Andres Munoz, Abhijit Mukherjee

ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology • 2013

Water management still remains a challenge for proton exchange membrane fuel cells. Byproduct water formed in the cathode side of the membrane is wicked to the air supply channel through the gas diffusion layer. Water emerges into the air supply channel as droplets, which are then removed by the air stream. When the rate of water production is higher than the rate of water removal, droplets start to accumulate and coalesce with each other forming slugs consequently clogging the channels and causing poor fuel cell performance. It has been shown in previous experiments that rendering the channels hydrophobic or super-hydrophobic cause water droplets to be removed faster, not allowing time to coalesce, and therefore making channels less prone to flooding. In this numerical study we analyze water droplet growth and detachment from a simulated hydrophobic air supply channel inside a proton exchange membrane (PEM) fuel cell. In these numerical simulations the Navier-Stokes equations are solved using the SIMPLER method coupled with the level set technique in order to track the liquid-vapor interface. The effect of the gravity field acting in the −y, −x, and +x directions was examined for an array of water flow rates and air flow rates. Detachment times and diameters were computed. The results showed no significant effect of the gravity field acting in the three different directions as expected since the Bond and Capillary numbers are relatively small. The maximum variations in detachment time and diameter were found to be 8.8 and 4.2 percent, respectively, between the horizontal channel and the vertical channel with gravity acting in the negative x direction, against the air flow. Droplet detachment was more significantly affected by the air and water flow rates.

, Woranunt Lao-atiman

• 2016

A zinc-air fuel cell (ZAFC) is attracting widespread interest for electricity generation. Furthermore, ZAFC combining with alkaline zinc electrolyzer is a potential candidate for an energy storage system. This work aims to develop dynamic mathematical models of ZAFC and alkaline zinc electrolyzer and to investigate the effects of operating parameters on the cell performance. The ZAFC was devised as a tubular cell with electrolyte flow inside. Potassium hydroxide (KOH) solution mixed with zinc powder was used as the electrolyte. Stainless steel mesh and nickel foam were used as current collectors of anode and cathode, respectively. Manganese dioxide mixed with graphite used as the catalyst was coated on nickel foam. The electrolyzer cell was devised as electroplating cell with stirred electrolyte. KOH solution mixed with zinc oxide (ZnO) was used as the electrolyte of the electrolyzer. Copper sheet and nickel foam were used as the current collectors of cathode and anode, respectively. The developed models were implemented in MATLAB and validated with experimental data. Good agreement between the predicted data and experimental data was obtained for both ZAFC and electrolyzer. The proposed models were then used to investigate the effects of four parameters: KOH concentration, flow, zincate ion concentration and conductive carbon. By increasing KOH concentration, the cell voltage increased. Nevertheless, at the KOH concentration above 7 M, the cell voltage dropped as the KOH concentration increased because of the adverse effects on ionic conductivity and anodic exchange current density. ZAFC performance improved by using high flow rate. For long-time operation, using higher flow rate could maintain zinc content and electrolyte concentration better than that of lower flow rate. Higher concentration of zincate ion resulted in lower Nernst potential and cell voltage. A Higher amount of ZnO provided lower electrode conductivity and active area of zinc electrode. Adding carbon did not improve cell performance significantly. For the electrolyzer, the highest ionic conductivity was also observed at 7 M. Therefore, this concentration provided lowest cell voltage at high current. KOH concentration lower or greater than 7 M provided higher cell voltage. Below the saturation limit of zincate ion, increasing zincate ion concentration decreased cell voltage. Increasing zincate ion concentration above the saturation limit provided no significant improvement. For current efficiency (C.E.) of zinc electrolyzer, higher current density provided higher C.E. in all conditions. Moreover, increasing concentration of both KOH and zincate ion increased C.E.

• 2014

<div class="section abstract"> <div class="htmlview paragraph">SAE J2601 establishes the protocol and process limits for hydrogen fueling of light duty vehicles. These process limits (including fuel temperature, the maximum fuel flow rate, and rate of pressure increase and end pressure) are affected by factors such as ambient temperature, fuel delivery temperature and initial pressure in the vehicle’s compressed hydrogen storage system. SAE J2601-2014 establishes standard fueling protocols based on a look-up table approach with performance targets. The current standard is table-based and provides concise performance targets for both communications and non-communications fueling as described in <span class="xref">Sections 7</span> through <span class="xref">10</span>.</div> <div class="htmlview paragraph">An important factor in the performance of hydrogen fueling is the station’s dispensing equipment cooling capability and the resultant fuel delivery temperature “T” rating. SAE J2601 has a reference fueling target of 3 minutes with 95-100% SOC (with communications) with a T40 rated dispenser as specified in <span class="xref">section 6.1</span>. However, with lower fuel delivery temperature dispenser ratings (T30 or T20) and/or at high ambient temperatures, fueling times may be longer.</div> <div class="htmlview paragraph">SAE J2601 includes standard fueling tables for communications and non-communications fueling, as well as a non-standard, development fueling protocol. For fueling with communications, this standard is to be used in conjunction with SAE J2799, Hydrogen Surface Vehicle to Station Communications Hardware and Software. <span class="xref">Table 1</span> below depicts the scope of SAE J2601-2014 and potential work items for future revisions. SAE J2601-2014 also includes, in <span class="xref">Appendix H</span>, a non-standard development fueling protocol called the MC Method.</div> <div class="htmlview paragraph">SAE J2601 includes protocols for two pressure classes (35 and 70 MPa), three fuel delivery temperatures (-40 °C, -30 °C, -20 °C) and compressed hydrogen storage system sizes from 49.7 to 248.6 L. Future versions of J2601 may incorporate warmer fuel delivery temperatures (-10 °C and ambient) and smaller compressed hydrogen storage system for motorcycles.</div> </div>

Ruitao Li, Yi Ding, Yue Zhang et al.

Electroanalysis • 2024

Abstract The successful application of bioelectrochemical systems in the future depends on the improving of electrode performance while decreasing material costs. This study explores the use of chitosan supported on different kinds of carbon materials to modify graphite electrode for the electricity generation performance of Geobacter sulfurreducens . The novel hierarchically carbon composites modified electrodes were obtained by a simple and environment‐friendly method. Among the proposed composites, the optimal composite CS/CB (5 h) possessed a better performance for the promotion of electrochemically active biofilm (EAB) growth and enhancing current generation compared with other composites. Based on morphological, chemical, and electrochemical evidences, we conclude that the CB was coated on the surface of CS to form the CS/CB decorated graphite electrode, and CS/CB (5 h) electrode exhibited significant load‐bearing capacity for bacteria colonization and enhanced the contact between bacteria and electrode, which improved the direct electron transfer process. The microbial three‐electrode system equipped CS/CB (5 h) device delivered a high current density of 1457±69 μA/cm 2 . The current density was increased to 3 times higher than that of the unmodified electrode. The use of this CS/CB (5 h) composite can substantially improves EAB growth and enhance power production of bioelectrochemical systems.

Tenzin Pema, Ankit Kumar, Babita Tripathi et al.

Catalysts • 2023

In this study, multifunctional lithium-doped bismuth ferrite [BiFe1−xLixO3]-graphene nanocomposites (x = 0.00, 0.02, 0.04, 0.06) were synthesized by a sol-gel and ultrasonication assisted chemical reduction method. X-ray diffraction and FESEM electron microscopy techniques disclosed the nanocomposite phase and nanocrystalline nature of [BiFe1−xLixO3]-graphene nanocomposites. The FESEM images and the EDX elemental mapping revealed the characteristic integration of BiFe1−xLixO3 nanoparticles (with an average size of 95 nm) onto the 2D graphene layers. The Raman spectra of the [BiFe1−xLixO3]-graphene nanocomposites evidenced the BiFe1−xLixO3 and graphene nanostructures in the synthesized nanocomposites. The photocatalytic performances of the synthesized nanocomposites were assessed for ciprofloxacin (CIP) photooxidation under UV-visible light illumination. The photocatalytic efficiencies of [BiFe1−xLixO3]-graphene nanocomposites were measured to be 42%, 47%, 43%, and 10%, for x = 0.00, 0.02, 0.04, 0.06, respectively, within 120 min illumination, whereas the pure BiFeO3 nanoparticles were 21.0%. BiFe1−xLixO3 nanoparticles blended with graphene were explored as cathode material and tested in a microbial fuel cell (MFC). The linear sweep voltammetry (LSV) analysis showed that the high surface area of BiFeO3 was attributed to efficient oxygen reduction reaction (ORR) activity. The increasing loading rates of (0.5–2.5 mg/cm2) [BiFe1−xLixO3]-graphene composite on the cathode surface showed increasing power output, with 2.5 and 2 mg/cm2 achieving the maximum volumetric power density of 8.2 W/m3 and 8.1 W/m3, respectively. The electrochemical impedance spectroscopy (EIS) analysis showed that among the different loading rates used in this study, BiFeO3, with a loading rate of 2.5 mg/cm2, showed the lowest charge transfer resistance (Rct). The study results showed the potential of [BiFe1−xLixO3]-graphene composite as a cost-effective alternative for field-scale MFC applications.

Jonghyun Hyun, Seok Hwan Yang, Gisu Doo et al.

Journal of The Electrochemical Society • 2023

Compared to the remarkable advances in anion exchange ionomers (AEIs), the catalyst layer (CL) of the anion exchange membrane fuel cell (AEMFC) has not been sufficiently engineered. Our molecular simulations reveal that the AEIs widely used in this field have weak interaction with the carbon support, presenting the possibility of significant ionomer aggregation in CL. To demonstrate the issue of ionomer–carbon interaction, we investigated CL morphology for various AEIs including polycarbazole-based ionomer (QPC-TMA), FAA-3, PiperION, Sustainion, and compared them with Nafion ionomer that has strong interaction with carbon. In contrast to the uniform Nafion distribution and open-pore structure of Nafion-based CLs, these AEIs are locally aggregated in CL and clog the interstitial pores between the catalyst particles. Furthermore, the comparison of two AEIs with distinct ionomer–carbon interaction energies exhibits that the ionomer with a lower ionomer–carbon interaction energy leads to larger kinetic and mass transport overvoltages. This study provides a fresh perspective that ionomer–carbon support interaction has a significant effect on the structure and performance of the CL.

Reza Agahi

Abu Dhabi International Petroleum Exhibition & Conference • 2019

Abstract Waste heat is the by-product of industrial energy usage. Approximately one-third of the energy consumed by the oil and gas industry is discharged as thermal losses into the environment or via cooling systems. And the main reasons for waste heat discharge are process inefficiencies and technology limitations in the conversion of thermal to mechanical energy. Nevertheless, because the oil and gas industry demands large amounts of thermal, electrical and mechanical energy, a huge amount of waste heat is subsequently available. Organic Rankine Cycle (ORC) technology has made economical utilization of lower temperature heat sources possible. ORC's efficiency percentage for waste heat recovery varies between single digit to the mid-20s, depending on the waste heat source temperature and the cooling medium. Even the recovery of a few MW of thermal energy with a single-digit cycle efficiency for a plant consuming an average of 100 MW (134 102 hp) thermal energy is a considerable efficiency improvement. Studies by the Oakridge National Laboratory (USA) show that 75% of waste heat comes with sufficiently high temperatures (> 150°C, or > 302°F). This report projects a 2-5-year return of investment for ORC-based waste heat to power plant systems, which represents an attractive financial payback. The recovery of waste heat from oil and gas operations remains mostly underutilized. Furthermore, economically feasible power generation from waste heat has been limited to medium- to high- temperature waste heat resources. This paper will explore technical solutions to these challenges facing the oil and gas industry In this paper, three cases of waste heat from a gas turbine's exhaust flue gas are presented. The turbines have nominal output of 7.5, 15, and 25 MW (10 057, 20 115 and 33 525 hp) electrical power at an ambient air temperature of 15°C (59°F). A heat recovery unit (HRU) can recover thermal energy from exhaust flue gas. The heat recovery loop (HRL) could exchange thermal power with an ORC system, which in turn has the potential to produce electrical power. It will be demonstrated that this configuration has a HRL/ORC cycle efficiency of approximately 10% when the ambient air temperature is about 30°C (86°F).

Yun Zhang, Feng Liu, Yidong Lin et al.

Water • 2022

This paper studies the effects of planting plants and coupled microbial fuel cells (MFCs) on the decontamination capacity and purification mechanism of constructed wetlands (CWs). Four systems were set, namely CW-without plants (A1), CW-with plants (A2), CW-MFC-without plants (A3) and CW-MFC-with plants (A4). The daily reductions per unit area of chemical oxygen demand (COD) were 48.72 ± 5.42, 51.26 ± 4.10, 53.49 ± 5.44 and 58.54 ± 4.16 g·(d·m2)−1, respectively. The daily reductions per unit area of nitrogen (N) were 11.89 ± 0.73, 12.38 ± 0.76, 12.24 ± 0.79 and 13.61 ± 1.07 g·(d·m2)−1, respectively. After studying the pollutant removal efficiency, it was found that the unit area of A4 removes the highest number of pollutants, improving the area efficiency of the wetland system and fundamentally alleviating the disadvantage of the large land footprint of wetland processes. The average output voltages of A3 and A4 were 568.29 and 717.46 mV, respectively, and the maximum power densities were 4.59 and 15.87 mW/m3, respectively. In addition, after high-throughput analysis of microbial samples, anaerobic ammonia oxidising (anammox) bacteria were found to remove N from the system in the anaerobic anode region.

Gizem Hazan AKÇAY, İrfan AR

Afyon Kocatepe University Journal of Sciences and Engineering • 2023

Microbial fuel cell is a bioelectrochemical system that generate electricity with the oxidation of organic substrates by exoelectrogenic microorganisms. It can be said that the studies on microbial fuel cells (MFCs) are generally aimed to increase the amount of energy produced. In this study, domestic wastewater treatment was investigated by using a two-chamber microbial fuel cell. Ankara Tatlar Wastewater Treatment Plant influent water was used as substrate. In order to reduce the diffusional resistance by reducing the distance between the anode and cathode electrode, the cathode chamber was placed in the middle of the anode chamber. Anode and cathode chambers separated by Nafion 117 membrane. In addition, an anode consisting of a stainless-steel mesh and a graphite supported catalyst has been developed to increase the electricity generation potential. During the experiment, the maximum voltage and the maximum power density values were obtained as 595 mV and 205.867 mW/m2 respectively. COD value is a criteria which indicates the waste treatment ability of the systems. For this experiment COD values of the wastewaster were measured both the beginning and the end of the experiment as 451 mg/L O2 and 361 mg/L O2. These results proved that the developed electrode structure is at a comparable level with the values reported in the literature for two-chamber MFC studies.

Ambika Arkatkar, Arvind Kumar Mungray, Preeti Sharma

Journal of Basic Microbiology • 2020

Abstract Bacterial isolates Pseudomonas aeruginosa BR, Alcaligenes faecalis SW and Escherichia coli EC from a microbial fuel cell (MFC) were cocultured with each other. The isolates were added in a specific sequence one after the other (two cultures in one reactor). The study helped us conceptualise the synergistic and antagonistic behaviour of bacterial isolates and also emphasised the sequence in which a culture can be introduced in an anode chamber. The coculture conditions were evaluated on the basis of redox activity, electron transfer rate, columbic efficiency, and internal resistances. A good syntropy in terms of power production was found between P. aeruginosa BR and E. coli EC that recorded a power generation of 207.593 ± 1.705 µW/m 2 . The addition of any culture in any sequence affected the performance of P. aeruginosa BR. This culture when added as a secondary culture in the reactor enhanced the performance of that reactor. The sequence of addition of a culture in a reactor affected the performance in the combinations of (a) P. aeruginosa BR and A. faecalis SW and (b) A. faecalis SW and E. coli EC.

Israa K. Abdul-Wahid, Saleem M. Obyed, Basim O. Hasan

Recent Innovations in Chemical Engineering (Formerly Recent Patents on Chemical Engineering) • 2021

Microbial fuel cells (MFCs) have been developed impressively over recent years. In order to take this technology from research to application, the performance of these systems needs to be further investigated and optimized. The electrode materials and operating conditions play a vital role in MFCs performance. In the current work, dual chamber MFC was used to investigate the performance of different electrode materials under stationary and flow conditions. Microorganism solution of Klebsiella oxytoca and Citrobacter Freundii inoculum was used in the anode chamber. Three electrode materials were investigated, namely activated carbon, graphite, and titanium. High current density and power output were obtained by activated carbon electrode and graphite, while titanium showed poor performance for bio-electricity production. The low flow velocity (or Reynolds number) in catholyte was found to enhance the energy production, while the high velocity caused a reduction in the produced current. The aeration of the cathode chamber had a negative effect on the produced current due to the transfer of dissolved oxygen to the microorganism chamber. Activated carbon showed high performance due to its high surface area with the achieved maximum power density of 462.74 mW/m2 at Reynolds number of 7030.

Sneh L. Jain, J. Barry Lakeman, Kevin D. Pointon et al.

Journal of Fuel Cell Science and Technology • 2006

This paper describes a direct carbon fuel cell (DCFC) based on a solid oxide fuel cell (SOFC) system which has been used to assess the performance of a high surface area carbon fuel material. The cell, consisting of a co-fired anode, electrolyte, and cathode, has been produced by standard tape casting methods and is of tubular geometry. The operating conditions of the cell require a 62mol%Li2CO3 and 38mol%K2CO3 eutectic secondary electrolyte and the operation of the cell is described over the temperature range 525–700°C. The cell performance has been examined by standard electrochemical methods.

Jermaine Chambers, Kaia Gomez, Williamson Gustave

Qeios • 2024

In recent years microbial fuel cells have been studied for their biosensing properties. Consequently, sediment microbial fuel cells (sMFCs) have been found to be able to detect minor oil spills in freshwater. However, it was previously unknown whether sMFC properties as a biosensor would be able to produce the same results in a saltwater environment. Therefore, sMFCs at various external resistances (220 Ω, 300 Ω, 430 Ω, 510 Ω, 1000 Ω and 2000 Ω) were assembled to assess their ability to detect oil in seawater. The results indicated that as oil was added to the cathode of the microbial fuel cells, there was a clear and gradual decrease in the voltage output due to the oil’s interference with oxygen dissolvability in seawater; However, the relationship between the change in voltage and change in time was less linear than the change observed in previous studies, and inconsistent across the different voltages. The variation observed may be due to the absence of a catalyst, such as platinum, which would have sped up the rate of the decrease in voltage. This study illustrates that sediment microbial fuel cells provide a cost effective and environmentally friendly method to detect minor oil spills in seawater.

Amira Suriaty Yaakop, Akil Ahmad, Fida Hussain et al.

International Journal of Chemical Engineering • 2023

Microbial fuel cell (MFC) is a method that is both effective and environmentally friendly for producing renewable electricity. Several studies have shown that one of the major challenges is the generation of electrons as a result of poor exploitation of organic substrates. One of the most talked about issues in modern molecular fusion is the reutilization of biological organic waste in an MFC. In this article, the effective utilization of domestic organic waste as an organic supply for bacterial species to generate energy was highlighted. The findings that were obtained corresponded to the one-of-a-kind MFC operation in which a voltage of 110 mV was generated in a time span of 12 days during operation with an external resistance of 500 ῼ. With an internal resistance of 117 ῼ, the maximum power density and the current density were recorded 0.1047 mW/m2 and 21.84 mA/m2, respectively. According to the results of the biological study, strains of bacteria such as Pseudomonas aeruginosa, Acinetobacter schindleri, and Pseudomonas nitroreducens are the ones responsible for producing energy. In addition, final remarks with proposals for the future have been enclosed.

G. Lota, E. Frackowiak

Fuel Cells • 2010

Abstract We report on the pseudo‐capacitance induced by a nitrogen substituted in the carbon network composite prepared by a simple carbonisation (750 °C) of formaldehyde and melamine in the presence of carbon nanotubes. Nitrogen content in the composites varied from 7.4 to 21.7 wt.%. Such materials have a higher density than activated carbons, hence, they can supply better volumetric capacity. N‐rich composites show an excellent charge propagation at current loads from 500 mA g –1 to 50 A g –1 because of multiwalled nanotubes which play a conducting as well as a supporting role. The electrochemical performance of various composites was investigated in two‐ and three‐electrode cells using acidic (1 mol L –1 H 2 SO 4 ), alkaline (6 mol L –1 KOH), neutral (1 mol L –1 Na 2 SO 4 ) and organic electrolytes (1 mol L –1 TEABF 4 in acetonitrile). Organic and neutral medium is not adapted for N‐rich carbon electrodes of supercapacitor. The detailed electrochemical characterisation pointed out the differences of charge propagation of electrodes with the different polarity.

Devesh D Shreeram, Warunya Panmanee, Cameron T McDaniel et al.

Journal of Industrial Microbiology and Biotechnology • 2018

Abstract Pseudomonas aeruginosa is a metabolically voracious bacterium that is easily manipulated genetically. We have previously shown that the organism is also highly electrogenic in microbial fuel cells (MFCs). Polarization studies were performed in MFCs with wild-type strain PAO1 and three mutant strains (pilT, bdlA and pilT bdlA). The pilT mutant was hyperpiliated, while the bdlA mutant was suppressed in biofilm dispersion chemotaxis. The double pilT bdlA mutant was expected to have properties of both mutations. Polarization data indicate that the pilT mutant showed 5.0- and 3.2-fold increases in peak power compared to the wild type and the pilT bdlA mutant, respectively. The performance of the bdlA mutant was surprisingly the lowest, while the pilT bdlA electrogenic performance fell between the pilT mutant and wild-type bacteria. Measurements of biofilm thickness and bacterial viability showed equal viability among the different strains. The thickness of the bdlA mutant, however, was twice that of wild-type strain PAO1. This observation implicates the presence of dead or dormant bacteria in the bdlA mutant MFCs, which increases biofilm internal resistance as confirmed by electrochemical measurements.

K. Sathish Kumar, Omar Solorza-Feria, Rafael Hernández-Vera et al.

Journal of New Materials for Electrochemical Systems • 2012

A single-chamber microbial fuel cell (SCMFC) with a carbon supported Pt-cathode for the oxygen reduction reaction (ORR), and loaded with a sulfate reducing bacterial consortium as biocatalyst in the anodic chamber was characterized by polarization by variable resistance (VR) and linear sweep voltammetry (LSV) methods. From VR a whole cell configuration maximum volumetric power of 92.5 mW m-3 was attained at a current density of 459 A m-3 and voltage of 0.202 V. The LSV method of whole cell configuration gave a higher maximum power density of 197.5 mW m-3 at current density of 696 mA m-3 at the potential of 0.284V; this disagreement was ascribed to possible reduction of power and potential overshoot with the LSV. There was a fair agreement between internal resistance values of whole cell configuration determined by VR and electrochemical impedance spectroscopy (EIS): 2225 and 2307 Ω , respectively. Yet, internal resistance measured by LSV was 30% lower for the whole cell configuration. Both LSV and EIS show the advantage of reduced potential overshoot; yet, EIS provides more detailed information on equivalent circuit of the cell and resistance contributions of the electrodes, electrolyte and membrane. Further cyclic voltammetry tests gave midpoint potential of -0.215 V vs saturated calomel electrode, a value close to those reported for bacterial cytochromes involved in extracellular electron transfer processes. It is concluded that in spite of particular advantages of some techniques over others, the combination of electrochemical methods can be very valuable for shedding light and internal checking of the main characteristics of a microbial fuel cell.

Kam-Khong Chan, Wei-Eng Thung, Soon-An Ong et al.

IOP Conference Series: Earth and Environmental Science • 2020

Abstract Metal contaminated wastewater effluent from industries has caused several environmental problems and public health due to its toxicity. Conventional heavy metal reduction processes are neither economical nor environmentally friendly. A synergy economical single chamber up-flow membrane-less microbial fuel cell (UFML-MFC) was fabricated to study the feasibility of heavy metal reduction and voltage generation. Cu (II) was used as electron acceptor to explore the mechanism of metal treatment in UFML-MFC. The performances of the UFML-MFC were investigated with 0 mg/L, 5 mg/L and 10 mg/L concentration of Cu (II) in terms of voltage output, chemical oxygen demand (COD) reduction and Cu (II) reduction efficiency and electrode spacing distance. UFML-MFC used carbon felt as anode and cathode material where anode region was filled with 0.2 cm of gravels at anode region. Overall performance deteriorated with increased initial concentration of Cu (II). Voltage generation decreased from 71 mV to 11.1 mV. COD reduction decreased from 56% to 36%. Moreover, the Cu (II) reduction efficiency was reduced from 87.56% to 36.98%. These results showed that the increased concentration of the Cu (II) could potentially reduce the microbial activities. However, UFML-MFC showed that the shorter distance of electrode spacing (anode and cathode) could enhanced the voltage output. These results showed the great ability of integrating UFML-MFC for heavy metal reduction.

Md. Mostaqur Rahman

International Journal of Engineering Materials and Manufacture • 2021

A microbial fuel cell (MFC) is a device that converts bio-chemical energy into electrical energy during substrate oxidation with the aid of microorganisms (bacteria). The energy contained in waste water is converted to the electrical power by the action of bacteria. The principle of MFC is to transfer electrons from the microorganisms to electron acceptor at a higher electrochemical potential. An experimental study was performed to find the most efficient industrial waste water that can produce highest and stable electrical power by the MFC and to determine the removal rate of pollutant from the waste water by the MFC. Two MFC, namely one PEM MFC and two PEM FMC, has been fabricated for this study. The three different waste water samples used were Dyeing Waste Water-1 (DWW-1), Dairy Industry Waste Water (DIWW) and Dyeing Waste Water-2 (DWW-2). The highest rate of voltage generation is achieved when the MFC was operated with DWW-1 (1.06 V), DIWW (0.95 V) and DWW-2(0.644 V), respectively. Based on the graph pattern the DWW-1 provided the best record in terms of electrical energy generation.

Chih-Tang Sah, Fredrik A. Lindholm

Journal of Applied Physics • 1984

This paper analyzes the performance improvements obtainable from extending the traditionally thin back-surface-field (BSF) layer deep into the base of silicon solar cells under terrestrial solar illumination (AM1). This extended BSF cell is also known as the back-drift-field cell. About 100 silicon cells have been analyzed, each with a different emitter or base dopant impurity distribution whose selection was based on physically anticipated improvements. The four principal performance parameters (the open-circuit voltage, the short-circuit current, the fill factor, and the maximum efficiency) are computed using a program which numerically solves the six Shockley equations under AM1 solar illumination at 88.92 mW/cm2, at an optimum cell thickness of 50 μm. The results show that very significant performance improvements can be realized by extending the BSF layer thickness from 2 μm (18% efficiency) to 40 μm (20% efficiency). The immunity of cell performance to recombination defect or impurity center is also improved by a factor of 2 to 3 in the recombination center density. For 20% p+/n/n+ cells with about 20-μs base lifetime, a 20-μm BSF penetration is sufficient. At this or deeper penetrations, interband Auger recombination in the emitter layer becomes the limiting factor and affects mainly the short-circuit current but not the open-circuit voltage which has saturated to about 710 mV.

Raden Darmawan, Sri Rachmania Juliastuti, Nuniek Hendrianie et al.

AIMS Environmental Science • 2021

<abstract> <p>Carcinogenic hexavalent chromium is increasing worldwide due to the increased electroplating, welding and textile industry. On the other hand, molasses, the sugar factory's byproduct with high organic compounds (sugars), may pollute the environment if it is not processed. However, microbial fuel cell (MFC) seems to be a promising technology due to its ability to produce electrical energy from pollutant degradation using microbes while reducing hexavalent chromium to trivalent chromium with less toxicity. Carbon felt was used at both electrodes. This research aimed to determine the effect of modifying the anode with rice bran and cathode with Cu catalyst towards electricity generation and pollutant removal in molasses and reducing Cr (Ⅵ) into Cr (Ⅲ) using tubular microbial fuel cells. Moreover, the effect of mixing Sidoarjo mud and <italic>Shewanella oneidensis</italic> MR-1 as electricigen bacteria toward electrical energy production and pollutant removal was determined. Experiments revealed that the S/CM/AM variable, which only used <italic>Shewanella oneidensis</italic> MR-1 as an electricigen bacteria with both modified electrodes, produced the highest total power density of 530.42 mW/m<sup>2</sup> and the highest percentage of Cr (Ⅵ) reduction of 98.87%. In contrast, the highest microbial population of 66.5 × 10<sup>10</sup> cells/mL, 61.28% of Biological Oxygen Demand (BOD<sub>5</sub>) removal and 59.49% of Chemical Oxygen Demand (COD) were achieved by SSi/CM/AM variable, mixing <italic>Shewanella oneidensis</italic> MR-1 and Sidoarjo mud as an electricigen bacteria with both modified electrodes. Therefore, this study indicates that double chamber tubular microbial fuel cells may be a sustainable solution for managing molasses and carcinogen hexavalent chromium.</p> </abstract>

Triyanto Pangaribowo, Wahyu Mulyo Utomo, Abdul Hamid Budiman et al.

Journal of Robotics and Control (JRC) • 2024

Open cathode proton exchange membrane fuel cells (OC-PEMFC) are devices that produce electrical energy through an electrochemical reaction between hydrogen and oxygen gas. Rapid load changes often lead to fluctuations in the flow of hydrogen entering the OC-PEMFC system. Increased load directly correlates with higher hydrogen gas consumption. However, if there is a delay in adjusting the gas flow rate to changes in load, it can trigger fluctuations in the amplitude and frequency of the output voltage. This fluctuation ultimately disrupts the stability of the power supply to the load, and reducing efficiency. Therefore, this paper presents a novel hybrid system that integrates wavelet and clipping techniques to regulate a more stable hydrogen flow, enhancing efficiency and accuracy under constant load conditions. A wavelet control system is used to mitigate noise, coupled with amplitude limitation through clipping techniques. This control system is implemented in OC-PEMFC model that is validated with experimental data. The performance analysis of this hybrid system reveals a 1.95 % increase in efficiency and attains high accuracy, as evidenced by a low ISE value of 0.028 during interference.

Magdalena Dudek, Andrzej Raźniak, Jarosław Markowski et al.

E3S Web of Conferences • 2023

This article presents the results of experimental investigations on an advanced model of a polymer exchange membrane fuel cell (PEMFC) stack designed to serve as a charging unit for electric vehicle batteries or off-grid distributed power sources. The assembled 720 W PEMFC stack comprises two 360 W modules that can be electrically connected in series or parallel. A liquid cooling system for the PEMFC stack has also been constructed. The dependencies – voltage ( U ) versus current ( I ) and current ( I ) versus electrical power ( P ) – for single modules, as well as for the electrically connected two-module PEMFC stack, are determined. Additionally, the hydrogen utilization versus the electrical power ( P ) of the PEMFC stack is examined. The electrical efficiency of the PEMFC stack varies between 42% and 50%, depending on the electrical power. An adjustable DC/DC converter, operating in two modes (step-down or stepup), is proposed as a device to integrate a lithium-ion (Li-ion) battery pack with approximately 720 W PEMFC stack. The electrical architecture of the integrated system, comprising the PEMFC stack, DC/DC converter, and Li-ion battery pack, is investigated and discussed in this paper. It was found that the electrical efficiency of the proposed DC/DC converter varies depending on the electrical power, reaching a peak efficiency of 95%– 98%. The environmental benefit, in terms of reducing CO 2 emissions when charging the battery, was also identified.