Discover insights from thousands of peer-reviewed papers on microbial electrochemical systems
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 (&gt; 150°C, or &gt; 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).
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.
Yuji Okuyama, Tomohiro Kuroha, Yamauchi Kosuke et al.
ECS Meeting Abstracts · 2020
Barium zirconate have high chemical stability with CO 2 comparison with barium cerate. Acceptor doped barium zirconate show high proton conductivity [1]. The proton conductivity of yttrium doped barium zirconate is 1×10 -2 Scm -1 at 600 ℃ and it is attracted as the electrolyte of fuel cell and water vapor electrolysis cell. The fuel cell using proton conducting oxide was called to PCFC (proton ceramic fuel cell) and work at the intermediate temperature. PCFC is expected to be the energy conversion device in future because of high efficiency [2] and low production cost [3]. Generally, nickel is used as anode of PCFC. The anode overpotential of nickel is lower than that of the other metals. However, the nickels dissolve to the proton conducting oxide and possibly increase the ohmic resistance of electrolyte. Moreover, the nickel and the electrolyte possibly form the blocking layer such as the complex oxide. Although the proton conductivity of yttrium doped barium zirconate is highest in the zirconate-type proton conductor, BaY 2 NiO 5 is formed between the nickel and the yttrium doped barium zirconate [4] and it might work as the blocking layer of proton. In this study, the reaction product between NiO and BaZr 0.8 M 0.2 O 3-δ ( M =Sc, In, Yb, Y, Gd) were confirmed by X-ray diffraction analysis. In order to clarify the NiO dissolution effect on the proton transport properties of BaZr 0.8 M 0.2 O 3-δ ( M =Sc, In, Lu, Yb, Y), the partial conductivity of the proton and the hole for BaZr 0.8 M 0.2 O 3-δ ( M =Sc, In, Lu, Yb, Y) with NiO were measured at temperature range of 200-600 ℃ by impedance analysis. The current efficiency on the polarization properties, then was examined for the fuel cell system using Acceptor-doped barium zirconate with NiO as electrolyte. Moreover, we investigated the effect of dopants on the ease of cell fabrication. The conventional ceramic tape-casting and firing process for fabricating laminated ceramic electronic devices was used, which is important for practical use. The power generation performance of planer cells fabricated by this process was also measured. The X-ray diffraction patterns of 0.4 mol% NiO doped BaZr 0.8 M 0.2 O 3-δ ( M = Sc, In, Yb, Y, Gd) were measured for the the samples as-sintered and annealed under 1%H 2 at 873K. The peak of the NiO or Ni phase except the barium zircanate phase was observed for 0.4 mol% NiO doped BaZr 0.8 M 0.2 O 3-δ ( M = Sc, In, Yb). On the other hand, the Ba M 2 NiO 5 phase was observed for M =Y, Gd. When the ionic radius of dopant is in excess of the size of Yb, the Ba M 2 NiO 5 was formed as the reaction product between NiO and BaZr 0.8 M 0.2 O 3-δ . The proton conductivity of the series of BaZr 0.8 M 0.2 O 3-δ containing no NiO increased in the order of In<Sc<Lu<Yb<Y. On the other hand, there was no distinct difference of the hole conductivity for dopant. PCFC using BZ M 20 ( M =Lu, Yb, Tm, Y) has an energy efficiency of more than 0.8 at 873 K. The proton conductivity decreased and the hole conductivity did not change for all series of BaZr 0.8 M 0.2 O 3-δ due to NiO dissolution in BaZr 0.8 M 0.2 O 3-δ . Therefore, proton transport number and the efficiency of the fuel cell decrease by addition to NiO. Considering the above, the ytterbium-doped barium zirconate did not form a complex oxide with NiO and might have high proton conductivity. The performance of PCFC using BZYb20 as electrolyte was measured. The maximum power density values at 600 and 700 °C were 0.50 and 0.70 Wcm −2 for the planar cells using BZYb20, respectively. Electrochemical impedance spectroscopy of the cell showed that the ohmic resistance was 0.28 Ωcm 2 at 600 °C, which was approximately three times larger than the resistance value calculated using the bulk conductivity of BZYb20 and the electrolyte thickness and was in agreement with the resistance value of BZYb20 with NiO. [1] K.D. Kreuer et al., Solid State Ionics 145(2001)295-306. [2] Y. Matsuzaki et al., Scientific Reports, 5:12640(2015)1-10. [3] A. Doubois et al., ECS Transaction 78(1) (2017)1963-1972. [4] J. Tong et al., J. Mater. Chem. , 20(2010)6333.
Pengcheng Zhu, Shumin Zhuo, Weiying Zhang et al.
Journal of Applied Polymer Science · 2023
Abstract Microbial fuel cells (MFCs) are a potential biotechnology for simultaneous degradation of organic wastewater and power generation. In this paper, a biocompatible composite is constructed around a copper mesh with sodium alginate/agar and activated carbon (CM‐SA/AC) and acts as an efficient anode for MFCs after being microbe immobilized. The power performance of the MFC with CM‐SA/AC anode is investigated. The results show that the addition of activated carbon is conducive to the immobilization of bacteria on CM‐SA/AC anode and fast start‐up of MFCs. The power density reaches 1088.6 mW/m 2 , which is 2.03 times and 1.75 times that of CM‐SA (without activated carbon) anode and carbon felt anode, respectively. In case of a candied wastewater treatment, the MFC with immobilized CM‐SA/AC anode exhibits a much higher power density (724.5 mW/m 2 ) than that with carbon felt anode (145.0 mW/m 2 ), together with a longer stabilization time and a smaller charge‐transfer resistance. The total removal rate of chemical oxygen demand (COD) reaches 79.4 ± 0.65%. The present study will facilitate the development of inexpensive and biocompatible anodes to facilitate the application of MFCs in wastewater treatment.
Robyn Barbato, Robert Jones, Michael Musty et al.
· 2025
Electrogenic bacteria produce power in soil based terrestrial microbial fuel cells (tMFCs) by growing on electrodes and transferring electrons released from the breakdown of substrates. The direction and magnitude of voltage production is hypothesized to be dependent on the available substrates. A sensor technology was developed for compounds indicative of anthropological activity by exposing tMFCs to gasoline, petroleum, 2,4-dinitrotoluene, fertilizer, and urea. A machine learning classifier was trained to identify compounds based on the voltage patterns. After 5 to 10 days, the mean voltage stabilized (+/- 0.5 mV). After the entire incubation, voltage ranged from -59.1 mV to 631.8 mV, with the tMFCs containing urea and gasoline producing the highest (624 mV) and lowest (-9 mV) average voltage, respectively. The machine learning algorithm effectively discerned between gasoline, urea, and fertilizer with greater than 94% accuracy, demonstrating that this technology could be successfully operated as an environmental sensor for change detection.
Irene Bavasso, Luca Di Palma, Debora Puglia et al.
Polymer Engineering & Science · 2019
Nanocomposite membranes based on polyethersulfone (PES) and nanomagnetite have been investigated with regards to the effect of pretreatments on the electrochemical performance of microbial fuel cells (MFCs). Nanocomposite membranes containing various amounts of Fe 3 O 4 (5, 10, and 20 wt%) were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, and tensile tests. The application in MFC systems requires also chemical characterizations such as ion exchange capacity, water uptake, and oxygen permeability. The best formulation (PES10) showed electrochemical properties similar to the PES20. With the aim of obtaining a high‐performance membrane with a low filler dosage, a pretreatment procedure (1 h of boiling step in deionized water and 1 h of immersion in 0.5 M of H 2 SO 4 ) was adopted. The results of such pretreatment in terms of maximum power and current density were 10.59 ± 0.72 mW/m 2 and 52.07 ± 0.86 mA/m 2 , respectively. The adoption of a pretreatment avoids the need of higher amount of nanofillers that can affect membrane surface roughness and its processing. Overall, the nanocomposite membranes represent a suitable technology in the MFC process. POLYM. ENG. SCI., 60: 371–379, 2019. © 2019 Society of Plastics Engineers
Cheng Li, Hong Liu
ECS Meeting Abstracts · 2018
Mixed species biofilms have been able to generate current densities of over 20 A/m 2 in microbial fuel cells (MFCs), while also offering advantages in stability, substrate flexibility, and culture maintenance costs. To further increase the current density, a possible approach is to enhance the conductivity of biofilms and thereby the direct extracellular electron transfer within the biofilms and to the anode. While examination of conductivity in microbial samples is still in its relative infancy and conceptual models in terms of conductive mechanisms are still being developed and debated, our study has demonstrated that current-producing mixed species biofilms can exhibit high conductivity across non-conductive gaps. Differential responses observed over varying potentials also suggest that a redox driven conductivity mechanism is dominant in the tested mixed-species biofilms. Considering that some redox conductive organic polymer films possess negative magnetoresistance property (resistivity of a conductive material decreases as the magnetic field strength increases) and magnetic field may stimulate enzyme activity in certain anaerobic wastewater treatment systems, our mixed species biofilms were exposed to low intensity magnetic field to investigate the conductivity change and performance enhancement. Exposure of the biofilms to magnetic field has led to an over 100% increase in biofilm conductance and over 300% increase in current density. Application of the low intensity magnetic field also encouraged the enrichment of Geobacter spp. in biofilms. Short term application of magnetic field also increased the conductivity of anodic biofilms, resembling the negative magnetoresistivity that has not been observed in conductive biofilms before. These results not only enhance our understanding of the electrical conductivity in microbial aggregates, but also inform rational design and operation of microbial-based fuel cells.
Shiladitya Mukherjee, J. Vernon Cole, Kunal Jain et al.
ASME 2009 7th International Conference on Fuel Cell Science, Engineering and Technology · 2008
In Proton Exchange Membrane Fuel Cells (PEMFCs), water management and the effective transport of water through the gas-diffusion-layer (GDL) are key issues for improved performance at high power density and for durability during freeze-thaw cycles. The diffusion layer is a thin (∼150–350μm), porous material typically composed of a web of carbon fibers and particles, and is usually coated with hydrophobic Teflon to remove the excess water through capillary action. In-situ diagnostics of water movement and gas-reactant transport through this thin opaque substrate is challenging. Numerical analyses are typically based on simplified assumptions, such as Darcy’s Law and Leverett functions for the capillary pressure. The objective of this work is to develop a high fidelity CFD modeling and analysis tool to capture the details of multiphase transport through the porous GDL. The tool can be utilized to evaluate GDL material design concepts and optimize systems based on the interactions between cell design, materials, and operating conditions. The flow modeling is based on the Lattice Boltzmann Method (LBM). LBM is a powerful modeling tool to simulate multiphase flows. Its strength is in its kinetic theory based foundation, which provides a fundamental basis for incorporating intermolecular forces that lead to liquid-gas phase separation and capillary effects without resorting to expensive or ad-hoc interface reconstruction schemes. At the heart of the solution algorithm is a discrete form of the well-known Boltzmann Transport Equation (BTE) for molecular distribution, tailored to recover the continuum Navier-Stokes flow. The solution advances by a streaming and collision type algorithm, mimicking actual molecular physics, which makes it suitable for porous media involving complex boundaries. We developed a numerical scheme to reconstruct various porous GDL microstructures including Teflon loading. Single and multiphase LBM models are implemented to compute permeability. Predicted values are in good agreement with measured data. The present modeling approach resolves the GDL microstructures and captures the influence of fiber orientation on permeability and the influence of Teflon loading on the development of preferential flow paths through the GDL. These observations can potentially guide the development of novel GDL materials designed for efficient removal of water.
Cong Xu, Lorenz T. Biegler, Myung S. Jhon
AIChE Journal · 2006
Abstract An H 2 Polymer Electrolyte Membrane (PEM) Fuel Cell power generation system composed of three subsystems: fuel reforming, fuel cell stack, and post combustion is examined. The system is simulated and optimized with a fuel cell model integrated within the process flow sheet. A case study optimization of the entire power generation system is presented and the influence of heat integration on the optimization is demonstrated. Our objectives are to maximize the energy and system efficiencies as well as the system profit. Here, optimization formulations with heat integration are used to realize our objectives, which explore the synergy between optimization and heat integration. Our results showed that we can achieve an energy efficiency as high as 58.30% and a system efficiency as high as 28.35%. For comparison, we provide results obtained from sequential process optimization followed by heat integration. The gain from the synergy is mostly exemplified in the profit maximization study, where the profit increases by almost 27.15% in the best case. Finally, we obtain optimization results that include feed vaporization of water to steam as a comparison for the heat integration. These results demonstrate the importance of simultaneous optimal heat integration for fuel cell‐based processes. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Vahid Rezaee, Arash Houshmand
Bulletin of the Polytechnic Institute of Iași. Electrical Engineering, Power Engineering, Electronics Section · 2022
Abstract In this study, the performance analysis of waste heat recovery systems in a power generation system consisting of 13000 Proton Exchange Membrane Fuel Cells (PEMFC) in a stack has been investigated. Organic Rankine Cycle (ORC) and Kalina Cycle System 11 (KCS11) as bottoming cycles to convert generated waste heat of stack into electricity were compared with each other in a defined hybrid system. The improvement of system with an exact energy and exergy analysis after utilizing the waste heat in the hybrid system has been analyzed. Results show that the energy efficiency of combined system using Organic Rankine Cycle and Kalina Cycle System 11 increase by about 5% and 1.75% respectively. In addition, exergy analysis results indicate that exergy efficiency of combined system using Organic Rankine Cycle and Kalina Cycle System 11 increases by about 4% and 1.5% respectively. The total exergy destruction rate obtained for the hybrid power systems is 235.5 kW when ORC is used and 329.7 kW when KCS11 is used respectively. Results show that in presented systems ORC has higher energy and exergy efficiencies than KCS11 but different used working fluids and equipment of systems must also be considered from an economical point of view.
Yifeng Zhang, Booki Min, Liping Huang et al.
Applied and Environmental Microbiology · 2009
ABSTRACT Electricity generation from wheat straw hydrolysate and the microbial ecology of electricity-producing microbial communities developed in two-chamber microbial fuel cells (MFCs) were investigated. The power density reached 123 mW/m 2 with an initial hydrolysate concentration of 1,000 mg chemical oxygen demand (COD)/liter, while coulombic efficiencies ranged from 37.1 to 15.5%, corresponding to the initial hydrolysate concentrations of 250 to 2,000 mg COD/liter. The suspended bacteria found were different from the bacteria immobilized in the biofilm, and they played different roles in electricity generation from the hydrolysate. The bacteria in the biofilm were consortia with sequences similar to those of Bacteroidetes (40% of sequences), Alphaproteobacteria (20%), Bacillus (20%), Deltaproteobacteria (10%), and Gammaproteobacteria (10%), while the suspended consortia were predominately Bacillus (22.2%). The results of this study can contribute to improving understanding of and optimizing electricity generation in microbial fuel cells.
Chetan Laddha
ADIPEC · 2023
Abstract Ammonia is a dense energy carrier with high energy density and established supply chain for transport, and storage of hydrogen. Ammonia is a common commodity used in the fertiliser and chemical sector and has a potential to become an affordable and sustainable energy carrier to meet growing demand for industrial decarbonisation. The transport of hydrogen over long distances require an efficient and cost competitive carrier. Potential options for hydrogen carrier are ammonia, liquid organic hydrogen carrier (LOHC), liquid hydrogen, compressed hydrogen, and methanol. This paper describes an innovative ceramics-based solid oxide fuel cell technology for conversion of ammonia into fossil fuel parity energy at a thermal efficiency of 85%. The technology is based on proton conducting ceramics (PCC) electrochemical pathway which eliminates NOx emissions by design and ammonia slippage by catalyst performance and reactor design. The technology has been developed over 7 years, between 2016 to 2022, and the ammonia utilisation capabilities has been proven through demonstrations conducted for O&G and industrial companies. The technology uses low-cost and widely available ceramics-based catalyst. The technology is particularly suited for industrial decarbonisation because of the ability to yield high efficiency and the ability to produce low-cost heat at 700C and hydrogen as byproducts.
Myong-Hwan Kim, Seung Eul Yoo, Youngmo Goo
ECS Meeting Abstracts · 2016
In generally, Bipolar plate is vital component of PEM fuel cells, which supplies fuel and oxidant to reactive sites, removes reaction products, collects produced current and provides mechanical support for the cells in the stack. At the present, the bipolar plate for fuel cell vehicle is metallic separators formed of metallic materials such as stainless steel. The existing bipolar plate includes a land(contacting) portion directly bonded to the gas diffusion layer(GDL) and a channel portion that serves as a supply passage of reaction gases and an exhaust passage of water between land portions. In the typical separator, the land portion and the channel portion are disposed in a longitudinal direction and a flow field area in which the channel portion is formed both have a longitudinal structure. Also, the land portion and the channel portion are distinctly separated from each other.However, in the case of a typical separator, this non-uniformity causes a concentration difference between the area that the channel portion contacts and the area that the land portion contacts among the whole area of the MEA where the electrochemical reaction occurs and the performance of fuel cell is decreased.In this paper, a porous separator with various structures for a fuel cell, which causes the high diffusion of reactant gases was studied for increasing the performance of fuel cell. Also, we conducted an analysis of the properties(contact resistance, corrosion etc.), machinability(uniformity of thickness, change of hole structure etc.) and performance according to hole and pitch structure.In conclusions, the porous separator with optimum structure shows the performance above 200mA/cm 2 at 0.6V in comparision with the typical separator. It is considered to be minimize concentration differences between area in a gas diffusion layer and achieve uniform electrochemical reaction and electricity generation over the whole reaction are, by improving the structure of a flow field in which reactant gases flow.
Lanka Tata Rao, Satish Kumar Dubey, Arshad Javed et al.
Journal of Electrochemical Energy Conversion and Storage · 2020
Abstract Paper-based membraneless microfluidic fuel cell (PMMFC) has emerged as an alternative to conventional fuel cells. Extraction of optimum energy yield from these PMMFCs requires selection and study of various design and operating parameters. In this context, this paper presents reliability analysis and robust design of PMMFC composed of air-breathing graphite electrodes using multiple concentrations of formic acid and sulfuric acid as fuel and electrolyte, respectively. Combinations of four different grades of pencils are employed to prepare the electrodes using various pencil strokes. PMMFC is analyzed for two different orientations—horizontal and vertical, and the maximum power outputs were recorded. In order to analyze the combined effects of different factors governing the performance of PMMFC, a statistical approach of full factorial design is utilized to perform analysis of mean (ANOM), analysis of variance (ANOVA), signal to noise ratio (SNR), and desirability study. The response equations in terms of coded values of the factors are also derived. Rigorous desirability study, with the optimized parameters, concludes that the best desirability values for the horizontal and vertical arrangements of PMMFC are 0.8842 and 0.92768, respectively. Overall, this study helps to develop reliable, robust, and efficient PMMFC for many realistic applications.