Prem Chandra, Enespa, Ranjan Singh et al.

Microbial Cell Factories • 2020

Abstract Lipases are very versatile enzymes, and produced the attention of the several industrial processes. Lipase can be achieved from several sources, animal, vegetable, and microbiological. The uses of microbial lipase market is estimated to be USD 425.0 Million in 2018 and it is projected to reach USD 590.2 Million by 2023, growing at a CAGR of 6.8% from 2018. Microbial lipases (EC 3.1.1.3) catalyze the hydrolysis of long chain triglycerides. The microbial origins of lipase enzymes are logically dynamic and proficient also have an extensive range of industrial uses with the manufacturing of altered molecules. The unique lipase (triacylglycerol acyl hydrolase) enzymes catalyzed the hydrolysis, esterification and alcoholysis reactions. Immobilization has made the use of microbial lipases accomplish its best performance and hence suitable for several reactions and need to enhance aroma to the immobilization processes. Immobilized enzymes depend on the immobilization technique and the carrier type. The choice of the carrier concerns usually the biocompatibility, chemical and thermal stability, and insolubility under reaction conditions, capability of easy rejuvenation and reusability, as well as cost proficiency. Bacillus spp., Achromobacter spp., Alcaligenes spp., Arthrobacter spp., Pseudomonos spp., of bacteria and Penicillium spp., Fusarium spp., Aspergillus spp., of fungi are screened large scale for lipase production. Lipases as multipurpose biological catalyst has given a favorable vision in meeting the needs for several industries such as biodiesel, foods and drinks, leather, textile, detergents, pharmaceuticals and medicals. This review represents a discussion on microbial sources of lipases, immobilization methods increased productivity at market profitability and reduce logistical liability on the environment and user.

Daniel Wichmann, Philip Engelhardt, Roland Wruck et al.

ECS Transactions • 2010

Within the scope of a German cooperative project a consortium with partners from industry and academia develops a Reformed Methanol Fuel Cell System (RMFC) on the basis of a HT-PEM fuel cell with an electric power output of 30 W. The fuel cell system is used as a hybrid system with an accumulator as an energy supply for golf-caddies. The Steam Reforming of Methanol (SRM) is applied for hydrogen production in a micro-structured reactor which is built on the basis of thin hydroformed metal sheets. An innovative heat exchanger design allows the integration of all relevant fuel processing steps (catalytic combustion, vaporization, reforming, heat exchange) into a single component and also the integration with the HT-PEM fuel cell as such. The fuel processor was tested with different types of catalysts (base metal, precious metal). It turns out that among the catalysts tested a precious metal catalyst has the best stability and performance.

Chunjuan Shen, Sichuan Xu, Yuan Gao

Polymers • 2021

Based on the dynamic cycle condition test of a 4.5 kW fuel cell stack, the performance attenuation and individual cell voltage uniformity of the proton exchange membrane fuel cell (PEMFC) stack was evaluated synthetically. The performance decay period of the fuel cell stack was 180–600 h, the decrease of voltage and power was evaluated by rate and amplitude. The results show that the performance of the fuel cell stack decreased with the increase of test time and current density. When the test was carried out to 600 h, under rated operating conditions, the voltage attenuation rate was 130 μV/h, and the voltage reduced by 71 mV, with a decrease of 10.41%. The power attenuation rate was 0.8 W/h, with a decrease of 10.42%. The statistical parameter variation coefficient was used to characterize the voltage consistency of individual cells. It was found that the voltage uniformity is worse at the high current density point and with a long-running process. The variation coefficient was 3.1% in the worst performance.

Feng Zhao, Qingzhi Wang, Ying Zhang et al.

Microbial Cell Factories • 2021

Abstract Background Pseudomonas aeruginosa , the rhamnolipids-producer, is one of dominant bacteria in oil reservoirs. Although P. aeruginosa strains are facultative bacteria, the anaerobic biosynthesis mechanism of rhamnolipids is unclear. Considering the oxygen scarcity within oil reservoirs, revealing the anaerobic biosynthesis mechanism of rhamnolipids are significant for improving the in-situ production of rhamnolipids in oil reservoirs to enhance oil recovery. Results Pseudomonas aeruginosa SG anaerobically produced rhamnolipids using glycerol rather than glucose as carbon sources. Two possible hypotheses on anaerobic biosynthesis of rhamnolipids were proposed, the new anaerobic biosynthetic pathway (hypothesis 1) and the highly anaerobic expression of key genes (hypothesis 2). Knockout strain SGΔrmlB failed to anaerobically produce rhamnolipids using glycerol. Comparative transcriptomics analysis results revealed that glucose inhibited the anaerobic expression of genes rmlBDAC , fabABG , rhlABRI , rhlC and lasI . Using glycerol as carbon source, the anaerobic expression of key genes in P. aeruginosa SG was significantly up-regulated. The anaerobic biosynthetic pathway of rhamnolipids in P. aeruginosa SG were confirmed, involving the gluconeogenesis from glycerol, the biosynthesis of dTDP- l -rhamnose and β-hydroxy fatty acids, and the rhamnosyl transfer process. The engineered strain P. aeruginosa PrhlAB constructed in previous work enhanced 9.67% of oil recovery higher than the wild-type strain P. aeruginosa SG enhancing 8.33% of oil recovery. Conclusion The highly anaerobic expression of key genes enables P. aeruginosa SG to anaerobically biosynthesize rhamnolipids. The genes, rmlBDAC , fabABG , rhlABRI , rhlC and lasI , are key genes for anaerobic biosynthesis of rhamnolipid by P. aeruginosa . Improving the anaerobic production of rhamnolipids better enhanced oil recovery in core flooding test. This study fills the gaps in the anaerobic biosynthesis mechanism of rhamnolipids. Results are significant for the metabolic engineering of P. aeruginosa to enhance anaerobic production of rhamnolipids.

Baroud Zakaria, Gazzam Noureddine, Benalia Atallah et al.

IET Renewable Power Generation • 2018

In this study, an algebraic‐observer‐based output‐feedback controller is proposed for a proton exchange membrane fuel cell (PEMFC) air‐supply subsystem, based on both algebraic differentiation and sliding‐mode control approaches. The goal of the design is to regulate the oxygen excess ratio (OER) towards its optimal set point value in the PEMFC air‐supply subsystem. Hence, an algebraic estimation approach is used to reconstruct the OER based on a robust differentiation method. The proposed observer is known for its finite‐time convergence and low computational time compared to other observers presented in the literature. Then, a twisting controller is designed to control the OER by manipulating the compressor motor voltage. The parameters of the twisting controller have been calculated by means of an off‐line tuning procedure. The performance of the proposed algebraic‐observer‐based output‐feedback controller is analysed through simulations for different stack‐current changes, for parameter uncertainties, and for noise rejection. Results show that the proposed approach properly estimates and regulates the OER in finite‐time.

Asmaa G. Almahdy, Ahmed El-Sayed, Marwa Eltarahony

Microbial Cell Factories • 2024

Abstract Background The continuous progress in nanotechnology is rapid and extensive with overwhelming futuristic aspects. Through modernizing inventive synthesis protocols, a paradigm leapfrogging in novelties and findings are channeled toward fostering human health and sustaining the surrounding environment. Owing to the overpricing and jeopardy of physicochemical synthesizing approaches, the quest for ecologically adequate schemes is incontestable. By developing environmentally friendly strategies, mycosynthesis of nanocomposites has been alluring. Results Herein, a novel architecture of binary CuO and TiO 2 in nanocomposites form was fabricated using bionanofactory Candida sp. , for the first time. For accentuating the structural properties of CuTi nanocomposites (CuTiNCs), various characterization techniques were employed. UV-Vis spectroscopy detected SPR at 350 nm, and XRD ascertained the crystalline nature of a hybrid system. However, absorption peaks at 8, 4.5, and 0.5 keV confirmed the presence of Cu, Ti and oxygen, respectively, in an undefined assemblage of polygonal-spheres of 15–75 nm aggregated in the fungal matrix of biomolecules as revealed by EDX, SEM and TEM. However, FTIR, ζ-potential and TGA reflected long-term stability (− 27.7 mV) of self-functionalized CuTiNCs. Interestingly, a considerable and significant biocide performance was detected at 50 µg/mL of CuTiNCs against some human and plant pathogens, compared to monometallic counterparts. Further, CuTiNCs (200 µg/mL) ceased significantly the development of Staphylococcus aureus , Pseudomonas aeruginosa and Candida albicans biofilms by 80.3 ± 1.4, 68.7 ± 3.0 and 55.7 ± 3.0%, respectively. Whereas, 64.63 ± 3.5 and 89.82 ± 4.3% antimicrofouling potentiality was recorded for 100 and 200 µg/ml of CuTiNCs, respectively; highlighting their destructive effect against marine microfoulers cells and decaying of their extracellular polymeric skeleton as visualized by SEM. Moreover, CuTiNCs (100 and 200 µg/ml) exerted significantly outstanding disinfection potency within 2 h by reducing the microbial load (i.e., total plate count, mold & yeast, total coliforms and faecal Streptococcus ) in domestic and agricultural effluents reached >50%. Conclusion The synergistic efficiency provided by CuNPs and TiNPs in mycofunctionalized CuTiNCs boosted its recruitment as antiphytopathogenic, antibiofilm, antimicrofouling and disinfectant agent in various realms.

Qi Feng, Longjun Xu, Chenglun Liu et al.

Research Square • 2021

Abstract This was the first attempt to investigate the bioelectricity output based on solid-liquid cooperation in the microbial fuel cell (MFC) treatment of oil-based drill sludge by adjusting the stirring rate (SR) and supplementing oil-based drill cuttings (OBDCs). According to the results, the maximum power density output reached 671 mW/m 2 (5.4 kW h/m 2 ) when the stirring rate was 100 r/min and the OBDCs concentration was 2 g/L in the anode chamber, which was more than 2.4 times as high as that of the control group and significantly higher than those of other MFCs. Extremely high removal efficiencies of chemical oxygen demand (COD), ammonia and total inorganic nitrogen (TIN) were realized in optimization, with values of 52.3 ± 1.9% (the removal quality was 12081 ± 432 mg/L), 74.5 ± 0.2% and 58.9 ± 0.2%, respectively. Electrochemical analyses and high-throughput sequencing revealed that the cooperation of stir with OBDCs could activate microbial activity while reducing the overpotential loss in anode systems and thus responsible for the enrichment of electrogenic bacteria with extracellular electron transfer functions (such as Proteobacteria , Bacteroidetes and Actinobacteria ) and denitrifying bacteria (such as Bacilli and Anaeroli neae and Rhodopseudomonas ). Moreover, substrate characterization (via Fourier-transform infrared spectrometry (FT-IR) and X-ray diffraction (XRD)) showed that organic matter might converted into small molecules without intermediates. This investigation offers a new strategy for the treatment /application of solid and liquid produced from oil and gas fields by bioelectrochemical technology.

Zhongyang Wang, Yang Zhao, Vijay Ramani

ECS Meeting Abstracts • 2019

There is a growing interest in using anion exchange membranes (AEMs) as separators in alkaline membrane fuel cells (AMFCs) and in other energy conversion and storage systems such as redox flow batteries (RFBs), alkaline water electrolyzers (AWEs) and reverse electrodialysis (RED) cells. The most commonly used cation group in AEMs is the benzyl trimethylammonium cation. However, it had been shown that quaternary ammonium-based AEMs are sensitive towards Hofmann elimination [1] and direct nucleophilic elimination reactions [2] that result in loss of ion exchange capacity (IEC) and ionic conductivity. To solve the alkaline stability issue inherent to quaternary-ammonium-group-containing AEMs, alternative cations such as piperidinium-based cations has been proposed and investigated. The piperidinium-based AEM was able to maintain its ca. 90% of its initial IEC after immersion into 1M KOH at 80 ºC for 30 days. Such piperidinium-based AEMs showed higher alkaline stability than benzyl-trimethylammonium-based AEM ( ca. 20% degradation in 1M KOH at 60 ºC for 30 days) [3]. The improved alkaline stability was mainly attributed to the avoidance of attaching quaternary ammonium onto benzylic position. The planar structure of piperidinium-based cation slows down the β-elimination phenomenon. Also, there is no ether linkage with the polymer backbone and hence, the stability of polymer backbone is superior. The chloride ion conductivity of the piperidinium-based AEM was 65 mS/cm at 80 ºC under an IEC of 2.26 mmol/g. An AEMFC was assembled using our piperidinium-based AEM with Pt/C catalysts used for both anode and cathode. A peak power density of 700 mW/cm 2 with 2 A/cm 2 current density was obtained at 70 ºC without any backpressure. References [1] C.G. Arges, L. Wang, J. Parrondo, V. Ramani, Journal of The Electrochemical Society, 160 (2013) F1258-F1274. [2] S. Chempath, J.M. Boncella, L.R. Pratt, N. Henson, B.S. Pivovar, The Journal of Physical Chemistry C, 114 (2010) 11977-11983. [3] Z. Wang, J. Parrondo, V. Ramani, Journal of The Electrochemical Society, 164 (2017) F1216-F1225.

Carlos Armenta-Déu

Recent Progress in Science and Engineering • 2025

This work focuses on designing a control unit for improving Proton Exchange Membrane Fuel Cell (PEMFC) performance powering electric vehicles when operating in variable atmospheric pressure conditions, a current situation in mountainous countries with sudden changes in road altitude. The paper studies and analyzes the PEM fuel cell behavior working with hydrogen supply from a pressurized tank and oxygen input from atmospheric air supply in journeys with continuous variation of road level due to the orography. The work proposes a control unit that regulates hydrogen and oxygen partial pressure to match each other, assuring correct fuel cell operation and improving performance. A simulation for a fuel cell powering a standard electric vehicle shows that fuel cell performance improves by 8.5%, enlarging the driving range by 7.8% and prolonging the fuel cell lifespan. The control unit is adaptive to all-electric vehicles powered by a PEM fuel cell. Although the simulation test runs for altitudes between sea level and 2000 m, it is valid for any altitude variation from sea level to 6000 meters, representing the practical totality of world roads.

Ika Dyah Widharyanti, Muhammad Andiri Hendrawan, Marcelinus Christwardana

International Journal of Renewable Energy Development • 2020

The plant microbial fuel cell (PMFC) is a technology built to produce renewable and sustainable electricityin order to meet the increasing global demand. This study demonstrates the potential application of PMFC in swamps dominated by water hyacinth to produce biological energy and plant biomass.In this research, the plant was integrated into a microbial fuel cell that adopts various types of anode materials such as carbon felt, iron and zinc, with a varying distance of 10 and 20 cm between the anode and cathode. Organic compounds emerging from the photosynthesis process were deposited by plant roots, which were then oxidized by bacteria in the mud media. The result showed that the developed PMFC produced a voltage and current density of 244.8 mV and 185.4 mA/m2, respectively, for 30 days, with a maximum power of 100.2 mW/m2 in the cells using zinc as anode material with an electrode spacing of 10 cm. Furthermore, the pH value on PMFC with a longer electrode was higher than the shorter distance due to the protons' inability to move from anode to cathode against the force of gravity. In conclusion, PMFC which utilizes water hyacinth has a good performance in converting chemical energy from the substrate into electrical energy, and has the potential to be developed in underdeveloped areas.

Aisha Buhari Salisu, Hindatu Yusuf, Shiaka Gimba Peter et al.

UMYU Scientifica • 2023

Microbial fuel cells (MFCs) are technologies that directly transform chemical energy into electrical energy by oxidizing organic matter using bacteria as biocatalysts. MFCs offer a potential technology for converting wastewater into useful energy source and at the same time serve as wastewater treatment facilities. This makes it superior to other wastewater treatment methods. This study focused on the utilization of MFCs to generate bioelectricity from sewage wastewater using cow urine as inoculum and identify the bacteria colonizing the anode electrode. The experiment were conducted using two-chambered MFC constructed using locally sourced materials. Wastewater was characterized using standard methods. The characteristics of the sewage wastewater are: 680 mg/L Chemical oxygen Demand (COD), 457 mg/L Biochemical oxygen Demand (BOD) and pH of 7.4. The maximum voltage, power and current density obtained were 196 mV, 18.26 mW/m2 and 97 mA/m2 respectively. The MFC shows a reduction in COD value by 82 % (680mg/L initial and 120 mg/L final).The identification of the anodic biofilms showed the presence of Bacillus spp and klebsiella spp based on their microscopic and biochemical characterization. The results of this study can contribute to improve understanding and optimizing electricity generation in MFC, Further study would be conducted in order to identify the microorganisms at molecular level.

Danang Jaya, Tunjung Wahyu Widawati, Firda Ellysa et al.

RSF Conference Series: Engineering and Technology • 2021

Indonesia's rapid population growth means that power demand will continue to rise year after year. Indonesia's growing population has resulted in an increase in restaurants, including Chinese food restaurants. As the number of restaurants grows, so does the amount of waste produced. Microbial Fuel Cells (MFC) that create electrical energy are one solution to this challenge. The study aimed to explore the utilization of MFC systems for power generation. It measured the performance of MFC in liquid waste in generating electrical value by utilizing a series of electrode types, particularly Aluminum (Al), Copper (Cu), Zinc (Zn), and Lead (Pb), and a blend of the four types of electrodes. The measured electrical value indicated that MFC can produced the high electrical voltage value was the pair of zinc (anode) and copper (cathode) of (0.863 V) and then the highest electric current value is 0.14 mA with electrode Cu and Zn. The maximum power density is 0.00464 W/m2 using a combination of Zn/Cu electrodes and then electrical energy with highest value is 0.75168 J with Zn/Cu.

Samudro Ganjar, Syafrudin Syafrudin, Wisnu Wardhana Irawan et al.

E3S Web of Conferences • 2017

Moisture content which affects the decomposition of organic material is one of composting parameters. The optimum moisture content indicates the higher power generation. This research aims to determine the optimum moisture content toward power density during the composting process in DGACSMFCs. The reactor was designed with dual graphene anode placed on the base and a half of reactor height in 2 L effective volume. Moisture content was varied at 40%; 50%; 60%; with 4 turning frequency, C/N ratio 30:1, and the mixed waste-leaves litter and canteen based food waste, during 23 days of the observation time. Other parameters of the composting process such as pH, temperature, C-Organic, N-Total, P-Total, and K-Total were also observed as control parameters. The result shows that the optimum moisture content is 60% with power density 17.74 mW/m 2 , and the final compost characteristics are meet the compost requirement based on SNI 19-7030-2004 about the specification of compost from domestic waste..

Mochammad Purwanto, M Anuari Ramdani, Wildan Wahyu Firdhaus et al.

Engineering Headway • 2024

The Dual-Chamber Microbial Fuel Cell system has been successfully developed to produce bioelectricity based on tofu liquid waste. In this study, variations of the operating parameters of the MFC were carried out, namely differences in electrolyte solutions of potassium permanganate (KMnO₄) and potassium dichromate (K₂Cr₂O₇). In addition, the configuration of the reactor circuit used is a series reactor circuit and a single reactor. The results of the MFC process show that the maximum electric voltage and current strength values obtained in the KMnO₄ electrolyte solution are 880 mV and 0.352 mA, respectively. Meanwhile, the maximum electric voltage and current strength in the K₂Cr₂O₇ electrolyte solution are 569 mV and 0.228 mA. Furthermore, the use of potassium permanganate is known to produce a maximum power density of 20.88 mW/cm², which is two times greater than the maximum power density value produced by potassium dichromate, which is 8.73 mW/cm². Whereas the difference in the reactor series shows that the series reactor circuit can increase the maximum power density value of 356.61 mW/cm², higher than the single reactor which is 26.21 mW/cm². Based on all the data generated from this study, tofu liquid waste has the potential as the main ingredient in the MFC process to produce bioelectricity.

Maheshi Somasiri, Tanusha Amandani, Charitha Basnayaka et al.

bioRxiv (Cold Spring Harbor Laboratory) • 2023

ABSTRACT High cathodic overpotential of the oxygen reduction reaction (ORR) in MFC carbon-based cathodes is one of the key barriers to the widespread adoption of the technology. Current Pt-based ORR catalysts are expensive. The use of novel and inexpensive catalysts as replacements for platinum is therefore desirable. In this study, nanomaterials were directly chemically synthesized on carbon microfiber electrodes to improve the performance of lake sediment inoculated MFCs. Nanomaterial of MnO 2 , MnO 2 /polyaniline (PANI), ZnO/NiO and ZnO/NiO/PANI attachments were directly chemically synthesized on the carbon material and used as cathode electrodes. The maximum power densities recorded for the different treatments were; MnO 2 78.5 mW/m 2 , MnO 2 /PANI (Polyaniline) 141.6 mW/m 2 , ZnO/NiO 67.6 mW/m 2 , and ZnO/NiO/PANI 129.4 mW/m 2 . The current and poswer densities were more than six-fold higher in ZnO/NiO/PANI and MnO 2 /PANI nanoparticle modified cathodes compared to the control MFCs with no catalyst. Cyclic voltammetry (CV) and FTIR data and SEM images suggest that the nanoparticle attached carbon material is morphologically, chemically and electrochemically different from the controls with no nanomaterial attachment. The outcome of this study demonstrates that nanomaterials-incorporated carbon microfiber cathodes bring about significant enhancements to power densities and may potentially have applications in cost-effective MFCs.

Carlo Santoro, Alexey Serov, Claudia W. Narvaez Villarrubia et al.

Scientific Reports • 2015

Abstract For the first time, a new generation of innovative non-platinum group metal catalysts based on iron and aminoantipyrine as precursor (Fe-AAPyr) has been utilized in a membraneless single-chamber microbial fuel cell (SCMFC) running on wastewater. Fe-AAPyr was used as an oxygen reduction catalyst in a passive gas-diffusion cathode and implemented in SCMFC design. This catalyst demonstrated better performance than platinum (Pt) during screening in “clean” conditions (PBS) and no degradation in performance during the operation in wastewater. The maximum power density generated by the SCMFC with Fe-AAPyr was 167 ± 6 μW cm −2 and remained stable over 16 days, while SCMFC with Pt decreased to 113 ± 4 μW cm −2 by day 13, achieving similar values of an activated carbon based cathode. The presence of S 2− and "Equation missing"<!-- image only, no MathML or LaTex -->showed insignificant decrease of ORR activity for the Fe-AAPyr. The reported results clearly demonstrate that Fe-AAPyr can be utilized in MFCs under the harsh conditions of wastewater.

Wilgince Apollon, Juan Vidales-Contreras, Humberto Rodríguez-Fuentes et al.

Energies • 2022

Plant microbial fuel cells (P-MFCs) are sustainable and eco-friendly technologies, which use plant root exudates to directly nourish the electrochemically active bacteria (EABs) to generate sustainable electricity. However, their use in evaluating plant growth has been insufficiently studied. In this study, interconnection between plant growth and the production of bioelectricity was evaluated by using P-MFCs inoculated with 642.865 mL ≅ 643 mL of livestock’s urine such as cow urine, goat urine, and sheep urine. The greatest mean stem diameter of 0.52 ± 0.01 cm was found in P-MFC-3 inoculated with goat urine, while the P-MFC-2 treated with cow urine reached a higher average number of roots with a value of 86 ± 2.50 (95% improvement) (p &lt; 0.05). Besides, P-MFC-4 presented greater height of 50.08 ± 0.67 cm. For polarization curve experiment a higher maximum power density of 132 ± 11.6 mW m−2 (931 mA m−2) was reached with cow urine; in turn, with regard to the long-term operation, the same reactor indicated a higher maximum average power density of 43.68 ± 3.05 mW m−2. The study’s findings indicated that Stevia P-MFC inoculated with urine was a good option to increase the biomass amount for the agricultural plants along with power generation. Further, this study opens the way for more investigation of evaluating the impact of P-MFC on plant growth.

Margaret. A. Adekanle, Julius K. Oloke, O. Catherine Adekunle et al.

Global Journal of Pure and Applied Sciences • 2020

Power supply has remained a challeng issue in developing coutries. The aim of this study was to evaluate the potentials of selected yeast species for bioelectricity generation. Different yeast species were isolated from cassava wastewater, whey wastewater, human urine, and rabbit dung using the spread plate method. These isolates were identified using analytical profile index (API). Results obtained revealed the identity of the isolated yeast species as Candida famata, Candida hellenical. Candida tropicalis and Saccharomyces cerevisia (using API method).The isolated yeast species were used singly, and as a consortium for bioelectricity generation, and yeast in continuous mode. The same wastes as used for the isolation process were evaluated as possible substrates for the generation of bioelectricity. Out of the four wastes used, cassava processing wastewater gave the highest bioelectricity potential and was subsequently used as substrate for further study. Saccharomyces cerevisiae elicited the highest electricity generation when the four yeast species were used singly (1.08V). A consortium of the four isolates elicited a synergis effect, generating 1.57V of voltage. Stacking of the Microbial Fuel Cell(MFC) components improved voltage to 2.4V due to its lower internal resistance within the stacked materials. It is apparent from the results obtained in this study that when properly harnessed, microbial fuel cells (MFCs) technology could serve as alternate source of renewable energy.&#x0D; Keywords: Microbial fuel cells, Waste, yeasts, Salt- Bridge, Nafion117.

Catalina González-Nava, Michel Canul-Chan, Juan Campos et al.

Revista Internacional de Contaminación Ambiental • 2024

Microbial fuel cells (MFC) constitute an attractive alternative as an environmental remediation technology since they can generate electrical current using organic waste as a substrate. Since the performance of MFCs depends on the characteristics of the biofilm on the anode surface, it is important to assess the genetic information of the microorganisms that grow on the electrode. For this purpose, a sewage sludge sample was obtained from a wastewater treatment plant and used to inoculate a type H MFC. Electrochemical characterization, on one hand, indicates that while the biofilm has a typical electrochemical performance reflected by the generated voltage (near 0.4 V) and by the electroactivity observed in cyclic voltammetry experiments, and on the other hand, the metagenomic analysis shows that the most abundant genera are Pseudomonacea, Nitrosomonas, Hyphomonas, and Opitutus. The study also indicates that the biofilm’s electroactive microorganisms can metabolize amino acids, lipids, and carbohydrates and possess genetic tools for ionic transport and energy production. Regarding the electron acceptor/donator capabilities, several oxidases, reductases, and complexes were identified, mainly terminal cytochrome C oxidase and respiratory complex I, which could be associated with the exoelectrogenic capacity of the microorganisms. Finally, the metagenomic information indicates that the biofilm can synthesize rhamnose, sialic acid, and alginate molecules, which could possibly be associated with the formation and consolidation of the microbial biofilm.

Teng Howe Cheng, Kok Boon Ching, Chessda Uttraphan et al.

Indonesian Journal of Electrical Engineering and Computer Science • 2020

Plant microbial fuel cell (P-MFC) is an electrochemical reactor that converts organic compounds to electrical energy through the catalytic reaction from electrochemically active bacteria (EAB). However, there is no sign of an attempt in developing the functional model in predicting the energy conversion and utilization of P-MFC. In this study, an analytic model is proposed to show the whole production process of the organic compound to electrical energy generation. &lt;em&gt;Pandanus Amaryllifolius&lt;/em&gt; plant was used as sources of photosynthate, where biomass product from rhizodeposition, acetate was produced, and soil bacteria as the microbial culture, and air as the input to the cathode chamber. The proposed analytical model is able to predict the output of the P-MFC using the parameters from the experiment. The generated data from the model was then compared with the monitored data from the &lt;em&gt;Pandanus Amaryllifolius &lt;/em&gt;P-MFC. The results show the electrical power output has a high similarity pattern with the bacterial growth curve model and able to achieve the coulombic efficiency of 95.32%.

K. Sathish Kumar, Omar Solorza-Feria, G. Vázquez-Huerta et al.

ECS Transactions • 2011

Anode-respiring bacteria (ARB) perform an unusual form of respiration in which their electron acceptor is a solid anode. The focus of this study was to characterize the electrical stress direct evolution of biocatalysts as a way of enriching the community with ARB for microbial fuel cell. We gave the electrical stress continually to the Texcoco bacterial community at -150mV/SCE. The 4th day current started to increase and attained the maximum current of 0.35mA in the 15 th day. The current in this period was associated to biofilm growth. On the 15thday and by using cyclic voltammetery, an irreversible electron transfer reaction of alkaliphilic cytochrome was found, due to the electrode fouling. From the impedance measurement, the biofilm ARB resistance was determined (~250Ω). Further confocal microscopy studies of biofilm ARB revealed ~6µm thickness. In the single chamber microbial fuel cell, the electrochemical stressed biofilm-ARB exhibited a maximum power density of 79mW/m2

B. Li, Z. Zhao, Z. Weng et al.

Fuel Cells • 2020

Abstract To boost the performance of microbial fuel cells (MFCs), a novel material of polypyrrole nanowires (PPy‐NWs) modified by carbon dots (CDs) is synthesized by polymerizing pyrrole monomers and CDs, in which CDs are attached and distributed on the surface of the PPy‐NWs, thus leading to the rough surface with a special dot‐line structure. Such CDs/PPy‐NW composite with special unique structure exhibits superior properties, and excellent performance is found for MFC using CDs/PPy‐NW composite as anode. The electron transfer rate increases to 0.0934 s −1 with a sharp rise by 26% over pure PPy‐NWs, and the resistances of CDs/PPy‐NW electrode are only one third of those of pure PPy‐NWs electrode. Further, the mini‐MFC equipped with the CDs/PPy‐NW composite as anode exhibits a high open circuit voltage (630 mV) and its maximum power density with a value of 291.4 mW m −2 is twice that of the mini‐MFC equipped with pure PPy‐NWs anode. These results demonstrate CDs/PPy‐NW with a unique dot‐line structure as a more promising anode material for MFC application.

Pingying Zeng, Kang Wang, Ryan Falkenstein-Smith et al.

ASME 2014 12th International Conference on Fuel Cell Science, Engineering and Technology • 2014

This study examines the successful development of a combustion-driven thermal transpiration-based combustor and a self-sustaining gas pump system having no moving parts and using readily storable hydrocarbon fuel. A stacked configuration was then integrated into the combustor creating a self-sustaining power generation system. In recent years, power generation devices employing hydrocarbon fuels rather than electrochemical storage as energy feedstock have been studied extensively due to the much higher energy densities of hydrocarbon fuels than the best available batteries. While many devices have been proposed including internal combustion engines and gas turbines, they all require the use of air to obtain a higher energy density so that only one reactant (fuel) need be carried. Thermal transpiration was accomplished by meeting two essential conditions: (1) gas flow in the transitional or molecular regime using glass microfiber filters as transpiration membranes and (2) a temperature gradient through the membrane using catalytic combustion downstream of the membrane. A cubic combustor was designed to house the thermal transpiration membrane and develop into a self-sustaining gas pump system. Fuel/Air would feed through an inlet into a mixing chamber that would flow into the thermal guard containing the thermal transpiration membrane. The thermal guard was developed from a high thermal conductivity stainless steel made into a cubic formation by using a 3D printing process. This configuration allowed both fuel and air to be transpired through the membrane meaning it was not possible for any reactant flow to occur as a result of the fuel supply pressure and only the membrane could draw reactants into the device. In addition to pumping, a single-chamber solid-oxide fuel cell (SC-SOFC) was incorporated into combustion driven thermal transpiration pumps to convert chemical or thermal energy into electrical energy for a self-contained portable power generation system. Experiments showed that transpiration pumps with larger porosity and larger overall size exhibited better performance, though membrane pore size had little effect. These results were quantitatively consistent with theoretical predictions. By exploiting the temperature and fuel/oxygen concentrations within the transpiration pump, the SOFC achieved a maximum power density of 40 mW/cm2. Despite being far lower than necessary for a power source to be competitive with batteries, this preliminary study signifies an on-going positive efficiency that has potential for improvement through optimizing SOFC technology.

Sona Kazemi, Madjid Mohseni, Khalid Fatih

Journal of Chemical Technology &amp; Biotechnology • 2014

Abstract BACKGROUND High cost and ohmic loss are two issues that microbial fuel cells ( MFC ) face before becoming economically viable. To address the high cost and ohmic loss issues, a flat‐plate MFC ( FPMFC ) configuration applying a passive air‐breathing cathode and a three‐dimensional anode was introduced. Electricity generation was examined in the FPMFC through operation in the presence and absence of a proton exchange membrane ( PEM ), and in batch and continuous modes. RESULTS Continuous operation of the FPMFC in the presence of a PEM favored power generation, mainly due to elimination of oxygen and biomass in the anode. Peak power density of 18 Wm ‐3 was produced in the presence of a PEM (ohmic resistance 40 Ω cm 2 ), which was more than 5‐fold higher than that with J‐cloth. During batch operation, the power density increased and reached maximum in the third batch (18 W m ‐3 at 60 A m ‐3 ). Greater stability was observed during continuous operation resulting in a 2.5‐fold increase in peak power density (44 W m ‐3 at 146 A m ‐3 ). CONCLUSION The passive air‐breathing FPMFC showed promising performance, offering a more economically viable configuration than the conventional FPMFCs using active (air, ferricyanide, and ferric iron) cathodes. © 2014 Crown copyright. Journal of Chemical Technology &amp; Biotechnology © 2014 Society of Chemical Industry

Sun-Joon Byun, Zhen Huan Wang, Jun Son et al.

Preprints.org • 2017

We propose a wave-like design on the surface of cathode channels (wave form cathode channels) to improve oxidant delivery to gas diffusion layers (GDLs) [1-2]. We performed experiments using PEMFCs combined with wave form surface design on cathodes. We varied the factors of the distance between wave-bumps (the Adhesive distance, AD), and the size of the wave-bumps (the Expansion ratio, ER). The ADs are 3, 4, and 5 times the size of the half-circle bump&amp;rsquo;s radius, and the ERs are 1/1.5, 1/2, and 1/3 times the channel&amp;rsquo;s height. We evaluated the performances of the fuel cells, and compared the current-voltage (I-V) relations. For comparison, we prepared PEMFCs with conventional flat-surfaced oxygen channels. Our aim in this work is to identify fuel cell operation by modifying the surface design of channels, and ultimately to find the optimal design of cathode channels that will maximize fuel cell performance.

Johanna Dombrovskis, Victor Shokhen, Lisa Kylhammar et al.

ECS Meeting Abstracts • 2024

The fuel cell market is maturing, and the production volumes are increasing. In parallel, expectations on performance, lifetime and operational range for fuel cell stacks are growing. As fuel cell technology matures, more fuel cell stacks are used in real life applications instead of laboratory environment. These positive developments bring with them new challenges and opportunities to learn. Several of these challenges and their impact on stack design and validation will be discussed. The focus will be on optimization of useful stack power density, fuel cell stack conditioning, enlarging the LT-PEM fuel cell operation range and on durability testing. This talk addresses why conditioning and durability testing are closely connected and illustrates how this can impact stack platform and fuel cell development. In addition, the interactions between power density, stack integration and stack operational window are illustrated showing how each of these parameters could be optimized utilizing a current distribution plate and what trade-offs are relevant for optimized fuel cell stack and system performance. Powercell is active in various market segments and has developed stacks and stack components for ~20 years. The optimizations and trade-offs described hinge heavily on key PEM stack requirements which can be widely different in different PEM fuel cell market sectors, as illustrated by the emerging usage of fuel cells in aviation.

S. Mateo, A. Gonzalez del Campo, J. Lobato et al.

Biotechnology Progress • 2016

In this work, the long‐term effects of transient chemical oxygen demands (COD) concentrations over the performance of a microbial fuel cell were studied. From the obtained results, it was observed that the repetitive change in the COD loading rate during 12 h conditioned the behavior of the system during periods of up to 7 days. The main modifications were the enhancement of the COD consumption rate and the exerted current. These enhancements yielded increasing Coulombic efficiencies (CEs) when working with COD concentrations of 300 mg/L, but constant CEs when working with COD concentrations from 900 to 1800 mg/L. This effect could be explained by the higher affinity for the substrate of Geobacter than that of the nonelectrogenic organisms such as Clostridia . © 2016 American Institute of Chemical Engineers Biotechnol. Prog. , 32:883–890, 2016

Z. Fu, K. Li, L. Pu et al.

Fuel Cells • 2016

Abstract One of the main limiting factors for scaling up microbial fuel cells (MFCs) technology is to develop low‐cost and high‐efficiency cathode. A new and simplified approach was developed by using a commercial waterproof breathable membrane (WBM) as gas diffusion layer (GDL) material as substitution for conventional polytetrafluoroethylene (PTFE) GDL. Air‐cathode with the WBM pasted (AC‐P) onto the stainless steel mesh (SSM) achieved a maximum power density of 611 ± 10 mWm −2 , which was similar to that using a PTFE GDL by rolling method (645 ± 12 mWm −2 , AC‐R). Physical and electrochemical techniques were employed to investigate the morphology and electrochemical characteristics of the cathode. The result demonstrated that AC‐P had a higher current density and internal resistance than AC‐R. Besides, the WBM had a higher porosity and uniform texture. The study showed that the WBM was a kind of good GDL material for easy preparation, low cost and stable performance of cathode construction.

Sadiq Haruna, Hindatu Yusuf, Ahmad Muhammed Gumel et al.

Dutse Journal of Pure and Applied Sciences • 2024

Microbial fuel cells (MFCs) have shown promise as a sustainable technology for wastewater treatment and energy recovery. In this study, cattle dung was used as an inoculum and kitchen waste (KW) from Dutse urban, Nigeria was used as a substrate for bioelectricity generation in MFC. The MFC was operated in a fed-batch mode over 37 days, spanning three cycles. During characterization, the chemical oxygen demand (COD) of the KW was found to be 30421 ± 124 mg/L, indicating a high concentration of organic pollutants. The MFC's performance was evaluated based on the voltage generated, with the first cycle reaching a peak of 254 mV, the second cycle 247 mV, and the third cycle 242 mV. Current and power densities during the three cycles decreased gradually from 66.84 mA/m² and 16.84 mW/m² in the first cycle to 63.68 mA/m² and 15.41 mW/m² in the third cycle respectively. Furthermore, there was a notable reduction in COD from the influent diluted from initial measured COD, from 1120 ± 63 mg/L to an effluent level of 226 ± 49 mg/L, indicating approximately 80% removal rate. The pH of the anolyte progressively dropped with each cycle, reflecting the metabolic activities of bacteria in the anode chamber. The findings underscore MFC's potential for organic waste management and electricity generation, with results outperforming some contemporary studies.

Xiuwei Fu, Li Fu, Hashem Imani Marrani

Journal of New Materials for Electrochemical Systems • 2021

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

Victoria Marie Ehlinger, Ahmet Kusoglu, Adam Z. Weber

ECS Meeting Abstracts • 2019

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

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

E3S Web of Conferences • 2021

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

Atsushi Aoki, Akebono Tanaka

ECS Meeting Abstracts • 2018

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

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

Materials • 2022

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

Tejas Ambekar

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

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

Kalagbor IA

Open Access Journal of Waste Management &amp; Xenobiotics • 2019

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

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

Water Science and Technology • 2009

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

Subha Chandrasekarabarathi, Priya ArunKumar, Rajesh Banu Jeyakumar

Environmental Progress &amp; Sustainable Energy • 2023

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

Samindi Madhubha Jayawickrama, Tsuyohiko Fujigaya

ECS Meeting Abstracts • 2019

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

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

International Journal of Renewable Energy Development • 2020

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