Sameer Al‐Asheh, Marzieh Bagheri, Ahmad Aidan

Engineering in Life Sciences • 2022

Abstract Removal efficiency of gold from a solution of pure tetrachloroaurate ions was investigated using microbial fuel cell (MFC) technology. The effects of type of catholyte solution and initial gold concentration on the removal efficiency were considered. Due to its presence at high levels in the gold wastewater, the effect of copper ions on the removal efficiency of the gold ions was also studied. The effects of pH and initial biomass concentration on the gold removal efficiency was also determined. The results showed that after 5 h contact time, 95% of gold removal efficiency from a wastewater containing 250 ppm of initial gold ions at ambient temperature using 80 g/L yeast concentration was achieved. After 48 h of the cell's operation under the same condition, 98.86% of AuCl 4 – ions were successfully removed from the solution. At initial gold concentration in the waste solution of 250 ppm, pH 2, and initial yeast concentration of 80 g/L, 100% removal efficiency of the gold was achieved. On the other hand, the most suitable condition for copper removal was found at a pH of 5.2, where 53% removal efficiency from the waste solution was accomplished.

Choudhary Suresh Kumar, Yadav Rajesh

International Journal of Zoological Investigations • 2022

Water pollution is one of the major ecological challenge for all forms of life. The major cause of water pollution is rapid industrialization. Industries use water for various activities and during these activities; they generate an enormous volume of wastewater. The wastewater can be collected either in a local sewer system, treated by wastewater treatment plants, or directly released into the environment. In case of direct discharge of wastewater into the different water bodies, it adversely affects the life which is dependent on this for their water needs. Industrial wastewater contains various microorganisms, organic (chlorides, sulphates, oil and grease, hydrocarbons, pesticides, herbicides, phenol, aliphatic compounds), and chemical compounds (heavy metals, detergents, pesticides, nitrogen, and phosphorus) which are harmful to the environment as well as to humans. Bacteria are the most common microorganisms which are present in industrial wastewater, some of these are helpful in the treatment of wastewater and some are pathogenic which is responsible for various types of waterborne diseases. Thus, this study reviews various types of Bacteria present in industrial wastewater in terms of their roles within the wastewater treatment process.

Zabdiel A. Juarez, Víctor Ramírez, Carlos Hernández-Benítez et al.

Catalysts • 2025

Wastewater treatment has become a priority in the global attempt to address environmental pollution. Conventional wastewater treatment processes are often limited by their high energy consumption, so it is necessary to develop new technologies. This work shows the results obtained using a passive aerated membraneless microbial fuel cell (PAML-MFC) system consisting of 10 individual units, designed to treat 1000 L/day of real wastewater, using granular activated carbon anodes and cathodes. The pilot-scale water treatment system under study combines design and materials to result in low-cost operation. After 300 days of treating real wastewater originally characterized by a chemical oxygen demand (COD) value of 500 mg/L on average, it was found that the PAML-MFC under study removed 60 to 80% of the COD contained in real wastewater. Under these conditions, the individual MFCs reached an average power density below 1 mW/m3.

Shelley D. Minteer

ECS Meeting Abstracts • 2023

Petroleum hydrocarbons are currently our major energy source and an important feedstock for the chemical industry. Beyond combustion, conversion of chemically inert hydrocarbons to more valuable chemicals is of considerable interest. However, two challenges hinder this conversion. One is the regioselective activation of inert carbon–hydrogen (C–H) bonds. The other is designing a pathway to realize this complicated conversion. This paper will discuss the use of alkane monoxygenases in bioelectrochemical systems for C-H activation, as well as enzyme cascades and hybrid catalytic cascades for the conversion of inert alkanes to complex organic molecules like imines with selectivity far beyond traditional homogeneous and heterogeneous catalysts.

Zhufan Lin, Xinyuan He, Huahua Li et al.

Processes • 2025

The reverse polarity biocathode culture (RPBC) is a technology for the rapid preparation of biocathodes, which quickly enrich electroactive bacteria (EAB) in the microbial fuel cell (MFC) anode and then transform the electrode function from bioanode to biocathode by reversing bioelectrode polarity. However, the mechanism of RPBC is still unclear, and methods to regulate performance and ensure the long-term stability of cultured biocathodes have not been established. This study investigated the correlation between electrogenic bacteria and the target reducing EAB, from two aspects: energy supply and the formation of a composite biofilm. The results showed that electrogenic bacteria provided energy for the reducing EAB through interspecies electron transfer. This process could be regulated by changing the electrode potential and substrate concentration to obtain an optimized biocathode. In addition, the RPBC forms a composite biofilm of electrogenic bacteria and reducing EAB, which significantly improves the enrichment efficiency and the amount of reducing EAB (compared with a direct biocathode culture, respectively, shortening the enrichment time by 80%, increasing the electroactivity by 12.4 times, and increasing the nitrate degradation rate by 4.85 times). This study provides insights into regulating the performance and maintaining the long-term stability of RPBC-cultured biocathodes.

Nazla Fauziyah Octaviani, Nisa Kartika, Anggita Rahmi Hafsari

Indonesian Journal of Environmental Sustainability • 2024

The uncontrolled nature of fossil fuels and their ecological consequences have moved emphasis to renewable energy and fuel cells, particularly in the transportation industry. The generation of energy from electrons generated from metabolic reactions aided by bacteria is studied in this paper. Microbial fuel cells (MFC) are an environmentally beneficial method of generating electricity while also purifying wastewater, with up to 50% chemical oxygen requirement elimination and power densities ranging from 420 to 460 MW/m2. This paper focuses on the technology that generates electricity by utilizing the metabolic power from electroactive bacteria as a renewable energy source. The method to collect data is a literature study. The result is seven species of electroactive bacteria potential from 7 articles, which can be used to generate MFC. In summary, using electroactive bacteria as MFC as a renewable energy source is possible because many sources of organic materials can be used as carbon sources for MFC, such as organic waste.

Tali Dotan, Yoo Kyung Go, Jesus Miguel Lopez Baltazar et al.

ECS Meeting Abstracts • 2025

Pyrolysis is the thermal decomposition of organic matter in the absence of oxygen 1 . This high-temperature process has been shown to produce carbon structures from photoresist since the 1990s. Using this technique, the photoresist is thermally reacted at high temperatures of 600 to 1100°C, forming a film with electrochemically active surfaces, providing glassy carbon-like properties. It has been demonstrated that better electrocatalytic behavior is obtained with carbon films prepared at the higher pyrolysis temperatures due to a differences in composition 1 . Additionally, pyrolysis has also been widely demonstrated for biowaste and various biomaterials. It is shown to be versatile, user-friendly, and has the potential for enhancement 1-3 . In this work, Shewanella Oneidensis bacterial biofilms are shown to provide conductive surfaces with properties that depend on the pyrolysis temperature in the range of 600 to 1100°C. The pyrolysis was carried out in a closed ceramic tube furnace under a 200mTorr vacuum at a heating rate of 5°C/ min. The pyrolysis process was characterized using thermogravimetric analysis and the resulting films were characterized by SEM, 4-point probe, Raman Spectroscopy, as well as by electrochemical characterization. This approach leverages the unique capabilities of S. oneidensis in metal ion reduction and nanoparticle biosynthesis, potentially allowing for the incorporation of catalytic nanoparticles within the electrode structure. The flexibility and distinctive properties of these biofilm-derived electrodes open up new possibilities for electrochemical CO 2 reduction and broader energy research applications, potentially contributing to the development of more efficient and selective catalytic systems for CO 2 utilization in a circular carbon economy. (1) Kim, J.; Song, X.; Kinoshita, K.; Madou, M.; White, R. Electrochemical Studies of Carbon Films from Pyrolyzed Photoresist. J. Electrochem. Soc. 1998 , 145 (7), 2314–2319. (2) Mohan, D.; Pittman, C. U.; Steele, P. H. Pyrolysis of Wood/Biomass for Bio-Oil: A Critical Review. Energy Fuels 2006 , 20 (3), 848–889. (3) Wang, G.; Dai, Y.; Yang, H.; Xiong, Q.; Wang, K.; Zhou, J.; Li, Y.; Wang, S. A Review of Recent Advances in Biomass Pyrolysis. Energy Fuels 2020 , 34 (12), 15557–15578.

Shuai Luo, Hongyue Sun, Qingyun Ping et al.

Energies • 2016

Bioelectrochemical systems (BES) are promising technologies to convert organic compounds in wastewater to electrical energy through a series of complex physical-chemical, biological and electrochemical processes. Representative BES such as microbial fuel cells (MFCs) have been studied and advanced for energy recovery. Substantial experimental and modeling efforts have been made for investigating the processes involved in electricity generation toward the improvement of the BES performance for practical applications. However, there are many parameters that will potentially affect these processes, thereby making the optimization of system performance hard to be achieved. Mathematical models, including engineering models and statistical models, are powerful tools to help understand the interactions among the parameters in BES and perform optimization of BES configuration/operation. This review paper aims to introduce and discuss the recent developments of BES modeling from engineering and statistical aspects, including analysis on the model structure, description of application cases and sensitivity analysis of various parameters. It is expected to serves as a compass for integrating the engineering and statistical modeling strategies to improve model accuracy for BES development.

Jan‐Niklas Hengsbach, Mareike Engel, Marcel Cwienczek et al.

ChemElectroChem • 2023

Abstract The concept of energy conversion into platform chemicals using bioelectrochemical systems (BES) has gained increasing attention in recent years, as the technology simultaneously provides an opportunity for sustainable chemical production and tackles the challenge of Power‐to‐X technologies. There are many approaches to realize the industrial scale of BES. One concept is to equip standard bioreactors with static electrodes. However, large installations resulted in a negative influence on various reactor parameters. In this study, we present a new single‐chamber BES based on a stirred tank reactor in which the stirrer was replaced by a carbon fiber brush, performing the functions of the working electrode and the stirrer. The reactor is characterized in abiotic studies and electro‐fermentations with Clostridium acetobutylicum . Compared to standard reactors an increase in butanol production of 20.14±3.66 % shows that the new BES can be efficiently used for bioelectrochemical processes.

Nhlanganiso Ivan Madondo, Emmanuel Kweinor Tetteh, Sudesh Rathilal et al.

Catalysts • 2022

Conventional anaerobic digestion is currently challenged by limited degradability and low methane production. Herein, it is proposed that magnetic nanoparticles (Fe3O4-NPs) and bioelectrochemical systems can be employed for the improvement of organic content degradation. In this study, the effect of electrode configuration was examined through the application of a bioelectrochemical system and Fe3O4-NPs in anaerobic digestion (AD). A microbial electrolysis cell with cylindrical electrodes (MECC) and a microbial electrolysis cell (MEC) with rectangular electrodes were compared against the traditional AD process. Biochemical methane potential (BMP) tests were carried out using digesters with a working volume of 800 mL charged with 300 mL inoculum, 500 mL substrate, and 1 g Fe3O4-NPs. The electrodes (zinc and copper) of both digesters were inserted inside the BMPs and were powered with 0.4 V for 30 days at 40 °C. The MECC performed better, improving degradability, with enhanced methane percentage (by 49% > 39.1% of the control), and reduced water pollutants (chemical-oxygen demand, total organic carbon, total suspended solids, turbidity, and color) by more than 88.6%. The maximum current density was 33.3 mA/m2, and the coulombic efficiency was 54.4%. The MECC showed a remarkable potential to maximize methane enhancement and pollution removal by adjusting the electrode configuration.

Yuman Guo, Yongqin Lv, Tianwei Tan

The Innovation Energy • 2024

<p>Bioelectrochemical systems hold promise for the sustainable transformation of carbon dioxide (CO<sub>2</sub>) using non-photosynthetic bacteria. Despite the progress made in developing electrodes and microbial platforms, significant challenges persist in optimizing electron transfer across the bio-abiotic interface. In this review, we delve into recent advances in fine-tuning bacteria-electrode interfaces to enhance bioelectrochemical CO<sub>2</sub> conversion and to better understand the electron transfer mechanisms between CO<sub>2</sub>-fixing microbes and electrodes. Notable achievements, such as single-atom catalyst design, heterologous expression of Mtr complexes, and multimodal characterization approaches, are discussed. However, electron transfer dynamics for many bacteria-electrode pairings remain incompletely understood, impeding the rational design of biosystems. Looking forward, a synergistic approach involving high-resolution characterization techniques, computational modeling, and targeted engineering of both microbial and electrode components is essential. Achieving finely tuned bio-abiotic interfaces at the molecular level holds the promise to revolutionize these bioelectrochemical platforms. With further optimization, scalable and sustainable CO<sub>2</sub> conversion may become technically and economically viable.</p>

Yang Liu, Hui Zhou, Weixiao Zhou et al.

Advanced Energy Materials • 2021

Abstract Functional bioelectronic implants require energy storage units as power sources. Current energy storage implants face challenges of balancing factors including high‐performance, biocompatibility, conformal adhesion, and mechanical compatibility with soft tissues. An all‐hydrogel micro‐supercapacitor is presented that is lightweight, thin, stretchable, and wet‐adhesive with a high areal capacitance (45.62 F g −1 ) and energy density (333 μWh cm −2 , 4.68 Wh kg −1 ). The all‐hydrogel micro‐supercapacitor is composed of polyaniline@reduced graphene oxide/Mxenes gel electrodes and a hydrogel electrolyte, with its interfaces robustly crosslinked, contributing to efficient and stable electrochemical performance. The in vitro and in vivo biocompatibility of the all‐hydrogel micro‐supercapacitor is evaluated by cardiomyocytes and mice models. The latter is systematically conducted by performing histological, immunostaining, and immunofluorescence analysis after adhering the all‐hydrogel micro‐supercapacitor implants onto hearts of mice for two weeks. These investigations offer promising energy storage modules for bioelectronics and shed light on future bio‐integration of electronic systems.

Qian Gong, Yingying Yu, Lixing Kang et al.

Advanced Functional Materials • 2022

Abstract The extraneural electrodes that cling to the nerve show great advantages in decreasing the damage of nerves, as compared to the intraneural electrodes. The grand challenge for the extraneural electrode is the instability of its electrode–nerve interface during nerve movement. In the proposed research, an adaptive, stretchable, and biocompatible carbonene extraneural electrode, which integrates rigid 2D defective graphene nanosheets on the soft carbon nanotube (CNT) fiber, is designed. The rigid nanosheets and the soft nanotubes are dominated by sp 2 nanocarbon, which is defined as carbonene. Benefiting from the soft and robust nature of the CNT fiber, the hybrid carbonene electrodes can be facile‐tailored into various complex shapes with a wide range of modulus (0.5–600 kPa), which plays a significant role in mechanical match of the modulus with that of the nerve. Moreover, the hybrid carbonene fiber exhibits excellent electrical conductivity (3.3 × 10 5 S m −1 ) and novel biocompatibility. As a result, the carbonene electrode shows a preferable performance compared to the traditional metal electrode, whose peak‐to‐peak action potential is 310% higher than the commercial Pt electrode. Overall, this work proposes a novel strategy for assembling the facile‐tailorable and biocompatible carbonene electrode, which can open an avenue for designing the next‐generation neural electrode.

Liang Wang, Suresh G. Advani, Ajay K. Prasad

ECS Meeting Abstracts • 2017

We have developed a self-healing membrane based on microcapsules prefilled with Nafion solution. The microcapsules are designed to rupture when they encounter defects formed in the membrane such as cracks and pinholes, and then release the prefilled Nafion solution to heal the defects in-situ. A procedure was developed to prepare microcapsules with a urea-formaldehyde shell prefilled with a Nafion/tributyl phosphate self-healing solution. The prepared microcapsules were characterized by SEM with focused ion beam (FIB) and optical microscopy. Proton conductivity, mechanical properties, swelling and water uptake of the composite membranes based on microcapsules were measured and compared with that of pure recast Nafion membranes. Fuel cell performance with 6 and 10 wt% microcapsules/Nafion membranes was compared with that of a pure recast Nafion membrane. Durability testing comprising 220 hours of OCV-hold with relative humidity cycling confirmed that the self-healing functionality could greatly extend the life span of the fuel cell membrane.

Giulia Massaglia, Marzia Quaglio

Nanomaterials • 2022

Porous 3D composite materials are interesting anode electrodes for single chamber microbial fuel cells (SCMFCs) since they exploit a surface layer that is able to achieve the correct biocompatibility for the proliferation of electroactive bacteria and have an inner charge transfer element that favors electron transfer and improves the electrochemical activity of microorganisms. The crucial step is to fine-tune the continuous porosity inside the anode electrode, thus enhancing the bacterial growth, adhesion, and proliferation, and the substrate’s transport and waste products removal, avoiding pore clogging. To this purpose, a novel approach to synthetize a 3D composite aerogel is proposed in the present work. A 3D composite aerogel, based on polydimethylsiloxane (PDMS) and multi-wall carbon nanotubes (MWCNTs) as a conductive filler, was obtained by pouring this mixture over the commercial sugar, used as removable template to induce and tune the hierarchical continuous porosity into final nanostructures. In this scenario, the granularity of the sugar directly affects the porosities distribution inside the 3D composite aerogel, as confirmed by the morphological characterizations implemented. We demonstrated the capability to realize a high-performance bioelectrode, which showed a 3D porous structure characterized by a high surface area typical of aerogel materials, the required biocompatibility for bacterial proliferations, and an improved electron pathway inside it. Indeed, SCMFCs with 3D composite aerogel achieved current densities of (691.7 ± 9.5) mA m−2, three orders of magnitude higher than commercial carbon paper, (287.8 ± 16.1) mA m−2.

Livinus A. Obasi, Okechukwu D. Onukwuli, Chukwunonso C. Okoye

Current Research in Green and Sustainable Chemistry • 2021

S Muljani, A Wulanawati

ALCHEMY Jurnal Penelitian Kimia • 2016

<p>Microbial fuel cell (MFC) represents a major bioelectrochemical system that converts biomass spontaneously into electricity through the activity of microorganisms. The MFC consists of anode and cathode compartments. Microorganisms in MFC liberate electrons while the electron donor is consumed. The produced electron is transmitted to the anode surface, but the generated protons must pass through the proton exchange membrane (PEM) to reach the cathode compartment. PEM, as a key factor, affects electricity generation in MFCs. The study attempted to investigate if the sulfonated polystyrene (SPS) membrane can be used as a PEM in the application on MFC. SPS membrane has been characterized using Fourier transform infrared spectrophotometer (FTIR), scanning electron microscope (SEM) and conductivity. The result of the conductivity (σ) revealed that the membrane has a promising application for MFC.</p>

Narangarav Terbish, Srinivasa R. Popuri, Ching-Hwa Lee

Fuel • 2023

Ho-Young Jung, Sung-Hee Roh

Journal of Nanoscience and Nanotechnology • 2020

A microbial fuel cell (MFC) is bioelectrochemical system that enables the biochemical activities of bacteria to generate electricity. A composite membrane was prepared from polyvinylidene fluoride nanofiber coated with perfluorinated sulfuric acid ionomer (PVDF-PFSA) and evaluated as a replacement for the commercially available Nafion membrane, which is commonly used in MFC reactors. The power density obtained with the PVDF-PFSA composite membrane was higher than that obtained with the Nafion membrane in MFC reactors. The PVDF-PFSA composite membrane produced a maximum power density of 548 mW/m 2 . Hence, the PVDF-PFSA composite reported here is a promising candidate for use as a proton exchange membrane in energy devices and water treatment systems.

P. Kiatkittikul, T. Nohira, R. Hagiwara

Fuel Cells • 2015

Abstract We have successfully prepared composite membranes consisting of the ionic liquid N ‐ethyl‐ N ‐methylpyrrolidinium fluorohydrogenate and the polymer 2‐hydroxyethylmethacrylate and have secured them on a polyimide (PI) membrane support. The resulting EMPyr(FH) 1.7 F–HEMA (9:1 molar ratio) composite possesses ionic conductivity of 75 mS cm −1 at 120 °C when a 16‐µm support is employed, showing improved performance with elevated temperature; this marks a significant difference from devices using conventional polytetrafluoroethylene supports. In the single cell test, a maximum power density of 31 mW cm −2 is observed at 120 °C. Cross‐sectional SEM images of the corresponding membrane electrode assemblies reveal no significant difference in membrane thickness before and after cell testing, implying that this support does not suffer from membrane softening issues.

Barbara Mecheri, Valerio C.A. Ficca, Maida Aysla Costa de Oliveira et al.

ECS Meeting Abstracts • 2017

Microbial fuel cells (MFCs) can be considered as an efficient and flexible platform for integrated waste treatment and energy recovery [1]. The extensive research work devoted to this technology over the past decade demonstrates the promising outlook of MFCs, but practical application is still limited by the high costs associated to the materials used for device assembly, such as cathode materials which accounts for over 50% of the overall MFC capital cost. The sluggish kinetics of oxygen reduction reaction (ORR) has led to the use of expensive catalysts, such as platinum, which is not suitable to be applied to sustainable technologies. Hence, a great variety of materials have been developed for MFC cathodes, including nitrogen-doped activated carbons and non platinum group metal catalysts. Such materials allow achieving ORR rate comparable to Pt, the morphology and structure of the catalysts playing an important role on the efficiency and durability of ORR active sites [2,3]. The development of new carbon nanostructures with highly tunable morphology and structure has led to the use of graphene for several applications, including as component for MFC cathodes [4,5]. However, challenges, such as complexity in synthesis and costs, still limit the applicability of graphene as cathode component of MFCs. Therefore, a facile and efficient approach to develop graphene based catalysts can be considered a promising direction to achieve sustainable wastewater treatment and bioenergy production by BESs. In this work, we report a facile method for large-scale preparation of ORR catalysts based on graphene oxide (GO) obtained by electrochemical oxidation of graphite in aqueous solutions of inorganic salts. We developed different strategies to include nitrogen functionalities in GO structure, including post treatments based on annealing with ammonia gas and one-step nitrogen-doping of GO. By combining the use of atomic force microscopy with electrochemical and spectroscopic techniques, we correlated the different morphology and surface chemistry of GO with catalytic activity towards ORR. Differences in catalytic activity obtained by supporting iron on GO surface were also elucidated, investigating the nature of ORR active sites. The applicability of GO-based materials as ORR cathodes of MFCs was evaluated by assembling single chamber air-cathodes MFCs operating with sodium acetate in phosphate buffer solution. Coulombic efficiency, polarization and power density curves, and voltage generation cycles over time were acquired. The body of results demonstrated the potential ability of GO electrocatalysts to substitute platinum for ORR in MFCs. Acknowledgements . The present work was carried out with the support of the “European Union's Horizon 2020 research and innovation programme” (under H2020-FTIPilot-2015-1, Grant Agreement n. 720367-GREENERNET), the University of Rome Tor Vergata (under the Research Call “Consolidate the Foundations”, project name: BEST WATER), and CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brazil. References. [1] A. Rinaldi, B. Mecheri, V. Garavaglia, S. Licoccia, P. Di Nardo, E.Traversa. Energ. Environ. Sci., 1 (2008) 417-429. [2] C. Santoro, A. Serov, L. Stariha, M. Kodali, J. Gordon, S. Babanova, O. Bretschger, K. Artyushkova, P. Atanassov, Energ. Environ. Sci. 9 (2016) 2346-2353. [3] A. Iannaci, B. Mecheri, A. D'Epifanio, M. J. Lázaro Elorri, S. Licoccia. Int J Hydrogen Energ. 41 (2016) 19637-19644. [4] H. Yuan, Z. He. Nanoscale 7 (2015) 7022-7029. [5] K. Parvez, S. Yang, Y. Hernandez, A. Winter, A. Turchanin, X. Feng, K. Müllen. ACS Nano. 6 (2012) 9541-9550.

Nabin Aryal, Arnab Halder, Minwei Zhang et al.

Scientific Reports • 2017

Abstract During microbial electrosynthesis (MES) driven CO 2 reduction, cathode plays a vital role by donating electrons to microbe. Here, we exploited the advantage of reduced graphene oxide (RGO) paper as novel cathode material to enhance electron transfer between the cathode and microbe, which in turn facilitated CO 2 reduction. The acetate production rate of Sporomusa ovata -driven MES reactors was 168.5 ± 22.4 mmol m −2 d −1 with RGO paper cathodes poised at −690 mV versus standard hydrogen electrode. This rate was approximately 8 fold faster than for carbon paper electrodes of the same dimension. The current density with RGO paper cathodes of 2580 ± 540 mA m −2 was increased 7 fold compared to carbon paper cathodes. This also corresponded to a better cathodic current response on their cyclic voltammetric curves. The coulombic efficiency for the electrons conversion into acetate was 90.7 ± 9.3% with RGO paper cathodes and 83.8 ± 4.2% with carbon paper cathodes, respectively. Furthermore, more intensive cell attachment was observed on RGO paper electrodes than on carbon paper electrodes with confocal laser scanning microscopy and scanning electron microscopy. These results highlight the potential of RGO paper as a promising cathode for MES from CO 2 .

Vlad I Redko, Elena M Shembel, Volodymyr S Khandetskyy et al.

ECS Meeting Abstracts • 2016

Proprietary non-destructive non-contact (NDT) electromagnetic, holographic interferometry, gas discharge visualization, and combined methods, developed by Enerize, enable to evaluate properties of nano-structured powder of electrode materials, polymer and solid inorganic electrolytes, and interface of multi-layered electrode structures. Developed non-destructive testing methods & devices enable to optimize the technology, and quality of initial materials, components, and cells, including in-line control during battery production. These methods allow insure the safety and reliability of the batteries and reduce the cost of production Electromagnetic NDT inspection consists in estimation of the level of magnetic fields interaction between the primary and secondary transducers from the currents induced by the primary field in investigated object. Primary transducer creates magnetic field at alternating current passage on it. This magnetic field excites eddy currents in investigated object. Eddy currents create secondary magnetic field, which is directed towards the primary one, and the total field is less by the value of the secondary field. The value of secondary field depends on the value of induced primary eddy currents, and their value directly depends on the quality and controlled object properties. Thus, one can judge about controlled object quality by the value of summary magnetic field. Using these methods we can control without contact the following values: conductivity, defect availability, dielectric permeability, thickness and solve many other problems of non-destructive testing. The non-contact feature of these methods allows in-line quality control during synthesis of component materials as well as during production and final assembly of batteries, supercapacitors, solar cells, etc. Application of these systems results in improved product reliability and safety, while lowering overall manufacturing costs by reducing wastage and preventing defective components from being incorporated into the finished product. A number of mathematical tools are used for process description and modeling, for signal processing, and for generating properties control information based on analysis the dependences between the parameters the fields that are applied and the electro-physical characteristics the test article that measured. These include: mathematical descriptions of elastic waves in isotropic and anisotropic media; Maxwell’s and Laplace’s equations; mathematical tools for spectral transformations in different orthogonal bases; methods of defect identification and the processing and analysis of images using fuzzy logic and artificial neural networks. During presentation will be presented NDT methods and systems developed by Enerize for the following electromagnetic testing: determine specific conductivity, electromagnetic properties and composition of powdered materials, including nano powdered oxides and graphite for Li-ion batteries electrodes ; specific conductivity of thin films (transparent conductive oxides for solar cells, solid and polymer electrolytes, polymer membranes for fuel cells, etc.); non-contact electromagnetic testing to determine the interface resistance between current collector and active electrode mass; nondestructive determination of defects in multilayer structures based on combined ultrasonic and electromagnetic methods (e.g., “jelly-rolls” for batteries and supercapacitors) and other. The developed methods and equipment can be adapted from measurements of test articles or materials under static conditions to dynamic measurements during material synthesis. Enerize owns 14 US patents, 1 Great Britain patent, and numerous US patent applications in the area of Li-ion batteries, solar cells, and non-destructive non-contact testing..

Zhongwei Chen

ECS Meeting Abstracts • 2019

Advanced battery technology plays key roles in pursuit of sustainable energy future by electrifying the transportation fleet and converting/storing the intermittent green energy source in grid scale. Among the candidates, lithium-sulfur (Li-S) battery has risen up as a particularly promising successor to the currently dominating lithium-ion batteries due to its intriguingly high energy density and cost effectiveness. However, the practical implementation of Li-S battery can be achievable only when several critical problems are well addressed, which involve the insulting nature of cathode materials, the unruly polysulfide shuttling behavior, low efficiency of metallic lithium redox reactions, etc. These bugbears have been haunting the Li-S system and obstructing its access to practically high capacity and long lifespan. Targeting at these problems, we have long been committed to pursuing high-efficiency Li-S electrochemistry with extensive research interests in multiple battery ingredients. Following the two strategic emphasis on conduction properties and sulfur confinement, a series of functional host materials with delicate nano-/micro-structures has been successfully developed to fulfill fast and durable sulfur electrochemistry, which enables high sulfur loading and minimum electrolyte with achievable energy density that meets the commercial benchmark. Beyond that, targeted surface functionalization has been dedicated on separator to regulate the diffusion behavior of polysulfide, while host strategy with rationally-designed architecture has been also employed in lithium anode to suppress the dendrite formation and enhance the redox reversibility. Through the multi-sectional improvements, we are aiming at the establishment of an interoperable mechanism at a system level to promote the fundamental understanding as well as the practical electrochemical performance of Li-S battery for future commercialization.

Jingjie Wu, Tianyu Zhang

ECS Meeting Abstracts • 2019

Electrocatalytic reduction of CO 2 into value added chemicals or fuels is a promising technique towards a carbon-neutral chemical process. The electrochemical reduction of CO 2 is a complicated process involving multiple protons coupled electron transfer, theoretically resulting in a variety of products (e.g. CO, HCOOH, CH 4 , C 2 H 4 and C 2 H 5 OH). Therefore, the major challenge in CO 2 reduction lies in the manipulation of the selectivity towards a specific product as demanded. However, the study on CO 2 reduction has not substantially advanced primarily because of the lack of fundamental understanding of the reaction mechanism and the challenge of discovering efficient and robust catalysts for the various multi-electron transfer processes. Researchers have screened a wide range of metal-based materials for electrochemical reduction of CO 2 , and found only copper-based metals exhibit selectivity towards formation of hydrocarbons and oxygenates at fairly high efficiencies while most others favor production of carbon monoxide or formate. Here we present the development of carbon materials as an alternative to Cu for efficient and high-rate electro-reduction of CO 2 into hydrocarbons and oxygenates. We will discuss the key structural and electronic factors that govern the selectivity of carbon catalysts towards production of CO, CH 4 and C 2 products (e.g. C 2 H 4 and C 2 H 5 OH). Three categories of carbon catalysts were developed based on the primary products of CO, CH 4 and C 2 H 4 in our group. The first carbon catalyst featuring the metal-nitrogen-carbon structure exclusively catalyzes CO 2 electro-reduction into CO. The second catalyst called functionalized carbon nanostructure can selectively reduce CO 2 into CH 4 with Faradaic efficiency up to 90% while the third one namely doped carbon nanostructure (e.g. N-doped graphene quantum dots) can yield C ≥2 products with a Faradaic efficiency up to 70%. Both carbon nanostructure can achieve partial current density at the scale of 100 mA cm -2 for target product at fairly low overpotentials. This study provides in-depth insights into developing high-performance carbon-based catalysts for electrochemical reduction of CO 2 .

Aya Mohamed, Peter Bogdanoff

ECS Meeting Abstracts • 2023

Solar powered electrochemical CO₂ reduction to disposable products is presently being developed as one of negative carbon emission technologies 1 . State-of-the-art electrocatalysts are mainly developed for the CO 2 reduction to hydrogen rich products or chemical feedstock materials while for the above-mentioned application solid carbon-rich products are desired (best pure carbon). Even though the formation of solid products is sometimes observed on catalysts (coking effect), this usually leads to an undesirable irreversible deactivation of their solid interfaces. Thus, the development of next generation CO 2 electrocatalysts is demanded based on liquid metal alloys such as galinstan (GaInSn). The advantage of using liquid phase electrodes is to eliminate coking and coarsening limitations that are associated with solid catalysts. For example, it has been reported that ceria-supported liquid galinstan can electrochemically produce carbonaceous materials from CO 2 gas 2 . This shows, that doping with additional active elements can change the CO 2 reduction activity of GaInSn in the direction of other desired products. Our work investigates the activity of galinstan for the electroreduction of CO 2 depending on alloying with additional metals (such as Ce, Ag, Pb). While pure GaInSn shows a predominant activity for the formation of C1 products (CO, HCOOH) in DMF/H 2 O electrolyte, we are mainly interested in the formation of solid carbon or oxalate. Therefore, our investigations aim at finding suitable modifications of GaInSn that achieve high selectivity for these products. Electrochemical analysis coupled with in-line gas chromatography and in-line mass spectroscopy are used to characterize the reactivity. Furthermore, the influence of the water content of the organic electrolyte on the product selectivity will be investigated. In particular, to suppress the observed low hydrogen evolution as a by-product even more efficiently. May, M. M.; Rehfeld, K., Negative Emissions as the New Frontier of Photoelectrochemical CO 2 Reduction. Advanced Energy Materials 2022, 2103801. Esrafilzadeh, D.; Zavabeti, A.; Jalili, R.; Atkin, P.; Choi, J.; Carey, B. J.; Brkljača, R.; O’Mullane, A. P.; Dickey, M. D.; Officer, D. L.; MacFarlane, D. R.; Daeneke, T.; Kalantar-Zadeh, K., Room Temperature CO 2 Reduction to Solid Carbon Species on Liquid Metals Featuring Atomically Thin Ceria Interfaces. Nature Communications 2019, 10 (1), 865. Figure 1

Shelley D. Minteer

ECS Meeting Abstracts • 2020

CO 2 reduction has the potential to address issues related to the environment and the energy crisis. However, the reduction of CO 2 is hard to achieve due to its kinetic and thermodynamic stability. Despite significant research effort, existing catalysts such as transition metals and metal complex suffer from either low selectivity and/or low CO 2 conversion efficiency. Biocatalysts are an attractive alternative owing to their highly selectivity, low overpotential and mild operating conditions. A recently developed molybdenum dependent formate dehydrogenase (Mo-FDH) from Escherichia coli is a biocatalyst that is easy to obtain and has high efficiency to interconvert formate and CO 2 . However, the direct electron transfer of Mo-FDH is inefficient, and so far, no immobilized mediating system has been designed with Mo-FDH to support CO 2 reduction. Low potential redox polymers are rare due to a limited number of mediators and stability issues. Here we developed a reductive redox polymer (cobaltocene modified poly allyl amine; Cc-PAA) to wire Mo-FDH at carbon electrode surfaces and simultaneously mediate electrons to facilitate the CO 2 reduction. The polymer film shows good stability and formate was the exclusive product. This electroenzymatic interface is able to reduce CO 2 to formate at a mild applied potential (-0.66 V. vs SHE) with a high Faradaic efficiency (99 ± 5%).

Toshihiro Takashima, Tomohiro Suzuki, Hiroshi Irie

ECS Meeting Abstracts • 2016

The utilization of carbon dioxide (CO 2 ) for the production of fuels and valuable chemicals has gained increasing attention as a strategy for solving both global energy and environmental issues.[1] Among the various proposed methods, the electrochemical reduction of CO 2 using electricity powered by renewable resources is attractive, and numerous electrode materials capable of converting CO 2 to carbon monoxide (CO), formate, methanol, methane, and other hydrocarbons have been identified in the past few decades. However, there still remain several fundamental challenges in the electrocatalytic reduction of CO 2 , such as high overpotential and low Faradaic efficiency due to the competitive hydrogen evolution reaction. Recently, it was reported that a palladium (Pd) nanoparticle electrode can reduce CO 2 to formate with high energy efficiency (with low overpotential) [1]. However, the electrode was also reported to be deactivated by adsorption of CO which is produced as a byproduct. In this study, to suppress the deactivation by CO, we focused on a Pd nanoparticle electrode modified covered with copper (Cu) because the binding energy of CO on Cu was reported to be weaker than that on Pd [3]. In addition, it is known that Cu monolayer can be formed on Pd support by using underpotential deposition (UPD) [4]. Thus, we prepared a Pd nanoparticle electrode covered with Cu monolayer (Cu/Pd electrode) and examined its CO 2 reduction activity and tolerance to CO. A Pd nanoparticle electrode was prepared by loading homogeneous catalyst ink onto a fluorine-doped tin oxide (FTO) electrode. The ink was composed of a mixture of Pd-supporting carbon black powder, Nafion, and isopropanol. The Pd-supporting carbon black powder was purchased from Premetek. UPD of Cu was carried out by holding the electrode potential at 0.35 V vs. reversible hydrogen electrode (RHE) for 50 s in a mixed solution of 50 mM sulfuric acid (H 2 SO 4 ) and 50 mM copper sulfate (CuSO 4 ). Electrolyses were performed in a gas-tight two-compartment electrochemical cell with a piece of anion exchange membrane as the separator. An aqueous solution of 0.5 M sodium hydrogen carbonate (NaHCO 3 ) saturated with CO 2 was used as an electrolyte. Figure 1 shows chronoamperograms for CO 2 reduction of Pd and Cu/Pd electrodes measured at -0.15 V vs RHE. In the initial stage, the current density of a Cu/Pd electrode was smaller than that of a Pd electrode. This is plausible because the surface area of Pd exposed to the electrolyte decreased by deposition of Cu. However, the Cu/Pd electrode was active for CO 2 reduction even after deposition of Cu and production of formate was confirmed by analysis of the electrolyte using gas chromatograph (GC). Notably, the reduction current of the Cu/Pd electrode maintained more steadily than that of the Pd electrode during long-term electrolysis, suggesting that the electrodeposited Cu monolayer improved the tolerance to CO. To examine the effect of Cu layer on CO adsorption, CO 2 reduction activity in the presence of CO was also investigate. When CO was introduced into the electrolyte by bubbling, the current density of both Pd and Cu/Pd electrodes decreased, however the degree of deactivation of the Cu/Pd electrode was less than that of the Pd electrode. These results indicate that the covering of Pd nanoparticle with Cu monolayer improves its tolerance to CO without losing CO 2 reduction activity. References [1] M. Aresta, A. Dibenedetto, A. Angelini, Chem. Rev. , 2014 , 114 , 1709-1742. [2] X. Min and M. W. Kanan, J. Am. Chem. Soc. , 2015 , 137 , 4701-4708. [3] A. A. Peterson and J. K. Nørskov, J. Phys. Chem. Lett. , 2012 , 3 , 251-258. [4] T. Chierchie and C. Mayer, Electrochim. Acta , 1988 , 33 , 341-345. Figure 1

Zhanxi Fan

Energy Lab • 2023

Electrochemical carbon dioxide (CO2) reduction is emerging as a promising technique to decrease atmospheric CO2 concentration and relieve energy pressure. Besides the single-carbon (C1) species, multi-carbon (C2+) products are more preferred because of their elevated energy density and/or larger economic value. Single atom catalysts (SACs) have been widely used in the field of catalysis due to their tunable active center and unique electronic structure. So far, extensive research progresses have been achieved in utilizing SACs to promote the CO2 reduction toward C1 products, but little attention is paid to the formation of high-value C2+ products. In this review, we present the recent advances of electrochemical reduction of CO2 to C2+ products with SACs. Firstly, the reaction mechanism of converting CO2 to C2+ products is briefly introduced. Then the general design principles of SACs toward C2+ products are systematically discussed. After that, we highlight the representative studies on the C2+ generation and the corresponding mechanism with SACs, including the copper and non-copper based SACs. Finally, we summarize the latest progresses and provide personal perspectives for the future design and target preparation of advanced SACs for the high-performance CO2 electrolysis to specific C2+ products.

Joana Madjarov, Ricardo Soares, Catarina M. Paquete et al.

Frontiers in Microbiology • 2022

Sporomusa ovata is a bacterium that can accept electrons from cathodes to drive microbial electrosynthesis (MES) of acetate from carbon dioxide. It is the biocatalyst with the highest acetate production rate described. Here we review the research on S. ovata across different disciplines, including microbiology, biochemistry, engineering, and materials science, to summarize and assess the state-of-the-art. The improvement of the biocatalytic capacity of S. ovata in the last 10 years, using different optimization strategies is described and discussed. In addition, we propose possible electron uptake routes derived from genetic and experimental data described in the literature and point out the possibilities to understand and improve the performance of S. ovata through genetic engineering. Finally, we identify current knowledge gaps guiding further research efforts to explore this promising organism for the MES field.

Vafa Ahmadi, Nabin Aryal

Fermentation • 2025

Optimal product synthesis in bioelectrochemical systems (BESs) requires a comprehensive understanding of the relationship between external voltage and microbial yield. While most studies assume constant growth yields or rely on empirical estimates, this study presents a novel thermodynamic model, linking anodic oxidation and cathodic carbon dioxide (CO2) reduction to methane (CH4) by growing microbial biofilm. Through integrating theoretical Gibbs free energy calculations, the model predicts electron and proton transfers for autotrophic methanogen and anode-respiring bacteria (ARB) growth, accounting for varying applied voltages and substrate concentrations. The findings identify an optimal applied cathodic potential of −0.3 V vs. the standard hydrogen electrode (SHE) for maximizing CH4 production under standard conditions (pH 7, 25 °C, 1 atm) regardless of ohmic losses. The model bridges the stoichiometry of anodic and cathodic biofilms, addressing research gaps in simulating anodic and cathodic biofilm growth simultaneously. Additionally, sensitivity analyses reveal that lower substrate concentrations require more negative voltages than standard condition to stimulate microbial growth. The model was validated using experimental data, demonstrating reasonable predictions of biomass growth and CH4 yield under different operating voltages in a multi substrate system. The results show that higher voltage inputs increase biomass yield while reducing CH4 output due to non-optimal voltage. This validated model provides a tool for optimizing BES performance to enhance CH4 recovery and biofilm stability. These insights contribute to finding optimum voltage for the highest CH4 production for energy efficient CO2 reduction for scaling up BES technology.

Tambakassi Mihin, Boris Tartakovsky, Oumarou Savadogo

ECS Meeting Abstracts • 2025

Introduction: Climate change, due to the release of greenhouse gases such as carbon dioxide (CO 2 ), is a global environmental issue. An effective energy transition relies on the substantial utilization of renewable energy sources and the development of CO 2 reduction products, such as e-fuels and e-chemicals. In particular, the potential for large-scale CO 2 reduction could contribute significantly to mitigating the greenhouse effect. Accordingly, promising CO 2 recycling approaches include electrochemical as well as bio-electrochemical methods. Currently, both methods for CO 2 reduction are limited by relatively low selectivity, high cost and low material stability, particularly with respect to cathode materials (Farooqi et al., 2023; Zhang et al., 2021). The approach presented in this study proposes using cathode materials based on synthesized non-noble bimetallic oxides for electrochemical and bioelectrochemical reduction of CO 2 . This is the first time a comparison of electrochemical and bioelectrochemical reduction of CO 2 is carried out. Experimental: Bimetallic oxides FeCuO, MnCuO, and SnCuO, CoMnO and FeSnO were synthesized using sol-gel methods in three molar ratios (1/2, 1/1, and 2/1) and characterized by XRD and EDS methods. The electrocatalyst was fabricated by mixing their powder with Nafion solution to obtain a paste, which is deposited on carbon felt. CO 2 reduction was performed in an electrolytic cell (EC) and a microbial electrosynthesis (MES) cell using sodium bicarbonate solution (pH 6.5, 0.5M) and enriched mixed acidogenic culture at pH 6.0, respectively. Batch activity tests were first carried out to evaluate the bimetallic oxides’ performances on CO 2 reduction by methanogenic and acidogenic microorganisms using serological bottles containing microbial cultures capable of reducing CO 2 and hydrogen to methane (CH 4 ) and volatile fatty acids (VFAs). The bimetallic oxides were used either in powder form at concentrations of 1–2.5 g/L or deposited on carbon felt at an active loading of 10 mg cm -2 . Among the five bimetallic oxides tested, three promising candidates were selecte. Stability tests were conducted with these oxides at three molar ratios at a current density of 156 A m -2 for 20 hours in an electrolytic cell. Electrochemical CO 2 reduction was subsequently performed using the most stable oxides across various current densities (13–100 A m -2 ) under standard conditions, and Coulombic efficiency (CE) was calculated. Additionally, bioelectrochemical reduction tests were conducted at 3, 5, and 8 A m -2 in a MES cell, inoculated with enriched mixed acetogenic culture (table 1). Both uncoated carbon felt, and carbon felt coated with FeSnO (1/1) were used as cathode materials. Analysis of gases and VFAs was performed using gas chromatography, while liquid chromatography was employed for alcohol analysis. Preliminary Results: The crystalline structure and the stoichiometric composition of the bimetallic oxides were confirmed, respectively by XRD and EDS characterization of annealed samples. Based on Cyclic Voltammetry, current-voltage polarization and Tafel plot curves, the electrolytic currents of the CO 2 electro-reduction were identified. Table 2 shows the CE of the electro-reduction of CO 2 to methanol and tert-butanol for various current density on the best bimetallic oxides FeCuO (2/1), CoMnO (2/1) and FeSnO (1/1), respectively. For these electrodes, the CE of the water electrolysis to hydrogen is, of course, significantly higher (at least 75%) than those of the electro-reduction of CO 2 . The CE of the CO 2 electro-reduction is less than 20%. The CE of the CO 2 electro-reduction to methanol is lower than that of its electrochemical reduction to tert-butanol. The highest CE of the CO 2 electro-reduction to e-fuels and e-chemicals is obtained on the FeCuO electrocatalyst. The optimum current density for CO 2 electro-reduction is in the range of 30-75 A m -2 . Table 3 shows the results of the bioelectrochemical reduction of CO 2 in MES cell using FeSnO (1/1) electrode. Calculated CE ranged from 60% to 88% at various current densities. The CE of CO₂ reduction to VFAs ranged from 53% to 79%, with a CO₂ conversion efficiency reaching 96% under continuous operation with CO₂ flow rates of 200 and 300 mL/day to the cathode compartment. Production of butyrate and caproate increased by 4.6 and 3.9 times, respectively, in the MES cell with the FeSnO (1/1) cathode compared to a MES cell with an uncoated carbon felt cathode. Conclusion: The study shows that selecting specific bimetallic oxides can influence microbial CO 2 reduction. Furthermore, converting an electrochemical cell to a microbial electrosynthesis cell by adding an enriched mixed acidogenic culture in the cathode compartment enhances CO 2 reduction. The findings also indicate that the microbial chain elongation activity of the mixed culture improves with the presence of certain bimetallic oxides, such as FeSnO. Figure 1

Jayachitra Murugaiyan, Anantharaman Narayanan, Samsudeen Naina Mohamed

Water Environment Research • 2024

Abstract Microbial electrolysis cell (MEC) is gaining importance not only for effectively treating wastewater but also for producing hydrogen. The up‐flow microbial electrolysis cell (UPMEC) is an innovative approach to enhance the efficiency, and substrate degradation. In this study, a baffled UPMEC with an anode divided into three regions by inserting the baffle (sieve) plates at varying distances from the cathode was designed. The effect of process parameters, such as flow rate (10, 15, and 20 mL/min), electrode area (50, 100, and 150 cm 2 ), and catholyte buffer concentration (50, 100, and 150 mM) were investigated using distillery wastewater as substrate. The experimental results showed a maximum of 0.6837 ± 0.02 mmol/L biohydrogen at 150 mM buffer, with 49 ± 1.0% COD reduction using an electrode of area 150 cm 2 . The maximum current density was 1335.94 mA/m 2 for the flow rate of 15 mL/min and surface area of 150 cm 2 . The results showed that at optimized flow rate and buffer concentration, maximum hydrogen production and effective treatment of wastewater were achieved in the baffled UPMEC. Practitioner Points Biohydrogen production from distillery wastewater was investigated in a baffled UPMEC. Flowrate, concentration and electrode areas significantly influenced the hydrogen production. Maximum hydrogen (0.6837±0.02mmol/L.day) production and COD reduction (49±1.0%) was achieved at 15 mL/min. Highest CHR of 95.37±1.9 % and OHR of 4.6±0.09 % was observed at 150 mM buffer concentration.

Tamilmani Jayabalan, Samsudeen Naina Mohamed, Manickam Matheswaran et al.

International Journal of Energy Research • 2021

Summary Development of economically viable cathode catalysts with practicability in the treatment of real effluents is one of the strenuous efforts among the multidisciplinary approaches in microbial electrolysis cell (MEC). Treatment of industrial effluents using this technology had resulted in simultaneous energy production in the form of hydrogen along with wastewater treatment, promoting both energy and environmental benefits. In this study, two metal oxides such as, Nickel Oxide (NiO) and Cobalt oxide (Co 3 O 4 ) were employed as the cathode catalyst using sugar industry effluent as the substrate for biohydrogen production in the MEC. The addition of NiO and Co 3 O 4 on nickel foam (NF) has demonstrated better hydrogen evolution performance than the control (uncoated) cathode. Electrochemical characterization of the modified cathodes revealed the improved capability analogous to the current density and hydrogen production rate (HPR) obtained in the experimentation. The best performance was achieved by NiO/NF with the maximum HPR of 3.39 ± 0.03 mmol/L/D, coloumbic efficiency of 58 ± 1.4%, hydrogen recovery of 27 ± 1.8% and COD removal efficiency of 52 ± 1.6% when operated with the applied voltage of 1.0 V. Hence, the potential of metal oxides was demonstrated for the candidature of efficient and economical cathode materials in MECs.

Putty Ekadewi, Rita Arbianti, Cristina Gomez et al.

Food Technology and Biotechnology • 2023

Research background. This study provides insight into the use of a designed microbial community to produce biohydrogen in simple, single-chamber microbial electrolysis cells (MECs). The ability of MECs to stably produce biohydrogen relies heavily on the setup and microorganisms working inside the system. Despite having the most straightforward configuration and effectively avoiding costly membranes, single-chamber MECs are prone to competing metabolic pathways. We present in this study one possible way of avoiding this problem using characteristically defined, designed microbial consortium. Here, we compare the performance of MECs inoculated with a designed consortium to MECs operating with a naturally occurring soil consortium. Experimental approach. We adapted a cost-effective and simple single-chamber MEC design. The MEC was gastight, 100 mL in volume, and equipped with continuous monitoring for electrical output using a digital multimeter. Microorganisms were sourced from Indonesian environmental samples, either as denitrifying bacterial isolates grouped as a designed consortium or natural soil microbiome used in its entirety. The designed consortium consisted of five species from the Pseudomonas and Acinetobacter genera. The headspace gas profile was monitored periodically with a gas chromatograph. At the end of the culture, the composition of the natural soil consortium was characterized by next generation sequencing and the growth of the bacteria on the surface of the anodes by field emission scanning electron microscopy. Results and conclusions. We found that MEC using a designed consortium presented a better H2 production profile, with the ability of the system to maintain headspace H2 concentration relatively stable for a long time after reaching stationary growth period. In contrast, MECs inoculated with soil microbiome exhibited a strong decline in headspace H2 profile within the same time frame. Novelty and scientific contribution. This work utilizes a designed, denitrifying bacterial consortium isolated from Indonesian environmental samples that can survive in a nitrate-rich environment. Here we propose using a designed consortium as a biological approach to avoid methanogenesis in MECs, as a simple and environmentally friendly alternative to current chemical/physical methods. Our findings offer an alternative solution to avoid the problem of H2 loss in single-chamber MECs along with optimizing biohydrogen production through bioelectrochemical routes.

Matthew Hardhi, Putty Ekadewi, Rita Arbianti et al.

E3S Web of Conferences • 2018

The increasingly adverse effects of climate change caused by a variety of fossil-based fuel demands an alternative to such fuel. Hydrogen is one of the potential renewable fuel that offers numerous advantages compared to its competitors. However, the dominant hydrogen production methods are still energy-heavy and dependent on fossil-based resources. Microbial electrolysis cell or MEC system is one of the leading solution towards replacing conventional hydrogen production method. A persistent downside to this system in the presence of methanogens that consumes the hydrogen product. This research proposes alternative biological method to control the methanogen colony by introducing isolates of denitrifying bacteria to the system which will act as inhibitor to hydrogenotrophic methanogen. The reactor implemented is a single-chambered, membrane-less 20-ml reactor. Net hydrogen yield produced in the cathodic headspace will be analyzed by gas chromatography (GC). Hydrogen yield for reactor with enriched cathode is expected to be higher in comparison to unenriched reactor, as nitrogen oxides produced during the metabolism of the denitrifiers were known to inhibit methanogen growth. Experimental results showed consistent higher H 2 yield in inoculated reactor compared to control reactor, where in the second cycle H 2 production increased 100% compared to the control.

Pooja Dange, Soumya Pandit, Dipak Jadhav et al.

Sustainability • 2021

Carbon constraints, as well as the growing hazard of greenhouse gas emissions, have accelerated research into all possible renewable energy and fuel sources. Microbial electrolysis cells (MECs), a novel technology able to convert soluble organic matter into energy such as hydrogen gas, represent the most recent breakthrough. While research into energy recovery from wastewater using microbial electrolysis cells is fascinating and a carbon-neutral technology that is still mostly limited to lab-scale applications, much more work on improving the function of microbial electrolysis cells would be required to expand their use in many of these applications. The present limiting issues for effective scaling up of the manufacturing process include the high manufacturing costs of microbial electrolysis cells, their high internal resistance and methanogenesis, and membrane/cathode biofouling. This paper examines the evolution of microbial electrolysis cell technology in terms of hydrogen yield, operational aspects that impact total hydrogen output in optimization studies, and important information on the efficiency of the processes. Moreover, life-cycle assessment of MEC technology in comparison to other technologies has been discussed. According to the results, MEC is at technology readiness level (TRL) 5, which means that it is ready for industrial development, and, according to the techno-economics, it may be commercialized soon due to its carbon-neutral qualities.

Jiaxin Wang, Yanchun Li, Miaomiao Liu et al.

ChemPlusChem • 2020

Abstract Microbial electrolysis cells (MECs) is one of the promising biohydrogen production technologies for which low‐cost cathode materials are required and developed to propel the rapid development of MECs. Herein, the preparation of a low‐cost Ce 0.1 −Ni−Y composite is reported by using Y zeolite as carrier loaded with nickel (Ni) and cerium (Ce) as active components and its prominent electrochemical performance. The XPS analysis reveals that strong electronic interaction between Ni and Ce makes a great contribution to the electrochemical performance enhancement. The Ce 0.1 −Ni−Y with a peak current density of 39.8 A⋅m −2 in LSV, Tafel slope of 40.81 mV⋅dec −1 , ECSA of 34.3 and hydrogen yield of 0.312±0.013 m 3 ⋅m −3 d −1 are significantly superior to that of its parent Ni−Y counterpart and rival the performance of commercially Pt/C, which renders it a very promising hydrogen evolution catalyst for MECs.

Ferdy Christian Hartanto, Nadia Nurul Atikah, Mohammad Sahid Indrawan et al.

International Journal of Oil Palm • 2022

Palm oil mill effluent contains organic matter and microorganisms that can potentially be reused despite of its impact to the environment. Microbial electrolysis cell is a method that utilizes electrogenic bacteria to produce hydrogen gas. This study aims to explore the potential for utilizing palm oil mill effluent to produce hydrogen gas using microbial electrolysis cells. Experiments were conducted in a specially built MEC reactor with a 3.5 L capacity with 0.5, 1.0, and 1.5 V with carbon fiber cloth as electrodes. A gas analyzer was used to measure hydrogen gas over the course of 24 h at a 2 h interval. Palm oil mill effluent was utilized as a substrate, while distilled water was used as a control. Experiments demonstrate that the amount of hydrogen gas produced increases as the voltage increases, with values of 37 mg m-3 at 0.5 V, 136 mg m-3 at 1.0 V, and 358 mg m-3 at 1.5 V. When comparing the yield of hydrogen gas produced with distilled water substrate at 1.5 V, the yield of palm oil mill effluent substrate is always higher. This could be due to microbial activity increasing the rate of electrolysis of the substrate into hydrogen gas.

Line Schultz Jensen, Christian Kaul, Nilas Brinck Juncker et al.

Energies • 2022

The need for renewable and sustainable fuel and energy storage sources is pressing. Biohydrogen has the potential to be a storable energy carrier, a direct fuel and a diverse building block for various downstream products. Utilizing microbial electrolysis cells (MECs) to produce biohydrogen from residue streams, such as the organic fraction of municipal solid waste (OFMSW), agricultural residues and wastewater facilitate utilization and energy recovery from these streams, paving the path for a circular economy. The advantages of using hydrogen include high gravimetric energy density and, given the MEC pathway, the ability to capture heavy metals, ammonia and phosphates from waste streams, thereby allowing for multiple revenue streams emanating from MECs. A review of the MEC technology and its application was carried out to investigate the use of MEC in sustainable biohydrogen production. This review summarizes different MEC designs of varying scales, including anode materials, cathode materials, and configuration possibilities. This review highlights the accomplishments and challenges of small-scale to large-scale MECs. Suggestions for improving the successful upscaling of MECs are listed, thus emphasizing the areas for continued research.