A. Mukherjee, R. Patel, P. Zaveri et al.

Letters in Applied Microbiology • 2022

Abstract Microbial fuel cell (MFC) is an emerging technology which has been immensely investigated for wastewater treatment along with electricity generation. In the present study, the treatment efficiency of MFC was investigated for hydrocarbon containing wastewater by optimizing various parameters of MFC. Mediator-less MFC (1·2 l) was constructed, and its performance was compared with mediated MFC with Escherichia coli as a biocatalyst. MFC with electrode having biofilm proved to be better compared with MFC inoculated with suspended cells. Analysis of increasing surface area of electrode by increasing their numbers indicated increase in COD reduction from 55 to 75%. Catholyte volume was optimized to be 750 ml. Sodium benzoate (0·721 g l–1) and actual common effluent treatment plant (CETP) wastewater as anolyte produced 0·8 and 0·6 V voltage and 89 and 50% COD reduction, respectively, when a novel consortium of four bacterial strains were used. Twenty MFC systems with the developed consortium when electrically connected in series-parallel connection were able to generate 2·3 V and 0·5 mA current. This is the first report demonstrating the application of CETP wastewater in the MFC system, which shows potential of the system towards degradation of complex organic components present in industrial wastewater.

A. Afify, A. M. Abd, El Gwad et al.

Journal of Agricultural Chemistry and Biotechnology • 2023

Microbial electrolysis cells (MECs) are important for environment and renewable energy source. They were used for bio-hydrogen production by bacteria from organic matters, which is biological method to treat wastewater. Therefore, in this study MEC was used for bio-hydrogen producing by two bacterial strains: Escherichia coli NRRL B-3008 and Pseudomonas aeruginosa ATCC 27853 in MEC 1 (300ml), MEC 2 (400ml) and MEC 3 (500ml) were applied from domestic wastewater. Volumes of MEC refer to anode chamber. Applied voltage of 0.4V, 0.6V and 0.8V was used as an external electrical circuit in MECs (1, 2 & 3). The lowest value of Bio-Hydrogen production rate (Bio-HPR) 112.28 cm 3 was obtained by domestic wastewater without bacteria in MEC 3 (500ml) at applied voltage 0.8V. While highest values of Bio-HPR 235.87 and 268.08 cm 3 were obtained by E. coli NRRL B-3008 and P. aeruginosa ATCC 27853 in MEC 3 (500ml) at applied voltage 0.8V from domestic wastewater respectively.

Rahma El-Sayad, Ahmed Khalil, Ali M. Basha

Journal of Contemporary Technology and Applied Engineering • 2023

. The rapid increase in human activity in recent years has increased energy demand and waste output. Although wastewater is frequently seen as a problem, it has the potential to be seen as a rich source of resources and energy. An appealing approach to lowering environmental pollution and supplying alternative energy sources is the treatment of contaminants found in wastewater combined with energy recovery. Microbial electrolysis cell (MEC) is one of the most effective waste-to-product conversion technologies available today. There are other methods for wastewater treatment and the production of hydrogen as dark fermentation and photo fermentation. This paper explores the interconnected fields of wastewater treatment and hydrogen production, highlighting their significance in addressing environmental challenges and promoting sustainable development. Various technologies and processes employed in wastewater treatment, such as microbial electrolysis cells (MECs), dark fermentation, and photo fermentation, are discussed in detail. Also, this paper compares MEC, photo fermentation, and dark fermentation for hydrogen production and wastewater treatment. Moreover, it shows some benefits and drawbacks of these technologies. In addition, the integration between these technologies is discussed in this review. Additionally, it provides some descriptive statistics about the outcomes. Finally, some recommendations are presented in the review for future work.

Ibdal Satar, M. Sirajuddin, Adidiya Permadi et al.

Indonesian Journal of Environmental Management and Sustainability • 2023

High organic pollutant in tofu wastewater (TWW) raises a negative impact on environmental sustainability and health. Therefore, the TWW must be treated before it is discharged into the environment. Microbial electrolysis cell (MEC) is one of the green technologies that can be used to treat wastewater and generate hydrogen as well. This work tries to investigate the performance of MEC based on the decrement of organic pollutants in TWW. Some important parameters of organic pollutants in TWW such as chemical oxygen demand (COD), biological oxygen demand (BOD), total suspended solids (TSS), total dissolved solids (TDS), total solid (TS), and pH were evaluated before and after MEC operation. The results showed that the COD and BOD levels decreased around 56% and 35% while pH increased from 7.90 to 7.16. Additionally, the TSS, TDS, and TS decreased by around 35.0%, 45.5%, and 33.2%. In addition, the optimum hydrogen yield (YH2) and hydrogen production rate (QH2) were obtained at 114 ± 0.1 mL H2/g COD 360 ± 20 mL H2/L/d. Overall, the MEC system could be used to reduce the level of organic pollutants in TWW and generated H2 at the same time.

Yunjeong Choi, Danbee Kim, Hyun-Rock Choi et al.

Bioengineered • 2023

ABSTRACT Fermentation effluents from organic wastes contain simple organic acids and ethanol, which are good electron sources for exoelectrogenic bacteria, and hence are considered a promising substrate for hydrogen production in microbial electrolysis cells (MECs). These fermentation products have different mechanisms and thermodynamics for their anaerobic oxidation, and therefore the composition of fermentation effluent significantly influences MEC performance. This study examined the microbial electrolysis of a synthetic fermentation effluent (containing acetate, propionate, butyrate, lactate, and ethanol) in two-chamber MECs fitted with either a proton exchange membrane (PEM) or an anion exchange membrane (AEM), with a focus on the utilization preference between the electron sources present in the effluent. Throughout the eight cycles of repeated batch operation with an applied voltage of 0.8 V, the AEM-MECs consistently outperformed the PEM-MECs in terms of organic removal, current generation, and hydrogen production. The highest hydrogen yield achieved for AEM-MECs was 1.26 L/g chemical oxygen demand (COD) fed (approximately 90% of the theoretical maximum), which was nearly double the yield for PEM-MECs (0.68 L/g COD fed). The superior performance of AEM-MECs was attributed to the greater pH imbalance and more acidic anodic pH in PEM-MECs (5.5–6.0), disrupting anodic respiration. Although butyrate is more thermodynamically favorable than propionate for anaerobic oxidation, butyrate was the least favored electron source, followed by propionate, in both AEM- and PEM-MECs, while ethanol and lactate were completely consumed. Further research is needed to better comprehend the preferences for different electron sources in fermentation effluents and enhance their microbial electrolysis.

Cong Wang, Dongdong Chang, Qi Zhang et al.

Bioresources and Bioprocessing • 2024

Lignocellulose pretreated using pyrolysis can yield clean energy (such as bioethanol) via microbial fermentation, which can significantly contribute to waste recycling, environmental protection, and energy security. However, the acids, aldehydes, and phenols present in bio-oil with inhibitory effects on microorganisms compromise the downstream utilization and conversion of lignocellulosic pyrolysates. In this study, we constructed a microbial electrolysis cell system for bio-oil detoxification and efficient ethanol production using evolved Escherichia coli to overcome the bioethanol production and utilization challenges highlighted in previous studies. In electrically treated bio-oil media, the E. coli -H strain exhibited significantly higher levoglucosan consumption and ethanol production capacities compared with the control. In undetoxified bio-oil media containing 1.0% (w/v) levoglucosan, E. coli -H produced 0.54 g ethanol/g levoglucosan, reaching 94% of the theoretical yield. Our findings will contribute to developing a practical method for bioethanol production from lignocellulosic substrates, and provide a scientific basis and technical demonstration for its industrialized application. Graphical abstract

Jieyi Peng, Shuo Zhao, Ying Li et al.

Fermentation • 2024

Microbial electrochemical systems have shown great value as a means of enhancing the efficiency of fermentation reactions, but at present, there is no reliable means to balance the extracellular electron supply and corresponding intracellular demands in these systems. The current work describes the unique use of an oxidation–reduction-potential (ORP)-level-controlled microbial electrolysis cell (MEC) system to successfully balance the extracellular electron supply and succinic acid fermentation via A. succinogenes (130Z). The ORP-controlled MEC system with neutral red (NR) yielded a significant increase in succinic acid production (17.21%). The utilization of NR in this MEC system improved the ORP regulatory sensitivity. The optimal approach to the ORP level control was the use of a −400 mV high-voltage electric pulse-based strategy, which increased the yield of succinic acid by 13.08% compared to the control group, and reduced the energy consumption to 52.29% compared to the potentiostatic method. When compared to the −1 V constant potential MEC system, the high-voltage electric pulse-based ORP strategy for the MEC system control provided sufficient electrons to this system while using less electricity (11.96%) and producing 12.48% (74.43 g/L) more succinic acid during fed-batch fermentation. The electronic utilization efficiency of the ORP-controlled MEC system was 192.02%, which was 15.19 times that of the potentiostatic system. The electronic utilization efficiency is significantly increased in the ORP-controlled MEC system. Succinic acid production is ensured by a high-voltage electric pulse-based method, while the influence on cell growth and power consumption are minimized. Fed-batch fermentation with the high-voltage electric pulse-based ORP strategy for MEC system control is noted to be ideal to achieve a further increase in succinic acid concentration and electronic utilization efficiency.

A. Tremouli, G. Kanellos, Evangelia Monokrousou et al.

Global NEST International Conference on Environmental Science & Technology • 2024

This study deals with the treatment of a potent two-phase olive mill waste (TPOMW) through the degradation of its phenolic content, with simultaneous bio-electrochemical reduction of CO2 to CH4, using a dual-chamber Microbial Electrolysis Cell (MEC). The MEC operated for 120 days and the effects of different dilutions (1:10, 1:5 and no dilution) and applied potentials (0.5 V and 1 V) on its performance were studied. The results showed that decreasing the dilution (from 1:10 to 1:5 and to no dilution) led to an increase of the COD removal (from 74%, to 77% and to 87%, respectively), of the total phenolic content removal (from 73%, to 76% and to 79%, respectively), as well as of the produced CH4 (from 0.08, to 0.48 and to 2.33 mmols, respectively). Increasing the applied potential (from 0.5 V to 1 V), while the TPOMW was employed in the anode with no dilution, resulted in further increase of both the COD and the total phenolic content removal to 91%, while the produced CH4 further increased to 2.88 mmols. The results indicate that the MEC technology can be potentially exploited for the treatment of the potent TPOMW and produce CH4 as a waste-to-energy source.

Hyungwon Chai, Bonyoung Koo, S. Son et al.

Energies • 2024

The electrode is a key component in a microbial electrolysis cell (MEC) that needs significant improvement for practical implementation. Accurate and reproducible analytical methods are substantial for the effective development of electrode technology. Linear sweep voltammetry (LSV) is an essential analytical method for evaluating electrode performance. In this study, inoculated carbon brush (IB), abiotic brush (AB), Pt wire (PtW), stainless steel wire (SSW), and mesh (SSM) were tested to find the most suitable counter electrode under different medium conditions. The coefficient of variation (Cv) of maximum current (Imax) was the most decisive indicator of the reproducibility test. This study shows that (i) the electrode used in operation is an appropriate counter electrode in an acetate-added condition, (ii) the anode LSV test should avoid the use of Pt wire as counter electrodes, and (iii) PtW is an appropriate counter electrode in cathode LSV in all conditions.

Y. Liu, Mohan Qin, Shuai Luo et al.

Scientific Reports • 2016

We report an integrated experimental and simulation study of ammonia recovery using microbial electrolysis cells (MECs). The transport of various species during the batch-mode operation of an MEC was examined experimentally and the results were used to validate the mathematical model for such an operation. It was found that, while the generated electrical current through the system tends to acidify (or basify) the anolyte (or catholyte), their effects are buffered by a cascade of chemical groups such as the NH3/NH4+ group, leading to relatively stable pH values in both anolyte and catholyte. The transport of NH4+ ions accounts for ~90% of the total current, thus quantitatively confirming that the NH4+ ions serve as effective proton shuttles during MEC operations. Analysis further indicated that, because of the Donnan equilibrium at cation exchange membrane-anolyte/catholyte interfaces, the Na+ ion in the anolyte actually facilitates the transport of NH4+ ions during the early stage of a batch cycle and they compete with the NH4+ ions weakly at later time. These insights, along with a new and simple method for predicting the strength of ammonia diffusion from the catholyte toward the anolyte, will help effective design and operation of bioeletrochemical system-based ammonia recovery systems.

Zhihong Liu, Aijuan Zhou, Zhang Jiaguang et al.

ACS Sustainable Chemistry & Engineering • 2018

Due to the limited hydrolysis rate of particulate organics and suitable substrates for hydrogen-producing bacteria in raw waste activated sludge (WAS), traditional fermentative hydrogen production has low hydrogen yield and energy recovery efficiency. The role of free nitrous acid (FNA) pretreatment on WAS and hydrogen recovery was investigated in a prefermentation–microbial electrolysis cells (MECs) system. The results demonstrated that WAS hydrolysis and acidification were enhanced by FNA pretreatment. Notably, the accumulation of acetic acid and propionic acid eventually reached to 55% and 22% during prefermentation. During MECs cascade utilization, volatile fatty acids (VFAs) were exhausted and the utilization efficiencies of soluble carbohydrates and proteins reached 62% and 41.5%, respectively. The hydrogen yield from FNA-pretreated sludge was 1.44 mL/g of volatile suspended solids, which was approximately 3 times than that of the control. High-throughput sequencing and canonical correspondence anal...

Wenzong Liu, Zhangwei He, Chunxue Yang et al.

Biotechnology for Biofuels • 2016

BackgroundBioelectrochemical systems have been considered a promising novel technology that shows an enhanced energy recovery, as well as generation of value-added products. A number of recent studies suggested that an enhancement of carbon conversion and biogas production can be achieved in an integrated system of microbial electrolysis cell (MEC) and anaerobic digestion (AD) for waste activated sludge (WAS). Microbial communities in integrated system would build a thorough energetic and metabolic interaction network regarding fermentation communities and electrode respiring communities. The characterization of integrated community structure and community shifts is not well understood, however, it starts to attract interest of scientists and engineers.ResultsIn the present work, energy recovery and WAS conversion are comprehensively affected by typical pretreated biosolid characteristics. We investigated the interaction of fermentation communities and electrode respiring communities in an integrated system of WAS fermentation and MEC for hydrogen recovery. A high energy recovery was achieved in the MECs feeding WAS fermentation liquid through alkaline pretreatment. Some anaerobes belonging to Firmicutes (Acetoanaerobium, Acetobacterium, and Fusibacter) showed synergistic relationship with exoelectrogens in the degradation of complex organic matter or recycling of MEC products (H2). High protein and polysaccharide but low fatty acid content led to the dominance of Proteiniclasticum and Parabacteroides, which showed a delayed contribution to the extracellular electron transport leading to a slow cascade utilization of WAS.ConclusionsEfficient pretreatment could supply more short-chain fatty acids and higher conductivities in the fermentative liquid, which facilitated mass transfer in anodic biofilm. The overall performance of WAS cascade utilization was substantially related to the microbial community structures, which in turn depended on the initial pretreatment to enhance WAS fermentation. It is worth noting that species in AD and MEC communities are able to build complex networks of interaction, which have not been sufficiently studied so far. It is therefore important to understand how choosing operational parameters can influence reactor performances. The current study highlights the interaction of fermentative bacteria and exoelectrogens in the integrated system.

Jun-Gyu Park, Beom Lee, Ui-Jung Lee et al.

Environmental Engineering Research • 2021

The microbial communities and operational performances of a conventional anaerobic digester (AD) and an AD combined with microbial electrolysis cells (ADMEC) were investigated. Primary sludge and waste-activated sludge were used as substrates, and next-generation sequencing (NGS) techniques were used to analyze the microbial characteristics. The results show that ADMEC can achieve a faster stabilization rate, higher organic decomposition, and methane production performance than AD. After both the ADMEC and AD reached a steady state, microbial results revealed that Methanobacterium beijingense and Methanosaeta concilii were the dominant methane-generating archaeal species in AD. In ADMEC, the relative abundance of methylotrophic methanogens (Thermoplasmata class), which has higher methane productivity than other methanogens, is significantly improved. For bacterial communities, an improved relative abundance of the Cloacamonas phylum, which is involved in amino acid fermentation, and in the Erysipelotrichi class, which grows well in environments with high organic concentrations, was observed in ADMEC. In summary, ADMEC is more efficient than AD because organic degradation and methanol production accelerated by bioelectrochemical reactions occur in ADMEC, leading to a favorable environment for the growth of methylotrophic methanogens in bulk solution.

Byeongcheol Kim, Euntae Yang, Bongkyu Kim et al.

Nanomaterials • 2022

Microbial electrolysis cells (MECs) have attracted significant interest as sustainable green hydrogen production devices because they utilize the environmentally friendly biocatalytic oxidation of organic wastes and electrochemical proton reduction with the support of relatively lower external power compared to that used by water electrolysis. However, the commercialization of MEC technology has stagnated owing to several critical technological challenges. Recently, many attempts have been made to utilize nanomaterials in MECs owing to the unique physicochemical properties of nanomaterials originating from their extremely small size (at least <100 nm in one dimension). The extraordinary properties of nanomaterials have provided great clues to overcome the technological hurdles in MECs. Nanomaterials are believed to play a crucial role in the commercialization of MECs. Thus, understanding the technological challenges of MECs, the characteristics of nanomaterials, and the employment of nanomaterials in MECs could be helpful in realizing commercial MEC technologies. Herein, the critical challenges that need to be addressed for MECs are highlighted, and then previous studies that used nanomaterials to overcome the technological difficulties of MECs are reviewed.

Angela Marchetti, Miriam Cerrillo Moreno, Roberto Lauri et al.

Processes • 2025

Microbial electrolysis cells (MECs) represent a pioneering technology for sustainable hydrogen production by leveraging bioelectrochemical processes. This study investigates the performance of a single-chamber cathodic MEC, where a cation exchange membrane separates the electrically active bioanode from the cathode. The system was constantly fed with a synthetic carbonaceous solution, employing a working potential of +0.3 V vs. SHE and an organic loading rate of 2 gCOD/Ld with a hydraulic retention time of 0.3 d. Notably, no methanogenic activity was detected, likely due to the establishment of an alkaline pH in the cathodic chamber. Under these conditions, the system exhibited good performance, achieving a current density of approximately 115 A/m3 and a hydrogen production rate of 1.28 m3/m3d. The corresponding energy consumption for hydrogen production resulted in 6.32 kWh/Nm3 H2, resulting in a slightly higher energetic cost compared to conventional electrolysis; moreover, an average energy efficiency of 85% was reached during the steady-state condition. These results demonstrate the potential of MECs as an effective and sustainable approach for biohydrogen production by helping the development of greener energy solutions.

Domenico Frattini, Gopalu Karunakaran, Eun-Bum Cho et al.

Processes • 2021

The use of microbial fuel cells (MFCs) is quickly spreading in the fields of bioenergy generation and wastewater treatment, as well as in the biosynthesis of valuable compounds for microbial electrolysis cells (MECs). MFCs and MECs have not been able to penetrate the market as economic feasibility is lost when their performances are boosted by nanomaterials. The nanoparticles used to realize or decorate the components (electrodes or the membrane) have expensive processing, purification, and raw resource costs. In recent decades, many studies have approached the problem of finding green synthesis routes and cheap sources for the most common nanoparticles employed in MFCs and MECs. These nanoparticles are essentially made of carbon, noble metals, and non-noble metals, together with a few other few doping elements. In this review, the most recent findings regarding the sustainable preparation of nanoparticles, in terms of syntheses and sources, are collected, commented, and proposed for applications in MFC and MEC devices. The use of naturally occurring, recycled, and alternative raw materials for nanoparticle synthesis is showcased in detail here. Several examples of how these naturally derived or sustainable nanoparticles have been employed in microbial devices are also examined. The results demonstrate that this approach is valuable and could represent a solid alternative to the expensive use of commercial nanoparticles.

Nhlanganiso Ivan Madondo, Sudesh Rathilal, Babatunde Femi Bakare

Catalysts • 2022

A vast quantity of untreated wastewater is discharged into the environment, resulting in contamination of receiving waters. A microbial electrolysis cell (MEC) is a promising bioelectrochemical system (BES) for wastewater treatment and energy production. However, poor design and control of MEC variables may lead to inhibition in the system. This study explored the utilization of Response Surface Methodology (RSM) on the synergistic aspects of MEC and magnetite nanoparticles for wastewater treatment. Influences of temperature (25–35 °C), voltage supply (0.3–1.3 V) and magnetite nanoparticle dosage (0.1–1.0 g) on the biochemical methane potentials (BMPs) were investigated with the aim of optimizing biogas yield, chemical oxygen demand removal and current density. The analysis of variance (ANOVA) technique verified that the quadratic models obtained were substantial, with p-values below 0.05 and high regression coefficients (R2). The optimum biogas yield of 563.02 mL/g VSfed, chemical oxygen demand (COD) removal of 97.52%, and current density of 26.05 mA/m2 were obtained at 32.2 °C, 0.77 V and 0.53 g. The RSM revealed a good comparison between the predicted and actual responses. This study revealed the effective utilization of statistical modeling and optimization to improve the performance of the MEC to achieve a sustainable and eco-friendly situation.

Zhang Min, Tang Rui, Li Yu

Water Science & Technology • 2024

ABSTRACT The anaerobic biodegradation of polycyclic aromatic hydrocarbons (PAHs) is challenging due to its toxic effect on the microbes. Microbial electrolysis cells (MECs), with their excellent characteristics of anodic and cathodic biofilms, can be a viable way to enhance the biodegradation of PAHs. This work assessed different cathode materials (carbon brush and nickel foam) combined with bioaugmentation on typical PAHs-naphthalene biodegradation and analyzed the inhibition amendment mechanism of microbial biofilms in MECs. Compared with the control, the degradation efficiency of naphthalene with the nickel foam cathode supplied with bioaugmentation dosage realized a maximum removal rate of 94.5 ± 3.2%. The highest daily recovered methane yield (227 ± 2 mL/gCOD) was also found in the nickel foam cathode supplied with bioaugmentation. Moreover, the microbial analysis demonstrated the significant switch of predominant PAH-degrading microorganisms from Pseudomonas in control to norank_f_Prolixibacteraceae in MECs. Furthermore, hydrogentrophic methanogenesis prevailed in MEC reactors, which is responsible for methane production. This study proved that MEC combined with bioaugmentation could effectively alleviate the inhibition of PAH, with the nickel foam cathode obtaining the fastest recovery rate in terms of methane yield.

Gao Lei, Yaoqiang Wang, Gang Xiao et al.

Catalysts • 2025

Hydrogen energy has emerged as a pivotal clean energy solution due to its sustainability and zero-emission potential. Microbial electrolysis cells are a promising technology for renewable hydrogen production, typically relying on expensive and unstable Pt/C catalysts for the hydrogen evolution reaction (HER). To address these limitations, this study develops a cost-effective and durable alternative approach. A cobalt–molybdenum (Co-Mo) alloy catalyst (denoted as CoMo/SS) was synthesized via a one-step electrodeposition method on 1000-mesh 316L stainless steel at a current density of 30 mA·cm−2 for 80 min, using an electrolyte with a Co-to-Mo ratio of 1:1. The electrochemical properties and hydrogen evolution performance of this catalyst in a microbial electrolysis cell were evaluated. Key results demonstrate that the CoMo/SS catalyst achieves a good catalytic performance of hydrogen evolution. The CoMo/SS cathode catalyst only requires an overpotential of 91.70 mV (vs. RHE) to reach a current density of 10 mA·cm−2 in 1 mol·L−1 KOH, with favorable kinetics, evidenced by a reduced Tafel slope of 104.10 mV·dec−1, enhanced charge transfer with a charge transfer resistance of 4.56 Ω, and a double-layer capacitance of 34.73 mF·cm−2. Under an applied voltage of 0.90 V, the CoMo/SS cathode exhibited a hydrogen production rate of 1.12 m3·m−3·d−1, representing a 33.33% improvement over bare SS mesh. This performance highlights the catalyst’s potential as a viable Pt/C substitute for scalable MEC applications.

Ki Nam Kim, Sung Hyun Lee, Hwapyong Kim et al.

Energies • 2018

A microbial electrolysis cell (MEC) consumes the chemical energy of organic material producing, in turn, hydrogen. This study presents a new hybrid MEC design with improved performance. An external TiO2 nanotube (TNT) array photoanode, fabricated by anodization of Ti foil, supplies photogenerated electrons to the MEC electrical circuit, significantly improving overall performance. The photogenerated electrons help to reduce electron depletion of the bioanode, and improve the proton reduction reaction at the cathode. Under simulated AM 1.5 illumination (100 mW cm−2) the 28 mL hybrid MEC exhibits a H2 evolution rate of 1434.268 ± 114.174 mmol m−3 h−1, a current density of 0.371 ± 0.000 mA cm−2 and power density of 1415.311 ± 23.937 mW m−2, that are respectively 30.76%, 34.4%, and 26.0% higher than a MEC under dark condition.

Maxime Blatter, Marc Sugnaux, Christos Comninellis et al.

ChemSusChem • 2016

Abstract A predictive model for the microbial/electrochemical base formation from wastewater was established and compared to experimental conditions within a microbial electrolysis cell. A Na 2 SO 4 /K 2 SO 4 anolyte showed that model prediction matched experimental results. Using Shewanella oneidensis MR‐1, a strong base (pH≈13) was generated using applied voltages between 0.3 and 1.1 V. Due to the use of bicarbonate, the pH value in the anolyte remained unchanged, which is required to maintain microbial activity.

Isaac Vázquez, Sven Kerzenmacher, Óscar Santiago

Frontiers in Energy Research • 2023

In the last years, microbial electrochemical technologies have received increasing attention due to their promising environmental potential. However, the identification of the most suitable materials for further development of these technologies tends to be challenging, especially for operation under realistic wastewater conditions. The objective of the present work is to carry out a systematic comparison of six anode materials (stainless-steel wool, carbon paper, graphite felt, graphite plate, graphite foil, and stainless-steel mesh) for microbial electrolysis cells operated for the treatment of brewery wastewater and determine the best material of these in sight of its electrochemical performance. For this purpose, the medium was semisynthetic brewery wastewater of low buffer capacity and low conductivity. The results suggest, that the degree of fermentation and characteristics of the studied media have only a minor impact on the limiting current density of the bioanodes. Here, the limiting current density of microbial anodes with stainless-steel wool (0.45 ± 0.07 mA·cm −2 ), a not so extensively studied promising material, outperformed commonly used materials such as graphite felt, without evidence of corrosion.

Mayank Dhadwal, Yang Liu, Bipro Ranjan Dhar

Processes • 2021

Reclamation and reuse of wastewater are increasingly viewed as a pragmatic tool for water conservation. Greywater, which includes water from baths, washing machines, dishwashers, and kitchen sinks, is a dilute wastewater stream, making it an attractive stream for extraction of non-potable water. However, most previous studies primarily focused on passively aerated biological and physicochemical treatment processes for greywater treatment. Here, we investigated an integrated process of a microbial electrochemical cell (MEC) followed by granular activated carbon (GAC) biofilter for greywater treatment. The integrated system could achieve 99.3% removal of total chemical oxygen demand (TCOD) and 98.7% removal of the anionic surfactants (linear alkylbenzene sulphonates) from synthetic greywater at a total hydraulic residence time (HRT) of 25 h (1 day for MEC and 1 h for GAC biofilter). For one-day HRT, the maximum peak volumetric current density from MEC was 0.65 A/m3, which was comparable to that achieved at four-day HRT (0.66 A/m3). The adsorption by GAC was identified as a key mechanism for the removal of organics and surfactants. In addition, recirculation of liquid within the GAC biofilter was identified as a critical factor in achieving high-rate treatment. Although results indicated that GAC biofilter could be a standalone process for greywater, MEC can provide an opportunity for potential energy recovery from greywater. However, further studies should focus on developing high-rate MECs with higher energy recovery potential for practical operation.

Hasna Aprilia, Jelita Ninda Qorina, R. Arbianti et al.

AIP Conference Proceedings • 2021

One way to treat oil waste is a seawater desalination system that uses exoelectorgenic bacteria as an agent for the degradation of organic compounds contained in oil waste. Microbial Desalination Cell (MDC) is a development of Microbial Fuel Cell (MFC), a method that can eliminate salt content in seawater using electricity generated by bacteria from wastewater. Stacked Microbial Desalination Cell (SMDC) is an MDC development where SMDC uses many pairs of ion Exchange Membranes (IEMs) where IEMs are placed between the Anion Exchange Membrane (AEM) and the Cation Exchange Membrane (CEM). This is intended to increase the efficiency of electron transfer. SMDC can also return more energy than other types of MDC so that the cost is more effectively. In this research, using a 2-SMDC reactor configuration with graphite rods as anode, CFC coated with activated carbon as a cathode, potassium permanganate as catholyte, and adding ion exchange resin to salt chamber. Independent variables used in this research were activated carbon mass variations of 0, 2, and 4 g. Parameters that will be obtained are COD, electrical productivity, and pH. The results obtained in this study indicate that the optimum mass variation of activated carbon is 4 g by adding Ion Exchange resin (ratio Resin Na and Cl 1 : 1) with a COD reduction of 57.808% and produces electrical productivity of 0.000561 W/m3 , and the change in pH by 0.24.

Ganesan V. Murugesu, Saiful Nizam Khalid, H. Shareef

IEEE Access • 2022

Microbial fuel cells (MFCs) are a promising technology that use microorganisms to generate electrical energy from chemical energy. However, ultralow-power production and high-cost materials have become significant drawbacks in MFC development. Therefore, various methods have been proposed for increasing the output power of MFC. Among them, stacking multiple cells in a series has been suggested as the most promising method for generating high power in MFC. However, voltage reversal (VR) has become an issue that limits the electrical power generation in stacked MFC. Thus, this study investigates and discusses the actual cause of the voltage reversal phenomenon in a series-stacked MFC from the perspective of electron and proton transfer mechanisms. This paper also discusses the electronic control methods used to eliminate VR and challenges in MFC development. Furthermore, this review also briefly explains the evolution of MFC development stages and the factors influencing MFC performance. It is found that solving the VR issue in a series of stacked MFC is a significant factor in boosting MFC technology in the commercial world. In addition, reducing material and operational costs will promote future implementation of MFCs.

Ann Maria George, Aravind M. Nair, Harichand M Ramesh et al.

2024 IEEE International Conference on Signal Processing, Informatics, Communication and Energy Systems (SPICES) • 2024

Microorganisms are used in Microbial Fuel Cells, a promising technology that converts chemical energy into electrical energy. High-cost materials and ultralow-power production, however, have emerged as major obstacles to MFC growth. As a result, numerous strategies have been put forth to raise the MFC's output power. Among them, the most promising technique for producing high power in MFC has been proposed to be the stacking of numerous cells in succession. Voltage reversal (VR), however, is now a problem that restricts the amount of electricity that can be produced in stacked MFC. Thus, from the perspective of electron and proton transport mechanisms in a series-stacked MFC, this work explores and explains the true reason of the voltage reversal phenomena. The electronic control techniques utilized to remove obstacles in MFC growth are also covered in this study.

Tangming Li, Peiwen Yang, Jun Yan et al.

Molecules • 2024

Hexavalent chromium (Cr (VI)) and para-chlorophenol (4-CP) are prevalent industrial wastewater contaminants that are recalcitrant to natural degradation and prone to migration in aquatic systems, thereby harming biological health and destabilizing ecosystems. Consequently, their removal is imperative. Compared to conventional chemical treatment methods, CW-MFC technology offers broader application potential. Leersia hexandra Swartz can enhance Cr (VI) and 4-CP absorption, thereby improving wastewater purification and electricity generation in CW-MFC systems. In this study, three CW-MFC reactors were designed with L. hexandra Swartz in distinct configurations, namely, stacked, multistage, and modular, to optimize the removal of Cr (VI) and 4-CP. By evaluating wastewater purification, electrochemical performance, and plant growth, the optimal influent hydraulic retention time (HRT) was determined. The results indicated that the modular configuration at an HRT of 5 days achieved superior removal rates and power generation. The modular configuration also supported the best growth of L. hexandra, with optimal photosynthetic parameters, and physiological and biochemical responses. These results underscore the potential of modular CW-MFC technology for effective detoxification of complex wastewater mixtures while concurrently generating electricity. Further research could significantly advance wastewater treatment and sustainable energy production, addressing water pollution, restoring aquatic ecosystems, and mitigating the hazards posed by Cr (VI) and 4-CP to water and human health.

H. Salman

JOURNAL OF XI'AN UNIVERSITY OF ARCHITECTURE & TECHNOLOGY • 2020

Microbial desalination cells (MDCs) are considered as a new clean sustainable technology for simultaneous treatment of wastewater, desalination of saline water, and power generation. In this study, the performance of a stacked microbial desalination cell (SMDC) contained three desalination chambers was investigated. This SMDC which designed with three desalination chambers was fed with real domestic wastewater to the anode and actual wetland saline water to the desalination chambers. The results revealed that maximum COD removal efficiency, desalination efficiency, power generation, and coulombic efficiency were 100%, 96.8%, 877mW/m, 6.92%, respectively. These promising results indicated the validity of using SMDC for simultaneous desalination of actual wetland saline water, treatment of sewage treatment, and power generation. KeywordsStacked microbial desalination cell, , Power generation, Saline water, Biotreatment.

Arnas Klevinskas, Kristina Kantminienė, Nerita Žmuidzinavičienė et al.

Processes • 2021

The deteriorating environmental quality requires a rapid in situ real-time monitoring of toxic compounds in environment including water and wastewater. One of the most toxic nitrogen-containing ions is nitrite ion, therefore, it is particularly important to ensure that nitrite ions are completely absent in surface and ground waters as well as in wastewater or, at least, their concentration does not exceed permissible levels. However, no selective ion electrode, which would enable continuous measurement of nitrite ion concentration in wastewater by bioelectrochemical sensor, is available. Microbial fuel cell (MFC)-based biosensor offers a sustainable low-cost alternative to the monitoring by periodic sampling for laboratory testing. It has been determined, that at low (0.01–0.1 mg·L−1) and moderate (1.0–10 mg·L−1) concentration of nitrite ions in anolyte-model wastewater, the voltage drop in MFC linearly depends on the logarithm of nitrite ion concentration of proving the potential of the application of MFC-based biosensor for the quantitative monitoring of nitrite ion concentration in wastewater and other surface water. Higher concentrations (100–1000 mg·L−1) of nitrite ions in anolyte-model wastewater could not be accurately quantified due to a significant drop in MFC voltage. In this case MFC can potentially serve as a bioelectrochemical early warning device for extremely high nitrite pollution.

Sudarsu Ramanaiah, Cristina Cordas, Sara Matias et al.

Catalysts • 2021

The electrochemical features of microbial fuel cells’ biocathodes, running on wastewater, were evaluated by cyclic voltammetry. Ex situ and in situ electrochemical assays were performed and the redox processes associated with the presence of microorganisms and/or biofilms were attained. Different controls using sterile media (abiotic cathode microbial fuel cell) and membranes covering the electrodes were performed to evaluate the source of the electrochemistry response (surface biofilms vs. biotic electrolyte). The bacteria presence, in particular when biofilms are allowed to develop, was related with the enhanced active redox processes associated with an improved catalytic activity, namely for oxygen reduction, when compared with the results attained for an abiotic microbial fuel cell cathode. The microbial main composition was also attained and is in agreement with other reported studies. The current study aims contributing to the establishment of the advantages of using biocathodes rather than abiotic, whose conditions are frequently harder to control and to contribute to a better understanding of the bioelectrochemical processes occurring on the biotic chambers and the electrode surfaces.

Jiseon You, Hangbing Fan, Jonathan Winfield et al.

Molecules • 2020

Improving the efficiency of microbial fuel cell (MFC) technology by enhancing the system performance and reducing the production cost is essential for commercialisation. In this study, building an additive manufacturing (AM)-built MFC comprising all 3D printed components such as anode, cathode and chassis was attempted for the first time. 3D printed base structures were made of low-cost, biodegradable polylactic acid (PLA) filaments. For both anode and cathode, two surface modification methods using either graphite or nickel powder were tested. The best performing anode material, carbon-coated non-conductive PLA filament, was comparable to the control modified carbon veil with a peak power of 376.7 µW (7.5 W m−3) in week 3. However, PLA-based AM cathodes underperformed regardless of the coating method, which limited the overall performance. The membrane-less design produced more stable and higher power output levels (520−570 µW, 7.4−8.1 W m−3) compared to the ceramic membrane control MFCs. As the final design, four AM-made membrane-less MFCs connected in series successfully powered a digital weather station, which shows the current status of low-cost 3D printed MFC development.

Guozhen Wang, Yating Guo, Jiaying Cai et al.

RSC Advances • 2019

The objective of this study is to assess bioelectricity generation, pollutant removal and the bacterial communities on anodes in constructed wetlands coupled with microbial fuel cells, through feeding the systems with three different types of synthetic wastewater.

Aritro Banerjee, Rajnish Kaur Calay, Fasil Ejigu Eregno

Energies • 2022

Microbial fuel cells (MFC) are an emerging technology for wastewater treatment that utilizes the metabolism of microorganisms to generate electricity from the organic matter present in water directly. The principle of MFC is the same as hydrogen fuel cell and has three main components (i.e., anode, cathode, and proton exchange membrane). The membrane separates the anode and cathode chambers and keeps the anaerobic and aerobic conditions in the two chambers, respectively. This review paper describes the state-of-the-art membrane materials particularly suited for MFC and discusses the recent development to obtain robust, sustainable, and cost-effective membranes. Nafion 117, Flemion, and Hyflon are the typical commercially available membranes used in MFC. Use of non-fluorinated polymeric membrane materials such as sulfonated silicon dioxide (S-SiO2) in sulfonated polystyrene ethylene butylene polystyrene (SSEBS), sulfonated polyether ether ketone (SPEEK) and graphene oxide sulfonated polyether ether ketone (GO/SPEEK) membranes showed promising output and proved to be an alternative material to Nafion 117. There are many challenges to selecting a suitable membrane for a scaled-up MFC system so that the technology become technically and economically viable.

Paulina Rusanowska, Marcin Dębowski, Marcin Zieliński

Energies • 2025

Microalgae microbial fuel cells (pMFCs) are distinguished by their ability to combine waste utilization with the simultaneous recovery of energy and valuable materials. The generation of high current density is linked to the efficient electron transfer to the anode via the anodic biofilm and the high photosynthetic activity of the microalgae cultivated in the cathode chamber. This review explores the impact of wastewater type on energy production and wastewater treatment. Additionally, it discusses the challenges related to microalgae growth in the cathode chamber, the necessity of aeration, and the sequestration of carbon dioxide from the anode chamber. The efficiency of microalgae in utilizing nutrients from various types of wastewater is also presented. In conclusion, the comparison between wastewater treatment and energy balance in pMFCs and conventional wastewater treatment plants is provided. On average, MFCs consume only 0.024 kW or 0.076 kWh/kg COD, which is approximately ten times less than the energy used by activated sludge bioprocesses. This demonstrates that MFCs offer highly efficient energy consumption compared to traditional wastewater treatment systems while simultaneously recovering energy through exoelectrogenic, bioelectrochemical processes.

Kasparas Kižys, Domas Pirštelis, Ingrida Bružaitė et al.

Biosensors • 2025

Microbial fuel cells (MFCs) are one of the contributors to the novel sustainable energy generation from organic waste. However, the application of MFCs is limited due to the slow charge transfer between cells and electrodes. This problem can be solved by modifying cells with conductive polymers, such as polypyrrole (PPy). We investigated the viability and electroactivity of modified cells at five different pyrrole concentrations, namely 8, 25, 50, 100, and 200 mM. The 100 mM concentration of PPy solution had the highest impact on yeast cells’ proliferation and growth, with the CFU/mL of PPy-treated yeast cells being 0.6 × 107 ± 5 × 10−2. The power density of the constructed MFC was evaluated by using an external load. The MFCs were analyzed using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Although CV results with different pyrrole concentrations were similar, DPV indicated that yeast modification with 50 mM pyrrole resulted in the most significant current density, which may be attributed to an increase in charge transfer due to the conductive properties of polypyrrole. The power density achieved with modified yeast in wastewater, 12 mW/m2, reached levels similar to those in laboratory solutions, 45 mW/m2.

Murali Krishna Pasupuleti

AI in Renewable Energy Management: Tools for Optimizing Sustainable Power Systems • 2024

Abstract: This chapter explores the transformative impact of AI-enhanced renewable energy systems, focusing on how intelligent systems are revolutionizing the management of sustainable power. It delves into the core components of AI-driven energy systems, including advanced algorithms, smart grids, and optimized energy storage solutions. The chapter examines the application of AI in solar, wind, and hydropower systems, highlighting its role in predictive maintenance, real-time monitoring, and performance optimization. Additionally, it discusses AI's critical function in energy demand forecasting, load management, and the emerging field of energy trading. The chapter also addresses the technical challenges and economic opportunities associated with integrating AI into renewable energy systems, emphasizing the importance of innovation, cross-sector collaboration, and strategic planning for achieving global sustainability goals. Future trends in AI-enhanced renewable energy, such as advancements in AI algorithms, the integration of emerging technologies, and the development of autonomous energy management systems, are explored to provide a comprehensive understanding of the path towards a sustainable energy future. Keywords: AI-Enhanced Renewable Energy, Intelligent Systems, Sustainable Power Management, Predictive Maintenance, Energy Storage Optimization, Smart Grids, Energy Demand Forecasting, Load Management, Energy Trading, Renewable Energy Innovation, Autonomous Energy Systems, Quantum Computing in Energy, Internet of Things (IoT), Blockchain in Energy, Sustainable Energy Future.

Murali Krishna Pasupuleti

Empowered Future: AI-Driven Green Energy Systems for Sustainable Power Management • 2024

Abstract: This chapter explores how artificial intelligence (AI) is revolutionizing sustainable energy management, emphasizing the integration of machine learning, predictive analytics, smart grids, and IoT to optimize renewable energy sources. It discusses the environmental and economic benefits of AI-powered systems, including reduced carbon emissions, minimized energy waste, and improved grid stability. The chapter also addresses the challenges of data privacy, implementation costs, and ethical considerations while highlighting future trends and the importance of global collaboration to achieve a sustainable, energy-efficient future. Keywords: AI, sustainable energy, renewable energy, smart grids, machine learning, predictive analytics, energy management, carbon emissions, energy efficiency, IoT, environmental impact, data privacy, ethical considerations, global collaboration, energy optimization

Yi Wang, Lihua Zhou, Xiaoshan Luo et al.

ChemSusChem • 2018

Temperature is an important parameter for the performance of bioelectrochemical systems (BESs). Energy-intensive bulk water heating has been usually employed to maintain a desired temperature for the BESs. This study concerns a proof-of-concept of a light-to-heat photothermal electrode for solar heating of a local electroactive biofilm in a BES for efficient microbial energy harvesting at low temperatures as a replacement for bulk water heating approaches. The photothermal electrode was prepared by coating Ti3 C2 Tx MXene sunlight absorber onto carbon felt. The as-prepared photothermal electrode could efficiently raise the local temperature of the bioelectrode to approximately 30 °C from low bulk water temperatures (i.e., 10, 15, and 20 °C) under simulated sunlight illumination. As a result, highly efficient microbial energy could be harvested from the low-temperature BES equipped with a photothermal electrode without bulk water heating. This study represents a new avenue for the design and fabrication of electrodes for temperature-sensitive electrochemical and biological systems.

V. Ancona, A. Caracciolo, D. Borello et al.

International Journal of Environmental Impacts: Management, Mitigation and Recovery • 2020

Pollution of soil and water environments is mainly due to different anthropogenic factors, and the presence of organic contaminants, in particular persistent, bioaccumulative and toxic ones, arouses concern for their possible effects on environment and human health. One nature-based technology that can be used in biodegradation of contaminated soil and water is microbial fuel cells (MFCs). They are also capable of producing energy and of being used as environmental sensors. In this context, this article aims at presenting the capacity of MFCs to reduce environmental pollution by exploiting the process of bioelectrochemical utilization of organic matter via microbial metabolism, to generate usable byproducts, fuels and bioelectricity. The main characteristic of an MFC, when used for energy harvesting, is the absence of emissions of pollutant gases such as CO, CO 2 , SOx or NOx. This characteristic, together with the intrinsic capacity of bioreactors to decontaminate soils and water, is stimulating the research into engineering solutions exploiting the MFC potential. Among the different types of MFCs, as bioelectrochemical systems (BESs), the terrestrial microbial fuel cells and the wastewater microbial fuel cells convert energy using a biocatalyst (microorganism) and a biofuel (organic substrate) in basic environments such as soil and water. Consequently, MFCs can be used as energy sources for powering sensors with low-power and low-voltage characteristics or complete single nodes of a distributed wireless sensor network, if coupled with smart although more complex electronic circuit. Moreover, MFCs can be environmental sensors, suited to monitoring some environmental parameters influencing MFC functional behaviours such as pH and temperature. This article introduces the polluted environment scenarios where these technologies could be suitably applied together with the description of two main types of MFC structures and their functioning. Furthermore, some case studies in which MFCs are used in decontamination of polluted environments are described.

Yajing Guo, Jiao Wang, Shrameeta Shinde et al.

RSC Advances • 2020

The development of microbial fuel cell (MFC) makes it possible to generate clean electricity as well as remove pollutants from wastewater. Extensive studies on MFC have focused on structural design and performance optimization, and tremendous advances have been made in these fields. However, there is still a lack of systematic analysis on biocatalysts used in MFCs, especially when it comes to pollutant removal and simultaneous energy recovery. In this review, we aim to provide an update on MFC-based wastewater treatment and energy harvesting research, and analyze various biocatalysts used in MFCs and their underlying mechanisms in pollutant removal as well as energy recovery from wastewater. Lastly, we highlight key future research areas that will further our understanding in improving MFC performance for simultaneous wastewater treatment and sustainable energy harvesting.