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Soil microbial fuel cells (SMFCs) function as bioelectrochemical energy harvesters that convert electrons stored in soil organic matter into useful electrical energy. Broadly, an SMFC comprises three essential components: an anode buried in the soil (the negative terminal), a colony of exoelectrogenic microorganisms residing on this anode, and a cathode (the positive terminal). As the exoelectrogens respire, they release electrons to the anode, which acts as an external receptor. These released electrons then flow through a load (e.g. a resistor), connecting the anode and cathode. Though minuscule, the electrical power produced by SMFCs has a number of potential applications such as sustaining low-power embedded electronics, pollutant remediation, or as a bio-sensing proxy for soil qualities and microbial activity. This discussion aims to emphasize the potential of SMFCs in addressing real-world environmental issues and to generate interest in the larger scientific community for broad interdisciplinary research efforts, particularly in field deployments.

Microbial fuel cells (MFC) have emerged as a sustainable wastewater treatment technique that offers simultaneous energy generation; however, the high cost of electrodes and their reduced catalytic activity have hindered their widespread adoption. To overcome this, an activated carbon synthesised from Areca nut husk was coated on different anodes viz. Carbon cloth and Stainless Steel (SS) mesh. Activated carbon was found to be highly porous with a carbon content of 85.39%, and a surface area of 767.98 m2/g, and was found to be amorphous with a high degree of graphitic structure. The electrical conductivities of the catalyst-coated SS mesh and carbon cloth were comparable, and the performance of the MFC was studied using both electrodes as anodes. A batch MFC with modified SS mesh as anode exhibited the highest power density of 155.35 mW/m3 in synthetic wastewater and 101.68 mW/m3 in kitchen wastewater, with COD removal efficiencies of 95.32% and 95.24%, respectively. In a continuous mode, the MFC delivered a maximum current density and power of 52.38 mA/m2 and 21.60 mW, respectively, with a maximum COD removal efficiency of 80.70% for an HRT of 20 hrs. These findings underscore the viability of using biomass-derived activated carbon as an anode catalyst in both batch and continuous modes of MFC. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the feasibility of combining direct glucose alkaline fuel cell (DGAFC) with microbial fuel cell (MFC) process. The system of two DGAFC cells combined with an MFC cell was successfully operated for the first time with 1 g/L glucose in 50 mM carbonate buffer solution at a pH of 10.5. The combined system achieved 99% of Coulombic efficiency and produced 6.68 and 1.80 times the total Coulombs of two DGAFC cells and one MFC cell, respectively. No accumulation of gluconic acid and high glucose mineralization were detected in the combined system within 72 h. High performance of the combined system was attributed to the synergistic effect between glucose conversion to gluconic acid in the DGAFC and its utilization by electrochemically active bacteria and fermenters in the MFC. Our results could be useful for developing novel glucose fuel cell. [Display omitted] • DGAFC combined MFC process was successfully operated for the first time. • 99% of CE and efficient glucose mineralization were obtained. • The combined system harvested much higher Coulombs that DGAFC and MFC alone. • The synergistic effect between DGAFC and MFC was discussed. [ABSTRACT FROM AUTHOR]

Air cathode microbial fuel cell (MFC) can use the biological activities of microorganisms to convert organic matter into ideal electrical energy, but this efficiency has not been satisfactory. The air cathode requires an optimal catalyst to enhance the power output of the MFC by improving its low oxygen reduction reaction (ORR) activity. Micro Cu-doped Co3O4 nano-flower-like catalyst is successfully synthesized in this study using a metal-organic framework as the precursor material. The addition of 5% Cu induces a higher concentration of oxygen vacancies, thereby optimizing the local electronic state of the active site and enhancing the catalytic performance for oxygen reduction in the 5% Cu-Co3O4 material. Consequently, when equipped with this material, the power output of the air cathode MFC is approximately 2.85 times greater than that achieved with pure Co3O4. This provides a novel design idea for the application of nano-flower-like transition metal oxygen reduction catalysts in MFC. [ABSTRACT FROM AUTHOR]

The experimental results of the present study show that phenol had a certain inhibitory effect on its utilization by phenol-acclimatized activated sludge (PAAS), which was the inoculum for the microbial fuel cell (MFC) inoculation. In co-metabolic study, utilization of para-nitrophenol (PNP) at low concentrations (< 20 mg L−1) when used with phenol at a fixed concentration (250 mg L−1) favorably proceeded. The behavior was interpreted in terms of carbon catabolite repression (CCR), indicating phenol (250 mg L−1) positively affected consumption of PNP (< 20 mg L−1). The calculated values of degradation rate show the necessity of phenol presence in the system where phenol acted on the inoculum's ability to withstand the inhibitory effect of PNP. The MFC functionality in electricity generation is also definable by considering CCR applicability and the results show that the negative effect of PNP was repressed by the presence of phenol. For instance, 20 mg L−1 PNP + 250 mg L−1 phenol yielded the highest power density (66.2 mW m−2) and the lowest internal resistance (189 Ω). The PAAS performance was characterized to evaluate cells' capacity in utilizing inhibitory substrates, and several different models were used. The relevant kinetic parameters are described in terms of PAAS affinity toward the substrate (ks) and the microbe's sensitivity in responding to the toxic substrate (ki). Luong and Aiba equations were chosen to describe MFC behavior when the PAAS utilized phenol as the sole substrate. While Haldane model was more capable of addressing co-metabolic degradation of PNP. [ABSTRACT FROM AUTHOR]

Productive use of brewery wastewater (BWW) demands that measures be put in place to avert its environmental detrimental effect. A new development is the recycling of fruit waste for the purpose of increasing bioelectricity generation. This study was made to utilize fruit wastes as co-substrates in enhancing the double-chamber microbial fuel cell (MFC) bio-electrochemical remediation of BWW and simultaneous bioelectricity generation. The bio-electrochemical kinetics of bioelectricity generation were modelled using the Nernst-Monod model and a developed Nernst-Monod-Moser model. Zero- and first-order kinetic models were applied to model the chemical oxygen demand (COD) and biological oxygen demand (BOD) removal kinetics. BWW with an initial COD concentration of 865.26 mg/L and a BOD concentration of 438.27 mg/L was subjected to MFC bio-electrochemical remediation for 168 days using different pH (4.5–7.5) and fruit wastes (pineapple, orange, and mango fruit wastes) as co-substrates. The results demonstrated that bioelectricity generation as well as COD and BOD removal were greatly influenced by pH and fruit wastes' presence. BWW-MFC operations in the presence of mixed pineapple, orange, and mango fruit wastes generated the highest open-circuit voltage (820 mV) and maximum power density (994.78 mW/m2) with the highest Coulombic efficiency (32.79% for COD or 64.75% for BOD), COD (96.28%), and BOD (98.25%) removal efficiencies. Nernst-Monod and the developed Nernst-Monod-Moser bio-electrochemical kinetic models adequately described the bio-electrochemical kinetics, while the COD and BOD removal kinetics followed both zero-order and first-order kinetics. Therefore, fruit wastes as co-substrates can be utilized to achieve enhanced bio-electrochemical remediation and bioelectricity generation. [ABSTRACT FROM AUTHOR]

Currently, a large amount of pharmaceutical waste (PW) and its derivatives are being produced and, in some cases, inadequate management or treatment practices are applied. In this regard, this research explores the adoption of several alternatives to deal with these problems, including biocarbon within the framework of the circular economy. Photocatalytic nanomaterials have been also extensively discussed as a feasible way to remove pharmaceutical compounds in wastewater. Although there are existing reports in this area, this document provides a detailed study of the synthesis process, experimental conditions, the integration of photocatalysts, and their impact on enhancing photocatalytic efficiency. Additionally, the low cost and ease of fabrication of lab-scale microbial fuel cells (MFCs) are thoroughly examined. This innovative technology not only facilitates the degradation of hazardous compounds in wastewater but also harnesses their energy to generate electricity simultaneously. The aforementioned approaches are covered and discussed in detail by documenting interesting recently published research and case studies worldwide. Furthermore, this research is of significant importance because it addresses the valorization of PW by generating valuable by-products, such as H2 and O2, which can occur simultaneously during the photodegradation process, contributing to more sustainable industrial practices and clean energy technologies. [ABSTRACT FROM AUTHOR]

This study investigates the potential of a salt bridge‐mediated microbial fuel cell (MFC) for power generation and wastewater sludge treatment in breweries. Unlike traditional "one‐parameter‐at‐a‐time" methodologies, this study uses a three‐variable Box–Behnken design response surface methodology to optimize critical MFC operational parameters. The effects of parameters such as solution pH, salt bridge molarity, and temperature were studied in the range of 4 to 10, 1 to 5 M, and 20 to 45 g L−1. The optimum operating parameters were found to be solution pH of 5.853, salt bridge molarity of 3.343 M, and temperature of 32.5 °C for chemical oxygen demand and biological oxygen demand removal efficiencies of 92.485 % and 88.51 %, respectively. Temperature was found to be the most significant factor affecting the reactor's performance. [ABSTRACT FROM AUTHOR]

Current trends in fuel cell reliant energy technologies are rapidly growing to meet the modern global environmental and sustainability concerns. Among different types of fuel cells developed so far, polymer electrolyte membrane fuel cell revealed benefits of low price, high efficiency, and environmental safety. To attain further ecological and sustainable aspects, green nanomaterials have been developed to design electrodes, electrolytes, as well as membrane electrode assembly of polymer electrolyte membrane fuel cell. Consequently, as bioelectricity source, microbial fuel cells or bioreactors have been focused for safe energy production and conversion through biowastes and microbial/anaerobic conditions. Use of green nanocomposites in microbial fuel cell electrolyte membrane, electrode, and membrane electrode assembly has brought about new revolutions in this field. Keeping in view the next energy trends, this cutting-edge review is designed to portray the synthesis, characteristics, and potential of green nanocomposites in microbial fuel cell components. Literature has been investigated for the effect of the incorporation of green polymer/nanoparticle-based electrodes/electrolytes/catalysts and synthesis approaches to attain superior electrochemical features, power/current density, power output, proton conductivity, ion-exchange capacity, and fuel cell efficiency. Besides, principle/mechanism of microbial fuel cell functioning, challenges, and significant prospects have been covered in this innovative attempt. [ABSTRACT FROM AUTHOR]

Large-scale application of MFCs is limited by the high cost of electrode and low power density. In this study, the electrochemical structure and power output performance of three novel straw-derived biochar are discussed and characterized by scanning electron microscope, specific surface area, cyclic voltammetry, Raman spectrum, electrochemical impedance spectroscopy etc. Compared with the common carbon felt electrode, the optimal electricity generation ability and electrochemical affinity are obtained in corn straw biochar electrode: the rough surface with macroporous structure and high degree of graphitization facilitates the attachment of electroactive bacteria; the maximum output voltage, open circuit voltage, power density and coulombic efficiency reach 662.64±4.03 mV, 798.24±3.65 mV, 1.54±0.18 W m−2 and 50.39±1.68 %, respectively; the maximum COD removal efficiency of 77.45±1.69 % is achieved; exchange current density (4.6142×10−4 A cm−2) in corn straw electrode presents the better electrochemical activity than that of carbon felt electrode. These implies that corn straw-derived biochar is a competitive raw material for MFC anode. [Display omitted] • Biochar is equipped with natural macroporous structure and excellent conductivity. • Straw biochar electrode is economical and environmentally friendly. • Corn straw biochar electrode is superior in electrochemical performance and pollutant removal effect. [ABSTRACT FROM AUTHOR]

The increasing volume of wastewater from fish farming poses a serious environmental threat. This study investigated a novel treatment method for butter catfish (Ompok bimaculatus) wastewater using a constructed wetland-microbial fuel cell (CW-MFC) integrated with the water fern Azolla microphylla. The system was effective in removing pollutants like electrical conductivity (EC), total dissolved solids (TDS), ammonium, nitrate, nitrite, and phosphate were evaluated. Additionally, the electricity generation capabilities were measured. The CW-MFC system achieved significant removal rates: 67.65% for EC, 61.67% for TDS, 100% for ammonium, 75.00% for nitrate, 81.25% for nitrite, and 70.00% for phosphate. Furthermore, the system generated a maximum open-circuit voltage (OCV) of 690±90 mV, a current density (CD) of 7.29±0.43 mA/m2 and a power density (PD) of 0.37±0.04 mW/m2. Analysis of the microbial community revealed a diverse root consortium dominated by bacterial genera, including Phreatobacter, Emticicia, and Rhodobacter, along with fungal genera such as Strelitziana, Ramularia, Cladosporium, Trichomerium, Cercospora, Erythrobasidium and Fusarium. These findings suggest that CW-MFC systems integrated with A. microphylla offer a promising approach for sustainable and efficient treatment of wastewater from catfish farming while simultaneously generating bioelectricity. [ABSTRACT FROM AUTHOR]

To enhance the removal of COD (Chemical Oxygen Demand) by microalgae, this study constructed a novel microalgae–microalgae microbial fuel cell system (AA-MFC). It investigated the coupling relationship between the COD treatment efficiency at the anode and the production of high-value microalgal products at the cathode, as well as explored the effects of different initial inoculum densities and light–dark cycles. The experiment first measured the operational performance of the newly constructed AA-MFC in open-circuit and closed-circuit modes, demonstrating that this novel AA-MFC could start up rapidly within 32 h and operate stably. The results showed that the AA-MFC enhanced the removal of COD and the growth of microalgae biomass at the anode while maintaining stable power generation. When the initial inoculation density of the anode was 1.2 × 108 cell/cm2 and the light–dark cycle time was 18:6 h, the AA-MFC had the most obvious promoting effect on the COD removal of the anode. Compared with normal culture conditions, the COD removal rate increased by 26.0% to 96.1%. These results indicate that the AA-MFC can not only effectively remove pollutants, but also promote the accumulation of high-value microalgae biomass. [ABSTRACT FROM AUTHOR]

Bringing microbial fuel cells (MFCs) to market requires the use of non-precious metal catalysts. Therefore, we replaced the platinum (Pt) cathode with more cost-effective cadmium gallate (CdGa2O4) nanoparticles in the present research. The synthesis and characterization of cadmium gallate (CdGa2O4), and further its application as a cathode catalyst for oxygen reduction reaction (ORR) in a MFC. The physiochemical characterization indicates a high ORR property of CdGa2O4, attributed to the presence of active sites, high electronic conductivity, and high surface area. These features enhanced the bioelectricity production with simultaneous wastewater treatment which resulted into comparable performances to catalysts such as platinum (Pt). The electrochemical analysis shows that the loading rate of CdGa2O4 has a significant impact on the power output of the MFC. The highest volumetric power density was observed in CdGa2O4 with a loading of 1 mg/cm3 (8.2 W/m3). COD removal efficiency also showed a similar trend with respect to different loading rates. 1 mg/cm3 of CdGa2O4 showed the highest COD removal and Columbic efficiency of 83.8% and 11.7%, respectively. The low cost-to-performance ratio, high ORR activity, and high electric conductivity of CdGa2O4 prove that CdGa2O4 is a feasible substitute for Pt in large-scale operations of MFC. [ABSTRACT FROM AUTHOR]

The microbial fuel cell (MFC) is considered a modern technology used for treating wastewater and recovering electrical energy. In this study, a new dual technology combining MFC and a specialized biofilter was used. The anodic materials in the system were crushed graphite, either without coating (UFB-MFC) or coated with nanomaterials (nano-UFB-MFC). This biofilter served as a barrier to retain and remove turbidity and suspended solids, while also facilitating the role of bacteria in the removal of organic pollutants, phosphates, nitrates, sulfates, oil and greases. The results demonstrated that both systems exhibited high efficiency in treating kitchen wastewater, specifically greywater and dishwashing wastewater with high detergent concentrations. The removal efficiencies of COD, oil and grease, suspended solids, turbidity, nitrates, sulfates, and phosphates in first UFB-MFC were found to be 88, 95, 89, 86, 87, 75, and 94%, respectively, and in Nano-UFB-MFC were 86, 99, 95, 91, 81, 88, and 95%, respectively, with a high efficiency in recovering bioenergy reaching a value of 1.8 and 1.5 A m−3, respectively. The results of this study demonstrate the potential for developing MFC and utilizing it as a domestic system to mitigate pollution risks before discharging wastewater into the sewer network. [ABSTRACT FROM AUTHOR]

BACKGROUND: This work studied the treatment of a synthetic sphalerite acid mine drainage (AMD). The treatment was carried out by means of a previous concentration stage using electrodialysis, followed by electrodeposition using a bioelectrochemical system (BES). RESULTS: The best concentration results were obtained when operating the electrodialysis at 8 V and at a diluate/concentrate volume ratio of 3. This treatment yielded a concentrate fraction of about 25% of the volume and a clear fraction of about 75% of the volume. The concentrated fraction was treated in a BES for the electrodeposition of the metal contained. By operating a microbial fuel cell (MFC), the spontaneous reactions took place and, in 2 days, all the Fe3+ was reduced to Fe2+; then, all the Cu2+ was electrodeposited as pure Cu0 in about 8 days. The maximum current density attained in this stage was 0.1 mA cm−2 and the maximum power was 0.05 W cm−2. Then, a subsequent operation of a microbial electrolysis cell (MEC) allowed for the simultaneous recovery of the Fe2+, Ni2+, Zn2+, and Cd2+ as a mixed metal mass. CONCLUSION: The electrodialysis yielded a clear effluent representing 75% of the total volume and a concentrated effluent accounting for 25%. It was possible to treat the concentrated effluent in an MFC, recovering pure Cu0 with a net electricity generation. The non‐spontaneous metal reductions were subsequently accomplished by means of MEC, the electricity requirements being lower than those in the case of the raw AMD due to the higher mass transfer rate and the reduction of the Ohmic loses. © 2023 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

A two-chamber microbial fuel cell (MFC) with algal-film cathode was constructed. It showed good electric-generating performance with three electric-generating stages: start-up, development, and stable. An average output voltage reached ~0.412 V during the stable period. A maximum power density during continuous operation was 19.76 mW/m2. Bacterial samples were collected from the anode in the three stages (A1, A2, and A3), and their community structure and diversity were analyzed using Illumina MiSeq high-throughput sequencing technology. A total of 4238 operational taxonomic units were identified based on the number of taxa. At the phylum level, Proteobacteria and Bacteroidetes played a dominant role in the three stages and increased significantly during electricity generation. Compared with A1, the relative abundances of Proteobacteria in A2 and A3 increased by 23.30% and 32.06%, respectively, whereas those of Bacteroidetes in A2 and A3 increased by 5.56% and 14.50%, respectively. At the genus level, there were differences in the composition of bacterial communities among the three stages. Acinetobacter and Chlorobium became the dominant genera in A2, replacing Nitrospira and norank_f__Saprospiraceae in A1, and Sphingobacterium and Ochrobactrum became the dominant genera in A3. According to the sample cluster and principal component analyses, A1 was clustered into one class, and A2 and A3 were clustered into a second class. This work revealed bacterial community succession at the anode of an algal-film cathode MFC during the electricity generation process, which provides a theoretical basis for the subsequent promotion of electricity generation by algal-film cathode MFCs. [ABSTRACT FROM AUTHOR]

Some of the most popular technologies for wastewater sanitation, still face serious limitations related to high energy consumption requirements. In this context, microbial fuel cells (MFCs) constitute a promising approach since they do not require aeration and produce electricity at the same time. Limitations for these devices, however, are related to the cost of the constituents and the functionality of the arrangement. In this work, a semi‐cylindrical ceramic MFC was designed and constructed using a low‐cost commercial ceramic handcraft as a membrane, carbon felt, carbon cloth, and carbon cloth/activated carbon in different arrangements for the anode and cathode components. The best results were obtained using carbon felt as an anode and a cathodic zone built with carbon felt in which void regions were filled with activated carbon. This arrangement produced 85 mWm−2 for each cell. Evaluating the performance of the MFC in a modular system with eight cells using a different number of separations inside the module and different electrical connections, resulting in a 4‐compartment module that produced 90 mWm−2 with one single module and 95 mWm−2 with a serial arrangement of two modules. [ABSTRACT FROM AUTHOR]

With the rapid development of society, it is of paramount importance to expeditiously assess environmental pollution and provide early warning of toxicity risks. Microbial fuel cell–based self-powered biosensors (MFC-SPBs) have emerged as a pivotal technology, obviating the necessity for external power sources and aligning with the prevailing trends toward miniaturization and simplification in biosensor development. In this case, vigorous advancements in MFC-SPBs have been acquired in past years, irrespective of whether the target identification event transpires at the anode or cathode. The present article undertakes a comprehensive review of developed MFC-SPBs, categorizing them into substrate effect and microbial activity effect based on the nature of the target identification event. Furthermore, various enhancement strategies to improve the analytical performance like accuracy and sensitivity are also outlined, along with a discussion of future research trends and application prospects of MFC-SPBs for their better developments. [ABSTRACT FROM AUTHOR]

Improving catalytic activity of cathode with noble metal-free catalysts can significantly establish microbial fuel cells (MFCs) as a sustainable and economically affordable technology. This investigation aimed to assess the viability of utilizing tri-metal ferrite (Co0.5Cu0.5 Bi0.1Fe1.9O4) as an oxygen reduction reaction (ORR) catalyst to enhance the performance of cathode in MFCs. Trimetallic ferrite was synthesized using a sol–gel auto-combustion process. Electrochemical evaluations were conducted to assess the efficacy of as-synthesized composite as an ORR catalyst, employing electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). This evaluation revealed that the impregnation of bismuth in the Co–Cu-ferrite structure improves the reduction current response and reduces the charge transfer resistance. Further experiments were conducted to test the performance of this catalyst in an MFC. The MFC with tri-metal ferrite catalyst generated a power density of 11.44 W/m3 with 21.4% coulombic efficiency (CE), which was found to be comparable with commercially available 10% Pt/C used as cathode catalyst in MFC (power density of 12.14 W/m3 and CE of 23.1%) and substantially greater than MFC having bare carbon felt cathode without any catalyst (power density of 2.49 W/m3 and CE of 7.39%). This exceptionally inexpensive ORR catalyst has adequate merit to replace commercial costlier platinum-based cathode catalysts for upscaling MFCs. [ABSTRACT FROM AUTHOR]

This work used a unified dynamic model of microbial fuel cells (MFCs) and microbial electrolysis cells (MECs) that were combined to create MFC-powered MECs. This allowed for a completely sustainable and green system of hydrogen production and wastewater treatment. The main advantage that was envisioned for this coupled system was the elimination of the need for an external power source; the only feed to the system was the wastewater itself. We present the results of parameter estimation and model validation. The results showed the importance of minimizing internal resistance to increase hydrogen production. Better powering of MECs was achieved by setting MFCs in series rather than in parallel. [ABSTRACT FROM AUTHOR]

The rapid consumption of fossil fuels has led to calls to switch from non-renewable to renewable energy sources. Microbial fuel cells are a promising technology that simultaneously treats wastewater and produces power. This study used the Taguchi Experimental method to optimize anode thickness and pH to obtain the maximum power density of an air-cathode microbial fuel cell (ACMFC). The graphene-sponge (G-S) anode thickness and chamber pH were selected as operating parameters, with their corresponding levels. The L9 orthogonal array was chosen for the experimental design. According to the Taguchi Method, the optimum G-S anode thickness and chamber pH were determined to be 1.0 cm and 8.0, respectively. A confirmatory run was performed under these optimum conditions, and the maximum power density observed was 707.75 mW·m-3. Analysis of variance (ANOVA) was conducted to identify the percentage contributions of the operating parameters to the process, which were found to be 30.66% for pH and 69.34% for anode thickness. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are persistent environmental pollutants commonly found in water and sediments, posing significant health risks due to their toxicity, carcinogenicity, and mutagenicity. The stable and sustainable degradation of PAHs has garnered significant attention from researchers. Biological electrochemical systems (BESs) offer a promising approach with advantages in energy efficiency, safety, environmental protection, and long-term operation. This review examines the degradation performance and microbial community dynamics of BESs in the treatment of PAH-contaminated water and sediments. Additionally, the metabolites formed during the degradation process were also summarized. This review summarizes the degradation characteristics of PAH-contaminated water and sediments and aims to guide future research and optimize BESs for effective remediation of PAHs in various environmental settings. [ABSTRACT FROM AUTHOR]

The microbial fuel cell (MFC) is a renewable energy technology that utilizes the oxidative decomposition processes of anaerobic microorganisms to convert the chemical energy in organic matter, such as wastewater, sediments, or other biomass, into electrical power. This technology is not only applicable to wastewater treatment but can also be used for resource recovery from various organic wastes. The MFC usually requires an external controller that allows it to operate under controlled conditions to obtain a stable output voltage. Therefore, the application of a PID controller to the MFC is proposed in this paper. The design phase for this controller involves the identification of three parameters. Although the particle swarm optimization (PSO) algorithm is an advanced optimization algorithm based on swarm intelligence, it suffers from issues such as unreasonable population initialization and slow convergence speed. Therefore, this paper proposes an improved particle swarm algorithm based on the Golden Sine Strategy (GSCPSO). Using Circle chaotic mapping to make the distribution of the initial population more uniform, and then using the Golden Sine Strategy to improve the position update formula, not only improves the convergence speed of the population but also enhances convergence precision. The GSCPSO algorithm is applied to execute the described design process. The results of the simulation show that the designed control method exhibits smaller steady-state error, overshoot, and chattering compared with sliding-mode control (SMC), backstepping control, fuzzy SMC (FSMC), PSO-PID, and CPSO-PID. [ABSTRACT FROM AUTHOR]

This study investigated waste jasmine flower as a cellulose-based substrate for the reverse osmosis (RO) reject wastewater treatment in a single chamber microbial fuel cell (SCMFC). The two types of MFCs with and without alkaline pretreatment of waste jasmine flower as substrate were operated using a substrate concentration of 200 mg/L (200 mg of substrate in 1 L of RO reject wastewater). A maximum of 68% total dissolved solids (TDS) removal and maximum power density of 2 mW/m2 were obtained in the MFC with alkaline pretreated waste jasmine flower as the substrate. The performance of this MFC was found to be better than the MFC without alkaline pretreated waste jasmine flower. Three different concentrations of 200, 250, and 500 mg/L of the selected alkaline pretreated waste jasmine flower substrate were compared for checking the performance of MFC. The most efficient substrate concentration was found to be 200 mg/L. According to the polarization curves, ohmic losses predominated in the SCMFCs for both treated and non-treated substrates. [ABSTRACT FROM AUTHOR]

The purpose of this article is to assess the feasibility analysis of microbial fuel cells (MFCs), particularly in the configuration of dual chamber salt bridge microbial fuel cell (DCSB‐MFC), as a promising approach for simultaneous bioelectricity generation and wastewater remediation. The application of a salt bridge presents an economically viable alternative to the use of a proton exchange membrane, which is known for its high cost, in the construction of MFCs. This arrangement has been demonstrated to offer significant benefits in terms of enhancing the performance of new elements and evaluating operational parameters. However, it also encounters issues related to the total internal resistance (Rint) of the MFCs as well as power density (P). In addition, it has been found that traditional packing materials such activated carbon and gravel demonstrate poor permeability, internal resistance, and slow biofilm growth. Furthermore, there is a necessity to search for electrodes that possess high resistance to corrosion and are cost‐effective to achieve optimal bioelectricity generation. Therefore, this article aims to emphasize the research areas that require attention. By addressing these areas, the actual implementation of this configuration can be brought closer to practical implementation. [ABSTRACT FROM AUTHOR]

Microbial fuel cell (MFC) is a bioelectrochemical‐based reactor that can generate electrical energy directly from wastewater by utilizing microbial activity that oxidizes the waste organic matter. This study aims to synthesize polyaniline (PANI) and deposit on a graphite carbon electrode (GCE) and activated carbon cloth (ACC) surface to use as an anode material for MFCs. The MFC performance was evaluated using oxygen and ferricyanide as electron acceptors. PANI was electropolymerized from its aniline monomer and deposited using an electrophoretic deposition method onto the electrode surface. A PANI thin film was characterized using FTIR, field emission scanning electron microscopy (FESEM), BET, and electrochemical analysis. The analysis results show the characteristic peaks of PANI at 1557 cm−1, demonstratinjg the existence of quinoid rings (NQN), while the peaks at 1479 and 1400 cm−1 corresponding to the benzenoid (NBN) stretching in the PANI structure. The FESEM analysis confirmed that PANI appeared to have a porous structure on modified electrodes. It was found that the best system was MFC with ferricyanide as the electron acceptor. The highest power density produced is 254 mWm−2 from GCE‐PANI and 16.47 mWm−2 from ACC‐PANI. The normalized energy recovery of GCE‐PANI and ACC‐PANI in ferricyanide is 0.115 kWh kgCOD−1 and 5.67 × 10−3 kWh kgCOD−1, respectively. The COD removal was observed to be 88.8% for GCE‐PANI and 87.2% for ACC‐PANI from 1000 mg/L COD. [ABSTRACT FROM AUTHOR]

The increasing volume of wastewater from fish farming poses a serious environmental threat. This study investigated a novel treatment method for butter catfish (Ompok bimaculatus) wastewater using a constructed wetland-microbial fuel cell (CW-MFC) integrated with the water fern Azolla microphylla. The system was effectiveness in removing pollutants like electrical conductivity (EC), total dissolved solids (TDS), ammonium, nitrate, nitrite, and phosphate was evaluated. Additionally, the electricity generation capabilities were measured. The CW-MFC system achieved significant removal rates: 67.65% for EC, 61.67% for TDS, 100% for ammonium, 75.00% for nitrate, 81.25% for nitrite, and 70.00% for phosphate. Furthermore, the system generated a maximum open-circuit voltage (OCV) of 690±90 mV, a current density (CD) of 7.29±0.43 mA/m³and a power density (PD) of 0.37±0.04 mW/m³. Analysis of the microbial community revealed a diverse root consortium dominated by bacterial genera including Phreatobacter, Emticicia and Rhodobacter, along with fungal genera such as Strelitziana, Ramularia, Cladosporium,Trichomerium, Cercospora, Erythrobasidium and Fusarium. These findings suggest that CW-MFC systems integrated with A. microphylla offer a promising approach for sustainable and efficient treatment of wastewater from catfish farming while simultaneously generating bioelectricity.

This work used a unified dynamic model of microbial fuel cells (MFCs) and microbial electrolysis cells (MECs) that were combined to create MFC-powered MECs. This allowed for a completely sustainable and green system of hydrogen production and wastewater treatment. The main advantage that was envisioned for this coupled system was the elimination of the need for an external power source; the only feed to the system was the wastewater itself. We present the results of parameter estimation and model validation. The results showed the importance of minimizing internal resistance to increase hydrogen production. Better powering of MECs was achieved by setting MFCs in series rather than in parallel.

Microbial fuel cell (MFC) shows potential as an environmentally friendly energy technology, but the low power density restricts their practical applications. In this study, polypyrrole (PPy), carbon nanotubes (CNTs) and MoSe 2 were synthesized into a novel nanocomposite (PPy/MoSe 2 /CNTs) via a straightforward hydrothermal and in situ polymerization approach and served as the anode material of MFC. The charge transfer resistance (R ct) of the PPy/MoSe 2 /CNTs (4.75 Ω) anode was significantly lower than that of PPy/MoSe 2 (13.75 Ω) anode and MoSe 2 /CNTs (12.36 Ω) anode. Furthermore, the maximum power density of the PPy/MoSe 2 /CNTs-MFC was 4.43 W/m2, which was 1.99 times and 1.61 times higher than that of the PPy/MoSe 2 -MFC (2.22 W/m2) and MoSe 2 /CNTs-MFC (2.74 W/m2), respectively. High-throughput sequencing confirmed that PPy/MoSe 2 /CNTs bioanode demonstrated outstanding biocompatibility and the function of screening excellent electrogenic microbes. On the one hand, the good bioelectrocatalytic performance of the PPy/MoSe 2 /CNTs bioanode could be attributed to the abundant pyrrolic nitrogen in PPy, which enhanced the attachment of C-type cytochrome (Omcs) and promoted the direct electron transfer (DET) process between the biofilm and the electrode. In addition, the conductive bridging Mo–N bonds further promoted the direct transfer of electrons in PPy, mediating the long-distance DET process. On the other hand, well-dispersed MoSe 2 not only provided numerous active sites, but also enhanced the Se cycle of microorganisms by affecting their energy metabolism pathways, thereby improving their electricity generation capacity. In addition to the above, the high electrical conductivity of CNTs increased the interfacial charge transfer rate. This study explored the use of molybdenum-based ternary material as anode material to construct high-performance MFC, which provided meaningful information for future practical applications of MFC. [Display omitted] • A novel and biocompatible PPy/MoSe 2 /CNTs nanocomposite material was prepared. • The EET process was significantly enhanced by PPy/MoSe 2 /CNTs. • The power production of MFC with PPy/MoSe 2 /CNTs anode was greatly increased. [ABSTRACT FROM AUTHOR]

The Co/Co-Nx-embedded mesoporous 3D flower-like carbon sheet (Co/Co-N-MC-800) catalyst is successfully prepared from high N content H-1,2,4-Triazol-3-amine organic-ligand at different pyrolysis temperatures based on in situ pyrolysis Co-metal organic frame (MOF) (Co-PTA-MOF) precursor under nitrogen. The metal active center of the mesoporous Co/Co-N-MC-800 catalyst with more defect sites is situated in the positively charged 0 ~ + 2, and the bond spacing is consistent with the Co-N4 plane structure of the co-porphyrin. The obtained Co/Co-N-MC-800 possesses an excellent oxygen reduction reaction performance with a higher onset potential (0.92 V vs RHE) and half-wave potential (0.76 V vs RHE), which is closer to Pt/C and outstanding long-term stability with 89.1% current retention after 89 h and displays an optional power density of 1079.3 ± 22.5mW·m−2 in air-breath cathode microbial fuel cell (MFC). The improved catalytic performance maybe attributes to combination of the special 3D nanostructure, embedded cobalt nanoparticles (forming Co-Nx) and N-doped mesoporous carbon sheet material. The present study provides the technical and theoretical basis for the ORR through the cathode modification of MOF prepared from non-precious metal and N content organic-ligand. [ABSTRACT FROM AUTHOR]

Microbial fuel cell (MFC) has been regarded as a promising green and clean electricity generation device. The anode plays a crucial role in the electricity generation process within the MFC. This study employed a hydrothermal method for the doping of sulfur onto MXene nanosheets to alleviate the stacking, followed by an in situ polymerization process to fabricate sufur-doped MXene/polypyrrole (S–MXene/PPy) composite hydrogel on carbon felt (CF). The MFC constructed with this anode exhibited the highest power density of 8.05 W m−3 and a maximum output voltage of 646 mV, higher than that of MXene/PPy (623 mV, 6.03 W m−3), PPy (594 mV, 4.91 W m−3), and unmodified CF (574 mV, 4.05 W m−3). This improved performance can be attributed to the reduction of charge transfer resistance in the material while improving the bacteria affinity, leading to enhanced extracellular electron transfer (EET) efficiency. High-throughput sequencing indicates that the excellent biocompatibility significantly promotes the attachment and growth of electroactive microorganisms (Geobacter, 45.34%) on the S–MXene/PPy anode. This study demonstrates that S–MXene/PPy hydrogel has good potential as an anode from the perspective of MFC electricity generation and microbial analysis. [ABSTRACT FROM AUTHOR]

This study investigates the effect of microbial configuration on the electrochemical performance of photosynthetic microbial fuel cells (PMFCs). The PMFC configuration incorporating both bacteria and microalgae exhibited the highest open-circuit voltage (OCV) of 397.95 ± 31.53 mV, significantly higher than that of the OCVs obtained in the sterile control (C1) and the microalgae-only configuration (C2), which were 32.47 ± 22.43 mV and 284.59 ± 12.63 mV, respectively. Furthermore, the PMFC containing only microalgae achieved a current density (CD) of 20.96 ± 0.18 mA/m³ and a power density (PD) of 0.40 ± 0.01 mW/m³ under room temperature conditions. Notably, the combined bacteria and microalgae configuration demonstrated a substantial performance improvement, yielding a significantly higher CD of 49.33 ± 0.36 mA/m³ and PD of 0.78 ± 0.01 mW/m³ at room temperature. This configuration also achieved a maximum decolorization of 93.57 ± 0.10% with a corresponding algal biomass recovery of 134.90 ± 2.69 mg/L. These findings highlighted the critical role of microbial composition in PMFC performance. The combination of bacteria and microalgae yielded superior results compared to other configurations under the investigated conditions.

Abstract In this study, highly selenite-resistant strains belonging to Brevundimonas diminuta (OK287021, OK287022) genus were isolated from previously operated single chamber microbial fuel cell (SCMFC). The central composite design showed that the B. diminuta consortium could reduce selenite. Under optimum conditions, 15.38 Log CFU mL-1 microbial growth, 99.08% Se(IV) reduction, and 89.94% chemical oxygen demand (COD) removal were observed. Moreover, the UV–visible spectroscopy (UV) and Fourier transform infrared spectroscopy (FTIR) analyses confirmed the synthesis of elemental selenium nanoparticles (SeNPs). In addition, transmission electron microscopy (TEM) and scanning electron microscope (SEM) revealed the formation of SeNPs nano-spheres. Besides, the bioelectrochemical performance of B. diminuta in the SCMFC illustrated that the maximum power density was higher in the case of selenite SCMFCs than those of the sterile control SCMFCs. Additionally, the bioelectrochemical impedance spectroscopy and cyclic voltammetry characterization illustrated the production of definite extracellular redox mediators that might be involved in the electron transfer progression during the reduction of selenite. In conclusion, B. diminuta whose electrochemical activity has never previously been reported could be a suitable and robust biocatalyst for selenite bioreduction along with wastewater treatment, bioelectricity generation, and economical synthesis of SeNPs in MFCs.

Microbial fuel cells (MFCs) can realize the conversion of chemical energy to electrical energy in high-salt wastewater, but the easily deactivated cathode seriously affects the performance of MFCs. To enhance the stability and sustainability of MFC in such circumstances, a bimetallic organic framework ZIF-8/ZIF-67 was utilized for the synthesis of a carbon cage-encapsulated metal catalysts in this study. Catalysts with different Co and Ce ratio (Co@C (without the Ce element), CoCe0.25@C, CoCe0.5@C, and CoCe1@C) were employed to modify the activated carbon cathodes of MFCs. The tests demonstrated that the MFCs with the CoCe0.5@C cathode catalyst obtained the highest maximum power density (188.93 mW/m2) and the smaller polarization curve slope, which boosted the electrochemical activity of microorganisms attached to the anode. The appropriate addition of the Ce element was conductive to the stability of the catalyst's active center, which is beneficial for the stability of catalytic performance. Under the function of the CoCe0.5@C catalyst, the MFCs exhibited superior and stable norfloxacin (NOR) degradation efficiency. Even after three cycles, the NOR degradation rate remained at 68%, a negligible 5.6% lower than the initial stage. Furthermore, based on the analysis of microbial diversity, the abundance of electrogenic microorganisms on a bioanode is relatively high with CoCe0.5@C as the cathode catalyst. This may be because the better cathode oxygen reduction reaction (ORR) performance can strengthen the metabolic activity of anode microorganisms. The electrochemical performance and NOR degradation ability of MFC were enhanced in a high-salt environment. This paper provides an approach to address the challenge of the poor salt tolerance of cathode catalysts in MFC treatment, and presents a new perspective on resource utilization, low carbon emissions, and the sustainable treatment of high-salt wastewater. [ABSTRACT FROM AUTHOR]

The Microbial Desalination Cell (MDC) stands out as an innovative and a sustainable technology for both renewable energy generation and water treatment. The choice of electron acceptor significantly influences the efficiency of electricity flow. This study focuses on exploring the MDC performance under different conditions, including variations in cathode electron acceptors, initial pH levels, and hydraulic retention time (HRT). The investigation assesses simultaneous reduction of TDS and power generation from Caspian Sea water, a prominent saline water source in northern Iran, in both open-circuit (OC) and closed-circuit (CC) modes. The findings reveal that sodium hypochlorite, potassium permanganate, and potassium bromate as catholyte achieved TDS reduction rates of 84%, 77%, and 72%, respectively, under CC conditions at pH 5. Furthermore, it was observed that increasing HRT and pH levels lead to a decrease in desalination efficiency and power generation. Notably, the study highlights that the maximum power density was attained using permanganate, hypochlorite, and bromate as catholyte in both OC and CC configurations. By showcasing the adaptability of MDC performance with different cathode electron acceptors under varying conditions, this research offers valuable insights for optimizing MDC efficiency when treating real saline water sources. [ABSTRACT FROM AUTHOR]

The use of gas diffusion electrodes (GDEs) in microbial fuel cells (MFCs) can improve their cell performance, but tends to cause fouling. In order to allow long-term stable operation, the search for antifouling methods is necessary. Therefore, an antibacterial coating with ammonium compounds is investigated. Within the first 30 days of operation, the maximum measured power density of a GDE with antibacterial ionomer was 606 mW m−2. The GDE without an antifouling treatment could only reach a maximum of 284 mW m−2. Furthermore, there was an optimum in the loading amount with ionomer below 2.6 mg cm−2. Further investigations showed that additional aeration of the GDEs by a fan had a negative effect on their performance. Despite the higher performance, the antibacterial coating could not prevent biofilm growth at the surface of the GDE. The thickness of the biofilm was only reduced by 14–16%. However, the weight of the biofilm on the treated GDEs was 62–80% less than on a GDE without an antifouling treatment. Consequently, the coating cannot completely prevent fouling, but possibly leads to a lower density of the biofilm or prevents clogging of the pores inside the electrodes and improves their long-term stability. [ABSTRACT FROM AUTHOR]

The culture medium composition plays a critical role in optimizing the performance of microbial fuel cells (MFCs). One under-investigated aspect of the medium is the impact of the Wolf vitamin solution. This solution, known to contain essential vitamins like biotin, folic acid, vitamin B12, and thiamine, is believed to enhance bacterial growth and biofilm formation within the MFC. The influence of varying Wolf vitamin solution concentrations (2, 4, 6, 8, and 10 mL) on microbial fuel cell (MFC) performance is investigated in this study. Python 3.7.0 software is employed to enhance and anticipate the performance of MFC systems. Four distinct machine-learning algorithms, namely adaptive boosting (AdaBoost), extreme gradient boosting (XGBoost), categorical boosting algorithm (CatBoost), and support vector regression (SVR), are implemented to predict power density. In this study, a data split of 80% for training and 20% for testing was employed to optimize the artificial intelligence (AI) model. The analysis revealed that the optimal concentration of Wolf mineral solution was 5.8 mL. The corresponding error percentages between the experimental and AI-predicted values for current density, power generation, COD removal, and coulombic efficiency were found to be remarkably low at 0.79%, 0.5%, 1.89%, and 1.27%, respectively. These findings highlight the significant role of Wolf mineral solution in maximizing MFC performance and demonstrate the exceptional precision of the AI model in accurately predicting MFC behavior. [ABSTRACT FROM AUTHOR]

AbstractIncreasing industrialization and urbanization have contributed to a significant rise in wastewater discharge and exerted extensive pressure on the existing natural energy resources. Microbial fuel cell (MFC) is a sustainable technology that utilizes wastewater for electricity generation. MFC comprises a bioelectrochemical system employing electroactive biofilms of several aerobic and anaerobic bacteria, such as Geobacter sulfurreducens, Shewanella oneidensis, Pseudomonas aeruginosa, and Ochrobacterum pseudiintermedium. Since the electroactive biofilms constitute a vital part of the MFC, it is crucial to understand the biofilm-mediated pollutant metabolism and electron transfer mechanisms. Engineering electroactive biofilm communities for improved biofilm formation and extracellular polymeric substances (EPS) secretion can positively impact the bioelectrochemical system and improve fuel cell performance. This review article summarizes the role of electroactive bacterial communities in MFC for wastewater treatment and bioelectricity generation. A significant focus has been laid on understanding the composition, structure, and function of electroactive biofilms in MFC. Various electron transport mechanisms, including direct electron transfer (DET), indirect electron transfer (IET), and long-distance electron transfer (LDET), have been discussed. A detailed summary of the optimization of process parameters and genetic engineering strategies for improving the performance of MFC has been provided. Lastly, the applications of MFC for wastewater treatment, bioelectricity generation, and biosensor development have been reviewed. [ABSTRACT FROM AUTHOR]

The effects of salinity gradients (500–4000 mg·L−1 NaCl) on electricity generation, nitrogen removal, and microbial community were investigated in a constructed wetland-microbial fuel cell (CW-MFC) system. The result showed that power density significantly increased from 7.77 mW m−2 to a peak of 34.27 mW m−2 as salinity rose, indicating enhanced electron transfer capabilities under saline conditions. At a moderate salinity level of 2000 mg·L−1 NaCl, the removal efficiencies of NH4+–N and TN reached their maximum at 77.34 ± 7.61% and 48.45 ± 8.14%, respectively. This could be attributed to increased microbial activity and the presence of critical nitrogen-removal organisms, such as Nitrospira and unclassified Betaproteobacteria at the anode, as well as Bacillus, unclassified Rhizobiales, Sphingobium, and Simplicispira at the cathode. Additionally, this salinity corresponded with the highest abundance of Exiguobacterium (3.92%), a potential electrogenic bacterium, particularly at the cathode. Other microorganisms, including Geobacter, unclassified Planctomycetaceae, and Thauera, adapted well to elevated salinity, thereby enhancing both electricity generation and nitrogen removal. [ABSTRACT FROM AUTHOR]

Graphene oxide has attracted many interests in the recent decade due to its unique mechanical and chemical properties. This study focuses on the modification of graphene oxide and preparation proton exchange membrane (PEM) by sulfonated poly ether ether ketone (SPEEK) as base polymer for using in MFC as a modified membrane to remove COD and electricity generation. The scanning electron microscope (SEM) images, Fourier transform infrared (FTIR) and contact angle measurements were used to verify hydrophilic properties of the synthesized membranes. First, preparation procedures and properties of sulfonated reduced graphene oxide are briefly described. Subsequently, modification of proton exchange membrane from SPEEK polymer with prepared nano particle of sulfonated reduced graphene oxide 0.5 wt. % and its operation in MFC was considered. COD removal, power density, current density and coulombic efficiency were monitored during the process operation to evaluate the MFC performance. During the process operation, COD removal, power density, current density, and coulombic efficiency were tracked to assess the MFC performance. The power density and current density, 39.43 mW/m² and 161 mA/m² and the columbic efficiency 48.9 % was obtained, respectively. The COD removal of 89.5 % was obtained. [ABSTRACT FROM AUTHOR]

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Microbial fuel cells (MFCs) represent a promising avenue for sustainable energy production by harnessing the metabolic activity of microorganisms. In this study, a novel design of MFC—a Microfluidic Benthic Microbial Fuel Cell (MBMFC)—was developed, fabricated, and tested to evaluate its electrical energy generation. The design focused on balancing microfluidic architecture and wiring procedures with microbial community dynamics to maximize power output and allow for upscaling and thus practical implementation. The testing phase involved experimentation to evaluate the performance of the MBMFC. Microbial feedstock was varied to assess its impact on power generation. The designed MBMFC represents a promising advancement in the field of bioenergy generation. By integrating innovative design principles with advanced fabrication techniques, this study demonstrates a systematic approach to optimizing MFC performance for sustainable and clean energy production. [ABSTRACT FROM AUTHOR]

In the current study, bioelectricity and polyhydroxyalkanoate (PHA) production were integrated by a dual chamber microbial fuel cell (MFC) using Enterobacter sp. TS1L and textile wastewater (TW), and the method was evaluated. The highest open circuit voltage (OCV, 986.50 mV), current density (CD, 6.04 W/m3) and power density (PD, 0.32 W/m3) were observed when sterile TW was used as the substrate. Sterilization had no effect on electricity generation, while the OCV, CD and PD were not significantly different. The prolong MFC was operated by Enterobacter sp. TS1L using non-sterile TW for a period of 7 days. Throughout the 7-day operation, the experiment yielded a consistent CD output, ranging from 1.56 A/m3 to 2.31 A/m3. After MFC treatment, the quality of the effluent surpassed the Thailand water quality standard. A high percentage of decolorization (72.9%) was observed by Enterobacter sp. under TW-fed MFC. Thereafter, biomass was collected, then, PHA was extracted and characterized. The highest biomass (3.5 ± 0.6 g/L) and PHA (56.1 ± 1.5% cell dry mass, CDM) level were observed at 6 days of MFC operation. The isolated polymer from Enterobacter sp. TS1L was confirmed to be medium chain length-co-long chain length PHA (mcl-co-lcl PHA) containing 3-hydroxyhexadecanoate (3HD, C14) and 3-hydroxyoctadecanoate (3HOD, C18). [ABSTRACT FROM AUTHOR]

BACKGROUND: The microbial fuel cell (MFC) is a potential cost‐effective technology for the energy‐neutral treatment of wastewater. However, the successful implementation of this technology in resource recovery is still limited. In this study, a microbial electrochemical cell was designed and operated for 30 days. Critical factors for removal and recovery of nitrogen and phosphorus as struvite from wastewater were assessed. RESULTS: Optimization studies on critical factors such as the chemical oxygen demand (COD) of wastewater (500–2000 mg L−1) and cathode aeration rate (45–135 mL min−1) were conducted using a pure culture of Escherichia coli. The system yielded an average power density of 465 mW m−2, average current density of 915 mA m−2 and phosphorus recovery at an extent of 40% as struvite. Additionally, a maximum reduction in the COD of 90% with an average coulombic efficiency of about 82% was obtained at a short interval of 30 days. Solubility studies of the recovered struvite for 12 h at different pH values from 4.5 to 9 showed a maximum solubility of 80% at pH 4.5 and a minimum of 3.5% at pH 9. CONCLUSION: This study moves one step closer to applying MFC technology for nitrogen‐ and phosphorus‐rich wastewater treatment with concurrent struvite precipitation and electricity production. In this way, Sustainable Development Goals 2, 6 and 7 can be achieved through resource recovery, clean water and bioenergy. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Microbial fuel cell (MFC) is a promising technology for recovering energy in wastewater through bacterial metabolism. However, it always suffers from low power density and electron transfer efficiency, restricting the application. This study fabricated the MnCo2S4–Co4S3/bamboo charcoal (MCS-CS/BC) through an easy one-step hydrothermal method, and the material was applied to carbon felt (CF) to form high-performance MFC anode. MCS-CS/BC-CF anode exhibited lower Rct (10.1 Ω) than BC-CF (17.24 Ω) and CF anode (116.1 Ω), exhibiting higher electrochemical activity. MCS-CS/BC-CF anode promoted the electron transfer rate and resulted in enhanced power density, which was 9.27 times higher (980 mW m−2) than the bare CF (105.7 mW m−2). MCS-CS/BC-CF anode showed the best biocompatibility which attracted distinctly larger biomass (146.27 mg/μL) than CF (20 mg/μL) and BC-CF anode (20.1 mg/μL). The typical exoelectrogens (Geobacter and etc.) took dramatically higher proportion on MCS-CS/BC-CF anode (59.78%) than CF (2.99%) and BC-CF anode (26.67%). In addition, MCS-CS/BC stimulated the synergistic effect between exoelectrogens and fermentative bacteria, greatly favouring the extracellular electron transfer rate between bacteria and the anode and the power output. This study presented an efficient way of high-performance anode electrocatalyst fabrication for stimulating MFC power generation, giving suggestions for high-efficient energy recovery from wastewater. [ABSTRACT FROM AUTHOR]

The removal of nitrogen from wastewater is one of the challenges faced by environmental engineers globally. Autotrophic denitrification is a promising method for treating nitrate (NO3−) -contaminated wastewater because of its relatively low requirement for carbon and lesser sludge yield. Therefore, this study was aimed at investigating the autotrophic denitrification efficiency of two different dual-chamber configurations of microbial fuel cells (MFCs) in order to provide a foundation for building scalable, efficient, and sustainable denitrification systems. Analysis revealed that the maximum current density and power density were 4,327 mA/m3 and 1,441 mW/m3, respectively, in a cube-shaped dual-chamber MFC (C-MFC), whereas these values were 1,452 mA/m3 and 370 mW/m3, respectively, in an H-shaped dual-chamber configuration (H-MFC). In addition, the C-MFC and H-MFC achieved relatively high NO3− reduction rates of up to 28 and 15.6 g/m3/day, respectively. The cathodic coulombic efficiency was observed to be 57% in the C-MFC and 30% in the H-MFC. The average chemical oxygen demand removal efficiency was about 98% for both MFC configurations. High-throughput sequencing analysis revealed significant changes in the microbial community structure under different reactor configurations. The relative abundance of Proteobacteria (34.67%) and Firmicutes (18.59%) at the phylum level were higher in the C-MFC than the H-MFC, signifying that higher current generation can enhance the proliferation and microbial activity of autotrophic denitrifiers. [ABSTRACT FROM AUTHOR]

In this study, highly selenite-resistant strains belonging to Brevundimonas diminuta (OK287021, OK287022) genus were isolated from previously operated single chamber microbial fuel cell (SCMFC). The central composite design showed that the B. diminuta consortium could reduce selenite. Under optimum conditions, 15.38 Log CFU mL-1 microbial growth, 99.08% Se(IV) reduction, and 89.94% chemical oxygen demand (COD) removal were observed. Moreover, the UV–visible spectroscopy (UV) and Fourier transform infrared spectroscopy (FTIR) analyses confirmed the synthesis of elemental selenium nanoparticles (SeNPs). In addition, transmission electron microscopy (TEM) and scanning electron microscope (SEM) revealed the formation of SeNPs nano-spheres. Besides, the bioelectrochemical performance of B. diminuta in the SCMFC illustrated that the maximum power density was higher in the case of selenite SCMFCs than those of the sterile control SCMFCs. Additionally, the bioelectrochemical impedance spectroscopy and cyclic voltammetry characterization illustrated the production of definite extracellular redox mediators that might be involved in the electron transfer progression during the reduction of selenite. In conclusion, B. diminuta whose electrochemical activity has never previously been reported could be a suitable and robust biocatalyst for selenite bioreduction along with wastewater treatment, bioelectricity generation, and economical synthesis of SeNPs in MFCs. [ABSTRACT FROM AUTHOR]

Despite the high efficiency of microbial fuel cells (MFCs), MFCs cannot be a suitable alternative for treatment plants because of insufficient power generation and tiny reactors. Additionally, the increased reactor size and MFC stack result in a reduction in production power and reverse voltage. In this study, a larger MFC with a volume of 1.5 L has been designed called LMFC. A conventional MFC, called SMFC, with a volume of 0.157 L, was constructed and compared with LMFC. Moreover, the designed LMFC can be integrated with other treatment systems and generate significant electricity. In order to evaluate MFC's ability to integrate with other treatment systems, the LMFC reactor was converted into MFC-MBBR by adding sponge biocarriers. A 9.5 percent increase in reactor volume resulted in a 60 percent increase in power density from 290 (SMFC) to 530 (LMFC). An agitator effect was also investigated for better mixing and circulating substrate, which positively affected the power density by about 18%. Compared with LMFCs, the reactor with biocarriers generated a 28% higher power density. The COD removal efficiency of SMFC, LMFC, and MFC-MBBR reactors after 24 h was 85, 66, and 83%, respectively. After 80 h of operation, the Coulombic efficiency of the SMFC, LMFC, and MFC-MBBR reactors was 20.9, 45.43, and 47.28%, respectively. The doubling of coulombic efficiency from SMFC to LMFC reactor shows the design's success. The reduction of COD removal efficiency in LMFC is the reason for integrating this reactor with other systems, which was compensated by adding biocarriers. [ABSTRACT FROM AUTHOR]