Bioelectricity Generation In Microbial Fuel Cells Research Articles

The Role of EM4 (Effective Microorganisms) in Solid Waste-Powered Microbial Fuel Cells: Investigating Voltage Output and Electrical Conductivity For Bioelectricity Generation

The increasing global demand for renewable energy and sustainable waste management solutions has inspired interest in microbial fuel cells (MFCs) as a dual-purpose technology for bioelectricity generation and waste treatment. This study explores the role of EM4, a consortium of effective microorganisms, in enhancing the voltage output and electrical conductivity of solid waste-powered MFCs. A batch system bioreactor assessed the impact of varying organic waste-to-zeolite ratios on MFC performance. The results demonstrated that a 1:1 ratio of organic waste to zeolite produced the highest electrical conductivity (3160 µS/cm) and the most substantial voltage output (777.5 mV) by day three of the experiment. Statistical analysis, including ANOVA and Kruskal-Wallis tests, revealed significant differences in voltage output across treatments, with a positive correlation between electrical conductivity and voltage production. These findings highlight the potential of integrating EM4 and conductive materials like zeolite to optimize bioelectricity generation in MFCs, contributing to the advancement of sustainable energy technologies.

Enhancing microbial fuel cell performance for distillery wastewater treatment and bioelectricity generation: harnessing niacin as a redox mediator.

The role of redox mediators in improving electron transport from electrochemically active bacteria to the anode is crucial for enhanced bioelectricity output from microbial fuel cells (MFCs), which makes the selection of an ideal mediator very important. This study aims at exploring a new redox mediator niacin (vit B3) for enhanced bioelectricity generation in MFC while treating distillery wastewater through facile modification of anode electrode by niacin doping (MFC-NME) and simple application of niacin to the anolyte (MFC-NAA). Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) of NME confirmed the effective adsorption of niacin onto the carbon felt surface. Notably, MFC-NME exhibited a significantly higher power density (PD) of 6.36 W/m3 compared to MFC-NAA (4.59 W/m3) and control MFC (3.49W/m3). The charge transfer resistance (RCT) in MFC-NME (1.73 Ω) and MFC-NAA (2.06 Ω) were lowered by more than half than that in control MFC (4.33 Ω), which underscores the efficacy of niacin as a redox mediator. SEM analysis revealed improved bacterial attachment over the bioanode in the MFC-NME as compared to that of MFC-NAA and control MFC. Removal of chemical oxygen demand (COD) was higher in MFC-NAA (85%) and MFC-NME (80%) than in control MFC (73%) suggesting that niacin in the anolyte supported greater organic matter removal due to enriched microbial activity. Niacin used in anode modification shows great potential for improved electron transfer and enhanced bioelectricity production and supports greater wastewater treatment performance. The modified bioanode NME exhibits excellent stability.

Enhancing bioelectricity generation from wastewater in microbial fuel cells using carbon nanomaterials

AbstractBACKGROUNDMicrobial fuel cells (MFCs) offer a promising approach for treating wastewater and generating electrical energy simultaneously. However, their implementation in wastewater treatment plants is hindered by the limited electricity generation, often attributed to the electrolyte's high resistance. This study aimed to improve bioelectricity generation in MFCs by adding nanomaterials to the electrolyte to enhance conductivity.RESULTSThree types of nanomaterials – carbon nanotubes (CNTs), graphitic carbon nitride (g‐C3N4), and reduced graphene oxide (r‐GO) – were synthesized and addition to the electrolyte at a concentration of 50 mg in 1.5 L. MFC performance was evaluated, employed a hydraulic retention time (HRT) of 140 h, and compared to a control with no nanomaterials added. The addition of nanomaterials significantly improved MFC performance. Compared to the control, the MFCs with CNTs, g‐C3N4, and r‐GO exhibited higher voltage: 1.301 V (CNTs), 1.286 V (g‐C3N4), 1.280 V (r‐GO) versus 0.570 V (control); increased power density: 14.11 mW m−3 (CNTs), 13.78 mW m−3 (g‐C3N4), 13.66 mW m−3 (r‐GO) versus 2.71 mW m−3 (control); enhanced areal power density: 21.06 mW m−2 (CNTs), 20.57 mW m−2 (g‐C3N4), 20.39 mW m−2 (r‐GO) versus 4.04 mW m−2 (control); and improved coulombic efficiency: 19.43% (CNTs), 19.19% (g‐C3N4), 19.11% (r‐GO) versus 8.54% (control).CONCLUSIONIncorporating nanomaterials into the MFC electrolyte significantly increased bioelectricity generation by 5.21 times and coulombic efficiency by 2.28 times compared to the control. This improvement is attributed to the high specific surface area of the nanomaterials, which facilitates the adhesion and growth of microorganisms around the anode, enhancing direct electron transfer. © 2024 Society of Chemical Industry (SCI).

Generation of Bioelectricity in Microbial Fuel Cell using Kitchen Waste Obtained from Dutse Urban, Nigeria

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

Synergistic effect of TiO2 nanostructured cathode in microbial fuel cell for bioelectricity enhancement

Nano-bedecking of electrode with nanoparticles is an effective method to improve power generation of microbial fuel cells (MFCs). In this study, different concentrations (0.25 mg cm−2, 0.50 mg cm−2, 0.75 mg cm−2 and 1.0 mg cm−2) of TiO2 nanoparticles of size 10–25 nm were overlaid on the carbon cloth (CC) using spray pyrolysis technique and used as catalytic cathode in a dual-chambered microbial fuel cell treating distillery wastewater. Results evidenced that TiO2 nanoparticles modified cathode increased the power generation and recorded a highest power and current density of 162.5 ± 2 mW m−2 and 1.4 ± 0.005 A m−2, respectively. Carbon cloth coated with 0.50 mg cm−2 TiO2 nanoparticles showed 2.8 and 7.3 times higher current and power density as compared to uncoated cathode. MFC operated at a hydraulic retention time (HRT) and organic loading rate (OLR) of 72 h and 59.2 g COD L−1 d−1 showed a maximum chemical oxygen demand (COD) removal of 72.3% which was 15.3% higher than the control MFC. Likewise, the coulombic efficiency of control and modified MFC was 33% and 44%, respectively. The maximum NO3−- N, NO2−- N and NH4+- N removal efficiency of 77.3%, 49.9% and 59.4% were observed for TiO2 nanoparticles modified electrode which was 19.3%, 11.4% and 10.5% higher than control. TiO2 modified cathode was effective in enhancing the bioelectricity generation in MFCs.

Degradation and biotoxicity of azo dyes using indigenous bacteria-acclimated microbial fuel cells (MFCs)

This study explored a bioenergy platform of biodegradability and toxicity evaluation through microbial fuel cells (MFCs) modules for simultaneous decolorization and bioelectricity generation. The most appropriate decolorizer consortia NIU pond exhibited the extent of decolorization: Sunset Yellow FCF (93 %), Allura Red (96.6 %), and Tartrazine (91.41 %) in 3, 8, 12 h respectively. The ranking for bioelectricity generation in MFCs (unit: mW m−2) (Sunset Yellow FCF Degradation) was hot spring water (46.42) > hot spring soil (22.17) > NIU pond (17.75) > NIU soil (7.89). In the presence of the dye, power density was increased by 88 %, 84 % and 27 % for NP, HS, and HW, respectively. Acclimation process was inspected in terms of bioenergy-extracting capability to evaluate toxicity potency of model dyes. According to metagenomics analysis upon microbial populations before and after acclimation, indigenous microbial community was only predominated by Pseudomonas monteilii and of Bacillus pumilus. Significant increased biodiversity was evolved under selection of dye stress. After acclimation, community ecology in the consortia contained Klebsiella, Citrobacter, Enterococcus faecalis, Lactobacillus lactis, and Escherichia shigella. Tandem mass spectrometric analysis pointed out sunset yellow ECF was gradually degraded and decolorized intermediates steadily accumulated. MFC modules were promising platforms to select candidate biodecolorizers from microbial populations.

Deciphering electron-shuttling characteristics of microalgal metabolites upon bioelectricity-generating community in microbial fuel cells

This first-attempt study used novel electrochemical alternatives to decipher stimulating effects of microalgal metabolites toward interspecific interactions in microbial fuel cells (MFCs). Extracellular metabolites of Chlorella sp. could stimulate electroactive activity of electron shuttling toward bioelectricity generation in MFCs. Whether such metabolites could express stimulating potency toward bioenergy generation still strongly depend upon interspecific interactions of species diversity and evenness in MFCs. As cyclic voltammetry indicated, the most electroactive metabolites of Chlorella sp. were produced at 10th-15th day cultures (ca. mid or late exponential growth phase). Microbial community in higher species diversity and evenness owned higher adaptation to stimulate stable bioelectricity-generating capabilities for bioenergy extraction in MFCs. That is, community ecology directly controlled stability of electroactive properties to be fully induced in MFCs. Thus, the maximal species diversity and evenness might be more electrochemically favorable toward symbiotic microalgal–bacterial cultures for species coexistence as win-win situation.

Deciphering synergistic characteristics of redox mediators-stimulated echinenone production of Gordonia terrae TWIH01

This first-attempt study tended to decipher synergistic interactions of model redox mediators (RMs) to echinenone production for electrochemically-steered fermentation (ESF). The findings indicated that supplement of RMs could significantly stimulate the production performance of fermentation (e.g., 36% for 4-aminophenol) which was parallel with stimulation of bioelectricity generation in microbial fuel cells (MFCs) as prior studies mentioned. Although redox mediators could usually enhance electron transport extracellular compartment, the mechanisms of bioelectricity generation in MFCs and echinenone production in ESF were very likely functioned in the extracellular and the intracellular compartment, respectively. In MFCs, electron transfer towards biofilm anode for bioelectricity generation must be taken place. However, for ESF echinenone accumulation was very likely occurred in the intracellular compartment, thus electron transfer was predominantly implemented in the intracellular, not the extracellular compartment.

Porous Co3O4 decorated nitrogen-doped graphene electrocatalysts for efficient bioelectricity generation in MFCs

High-performance, low-cost, and robust oxygen reduction reaction (ORR) catalysts have played a very crucial role in the development of microbial fuel cells (MFCs). Herein, A novel in-situ Co3O4 nanoparticles (NPs) modified nitrogen-doped graphene with three-dimensional porous structure (3D GN-Co3O4) has been successfully synthesized and employed as an efficient ORR catalyst in MFCs. Benefiting from 3D porous architecture feature, highly intrinsic conductivity and synergistic effect between nitrogen-doped graphene and Co3O4 NPs, the 3D GN-Co3O4 as a cathode catalyst in alkaline condition realizes significantly enhanced electrochemical performance and outstanding cycling stability. Furthermore, the self-assembly of MFCs based on the 3D GN-Co3O4 cathode offers a high power density of 578 ± 10 mW m−2, which is even comparable to the commercial Pt/C.

Enhanced vanadium (V) reduction and bioelectricity generation in microbial fuel cells with biocathode

Abstract Microbial fuel cells (MFCs) represent a promising approach for remediation of toxic vanadium (V) contaminated environment. Herein, enhanced V(V) reduction and bioelectricity generation are realized in MFCs with biocathode. Synergistically electrochemical and microbial reductions result in the nearly complete removals of V(V) within 7 d operation with initial concentration of 200 mg L −1 . Maximum power density of 529 ± 12 mW m −2 is obtained. Electrochemical tests reveal that biocathode promotes electron transfers and reduces charge transfer resistance. XPS analysis confirms that V(IV) is the main reduction product, which precipitates naturally under neutral conditions. High-throughput 16S rRNA gene sequencing analysis indicates that the newly appeared Dysgonomonas is responsible for V(V) reduction and Klebsiella contributes mainly to bioelectricity generation in MFCs with biocathode. This study further improves the performance of remediating V(V) contaminated environment based on MFC technology.

Spontaneous arsenic (III) oxidation with bioelectricity generation in single-chamber microbial fuel cells

Arsenic is one of the most toxic elements commonly found in groundwater. With initial concentration of 200μgL−1, spontaneous As(III) oxidation is realized completely during 7 days operation in single-chamber microbial fuel cells (MFCs) in the present study, with the maximum power density of 752.6±17mWm−2. The product is less toxic and mobile As(V), which can be removed from aqueous solution more easily. High-throughput 16S rRNA gene pyrosequencing analysis indicates the existence of arsenic-resistant bacteria as Actinobacteria, Comamonas, Pseudomonas and arsenic-oxidizing bacteria as Enterobacter, with electrochemically active bacteria as Lactococcus, Enterobacter. They interact together and are responsible for As(III) oxidation and bioelectricity generation in MFCs. This study offers a potential attractive method for remediation of arsenic-polluted groundwater.

Deciphering electron-shuttling characteristics of thionine-based textile dyes in microbial fuel cells

Prior studies indicated that OH and/or NH2 substituent containing auxochrome compounds (e.g., 2-aminophenol and 1-amino-2-naphthol) could act as electron shuttles (ESs) to stimulate wastewater decolorization and bioelectricity generation in microbial fuel cells (MFCs). This study provided first-attempt to disclose how and why thionine-associated textile dyes (i.e., azure A and azure C) could also own such redox-mediating capabilities in MFCs. Due to the presence of iminium part as mediating group, N(CH3)2 or N(CH3)H substituent could effectively mediate electron transport compared to NH2 substituent for bioelectricity generation in MFCs. For dye-laden wastewater treatment, the presence of electron-mediating textile dyes (e.g., thionine, azure A and azure C) in MFCs is promising to stimulate biodegradation of organics and bioelectricity generation. With such ESs as stimulants, using MFC as operation strategy would be cost-effective for wastewater treatment as oxidation of organic pollutants could be automatically accelerated.

Metabolite analysis on reductive biodegradation of reactive green 19 in Enterobacter cancerogenus bearing microbial fuel cell (MFC) and non-MFC cultures

The first-attempt study uncovered metabolic pathways of reactive green 19 (RG19) decolorization by Enterobacter cancerogenus BYm30 in single chamber membrane-less microbial fuel cell (SCML-MFC) and non-MFC cultures. The finding indicated that menaquinone from BYm30 might play as a redox mediator (or an electron-shuttling carrier) to stimulate dye decolorization and bioelectricity generation in MFC. Due to the formation of reduced organic sulfides from RG19 in MFC, color removal in MFC was significantly faster than non-MFC cultures. In addition, tertiary alcohols and phenols originally present in LB broth might be degraded by BYm30 under anaerobic condition regardless of MFC or non-MFC condition. Apparently, these novel findings could clarify the mechanism(s) behind reductive decolorization of RG19 taking place in MFC and non-MFC conditions for wastewater decolorization.

Unveiling characteristics of dye-bearing microbial fuel cells for energy and materials recycling: Redox mediators

This study disclosed why and how some decolorized intermediates (e.g., 2-aminophenol) could act as electron-shuttling mediator(s) to enhance the capabilities of reductive decolorization and bioelectricity generation. It also selected several model auxochrome-containing compounds structurally associated to 2AP to explore how chemical structure influenced the feasibility of possible electron shuttles for power producing capabilities in microbial fuel cells (MFCs). The selection criteria of electron-shuttling mediators were suggested for optimal reductive decolorization and bioelectricity generation in MFCs for practical application.

Deciphering mediating characteristics of decolorized intermediates for reductive decolorization and bioelectricity generation

As decolorized intermediates could play a role of electron-shuttling mediator to enhance the performance of dye decolorization and bioelectricity generation, this study selected model compounds with auxochromes (e.g., benzene-1,2-diol, 1,2-diaminobenzene) to explore how chemical structure(s) affected color removal and power producing capabilities in microbial fuel cells (MFCs). According to cyclic voltammetry, respiratory testing and MFC data, promising electron-shuttling capabilities of aforementioned compounds were revealed using Proteus hauseri ZMd44, Aeromonas sp. C78, Acinetobacter johnsonii NIUx72 bearing MFCs. These findings clearly indicated that chemical structure(s) of decolorized mediators directly affected characteristics of simultaneous reductive decolorization and bioelectricity generation in MFCs, suggesting feasible operation strategy of MFCs for industrial applications.

Understanding interactive characteristics of bioelectricity generation and reductive decolorization using Proteus hauseri

This first-attempt study quantitatively explored interactive characteristics of bioelectricity generation and dye decolorization in air-cathode single-chamber microbial fuel cells (MFCs) using indigenous Proteus hauseri ZMd44. After approx. 15 cycles (30 days) acclimatization in dye-bearing cultures, P. hauseri could express its stable capability of simultaneous bioelectricity generation and color removal (SBP&CR) in MFCs. Evidently, appropriate acclimation strategy for formation of the electrochemically active anodic biofilm played a crucial role to enhance the performance of SBP&CR in MFCs. Gradually increased supplementations of C.I. reactive blue 160 resulted in progressively decreased decay rate of bioelectricity generation. That is, a dye decolorized in a faster rate would result in a lower capability for bioelectricity generation and vice versa. In addition, a reduced dye with less toxicity potency (e.g., 2-aminophenol) might work as a redox mediator of electron transport to anodic biofilm for bioelectricity generation in MFCs.