Dual Chamber Microbial Fuel Cell Research Articles

Relationship between organic removal and power production in a dual-chamber microbial fuel cell with intermittent mode

Unoptimised simultaneous performance in microbial fuel cell (MFC) is still a big concern due to a lack of information on the correlation between organic removal and power production. Its correlation becomes more substantial owing to the main factors which affect a concurrent condition. To contribute new insight, this study aimed to analyze the relationship between the main factors for determining the optimal condition of MFC performance. Dual-chamber MFC (DCMFC) was designed by modifying the anode chamber into two compartments, namely double anode chamber DCMFC (DAC-DCMFC), operated within 8 days running with intermittent mode. The differences of organic loading rate (OLR), 0.4; 1.0; 2.5 kg.m−3.d−1 represented low to high organic loadings and electrode material-based reactor types, were used to assign the optimal concomitant performance in DCMFC. A closed circuit voltage (CCV) wiring system plugged onto the data logger within running time was employed to evaluate the synchronous achievement. This study result was medium OLR 1.0 kg.m−3.d−1, and GNPs anode-PTFE cathode attained optimally in the performance. In addition, higher OLR does not indicate higher organic removal correlating linearly with power production. This finding contributes to the limitation of organic loading that biological role capabilities can use.

Investigation of microbial fuel cell performance based on the nickel thin film modified electrodes

Microbial fuel cells (MFCs) are a self-sustaining and environmentally friendly system for the simultaneous was tewater treatment and bioelectricity generation. The type and material of the electrode are critical factors that can influence the efficiency of this treatment process. In this study, graphite plates and carbon felt were modified through the electrodeposition of nickel followed by the formation of a biofilm, resulting in conductive bio-anode thin film electrodes with enhanced power generation capacity. The structural and morphological properties of the electrode surfaces were characterized using X-ray diffraction, energy-dispersive X-ray spectroscopy, elemental mapping, and field-emission scanning electron microscopy techniques. Maximum voltage, current density, and power generation were investigated using a dual-chamber MFC equipped with a Nafion 117 membrane and bio-nickel-doped carbon felt (bio-Ni@CF) and bio-nickel-doped graphite plate (bio-Ni@GP) electrodes under constant temperature conditions. The polarization and power curves obtained using different anode electrodes revealed that the maximum voltage, power and current density achieved with the bio-Ni@CF electrode were 468.0 mV, 130.72 mW/m2 and 760.0 mA/m2 respectively. Moreover, the modified electrodes demonstrated appropriate stability and resistance during successful runs. These results suggest that nickel-doped carbon-based electrodes can serve as suitable and stable supported catalysts and conductors for improving efficiency and increasing power generation in MFCs.

Co-Fe-N@biochar anode for improvment the electricity generation performance of microbial fuel cell

ABSTRACT Microbial fuel cells (MFCs) can generate energy while processing organic pollutants, which has a great impact on environmental wastewater treatment applications. In this study, a gel polymer was formed by Co-Fe-N co-doping biochar (Co-Fe-N@BC), which was used as the anode material to improve the electricity generation performance of MFC. The Co-Fe-N@BC material prepared at 900℃ carbonised biomass into more graphitic carbon, and its total resistance (3.56 Ω) was significantly reduced. In the corresponding dual-chamber MFC, the current density was 2.81 A/m2, and the power density reached 1181 mW/m2 at maximum. Among the materials tested, the Co-Fe-N@BC anode MFC had the highest chemical oxygen demand removal rate and coulombic efficiency, reaching 91% and 13%, respectively. It is proved that MFC with Co-Fe-N@BC anode has the best electrochemical performance.

Insights on hexavalent chromium(VI) remediation strategies in abiotic and biotic dual chamber microbial fuel cells: electrochemical, physical, and metagenomics characterizations

Hexavalent chromium [Cr(VI)] is one of the most carcinogenic and mutagenic toxins, and is commonly released into the environemt from different industries, including leather tanning, pulp and paper manufacturing, and metal finishing. This study aimed to investigate the performance of dual chamber microbial fuel cells (DMFCs) equipped with a biocathode as alternative promising remediation approaches for the biological reduction of hexavalent chromium [Cr(VI)] with instantaneous power generation. A succession batch under preliminary diverse concentrations of Cr(VI) (from 5 to 60 mg L−1) was conducted to investigate the reduction mechanism of DMFCs. Compared to abiotic-cathode DMFC, biotic-cathode DMFC exhibited a much higher power density, Cr(VI) reduction, and coulombic efficiency over a wide range of Cr(VI) concentrations (i.e., 5–60 mg L−1). Furthermore, the X-ray photoelectron spectroscopy (XPS) revealed that the chemical functional groups on the surface of biotic cathode DMFC were mainly trivalent chromium (Cr(III)). Additionally, high throughput sequencing showed that the predominant anodic bacterial phyla were Firmicutes, Proteobacteria, and Deinococcota with the dominance of Clostridiumsensu strict 1, Enterobacter, Pseudomonas, Clostridiumsensu strict 11 and Lysinibacillus in the cathodic microbial community. Collectively, our results showed that the Cr(VI) removal occurred through two different mechanisms: biosorption and bioelectrochemical reduction. These findings confirmed that the DMFC could be used as a bioremediation approach for the removal of Cr(VI) commonly found in different industrial wastewater, such as tannery effluents. with simultaneous bioenergy production.

Application of Microbial Fuel Cell (MFC) for Bioremediation of Ammonia

Ammonia is a poisonous compound that can harm fish. Fish feed and manure are the primary sources of ammonia in catfish farming ponds. High concentrations of ammonia can cause death. Therefore, it is necessary to control the presence of ammonia to minimize the potential for fish mortality. Microbial Fuel Cell (MFC) is a technology that can help with ammonia bioremediation. This study aims to analyze the effectiveness of Microbial Fuel Cell (MFC) in reducing ammonia. The research method used is an experimental research method with qualitative descriptive analysis. The research was conducted on a laboratory scale using a dual-chamber Microbial Fuel Cell (MFC) reactor connected using a salt bridge. This research was conducted with variations in the use of sticky media, including without media, with bioball, and with bioring media. The results showed that the percentage of ammonia reduction in each treatment was 94.52%, 98.09%, and 99.28%. From this research, it can be concluded that Microbial Fuel Cells (MFC) are effective in reducing ammonia.

Statistical optimization of waste molasses-based exopolysaccharides and self-sustainable bioelectricity production for dual chamber microbial fuel cell by Bacillus piscis

BackgroundThe application of exopolysaccharide-producing bacteria (EPS) in dual chamber microbial fuel cells (DCMFC) is critical which can minimize the chemical oxygen demand (COD) of molasses with bioelectricity production. Hence, our study aimed to evaluate the EPS production by the novel strain Bacillus piscis by using molasses waste. Therefore, statistical modeling was used to optimize the EPS production. Its structure was characterized by UV, FTIR, NMR, and monosaccharides compositions. Eventually, to highlight B. piscis' adaptability in energy applications, bioelectricity production by this organism was studied in the BCMFC fed by an optimized molasses medium.ResultsB. piscis OK324045 characterized by 16S rRNA is a potent EPS-forming organism and yielded a 6.42-fold increase upon supplementation of molasses (5%), MgSO4 (0.05%), and inoculum size (4%). The novel exopolysaccharide produced by Bacillus sp. (EPS-BP5M) was confirmed by the structural analysis. The findings indicated that the MFC's maximum close circuit voltage (CCV) was 265 mV. The strain enhanced the performance of DCMFC achieving maximum power density (PD) of 31.98 mW m−2, COD removal rate of 90.91%, and color removal of 27.68%. Furthermore, cyclic voltammetry (CV) revealed that anodic biofilms may directly transfer electrons to anodes without the use of external redox mediators. Additionally, CV measurements made at various sweep scan rates to evaluate the kinetic studies showed that the electron charge transfer was irreversible. The SEM images showed the biofilm growth distributed over the electrode’s surface.ConclusionsThis study offers a novel B. piscis strain for EPS-BP5M production, COD removal, decolorization, and electricity generation of the optimized molasses medium in MFCs. The biosynthesis of EPS-BP5M by a Bacillus piscis strain and its electrochemical activity has never been documented before. The approach adopted will provide significant benefits to sugar industries by generating bioelectricity using molasses as fuel and providing a viable way to improve molasses wastewater treatment.

Bioelectricity Generation from Bamboo Hydrolysate by Microbial Fuel Cells Using Pseudomonas Aeruginosa PR3 for Natural Resource Conservation

Microbial fuel cell (MFC) is a green technology that allows recovery of electricity from wastes, thus, it can be applied in environmental conservation, natural resource preservation and bioenergy production. As an attempt to efficiently utilize the increasing amount of bamboo wastes as an input for energy production, this study investigated the electricity generation efficiency of a dual-chamber MFC in sugar conversion into electricity using Pseudomonas aeruginosa PR3 and hydrolysates from the acid pretreatment of Bambusa stenostachya Hack.. MFCs were inoculated with PR3, acclimated with glucose then operated with bamboo hydrolysates containing different total reducing sugars as the anolytes. Total sugar consumption of the MFCs for electricity conversion varied from 76.25 to 96.30% after 48 hours of operation in bamboo hydrolysates. Results from electrochemical analysis showed that MFC with 9.0 g/L sugars from bamboo hydrolysates had better electricity production, with the maximum open-circuit voltage of 620 mV, current density of 1092.08 mA/m2 and power density of 91.16 mW/m2. Microbial communities in these MFCs could effectively recover electricity from up to 9.0 g/L reducing sugars in bamboo hydrolysates, preliminarily illustrating the applicability of the MFC technology in natural resource conservation as a way to produce alternative energy sources from the treatment of bamboo-processing wastes.

A Novel Computational Platform for Steady-State and Dynamic Simulation of Dual-Chambered Microbial Fuel Cell

Microbial fuel cell (MFC) is attractive for research community as a promising bioelectricity production technology using organic waste. However, due to low performance and erroneous reproducibility and replicability, MFC lacks industrial application. Additionally, the nonlinear dynamic behavior of MFC, along with the involvement of electrochemistry and biology in mathematical models, makes it difficult to comprehend and simulate. To overcome these barriers, this study provides a simulation platform for conducting theoretical studies using a fundamental mathematical model of MFC. This novel Simulink/MATLAB model is based on mass balance across both compartments of MFC, and provides power density as a function of a wide range of performance-affecting parameters. Model validation depicts only 2%–10% error. This model can provide a stepping stone to perform theoretical optimization and industrial application studies in future. By varying the values of different parameters; studies may be performed to spot optimum values of the most sensitive parameters. Therefore, using the proposed tool paves the path for further improvements in design, cost effectiveness and performance efficiency that ultimately promises up-scaling of MFCs as a renewable and alternative energy resource.

Investigating the effect of anode materials on the performance and microbial community in an integrated chamber-free microbial fuel cell

Conventionally, there are two basic configurations for microbial fuel cell (MFC), one with anode and cathode chambers, as known as dual-chamber MFC, one with only anode chamber and a air–cathode, called single-chamber MFC. However, electrode materials' complex configuration and high resistance limit their practical applications in power generation and wastewater purification. To this end, we constructed three MFCs using carbon felt, Ni/Ti, and Ag-Ni/Ti as anodes based on our previously constructed integrated chamber-free MFC (iMFC). After 21 days of operation, the Ag-Ni/Ti-MFC performed best in bioelectricity output and removal of target pollutants. The bioelectricity output parameters were an open-circuit voltage of 0.773 V, a maximum current density of 552.1429 mA/m2, and a power density of 426.8064 mW/m2. Furthermore, the MFC achieved removals of 67.90% for the chemical oxygen demand (COD), 55.20% for total nitrogen (TN), and 61.83% for ammonia nitrogen (NH3-N). Introducing silver nanoparticles to the transmembrane and outer membrane boosted the charge extraction efficiency in the MFCs. Moreover, 16S rDNA analysis indicated that typical electricity-producing bacteria, including Comamonas, Paraclostridium, and Asaccharospora, had a higher relative abundance in the Ag-Ni/Ti-MFC anode than in other anodes. Overall, the surface structure of different anode materials plays a critical role in bioelectricity generation and wastewater purification using iMFC by affecting the mass transfer of substrates and metabolites.

High electricity generation and wastewater treatment enhancement using a microbial fuel cell equipped with conductive and anti-biofouling CuGNSs/SPES proton exchange membrane

This research is the first to examine the use of biosynthesized Cu-Graphene nanosheets (CuGNSs) in a sulfonated polyethersulfone (SPES) matrix to fabricate an anti-biofouling proton exchange membrane (PEM) applied in a microbial fuel cell (MFC) for high power generation and treatment of ostrich skin tanning wastewater. The study involved fabricating CuGNSs/SPES membranes using a phase inversion method with different CuGNSs loadings (0.25, 0.5, 1.0, and 2.0 wt%), and characterizing them using several techniques, including FTIR, XRD, SEM, EDS, XPS, water uptake, cation exchange capacity, zeta potential, oxygen penetration, and antibacterial activity. The results showed that the presence of Cu, graphene, and biofunctionalities in the membrane's structure increased their hydrophilicity, proton selectivity, and anti-biofouling resistance, thereby improving the MFC's performance. The MFC using CuGNSs2.0/SPES generated a maximum power and current density of 84.1 mW/m2 and 320 mA/m2, respectively, which was twice higher than the MFC using Nafion117. The result was also confirmed by the proton conductivity and cation exchange capacity analysis, as the CuGNSs2.0/SPES showed a value of 1.84 mS/cm and 0.98 meq/g respectively, which was higher than Nafion117 (1.28 mS/cm and 0.83 meq/g). The modified membranes also exhibited a higher COD removal of ostrich tanning effluent (maximum 97.72%) and coulombic efficiency (maximum 43.29%), as well as maximum antibacterial activity against gram-negative and gram-positive bacteria (>95%). The study suggests that the new CuGNSs/SPES membranes can be effectively used in dual-chamber MFCs.

Copper recovery from printed circuit boards leaching solution with bioelectricity generation using microbial fuel cell

Recovery of valuable metals via leaching printed circuit boards (PCBs) has gained moment recently. This work studied the Microbial fuel cell (MFC) performances for recovery of Cu from a Cu2+ solution by examining key operating parameters. A dual-chamber MFC with 6cm × 6cm × 7cm dimensions was constructed. Both anode and cathode electrodes were made of a carbon cloth sheet. The anodic and cathodic chambers were separated by a Nafion membrane. The highest Cu recovery efficiency was 99.7% after 240h batch mode operation, yielding 102 mW/m2 MFC power density output using 1g/L Cu2+ solution as the catholyte (initial pH 3) and an anolyte containing 1g/L sodium acetate inoculated with a sludge from a wastewater treatment plant's anaerobic pond, with 2cm distance between the electrodes made of polyacrylonitrile polymer. The highest open circuit voltage, current density (based on cross-section cathode area) and power density with an external load of 1 kΩ was 555mV, 347mA/m2 and 193 mW/m2, respectively. Additionally, recovery of Cu in the leachate of PCBs using sulfuric acid leaching after 48h was performed and the highest Cu recovery was 50% in 48h.

Effects of External Resistance, New Electrode Material, and Catholyte Type on the Energy Generation and Performance of Dual-Chamber Microbial Fuel Cells

In this study, the effects of an external resistance, new electrode material, and non-conventional catholyte on the energy generation and performance of a dual-chamber MFC were evaluated. Ten different resistances (15 Ω–220 kΩ), hydrophilically-treated graphene and graphite electrodes, and a 0.1 M HCl solution as a catholyte were assessed. The results showed that greater energy generation and power density were achieved at an external resistance of 2 kΩ and internal resistance between 2 and 5 kΩ on average; meanwhile, the greatest coulombic efficiency was obtained at the lowest external resistance evaluated (15 Ω). Therefore, it is recommended to operate the MFCs at the external resistance between 2 and 5 kΩ to ensure the maximum power generation of the dual chamber MFCs. Regarding the two electrode materials evaluated as an anode and cathode, hydrophilically-treated graphene was found to be a much better material to enhance the energy production and performance of the MFC system; therefore, its use is suggested in experimental and practical applications. On the other hand, the use of HCl as a catholyte enhanced the performance of MFC (constant and steady potential and greater coulombic efficiency) in most cases.

Performance investigation and comparison of polypropylene to Nafion117 as the membrane of a dual-chamber microbial fuel cell

The high cost and recycling issues of common separators as the main components of Microbial fuel cells (MFCs) have slowed down the development of MFCs recently. In this paper, a polypropylene membrane is proposed as an inexpensive membrane that can be recycled with lower environmental impacts. An experiment is performed in a dual-chamber microbial fuel cell to investigate and compare the proposed membrane effectiveness to Nafion117. The dual-chamber MFC was used because of its ease of use. A mixture of microbes and glucose was fed to the cell during the experiment. The internal resistance and coulombic efficiency are calculated by measuring the circuit voltage, power density, and open-circuit voltage to monitor the performance. The maximum output voltage of 500 mV was attained at a resistance of 380 kΩ. Furthermore, the maximum output power density was 0.7 mW.m−2, which occurred for 3.3 mA.m−2.

Assessment of Graphite, Graphene, and Hydrophilic-Treated Graphene Electrodes to Improve Power Generation and Wastewater Treatment in Microbial Fuel Cells.

In this study, graphite, graphene, and hydrophilic-treated graphene electrodes were evaluated in a dual-chamber microbial fuel cell (DC-MFC). Free-oxygen conditions were promoted in anodic and cathodic chambers. Hydrochloric acid at 0.1 M and pH 1.1 was used as a catholyte, in addition to deionized water in the cathodic chamber. Domestic wastewater was used as a substrate, and a DuPontTM Nafion 117 membrane was used as a proton exchange membrane. The maximum power density of 32.07 mW·m-2 was obtained using hydrophilic-treated graphene electrodes and hydrochloric acid as catholyte. This power density was 1.4-fold and 32-fold greater than that of graphene (22.15 mW·m-2) and graphite (1.02 mW·m-2), respectively, under the same operational conditions. In addition, the maximum organic matter removal efficiencies of 69.8% and 75.5% were obtained using hydrophilic-treated graphene electrodes, for hydrochloric acid catholyte and deionized water, respectively. Therefore, the results suggest that the use of hydrophilic-treated graphene functioning as electrodes in DC-MFCs, and hydrochloric acid as a catholyte, favored power density when domestic wastewater is degraded. This opens up new possibilities for improving DC-MFC performance through the selection of suitable new electrode materials and catholytes.

Electrochemical impedance spectroscopy studies of the buffered and non‐buffered microbial fuel cell

AbstractThe positive effect of buffers to maintain a sui pH for microorganism growth and increase the electrolyte conductivity in microbial fuel cells (MFCs) encourages more studies on the development of new buffer solutions. The effect of types of biological buffers such as phosphate, tris, succinate, and maleate on power production in dual chamber MFC inoculated by saccharomyces cerevisiae has been examined. Electrochemical impedance spectroscopy has been used for evaluating the performance of the buffered and non‐buffered MFC systems. Considering the important impact of buffer type on the resistance of ion migration within the electrolyte and electron transport resistance of the cell components, the internal resistance of the MFC with different used buffers has been obtained and compared. According to the obtained results, the tris buffer solution showed a positive influence on the power output with a power density of 25.41% higher than phosphate.

Cu(II) and Cr(VI) Removal in Tandem with Electricity Generation via Dual-Chamber Microbial Fuel Cells

Microbial fuel cells (MFCs) have shown great advantages in electricity production, heavy metal removal, and energy recovery. However, the impact and mechanism of conflicting effects of numerous electron acceptors on heavy metal removal remain unknown. The effects of different initial heavy metal concentrations, cathodic dissolved oxygen, and electrode materials on the electricity generation and heavy metal removal efficiencies of Cu(II) and Cr(VI) were investigated in this study. When the initial concentration of Cr(VI) increased from 10 mg/L to 150 mg/L, the maximum voltage, coulomb efficiency, and maximum power density declined from 99 to 44 mV, 28.63% to 18.97%, and 14.29 to 0.62 mW/m2, and the removal efficiencies of Cu(II) and Cr(VI) decreased dramatically from 98.34% and 99.92% to 67.09% and 37.06%, respectively. Under anaerobic cathodic conditions, the removal efficiency and removal rate of Cu(II) and Cr(VI) were lower than those under aerobic conditions. When the cathode electrode was titanium sheet and graphite plate, the coulomb efficiency and maximum power density increased to 38.18%, 50.71%, 33.95 mW/m2, and 62.23 mW/m2. The removal efficiency and removal rates of Cu(II) and Cr(VI) were significantly increased to 98.09%, 86.13%, and 0.47, 0.50 mg/(L h) with a graphite plate, respectively. The pH of the cathode varied considerably greater as the MFC current increased. Cu(II) and Cr(VI) were removed and reduced to elemental Cu, Cu2O, and its oxides as well as Cr(OH)3 and Cr2O3 precipitates on the cathode electrode by cathodic bioelectrochemical reduction.

Sulfonated Polybenzimidazole as a PEM in a Microbial Fuel Cell: An Efficient Strategy for Green Energy Generation and Wastewater Cleaning

A microbial fuel cell (MFC) is a bioelectrochemical system that has a dual application: producing renewable energy and simultaneously purifying dirty water. However, low power density and high installation cost are the major limitations. To overcome these problems and to replace the highly expensive Nafion which is used as a proton exchange membrane (PEM) in MFCs, here, in this study, a high-molecular weight sulfonated oxybispolybenzimidazole (MSOPBI) membrane has been made from the newly synthesized sulfonated diacid monomer in a readily executable synthetic path and cost-effective manner, and finally, the MSOPBI membrane has been tested in a dual-chamber MFC. The newly synthesized MSOPBI membrane displayed less water uptake, moderate ion exchange capacity (IEC) and proton conductivity in the hydrated state, low dimensional swelling, and phase-separated morphology with enhanced mechanical strength due to the more compact and rigid structure of the membrane owing to the crosslinking between the sulfonic functional group and imidazole group. It demonstrated a higher MFC performance because of the various favorable factors including morphological features. The MFC operation in the presence of the MSOPBI membrane when compared with that with Nafion showed an open-circuit voltage (OCV) of 345 mV, a power density of 280 mW/m2, and a current density of 2.2 mA/m2 from the polarization curves with a relatively less voltage drop. Compared to Nafion, MSOPBI showed an increase in power density by 47%. Electrochemical analysis (OCV, cyclic voltammetry (CV), linear sweep voltammetry (LSV), Tafel curves) depicted the increased bioelectrochemical activity during the MFC operation in the presence of MSOPBI owing to its compositional and low-swelling characteristic functionality that impacted the decreased resistances and system losses toward enhanced power/energy output compared to that with the Nafion membrane. All these data together proved the effectiveness of the newly synthesized MSOPBI membrane for use in MFCs for the production of green energy and cleaning wastewater.

Performance of Sediment Microbial Fuel Cells in Generating Electricity using Fish Wastewater and Shrimp Wastewater as a Nutrient and Their Effect on Waste Quality

Sediment Microbial Fuel Cell (MFC) is a technology that can convert chemical energy into electrical energy through the process of nutrient degradation by microbes. Sediment taken from the bottom of shrimp ponds was added as a source of microbes, while fish and shrimp wastewater were used as a source of nutrients for microbes. This study aims to measure the performance of the SMFC system on fish effluent and shrimp effluent to produce bio-electricity while reducing the waste load. The research method was experimental laboratories. The treatment given was the different types of electrodes, namely zinc-copper and aluminum-copper. In addition, 0.2 M KMnO4 electrolyte solution was used. This study consisted of four stages: the manufacture of nutrients from fish and shrimp wastewater, the manufacture of a dual chamber MFC bioreactor, the measurement of electrical values, and the analysis of waste quality. Experiments were carried out for 30 days by measuring electricity every 24 hours. The average value of electricity generated in the nutrients of fish wastewater with Zn/Cu electrodes was 0.705 V and Al/Cu was 0.472 V. Meanwhile, the average value of electricity in shrimp wastewater nutrients with Zn/Cu electrodes was 0.630 V and Al/Cu was 0.625 V. The number of colonies after adding sediment in the shrimp wastewater sample were 8.9 x 106 CFU/mL, the fish wastewater sample was 9.5 x 106 CFU/mL. It indicates the presence of microorganisms that play a role in the SMFC system

Heterostructure-induced enhanced oxygen catalysis behavior based on metal cobalt coupled with compound anchored on N-doped carbon nanofiber for microbial fuel cell

High-efficiency oxygen reduction reaction (ORR) electrocatalyst in microbial fuel cells (MFCs) is important to boost the power production efficiency and reduce overall cost. Herein, we demonstrate a novel nitrogen (N)-doped carbon nanofiber (N-CNF) supported metal and metal compound heterostructure derived from metal-organic frameworks (MOFs), which endows superior electrocatalytic activity by optimizing the coupling modulation effect. The resulting cobalt/cobalt phosphide and cobalt/cobalt sulfide nanoparticles embedded in N-doped carbon nanofiber (Co/CoP/Co2P@N-CNF, Co/CoS2@N-CNF) present superior ORR activity and methanol tolerance. Moreover, the assembled MFCs modified with Co/CoP/Co2P@N-CNF and Co/CoS2@N-CNF composite also achieve higher power density (375.16 and 400.06 mW m−2) as well as coulombic efficiency (11.2 %, 12.4 %), superior than that of Pt/C electrode (333.70 mW m−2, 10.4 %). Impressively, the Co/CoS2@N-CNF electrode exhibits long-term stability and durability in dual-chamber MFCs. A high-performance heterostructure cathode with an effective strategy for bridging nanocatalysis and practical MFCs is reported and presented.

Copper removal from wastewater and electricity generation using dual-chamber microbial fuel cells with shrimp shell as the substrate

High-content solid waste (HCSWs) contains numerous polysaccharides and is widely recognized as an energy-generating substance. However, detailed studies on the use of HCSWs as substrates in microbial fuel cells (MFCs) to generate electricity and remove heavy metals from wastewater are scarce. In this study, the effects of shrimp shell (SS) and sodium acetate (SA), which are complex and simple substrates, respectively, as anodic carbon sources on the electricity generation performance of dual-chamber MFCs and the removal of Cu at the cathode were investigated. The structural characteristics of the anodic microbial communities of the MFCs were analyzed in terms of substrate type and concentration. The results demonstrated that the maximum voltage (206 mV) and maximum power density (28.82 mW/m2) of the MFC-SA were higher than those of the MFC-SS groups. The operating time and maximum power density increased with increasing SS concentration, and the maximum power density reached 24.75 mW/m2 at an SS concentration of 16 g/L. The Cu2+ ions in the catholyte were primarily reduced to elemental Cu and small amounts of Cu2O or CuO. The higher the concentration of SS, the higher the Cu removal rate, the greater the total amount of Cu removed, and the higher the MFC removal capacity. Pseudomonas was the only electroactive microorganism in the raw sludge, whereas Geobacter, Corynebacterium, Clostridium, Desulfovibrio, and Desulfosporosinus were detected in the MFCs at the end of the experiment. The relative abundance of the electroactive microorganisms increased from 19.4% to 36.0% as the SS concentration increased from 2 to 16 g/L. These results suggest that SS can be used as substrate for HCSW degradation to provide the energy required for heavy-metal reduction.