Microbial Fuel Cell For Generation Research Articles

Power generation and organics removal from wastewater using activated carbon nanofiber (ACNF) microbial fuel cells (MFCs)

Carbon-based materials are the most commonly used electrode material for anodes in microbial fuel cell (MFC), but are often limited by their surface areas available for biofilm growth and subsequent electron transfer process. This study investigated the use of activated carbon nanofibers (ACNF) as the anode material to enhance bacterial biofilm growth, and improve MFC performance. Qualitative and quantitative biofilm adhesion analysis indicated that ACNF exhibited better performance over the other commonly used carbon anodes (granular activated carbon (GAC), carbon cloth (CC)). Batch-scale MFC tests showed that MFCs with ACNF and GAC as anodes achieved power densities of 3.50 ± 0.46 W/m3 and 3.09 ± 0.33 W/m3 respectively, while MFCs with CC had a lower power density of 1.10 ± 0.21 W/m3 In addition, the MFCs with ACNF achieved higher contaminant removal efficiency (85 ± 4%) than those of GAC (75 ± 5%) and CC (70 ± 2%). This study demonstrated the distinct advantages of ACNF in terms of biofilm growth and electron transport. ACNF has a potential for higher power generation of MFCs to treat wastewaters.

Statistical Optimization of Medium Components to Enhance Bioelectricity Generation in Microbial Fuel Cell

In this work, sequential optimization strategy, based on statistical designs, was employed to enhance the generation of electricity in microbial fuel cell. For screening of growth medium composition significantly influencing electricity generation, the two-level Plackett–Burman design was used. Under our experimental conditions, glucose, KCl, and NaHCO3 were found to be the major factors of the electricity generation. A near optimum medium formulation was obtained using this method with increased voltage yield by 5.3 %. Response surface methodology was adopted to acquire the best process conditions. In this respect, the three-level Box–Behnken design was applied. A polynomial model was created to correlate the relationship between the three variables (glucose, KCl, and NaHCO3) and voltage yield. Estimated optimum levels of optimized variables for the generation of electricity were glucose 8.5 g/l, KCl 0.8 g/l, and NaHCO3 0.2 g/l. The optimum voltage yield was 738.72 mV which was 8.0 % than the basal medium.

Simultaneous anaerobic sulfide and nitrate removal coupled with electricity generation in Microbial Fuel Cell

Two-chamber Microbial Fuel Cells (MFC) using graphite rods as electrodes were operated for simultaneous anaerobic sulfide and nitrate removal coupled with electricity generation. The MFC showed good ability to remove substrates. When the influent sulfide and nitrate concentrations were 780mg/L and 135.49mg/L, respectively, the removal percentages of sulfide and nitrate were higher than 90% and the main end products were nitrogen and sulfate. The MFC also showed good ability to generate electricity, and the voltage went up with the rise of influent substrate concentrations. When the external resistance was 1000Ω, its highest steady voltage was 71mV. Based on the linear relationship between the electrons released by substrates and accepted by electrode, it was concluded that the electricity generation was coupled with the substrate conversion in the MFC.

Influence of Cathodal Performance on Electricity Generation of Microbial Fuel Cell with Refinery Oil Wastewater as Fuel

A double-chambered microbial fuel cell (MFC) was constructed to investigate the feasibility of electricity generation using microbial fuel cell with refinery oil wastewater as its fuel and the influence of cathodal performance. Results indicated that refinery oil wastewater could be used as fuel in MFCs to generate electricity; catholyte type could influence the electricity generation of MFCs directly and Fe (Ⅲ)-EDTA was the best choice, voltage generation and stable operational period of which were highest and longest; voltage generation increased following with catholyte concentration linear but had little relation to cathode areas.

Layer-by-layer assembled gold nanoparticles modified anode and its application in microbial fuel cells

Microbial fuel cells (MFCs) as one type of “green” energy source are drawing great attention among researchers. Anode performance is an important factor limiting the power output of MFCs for practical application. In this paper, the gold nanoparticles (Au NPs) modified carbon paper electrode was successfully constructed by layer-by-layer assembly technique for the first time. UV–vis spectroscopy was used to monitor the regular layer growth of the {PEI/Au}10 multilayer. The results of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in Fe(CN)63−/4− solution demonstrated that the Au NPs modified carbon paper electrode exhibited better electrochemical behavior than the bare carbon paper electrode, including relatively high electroactive surface areas, increased electron transfer rate and decreased interfacial electron transfer resistance. A two-chambered MFC equipped with the modified anode achieved a maximum power density of 346mWm−2 and a start-time for the initial maximum stable voltage of 175h, which were respectively 50% higher and 36% shorter than the corresponding values of the MFC with the unmodified anode. All the results indicated that the LBL assembly Au NPs-based modification on the anode was a simple but efficient method to incorporate Au NPs onto carbon paper electrodes and promoted the electricity generation of MFCs.

Thionine increases electricity generation from microbial fuel cell using Saccharomyces cerevisiae and exoelectrogenic mixed culture

Microbial fuel cells (MFCs) have been shown to be capable of clean energy production through the oxidation of biodegradable organic waste using various bacterial species as biocatalysts. In this study we found Saccharomyces cerevisiae, previously known electrochemcially inactive or less active species, can be acclimated with an electron mediator thionine for electrogenic biofilm formation in MFC, and electricity production is improved with facilitation of electron transfer. Power generation of MFC was also significantly increased by thionine with both aerated and non-aerated cathode. With electrochemically active biofilm enriched with swine wastewater, MFC power increased more significantly by addition of thionine. The optimum mediator concentration was 500 mM of thionine with S. cerevisae in MFC with the maximum voltage and current generation in the microbial fuel cell were 420 mV and 700 mA/m(2), respectively. Cyclic voltametry shows that thionine improves oxidizing and reducing capability in both pure culture and acclimated biofilm as compared to non-mediated cell. The results obtained indicated that thionine has great potential to enhance power generation from unmediated yeast or electrochemically active biofilm in MFC.

Electricity generation using p-nitrophenol as substrate in microbial fuel cell

The cell voltage and degradation rate of p-nitrophenol (PNP) were monitored in a two-chambered microbial fuel cell (MFC) system. Degradation metabolites in the anode solution of MFC were analyzed by gas chromatography–mass spectrometry (GC–MS). PNP was used as substrate by the MFC that was inoculated with anaerobic sludge. The results showed that electricity output increased with the PNP concentration increased, the MFC displayed a maximum power density of 1.778 mW m−2 and a maximum PNP degradation rate of 64.69% when PNP was used as a sole substrate. However, the cell voltage and the PNP degradation rate with sodium acetate (402.3 mV and 95.96%) were higher than those fed with glucose (341.9 mV and 83.51%) when glucose and sodium acetate were used as a substrate, respectively. Furthermore, GC–MS analysis showed that the PNP was biodegraded completely after 142 h in the MFC. These results demonstrate that PNP can be used for electricity generation in MFC for practical applications of wastewater treatment.

Carbonization and Activation of Inexpensive Semicoke‐Packed Electrodes to Enhance Power Generation of Microbial Fuel Cells

A simple and low-cost modification method was developed to improve the power generation performance of inexpensive semicoke electrode in microbial fuel cells (MFCs). After carbonization and activation with water vapor at 800-850 °C, the MFC with the activated coke (modified semicoke) anode produced a maximum power density of 74 Wm(-3) , 17 Wm(-3) , and 681 mWm(-2) (normalized to anodic liquid volume, total reactor volume, and projected membrane surface area, respectively), which was 124 % higher than MFCs using a semicoke anode (33 Wm(-3) , 8 Wm(-3) , and 304 mWm(-2) ). When they were used as biocathode materials, activated coke produced a maximum power density of 177 Wm(-3) , 41 Wm(-3) , and 1628 mWm(-2) (normalized to cathodic liquid volume, total reactor volume, and projected membrane surface area, respectively), which was 211 % higher than that achieved by MFCs using a semicoke cathode (57 Wm(-3) , 13 Wm(-3) , and 524 mWm(-2) ). A substantial increase was also noted in the conductivity, C/O mass ratio, and specific area for activated coke, which reduced the ohmic resistance, increased biomass density, and promoted electron transfer between bacteria and electrode surface. The activated coke anode also produced a higher Coulombic efficiency and chemical oxygen demand removal rate than the semicoke anode.

The Correlation of the Anodic and Cathodic Open Circuit Potential (OCP) and Power Generation in Microbial Fuel Cells (MFCs)

The overall open circuit potential (OCP) and short circuit potential of anodes and cathodes and the power generation in air-cathode membraneless single chamber microbial fuel cells (SCMFCs) were investigated in this study. Two SCMFCs with different anode areas (10 and 40 cm2) were tested in 8 weeks of experiments. At the beginning of the tests, the anodes were well colonized and the cathodes were in a clean condition. Anodic OCPs remained stable throughout the experiments while the cathodic OCPs decreased dramatically in the first week. The overall OCP of SCMFCs followed the cathodic OCP trend. The power generation of SCMFCs dropped dramatically in the first 3 weeks and then remained stable. The short circuit potential indicated that the performance of SCMFCs was mostly limited by the cathodic process of oxygen diffusion to the platinum.

Direct Electrochemistry of <I>Shewanella Loihica</I> PV-4 on Gold Nanoparticles-Modified Boron-Doped Diamond Electrodes Fabricated by Layer-by-Layer Technique

Microbial Fuel Cells (MFCs) are robust devices capable of taping biological energy, converting pollutants into electricity through renewable biomass. The fabrication of nanostructured electrodes with good bio- and electrochemical activity, play a profound role in promoting power generation of MFCs. Au nanoparticles (AuNPs)-modified Boron-Doped Diamond (BDD) electrodes are fabricated by layer-by-layer (LBL) self-assembly technique and used for the direct electrochemistry of Shewanella loihica PV-4 in an electrochemical cell. Experimental results show that the peak current densities generated on the Au/PAH multilayer-modified BDD electrodes increased from 1.25 to 2.93 microA/cm(-2) as the layer increased from 0 to 6. Different cell morphologies of S. loihica PV-4 were also observed on the electrodes and the highest density of cells was attached on the (Au/PAH)6/BDD electrode with well-formed three-dimensional nanostructure. The electrochemistry of S. loihica PV-4 was enhanced on the (Au/PAH)4/BDD electrode due to the appropriate amount of AuNPsand thickness of PAH layer.

Effects of electron donors and acceptors in generating bioelectrical energy using microbial fuel cells

BACKGROUND: In recent years, microbial fuel cells (MFCs) have emerged as a promising technology for recovering renewable energy from waste biomass, especially wastewater. In this study, the possibility of bioelectricity generation in two chambered mediator-less microbial fuel cells (MFCs) was successfully demonstrated using fermentable and non-fermentable substrates. METHODS AND RESULTS: Two different electron acceptors have been tested in the cathode chamber for the effects of reducing agent on the power generation in MFCs. The average voltages of 0.26±0.014 V and 0.36±0.02 V were achieved with acetate using oxygen and potassium ferricyanide as reducing agent, respectively. Similarly, with glucose the average voltages of 0.256±0.05 V and 0.340±0.04 V were obtained using oxygen and ferricyanide, respectively. Using potassium ferricyanide as the reducing agent, the power output increases by 39 and 43% with acetate and glucose, respectively, as compared to the dissolved oxygen. Slightly higher coulombic efficiency (CE%) was obtained in acetate as compared to MFCs operated with glucose. The maximum power densities of 124 mW/m 2 and 204 mW/m 2 were obtained using dissolved oxygen and K3Fe(CN)6, respectively. CONCLUSION(s): This study demonstrates that power generation from the MFCs can be influenced significantly by the different types of catholyte. Relatively higher CE was obtained with K3Fe(CN)6. Thus, application of K3Fe(CN)6 as the catholyte can be vital for scaling uppower generation from the MFCs forreal time applications.

Bioelectricity production using a new electrode in a microbial fuel cell

Electrode materials play a key role in enhancing the electricity generation in the microbial fuel cell (MFC). In this study, a new material (Ti-TiO(2)) was used as an anode electrode and compared with a graphite electrode for electricity generation. Current densities were 476.6 and 31 mA/m(2) for Ti-TiO(2) and graphite electrodes, respectively. The PCR-DGGE analysis of enriched microbial communities from estuary revealed that MFC reactors were dominated by Shewanella haliotis, Enterococcus sp., and Enterobacter sp. Bioelectrochemical kinetic works in the MFC with Ti-TiO(2) electrode revealed that the parameters by non-linear curve fitting with the confidence bounds of 95% gave good fit with the kinetic constants of η (difference between the anode potential and anode potential giving one-half of the maximum current density) = 0.35 V, K (s) (Half-saturation constant) = 2.93 mM and J (max) = 0.39 A/m(2) for T = 298 K and F = 96.485 C/mol-e(-). From the results observed, it is clear that Ti-TiO(2) electrode is a promising candidate for electricity generation in MFC.

Crumpled graphene particles for microbial fuel cell electrodes

Graphene has a promising role in electrode fabrication/modification for microbial fuel cell (MFC) applications but there is a lack of research on graphene in MFCs. This study has systematically investigated two types of graphene materials with very different morphologies, namely regular graphene (like flat sheets of paper) and crumpled particles (like crumpled paper balls), respectively, to modify anode and cathode electrodes in MFCs. The higher electricity generation with the crumpled graphene particles is attributed to their higher electrical conductivity in the thickness direction, their larger surface area, catalytic activities of oxygen reduction, and the open structure they pack into that facilitates mass transfer of the fuels and ions. The crumpled graphene-modified anode electrode produces the highest maximum power density (3.6Wm−3), twice that of the activated carbon-modified anode electrode (1.7Wm−3). The maximum power densities with the crumpled graphene- and flat graphene-modified cathode electrodes are 3.3Wm−3 and 2.5Wm−3, significantly higher than 0.3Wm−3 with the unmodified carbon cloth, although still lower than a platinum cathode electrode. These results have demonstrated that graphene-based materials, especially the crumpled graphene particles, can be effective electrode modifying materials for improving electricity generation in MFCs.

Electricity Generation in Microbial Fuel Cell by the Decomposition of Organic Slurry by E-Coli

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Fouling of proton exchange membrane (PEM) deteriorates the performance of microbial fuel cell

The fouling characteristics of proton exchange membrane (PEM) in microbial fuel cell (MFC) and the resulting deterioration of MFC performance were explored in this study. It was observed that the ion exchange capacity, conductivity and diffusion coefficients of cations of PEM were reduced significantly after fouling. Imaging analysis coupled with FTIR analysis indicated that the fouling layer attached on PEM consisted of microorganisms encased in extracellular polymers and inorganic salt precipitations. The results clearly demonstrate that PEM fouling deteriorated the performance of MFCs and led to a decrease in electricity generation. Cation transfer limitation might play an important role in the deterioration of MFC performance because of the membrane fouling. This was attributed to the physical blockage of charge transfer in the MFC resulted from the membrane fouling. With the experimental results, the effect of membrane fouling on the electrical generation of MFCs was evaluated. It was found that the decreased diffusion coefficients of cations and cathodic potential loss after membrane fouling contributed mainly to the deterioration of the MFC performance.

Mechanism and Characteristics of Electricity Generation in Microbial Fuel Cells Catalyzed by Mixed Culture

Dual-chamber microbial fuel cells(MFCs) were constructed by inoculating anaerobic sludge.The extracellular electron transfer mechanism of mixed bacteria in MFC anode chamber,the utilization of substrates and cathodic electron acceptors were investigated.The results showed that the mixed bacteria formed thick biofilm on carbon felt anode to facilitate the electron transfer between organic matter and MFC anode.Additionally,the MFC was capable of using a wide variety of organic compounds as electron donors for power generation,including monosaccharide,disaccharide as well as several types of small molecular organic fatty acid and ethanol.While sucrose and lactose as electron donors,the maximum power densities of the MFCs reached 69.69 mW/m2and 60.75 mW/m2,respectively.The highest COD loading of 123.55 mg L-1d-1was attained with ethanol as electron donor.Acidic permanganate as the cathodic electron acceptor could greatly increase power production with the maximum power density of 1 396.74 mW/m2.

Power generation from wastewater using single chamber microbial fuel cells (MFCs) with platinum-free cathodes and pre-colonized anodes

The effects of biofilm growth on anode and cathode surfaces on the power generation from wastewater in single chamber microbial fuel cells (SCMFCs) were investigated in this paper. SCMFCs with the clean/pre-colonized anodes and the platinum-based/platinum-free cathodes were operated for 26 weeks. The pre-colonized (4-week colonization) anodes were tested with three areas (2, 10 and 40cm2) and compared with the MFCs started with clean and sterilized anodes. The power generation of MFCs increased with the anode areas (2–10cm2), but kept a plateau for the anode area of 40cm2. The MFCs with the clean anodes had lower power generation (268mW/m2) than those with the pre-colonized anodes (801mW/m2) in the first week of operation. With the operation proceeding to 4–5 weeks, the power generation of the clean anodes and pre-colonized anodes became similar and stabilized at 470mW/m2. In terms of cathode performance, platinum-free cathodes (carbon cloth, surface area: 5cm2) and platinum-based cathodes (Pt loading: 0.5mgPt/cm2, surface area: 5cm2) were compared. The Pt-based cathodes had higher power generation (330mW/m2) than those of the Pt-free cathodes (253mW/m2) at the startup period, but the difference quickly vanished after a few weeks of operation. This study demonstrated that the advantage of the MFCs with the pre-colonized anodes and platinum-based cathodes disappeared after 3–5 weeks of operation due to the thick biofilm growth on anodes and the aerobic biofilm formation on cathodes. Pt-free cathodes with controlled biofilm growth are promising for low-cost materials, stable power generation and long-term operation of MFCs.

Power generation in MFCs with architectures based on tubular cathodes or fully tubular reactors

Tubular cathodes provide a method to obtain high surface areas for scaling up microbial fuel cells (MFCs), but the importance of the cathode shape is not known. We therefore examined power production using cathodes in various configurations (tubes or flat). The MFC with a single internal carbon cloth tube cathode (71 W/m(3)) produced more power than previously obtained with an ultrafiltration membrane (8 W/m(3)) due to the better performance of carbon material. This power density was slightly less than that of a flat carbon cloth cathode (81 W/m(3); 88 m(2)/m(3)) due to the lower total surface area of the tube (68 m(2)/m(3)) and not as a result of the tubular cathode shape. Adding a second tube increased power (83 W/m(3)) in proportion to specific surface area (93 m(2)/m(3)). Wrapping the cathode completely around the anode formed a fully tubular MFC (external tubular reactor) with a higher surface area that produced 128 W/m(3). Volumetric power density was highly correlated with cathode specific surface area (R(2) = 0.93, p = 0.008) and did not depend on the cathode shape (tubes, completely tubular, or flat). Thus, future MFC designs should focus on increasing cathode specific surface area.

Evaluation of full-strength paper mill effluent for electricity generation in mediator-less microbial fuel cells

In the search for renewable, sustainable and affordable energy sources, microbial fuel cells (MFCs) offer the advantage of a biological oxidation of pollutants to the direct generation of electricity by microorganisms. We thus examined the biodegradability and suitability of unamended paper mill effluent for power production in MFCs. In addition, an investigation of the response from indigenous waste microbes upon introduction of an exogenous Enterobacter cloacae culture was performed. Unamended effluent alone reached a substrate degradation rate (SDR) of 0.112 kg COD/m 3 day and 29.4 ± 2.4% total chemical oxygen demand (tCOD) removal, the power density peaked at 24 ± 3 mW/m 2 and 47.7% glucose increase at the termination of the reactor cycle after 12 ± 3 days. The introduction of E. cloacae in separate setups lowered electricity generation, but benefited remediation, power density decreased to 13 ± 2 mW/m 2 whereas the SDR increased to 0.257 kg COD/m 3 day. Also, there was 44.1% glucose removal in the presence of E. cloacae . It was concluded that unamended paper mill effluent can fuel electricity generation in MFCs with its concomitant remediation. The addition of E. cloacae to live paper mill effluent may be antagonistic in terms of electricity generation. Key words: Microbial fuel cells, paper mill effluent, bioremediation, substrate degradation rate, wastewater, renewable energy, electricity.

The Correlation of the Anodic and Cathodic Open Circuit Potential (OCP) and Power Generation in Microbial Fuel Cells (MFCs)

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