Anodic Chamber Of Microbial Fuel Cell Research Articles

Boosted biodegradation of recalcitrant bisphenol S by mix-cultured microbial fuel cells under micro-aerobic condition

As a substitute for bisphenol A (BPA), the potential toxicity and endocrine disruption of bisphenol S (BPS) have gradually attracted wide attention. Exploring methods to degrade BPS is of great significance. Microbial fuel cells (MFCs) have been extensively used for the removal of contaminants and have demonstrated excellent performances. In this paper, an efficient strategy of micro-aeration to the anode chamber of MFC was conducted to boost the biodegradation of BPS without inhibiting the current generation. The removal efficiency of BPS by MFC under the micro-aerobic condition was 36.35%, which was 1.8 times higher than that of the control group. The introduction of trace oxygen had a neglectable effect on the maximum power density of the system. This work not only enhanced the biodegradation of BPS in MFCs by a simple strategy but also showed that commonly thought of anaerobic MFCs could enrich more functional bacteria (Lentimicrobium, Chryseobacterium and Gordonia) under the micro-aerobic condition in terms of endocrine disruptors removal. Therefore, this paper can provide a reference for the methods of enhancing the BPS removal performance by MFC.

Combining biological denitrification and electricity generation in methane-powered microbial fuel cells

Methane has been demonstrated to be a feasible substrate for electricity generation in microbial fuel cells (MFCs) and denitrifying anaerobic methane oxidation (DAMO). However, these two processes were evaluated separately in previous studies and it has remained unknown whether methane is able to simultaneously drive these processes. Here we investigated the co-occurrence and performance of these two processes in the anodic chamber of MFCs. The results showed that methane successfully fueled both electrogenesis and denitrification. Importantly, the maximum nitrate removal rate was significantly enhanced from (1.4 ± 0.8) to (18.4 ± 1.2) mg N/(L·day) by an electrogenic process. In the presence of DAMO, the MFCs achieved a maximum voltage of 610 mV and a maximum power density of 143 ± 12 mW/m2. Electrochemical analyses demonstrated that some redox substances (e.g. riboflavin) were likely involved in electrogenesis and also in the denitrification process. High-throughput sequencing indicated that the methanogen Methanobacterium, a close relative of Methanobacterium espanolae, catalyzed methane oxidation and cooperated with both exoelectrogens and denitrifiers (e.g., Azoarcus). This work provides an effective strategy for improving DAMO in methane-powered MFCs, and suggests that methanogens and denitrifiers may jointly be able to provide an alternative to archaeal DAMO for methane-dependent denitrification.

Inhibition of AHL-mediated quorum sensing to control biofilm thickness in microbial fuel cell by using Rhodococcus sp. BH4

Anode biofilm thickness is a key point for high and sustainable power generation in microbial fuel cells (MFCs). Over time, the formation of a thicker biofilm on anode electrode hinders the power generation performance of MFC by causing a longer electron transfer path and the accumulation of undesirable components in anode biofilm. To overcome these limitations, we used a novel strategy named quorum quenching (QQ) for the first time in order to control the biofilm thickness on the anode surface by inactivation of signal molecules among microorganisms. For this purpose, the isolated QQ bacteria (Rhodococcus sp. BH4) were immobilized into alginate beads (20, 40, and 80 mg/10 ml sodium alginate) and added to the anode chamber of MFCs. The MFC exhibited the best electrochemical activity (1924 mW m−2) with a biofilm thickness of 26 μm at 40 mg Rhodococcus sp. BH4/10 ml sodium alginate. The inhibition of signal molecules in anode chamber reduced the production of extracellular polymeric substance (EPS) by preventing microbial communication amonganode microorganisms. Microscopic observations revealed that anode biofilm thickness and the abundance of dead bacteria significantly decreased with an increase in Rhodococcus sp. BH4 concentration in MFCs. Microbiome diversity showed an apparent difference among the microbial community structures of anode biofilms in MFCs containing vacant and Rhodococcus sp. BH4 beads. The data revealed that the QQ strategy is an efficient application for improving MFC performance and may shed light on future studies.

Improved Performance of Microbial Fuel Cell by In Situ Methanogenesis Suppression While Treating Fish Market Wastewater.

The fish market wastewater, which is rich in ammonium concentration, was investigated to explore its ability of in situ suppression of methanogenesis in the anodic chamber of microbial fuel cell (MFC) while treating it and to ensure non-reoccurrence of methanogenic consortia in the anodic chamber during its long-term operations. A lower specific methanogenic activity (0.097g chemical oxygen demand (COD)CH4/g volatile suspended solids (VSS). day) with a higher power density (3.81 ± 0.19W/m3) was exhibited by the MFC operated with raw fish market wastewater as compared to the MFC fed with synthetic wastewater (0.219g CODCH4/g VSS. day and 1.75 ± 0.09W/m3, respectively). The enhanced electrochemical activity of anodic biofilm of MFC fed with raw fish market wastewater than the MFC fed with synthetic wastewater further advocated the enhanced electrogenic activity and suppression of methanogenesis, because of the presence of higher ammonium content in the feed. This, in response, reduced the internal resistance (55Ω), enhanced the coulombic efficiency (21.9 ± 0.3%) and normalized the energy recovery (0.27 kWh/m3) from the MFC fed with fish market wastewater than the MFC fed with synthetic wastewater (92Ω, 15.7 ± 0.3% and 0.13kWh/m3, respectively). Thus, while treating the fish market wastewater in the anodic chamber of MFC, any costly and repetitive treatment procedures for anodic microorganisms are not required for suppression of methanogens to ensure higher activity of electrogenic bacteria for higher electricity harvesting.

Surfactant removal from wastewater using photo-cathode microbial fuel cell and laterite-based hybrid treatment system.

Sodium dodecyl sulfate (SDS) is a widely used anionic surfactant, which finds its way to the receiving water body due tothe incapability of conventional wastewater treatment systems to completely remove it. A hybrid treatment system consisting of upflow microbial fuel cell (MFC) with titanium dioxide (TiO2) as a photocathode catalyst was developed for treating synthetic wastewater spiked with SDS (10.00 ± 0.46mg L-1). Effluent from anodic chamber of MFC was passed through raw laterite soil filter followed by the photo-cathodic chamber with TiO2-coated cathode irradiated with theUV spectrum. This hybrid system was operated under varying hydraulic retention time (HRT) in anodic chamber of MFC. The SDS removal efficiency of more than 96% along with organic matter removal efficiency of more than 71% was obtained by this hybrid system at different HRTs. The MFC having cathode coated with TiO2 could generate a maximum power density of 0.73Wm-3 and 0.46Wm-3 at the HRT of 12h and 8h, respectively, showing the adverse effect of increased SDS loading rate on the electrical performance of MFC. This investigation highlighted the importance of HRT in anodic chamber of MFC and offered solution for effective removalof surfactant from wastewater.

Idea paper: Community‐interaction analyses contribute to improving the performance of microbial fuel cells

AbstractRenewable energy resources can potentially solve global warming issues that arise from the large amounts of CO2 emissions from currently used energy resources. Microbial fuel cells (MFC) can produce electrical energy from the environment, making them attractive for energy harvesting. The structures and mechanisms of MFC have been studied for a few decades, and the performance of MFC has constantly been improved using new materials in the devices or by interacting microbial species on the anode chamber of MFC. However, the ecological phenomena, especially inter‐species interactions, within the microbial community in MFC are still largely unknown. Analysis and control of the microbial community have high potential to improve the MFC performance. In this idea paper, I have provided ways to analyze the species interactions in the microbial communities of MFC: (a) empirical dynamic modeling for detecting species interactions in MFC, and (b) network analysis to explore the core microbe species in the MFC. The interaction analyses of the microbial communities in MFC devices can potentially contribute to improving the performance of MFC.

The optimization of growth parameters in a anodic chamber of a microbial fuel cell

The pollution is a result of drastically rising fossil fuel usage due to increased global population and industrialization. Today’s world needs to replace fossil fuels with new and renewable energy sources. Microbial Fuel Cells (MFCs) are devices that convert the chemical energy to direct electricity by microbial metabolic activity. Microbial growth was actualized at the anodic chamber of MFC and must be controlled carefully by microbial methods. The main aim of this study is optimizing the growth parameters of microorganisms in two-chambered MFC with optical density, dried and wet weight of microorganisms that were grown at the anode chamber of MFC. Moreover, the Chemical Oxygen Demand (COD) values of medium were determined at fed cycles of MFC. The total volume of MFC was 0.7 L and the connection was made with the salt bridge between anode and cathode compartments. The anode chamber was used for bacterial growth that was taken from Akkaya Dam slime, was fed with molasses medium at 5 days intervals. The OD values were determined with a spectrophotometer at 600 nm, COD values were determined with the standard method and wet-dry weight also determined as a function of the incubation period.

Improved Wastewater Treatment by Combined System of Microbial Fuel Cell with Activated Carbon/TiO2 Cathode Catalyst and Membrane Bioreactor

A two-stage continuous process was developed for treating medium-strength wastewater combining microbial fuel cell (MFC) using activated carbon (AC)/TiO2 composite as cathode catalyst and submerged membrane bioreactor (MBR). Synthetic wastewater, having total chemical oxygen demand (COD) of around 3 g/L, was introduced first in the anodic chamber of MFC in a continuous mode of operation followed by aerobic MBR. Submerged hollow-fibre ultra-filtration membrane assembly was attached to draw permeate from MBR. The electrical performance of MFC was evaluated by polarisation, which showed a maximum volumetric power density of 1.02 W/m3 with much lower whole-cell internal resistance of 10 Ω. The coulombic efficiency of MFC was estimated to be 0.31%, demonstrating AC/TiO2 composite as a promising cathode catalyst for applications in MFC. The permeate of MFC–MBR system showed 98.3 ± 0.3% and 81.9 ± 1.8% of COD and total Kjeldahl nitrogen removal efficiency, respectively, producing permeate with total suspended solids concentration of less than 5 mg/L. Thus, a two-stage reliable process for treatment of wastewater is demonstrated using integrated MFC–MBR for generating high-quality recyclable effluent and facilitating recovery of bio-electricity.

The changes of bacterial communities and antibiotic resistance genes in microbial fuel cells during long-term oxytetracycline processing

Microbial fuel cell (MFC) is regarded as a promising alternative for enhancing the removal of antibiotic pollutants. In this study, oxytetracycline served as an electron donor in the anode chamber of MFCs, and after continuous operation for 330 days, the efficiency of removal of 10 mg/L oxytetracycline in MFCs increased to 99.00% in 78 h, whereas removal efficiency of only 58.26% was achieved in microbial controls. Compared to microbial controls, higher ATP concentration and persistent electrical stimulation mainly contributed to bioelectrochemical reactions more rapidly to enhance oxytetracycline removal in MFCs. In addition, the analysis of bacterial communities revealed that Eubacterium spp.—as the main functional bacterial genus responsible for oxytetracycline biodegradation—flourished starting from merely 0.00%–91.69% ± 0.27% (mean ± SD) in MFCs. High-throughput quantitative PCR showed that the normalized copy numbers of total antibiotic resistance genes (ARGs) and mobile genetic elements in MFCs were 1.7364 and 0.0065 copies/cell respectively, which were markedly lower than those in the microbial controls. Furthermore, there was no significant correlation between oxytetracycline concentration in the influent and abundance of ARGs in effluent from MFCs. Nevertheless, Tp614, a transposase gene, was found to be enriched in both MFCs and microbial reactors, suggesting that it may be a common challenge for different biological processes for wastewater treatment. This study therefore showed a lower probability of upregulation and transmission of ARGs in MFCs when compared to a traditional anaerobic microbial treatment.

Dynamic modeling of a continuous two-chamber microbial fuel cell with pure culture of Shewanella

Microbial fuel cell is a bioreactor which converts the chemical energy stored in chemical bonds of the organic compounds to electrical energy through the catalytic reactions. In this work, the previous model which was proposed by our group [M. Esfandyari, M.A. Fanaei, R. Gheshlaghi, M.A. Mahdavi, Chemical Engineering Research and Design, 117 (2017) 34–42] for a batch two-chamber microbial fuel cell (MFC) is extended to the continuous operation. In the selected continuous MFC, lactate is used as the substrate, Shewanella as the microbial agent, and oxygen of air as the final electron acceptor in the cathode chamber. An experimental setup is applied for the collection of data needed for the verification of the proposed model. A Good agreement was observed between the predicted and the experimental data of the current and voltage produced by MFC as well as the substrate and carbon dioxide concentration in the liquid bulk of anode chamber of MFC. The proposed model has simple structure and can be used for the optimization, and design of control system of microbial fuel cell.

Enhanced Removal of Herbicide 2,4-dichlorophenoxyacetic Acid and Simultaneous Power Generation in Microbial Fuel Cells

This study investigated the effects of a widely used herbicide 2,4-dichlorophenoxyacetic acid on power generation, pollutants removal from microbial fuel cells (MFCs) and microbial community changes, and also explored anode pre-aeration for enhanced 2,4-D removal and power generation. The results showed that when 2,4-D was inputted to the anode chamber of MFCs which was previously enriched with acetate sodium as the fuel, the voltage output and power density declined and the internal resistance increased apparently. The maximum power density declined to 0.057 W·m-2 in the presence of 300 mg·L-1 2,4-D comparing to 0.151 W·m-2 obtained with acetate alone (850 mg·L-1), and the internal resistance increased from 524 Ω to 1230 Ω correspondingly. To accelerate 2,4-D removal rate and reduce its inhibition to anode exoelectrogens, 6h pre-aeration was applied to the anode chamber. Fast removal of 2,4-D was achieved during aeration period and simultaneous high maximum voltage output (0.42-0.47 V) was obtained. Anode microbial community changed after 2,4-D addition and several 2,4-D degrading bacteria and 2,4-D tolerant exoelectrogen were enriched. MFCs could be used for 2,4-D removal and simultaneous power generation through anode pre-aeration.

Stimulation of oxygen to bioanode for energy recovery from recalcitrant organic matter aniline in microbial fuel cells (MFCs)

The challenge of energy generation from biodegradation of recalcitrant organics in microbial fuel cells (MFCs) is mainly attributed to their persistence to degradation under anaerobic condition in anode chamber of MFCs. In this work, we demonstrated that electricity generation from aniline, a typical recalcitrant organic matter under anaerobic condition was remarkably facilitated by employing oxygen into bioanode of MFCs. By exposing bioanode to air, electrons of 47.2 ± 6.9 C were recovered with aniline removal efficiency of 91.2 ± 2.2% in 144 h. Limited oxygen supply (the anodic headspace was initially filled with air and then closed) resulted in the decrease of electrons recovery and aniline removal efficiency by 52.5 ± 9.4% and 74.2 ± 2.1%, respectively, and further decline by respective 64.3 ± 4.5% and 82.7 ± 1.0% occurred under anaerobic condition. Community analysis showed that anode biofilm was predominated by several aerobic aniline degrading bacteria (AADB) and anode-respiration bacteria (ARB), which likely cooperated with each other and finally featured the energy recovery from aniline. Cyclic voltammetry indicated that anodic bacteria transferred electrons to anode mainly through electron shuttle. This study provided a new sight to acquaint us with the positive role of oxygen in biodegradation of recalcitrant organics on anode as well as electricity generation.

Bio-electrochemical post-treatment of anaerobically treated landfill leachate

Bio-electrochemical treatment of anaerobically pre-treated landfill leachate was investigated in batch and continuous-flow two-chambered microbial fuel cells (MFCs). A high strength young landfill leachate was pre-treated using an upflow anaerobic sludge blanket reactor and the effluent resembling medium-aged landfill leachate was fed to the anode chamber of MFCs. The highest maximum current and power densities achieved in continuous-flow MFC with hydraulic retention time (HRT) of five days were 525mA/m2 (8227mA/m3) and 158mW/m2 (2482mW/m3), respectively. Increase of HRT from one day to five days resulted in the occurrence of partial nitrification, where influent ammonia was converted into nitrite presumably due to the inhibitory effects of free ammonia. The maximum power and current densities obtained in this study were higher compared to other studies with similar leachate characteristics. The results of this study suggest that MFCs can be exploited as a polishing step for anaerobically pretreated landfill leachate.

Organic Removal Efficiencies and Power Production Capabilities of Microbial Fuel Cells with Pure Cultures and Mixed Culture

The voltage and the power production of four pure cultures and a mixed culture in five identical continuous-flow microbial fuel cells (MFCs) were evaluated and compared in the present study. Each microbial fuel cell was operated at four different flow rates with the external load resistance of 1000Ω The result shows that good linear relationship between COD degradation rate and flow rate was obtained on the MFCs inoculated with Pseudomonas putida, Corynebacterium glutamicum and Comamonas testosteroni, not on the one inoculated with Arthrobacter polychromogenes. However, the relationship between COD degradation rate and flow rate on the MFC inoculated with mixed culture could be expressed as a binary quadratic equation. A lower influent pH favored the organic removal efficiency and degradation rate in the anode chamber of MFCs. The result also shows that the voltage outputs increased with the flow rate (shorter retention time) of anode chambers. However, good linear relationships between voltage and flow rate were only seen on the MFCs inoculated with Comamonas testosteroni and mixed culture. Among the five MFCs, the one inoculated with mixed culture displayed the highest voltage output at the same COD loading than others.

Design and fabrication of microbial fuel cell for generation of electricity

Energy need has been increasing worldwide exponentially. At present global energy requirements are mostly dependent on the fossil fuels, which eventually lead to foreseeable depletion of limited fossil energy sources. More recently, generation of electricity using microbial fuel cells (MFC) is seemingly gaining importance in the research. MFC is a biochemical-catalyzed system which generates electrical energy through the oxidation of biodegradable organic matter in the presence of either fermentative bacteria or enzyme under mild reaction conditions (ambient temperature and pressure) and bacterial energy is directly converted to electrical energy and to close the cycle, protons migrate through a proton exchange membrane (PEM) from anode to cathode. The present work deals with the designing and fabrication of two-chambered salt bridge microbial fuel cell with specific dimension. The efficiency of fabricated MFCs was checked by variation in current produced on different days of operation of MFC and effect of using dextrose in anodic chamber of MFC. The MFC was operated for 7 days with or without dextrose as carbon source. It was observed that while running MFC without dextrose the maximum current obtained was 13.6 μA and maximum voltage obtained was 146.8 mV. However while using 5% dextrose solution in the anodic-chamber the maximum current and voltage obtained was 170 μA and 216 mV respectively.