Microbial Fuel Cell System Research Articles

Design of intelligence‐based optimized adaptive fuzzy PID controllers for a two chamber microbial fuel cell

AbstractThe output voltage of microbial fuel cells (MFCs) needs to be controlled effectively to improve the operating efficiency of MFC system against the load variations, disturbances, and uncertainties. The output voltage control is purposed to provide the MFC with an appropriate amount of fuel required to maintain the stability of output voltage. In the applications, the MFC output voltage can be requested to track the variable reference voltage or to track the constant output voltage under changing conditions such as load change. For this purpose, two adaptive fuzzy PID (FPID) controllers powered by optimization algorithms were designed in this study to keep the output voltage value of the MFC at the desired values. This study extends the previous works by using optimization algorithms, such as particle swarm optimization (PSO) and gray wolf optimization (GWO) algorithms, to adjust fuzzy logic parameters, which are used for tuning Proportional‐Integral‐Derivative (PID) controllers. The optimization‐based adaptive FPID controllers play an active role in efficient, fast, and robust tracking of the reference voltage value with its adaptive structure. The designed adaptive control algorithms were tested under different cases, which involve the variation of the reference voltage and load conditions. The results show that both of these controllers can effectively control the output voltage of a MFC by regulating the flow rate of the fuel. In addition, the performances of the designed controller strategies according to the results obtained vary according to the reference signal. While PSO‐based FPID gives more successful results for positive step changes, GWO‐based FPID gives more successful results for negative step changes. These two control strategies show more efficient, robust, successful, and faster performances compared to the traditional PID controller.

Coupling Microbial Fuel Cell and Hydroponic System for Electricity Generation, Organic Removal, and Nutrient Recovery via Plant Production from Wastewater

The world is predicted to face serious threats from the depletion of non-renewable energy resources, freshwater shortage, and food scarcity. Microbial fuel cells (MFCs) are innovative bio-electrochemical devices capable of directly converting chemical energy into electrical energy using microorganisms as a catalyst. This ability has been explored for generating electricity using wastewater as an energy source, while simultaneously treating wastewater. On the other hand, hydroponics is the cultivation of plants in water without soil. The goal of this study was to develop a novel integrated microbial fuel cell-hydroponic system (MFC-Hyp system) that possesses the ability to concurrently generate electricity while degrading organic pollutants (Chemical oxygen demand, COD) in wastewater, remove and recover nutrients (phosphorus, P and nitrogen, N) from the wastewater, and produce edible plants. The MFC-Hyp system developed in this study produced a power density of 250.7 mW/m2. The power density increased by approximately 19% and the phosphorus recovery increased to 7.5% in the presence of Allium tuberosum compared to 4.9% without the plant (e.g., in the control). The removal efficiencies of nitrate, phosphate, and COD are 32%, 11%, and 80%, respectively. The results indicate that the novel integrated MFC-Hyp system can remove COD from wastewater, generate electricity using wastewater as an energy source, and utilize nutrients for growing plants; however, this system requires further improvement for field implementation.

Enhanced Swine Wastewater Treatment by Constructed Wetland—Microbial Fuel Cell Systems

This paper studies the effects of planting plants and coupled microbial fuel cells (MFCs) on the decontamination capacity and purification mechanism of constructed wetlands (CWs). Four systems were set, namely CW-without plants (A1), CW-with plants (A2), CW-MFC-without plants (A3) and CW-MFC-with plants (A4). The daily reductions per unit area of chemical oxygen demand (COD) were 48.72 ± 5.42, 51.26 ± 4.10, 53.49 ± 5.44 and 58.54 ± 4.16 g·(d·m2)−1, respectively. The daily reductions per unit area of nitrogen (N) were 11.89 ± 0.73, 12.38 ± 0.76, 12.24 ± 0.79 and 13.61 ± 1.07 g·(d·m2)−1, respectively. After studying the pollutant removal efficiency, it was found that the unit area of A4 removes the highest number of pollutants, improving the area efficiency of the wetland system and fundamentally alleviating the disadvantage of the large land footprint of wetland processes. The average output voltages of A3 and A4 were 568.29 and 717.46 mV, respectively, and the maximum power densities were 4.59 and 15.87 mW/m3, respectively. In addition, after high-throughput analysis of microbial samples, anaerobic ammonia oxidising (anammox) bacteria were found to remove N from the system in the anaerobic anode region.

Design and Development of Microbial Fuel Cells Based Low Power Energy Harvesting Mechanism for Ecological Monitoring and Farming of Agricultural Applications

Energy harvesting from the microbial fuel cells have a significant attention in the recent days, due to their cost efficiency, simple designing structure and self-powered system. Also, the emergence of internet of things plays a vital role in many real time application scenarios like agricultural purposes and activities. But, the incorporation of these techniques is one of challenging and interesting tasks in the research field. In the conventional works, the internet of things has been utilized as a cloud storage domain for activating the sensors used for environmental monitoring and controlling purposes. The main intention of this paper is to design a robust and cost-effective sludge water based microbial fuel cells, and utilize it for an internet of things incorporated ecological monitoring and farming applications by activating the smart sensors. It discusses about the various electrode combination with several mixture of substrate to study about the optimum performance of microbial fuel cells. To ease the comparative study, Thing Speak platform is used along with the necessary sensors for continuous monitoring. In addition to that, the efficiency of single and dual chamber microbial fuel cell is analyzed based on the set of parameters such as cost, size, and construction. In this work, the microbial fuel cell-based energy harvesting scheme is also developed with switched capacitance-based metal oxide semiconductor field effect transistor and relay-based charge pump circuit which can be incorporated to the internet of things based agriculture applications. Here, the cost analysis of microbial fuel cell with and without DC–DC converter have been compared for selecting the most suitable one for the application system. Moreover, the digital temperature and humidity sensor can be utilized with the proposed microbial fuel cell system for gathering the inputs of the ecological system, which acts as an interface of the microbial fuel cell and cloud systems. During experimentation, the results of both the energy harvesting schemes are evaluated and compared by using various performance indicators.

Modeling and testing the steady-state and transient behaviors of stacked microbial fuel cells under different electrical connection patterns

Microbial fuel cells (MFCs) represent a key solution in the context of sustainable energy development from organic material. Their implementation for real applications is still limited because of economic issues and low power densities. Several efforts have been done both to improve the economic performances by selecting low-cost materials and to increase the power output by realizing stacked configurations.The development of more complex configurations increases the difficulty of predicting the behavior of these bioenergy systems and their performances. In this contest numerical models, supported by the experimental activities, are very useful tools for forecasting the main biological, electrochemical and mass transfer processes occurring within MFCs during their operation in different conditions.In this paper, an electrical transient model, devoted to perform the stacked MFCs voltages and currents on equivalent electric circuits has been developed. The model, that is the superposition of an exponential pattern over a linear trend, is able to define the transient time domain of the voltage and current solutions of a specific electric circuit, enabling the scalability of the estimation of the electrical variables in stacked MFCs systems. The model calibration has been carried out by means of the experimental activities on a single MFC reactor as well as on a stacked MFCs configuration connected in parallel/series.The experimental activities have been performed by using a test bench consisting of the Agilent Digit Multimeters and a Resistance Box. The experimental tests have allowed to assess: i) the steady-state and transient behaviors of a single MFC; ii) the steady-state and transient behaviors of the stacked MFCs configurations.Results have highlighted that the developed model has proved to be an interesting tool for predicting the transient behavior of output currents and voltages after a step perturbation demonstrating how the MFCs evolve towards stable conditions as the load varies.

Electrical discharge machining as a surface treatment process for improving the performance of microbial fuel cells

Microbial fuel cells (MFCs), which generate low-pollution power through feeding organic trace minerals to bacteria, are crucial for applications involving energy recovery and environmental protection. In MFCs, electrodes critically influence the electrocatalytic process. In this study, an electrical-discharge-machining (EDM)-based surface treatment method for MFC electrodes was applied to a stainless-steel mesh (SSM), which was selected as an anode substrate. The experimental results indicated that EDM surface treatment formed a recast layer on the SSM anode surface. A few defects such as cracks and notches were observed after EDM surface treatment, which increased the surface and surface roughness of the SSM anode. To verify the effectiveness of the proposed EDM treatment, an Escherichia coli (HB101)-based single-chamber MFC system was fabricated, and the electrochemical activity of the EDM-treated anode was investigated through electrochemical analysis. The maximum power density of the MFCs equipped with the untreated SSM anode and the EDM-treated SSM anode under a pulse current of 1.5 A were 101.37 and 205.94 mW m−2, respectively. Thus, EDM surface treatment increased the power generated by the MFC by a factor of approximately 2. The proposed novel EDM surface treatment, therefore, has potential for development as a standard processing procedure for metal electrode substrates.

Effects of draw solutes on an integrated forward osmosis-Microbial fuel cell system treating a synthetic wastewater.

Microbial fuel cells (MFCs) and forward osmosis (FO) are both attractive and versatile wastewater treatment technologies that possess disadvantageous qualities that prevent their optimal performance. This study aimed to investigate how draw solute selection for FO treatment would affect MFC performance in a coupled FO-MFC system. Two types of draw solutes, NH4 HCO3 and NaCl, were studied, and it was found that 1.0M NH4 HCO3 (FO-MFC-A) and 0.68 M NaCl (FO-MFC-B) had similar water fluxes of 6.04 to 3.39 LMH and 6.25 to 3.54 LMH, respectively. The reverse salt flux from the draw decreased the feed solution resistance for both draw solutes, but the FO-MFC-A system (0.32 W m-2 ) had a higher maximum power density than the FO-MFC-B system (0.26 W m-2 ). The current density for the FO-MFC-B system increased due to continuous solution resistance decrease, whereas it remained constant for the FO-MFC-A. The difference in Coulombic efficiencies (32.8% vs. 25.6%) but similar Coulombic recoveries (10.2% vs. 11.4%) between the FO-MFC-A and FO-MFC-B systems suggested that the FO-MFC-A might have the inhibited microbial activity by high ammonium/ammonia. The FO-MFC-A system had the lower energy consumption for nutrient removal (2.01 kWh kg-1 NH4 + -N) and recovery (8.87 kWh kg-1 NH4 + -N). These results have shown that NH4 HCO3 as a draw solute can have advantages of higher power density, higher Coulombic efficiency, and recoverability for draw regeneration, but its potential inhibition on microbial activity must also be considered. PRACTITIONER POINTS: Forward osmosis can be connected to microbial fuel cells for wastewater treatment. Water recovery by forward osmosis can greatly reduce the wastewater volume to microbial fuel cells. Ammonium draw solutes can result in lower volumetric energy consumption. Ammonia inhabitation of anode microbes will decrease organic removal.

English

Microbial fuel cells (MFCs) are considered as one of the best prospective natural resources to be discovered on the way to reduce the dependence on fossil fuel-based electricity generation. However, low power generations from MFCs, expensive electrode materials, and the inability to scale-ups MFCs to industrially relevant capacities have made the usage of MFC even worse. The utilization of MFCs in the area of electro-chemistry and thermal science can be very promising in energy storage aspects. In this current study, we studied various combinations of electrode materials and processes that can be applied to construct economical MFCs on small scale. To figure out the best suited MFC setup, MFC systems are prepared using different electrode materials and impacts of these materials on voltage generation are investigated. The cells are observed for 10 h, and voltage generation is witnessed by natural chemical reaction. Then, voltage, current, and power density curves are generated. Next, a pseudo-two-dimensional (2D) physics-based mathematical full cell model is developed to investigate the best suited MFC as a potential energy storage device. It is observed that the numerical results generated from the model are in good agreement with those obtained from the experimental analyses. Hence, the model should be able to predict the better performing anode and cathode materials to build microbial fuel cells having a maximum amount of voltage storage capacity in a specific period. Details of this work will provide more useful information on the concept of MFC and design guidelines for several applications such as energy storage and transformation. Key words: Bacteria, electro-chemistry, physics-based, power, energy storage device, electrodes.

Optimization of Ammonia Nitrogen and Phosphorus Removal Performance and Analysis of Microbial Community Structure in Microbial Fuel Cells

In order to study the effects of operating conditions on the performance of a microbial fuel cell (MFC) for treating ammonia nitrogen (NH4+-N) and phosphate and the changes in the microbial community under optimized conditions, in this study, the response surface method (RSM) and central composite design (CCD) were used to carry out experiments and construct a model of the system to analyze the influence of the hydraulic retention time (HRT) and initial influent ammonia concentration on NH4+-N and the total phosphorus (TP) removal performance of the MFC, and the changes in the microbial community structure were analyzed. The results showed that: (1) the initial influent ammonia concentration had a greater impact than the HRT; (2) after optimizing the reaction conditions, the actual removal rates of NH4+-N and TP of the system were 94.88% and 59.39% (the predicted values were 90.18% and 56.25%), respectively; and (3) the total number of species in the optimization group decreased, and the richness of the microbial community decreased. The system conducted the orthoselection of the microbial community and optimized the structure of the microbial community. After the optimization, the dominant strains for ammonia and phosphorus removal on the cathode reactor of each system were strengthened at the phylum and genus levels. Under the coaction of the dominant strains, the efficiencies of nitrogen removal and phosphorus removal in the reactor were significantly improved. The performance optimization of and microbial community change in NH4+-N and TP removal in the MFC system were studied using RSM, which was helpful to improve the effect of nitrogen and phosphorus removal.

Superior dimethyl disulfide degradation in a microbial fuel cell: Extracellular electron transfer and hybrid metabolism pathways

To enhance the biological degradation of volatile organic sulfur compounds, a microbial fuel cell (MFC) system with superior activity is developed for dimethyl disulfide (DMDS) degradation. The MFC achieves a removal efficiency near 100% within 6 h (initial concentration: 90 mg L−1) and a maximum biodegradation rate constant of 0.743 mM h−1. The DMDS removal load attains 2.684 mmol h−1 L−1, which is 6.18–2440 times the loads of conventional biodegradation processes reported. Meanwhile, the maximum power density output and corresponding current density output are 5.40 W m−3 and 40.6 A m−3, respectively. The main mechanism of extracellular electron transfer is classified as mediated electron transfer, supplemented by direct transfer. Furthermore, the mass balance analysis indicates that methanethiol, S0, S2−, SO42−, HCHO, and CO2 are the main intermediate and end products involved in the hybrid metabolism pathway of DMDS. Overall, these findings may offer basic information for bioelectrochemical degradation of DMDS and facilitate the application of MFC in waste gas treatment. Environmental implicationDimethyl disulfide (DMDS), which features poor solubility, odorous smell, and refractory property, is a typical pollutant emitted from the petrochemical industry. For the first time, we develop an MFC system for DMDS degradation. The superior DMDS removal load per unit reactor volume is 6.18–2440 times those of conventional biodegradation processes in literature. Both the electron transfer route and the hybrid metabolism pathway of DMDS are cleared in this work. Overall, these findings give an in-depth understanding of the bioelectrochemical DMDS degradation mechanism and provide an efficient alternative for DMDS removal.

Degradation of Hydroquinone Coupled with Energy Generation through Microbial Fuel Cells Energized by Organic Waste

Microbial fuel cell (MFC) technology has captured the scientific community’s attention in recent years owing to its ability to directly transform organic waste into electricity through electrochemical processes. Currently, MFC systems faces a number of barriers, with one of the most significant being the lack of organic substrate to provide enough energy for bacterial growth and activity. In the current work, rotten rice was utilized as an organic substrate to boost bacterial activity to produce more energy and break down the organic pollutant hydroquinone in an effort to improve the performance of MFCs. There are only a few studies that considered the waste as an organic substrate and simultaneously degraded the organic pollutant vis-à-vis MFCs. The oxidation of glucose derived from rotten rice generated electrons that were transported to the anode surface and subsequently flowed through an external circuit to the cathode, where they were used to degrade the organic pollutant hydroquinone. The results were consistent with the MFC operation, where the 168-mV voltage was generated over the course of 29 days with a 1000 Ω external resistance. The maximum power and current densities were 1.068 mW/m2 and 123.684 mA/m2, respectively. The hydroquinone degradation was of 68%. For the degradation of organic pollutants and the production of energy, conductive pili-type bacteria such as Lacticaseibacillus, Pediococcus acidilactici and Secundilactobacillus silagincola species were identified during biological characterization. Future recommendations and concluding remarks are also included.

Enhancing Electron Transfer in a Biomimetic Nanocomposite Electrode for Microbial Fuel Cell Applications

Microbial fuel cells (MFCs) have emerged as a renewable energy source due to their ability for direct conversion of organic substrates into electrical energy. However, issues with low power density, limited long-term stability, and higher operational costs have slowed larger scale integration and adoption. One main factor impacting fuel cell performance is the bacterial interactions at the electrode interface and the associated electron transfer mechanisms which are being widely studied. To increase productive interactions between the microbes and anode, this work focused on the synthetic design of a conductive polysaccharide-based (i.e., agar, alginate, pectin) nanocomposite material. More specifically, metal-carboxyl (Fe3+ or V5+)coordination chemistry was used to photoinitiate the polymerization of polyaniline (PANI) directly on the backbone of the biopolymer matrix increasing the overall uniformity. Results show that the n-doped conducting polymer nanocomposite has enhanced current flow when exposed to E. Coli. Additionally, the electrode surface was modified via non-covalent linkages of organic fuels, such as glucose, with TiO2 nanoparticles to decrease bacteria-surface repulsions. Initial results show that the sugar functionalized electrodes demonstrated an increased electric response in conjunction with photochemical activity. This phenomenon was observed through decreased fluorescence intensity without a decrease in cell viability as well as increased open circuit potential in the presence of light. This ligand-metal charge transfer coupled with increased conductivity of a biomimetic bulk material has resulted in an overall improved MFC system.

Biodegradation of Reactive Red 195 azo dye and Chlorpyrifos organophosphate along with simultaneous bioelectricity generation through bacterial and fungal based biocathode in microbial fuel cell

A laboratory-scale dual-chambered bioanode and biocathode based Microbial Fuel Cell (MFC) was employed in the biodegradation of a dye Reactive Red 195 (RR195) and pesticide chlorpyrifos using bacterial and fungal strains. UV-spectrophotometery and and fourier transform infrared (FTIR) data showed removal rates of almost; 100% for both dye (150 mg/L) and pesticide (50 mg/L) with 70 and 81% Chemical Oxygen Demand (COD) in 18 h and 48 h respectively. Bio-electrochemical degradation of said pollutants was also coupled with simultaneous generation of electricity. The maximal cell potential was recorded to be 635 and 706 mV in bacterial and fungal MFC systems with corresponding power densities of 224.01 and 276.9mWm−2 respectively. Electrochemical performance of MFC reactors in term of cyclic voltammetry (CV) and chronoamperometry (CA) showed maximum electron transfer of 122 and 27.35 mA (applied voltage of −1 to +1 V (CV)) and current densities of 13.8 and 10.66mAcm−2 (CA) in the cathodic compartment where degradation of pollutants accomplished. The reactor was also tested for the simultaneous biodegradation of RR 195 dye in real wastewater along with bioelectricity production. The overall COD and colour removal efficiency was 72 %, and 95 % with concurrent increase in TDS, EC and with a maximum power density output of 519.49 mWm−2. The outcomes of this study revealed that MFC technology is highly effective in the treatment of ecological hazardous aromatic pollutants such as dyes (i.e., RR 195) and pesticides (e.g., chlorpyrifos) and for harnessing energy.

Microbial fuel cells for waste nutrients minimization: Recent process technologies and inputs of electrochemical active microbial system

Still, in the current period, non-renewable energy sources have contributed to fulfill the current energy requirement and it causes the deficit of available stocks with emission of pollutant byproducts components. In recent years, efforts were made to harness the sustainable/ renewable fuels from renewable sources/ waste, complex organic matters including biomass at global level. Researchers have put attention on harnessing energy from wastewater and MFCs systems. This MFC approach utilizes the wastewater as feed/ carbon sources to generate bioenergy such as bio- hydrogen and electricity in a sustainable and efficient way via completing the wastewater treatment. This approach consists of anode and cathode electrodes with proton exchange membrane (PEM). Microbial fuel cells are utilized with other effective approaches (anaerobic digestion/ fermentation, local demand-based-MFC approach) that are applied to utilize biowastes for microbial cell growth and electron emission. This review discusses the recent and technologically advanced approach such as microbial fuel cells (MFCs). MFCs can apply to fulfill the increasing trends of global energy demand, found with more utilization in home appliances in urban areas, industrial tasks and transportation sectors. Last few decades, there have been recent modifications in MFCs configurations and design that have improved performance of MFCs. Recent design and configuration of MFCs have shown the removal of maximum chemical oxygen demand (up to 94–97%) with generation maximum current output (up to 5.23 mA) from wastewater. This review presents a comprehensive collection of recent information about technologies and design of MFCs with implementation of microbial electrogene with development of wastewater treatment having sustainable fuel/ energy generation at an effective level.

General aspects and novel PEMss in microbial fuel cell technology: A review

The current scenario of energy production is mostly shifted towards sustainable renewable energy sources. Other than the energy production from natural resources such as sun, wind and water, microbial fuel cell system (MFC) has earned attraction in recent times. These microbial fuel cell systems are bioelectrochemical cell that possesses a unique ability to generate power as well as treats wastewater simultaneously. In this paper, an overview of the microbial fuel cell system and the effect of significant components on the performance of microbial fuel cell systems are reviewed. Firstly, the importance of the MFC system in power generation, its components, the working principle and various configurations of the MFC were briefly introduced. Biofilm plays a major role in the MFC system. Thus the importance of bio film, bio film formation and characterization techniques are summarised. Further, the review mainly addresses the mechanism of conventional and novel membrane materials on the performance of the MFC system. In addition, special emphasis on ceramic-based materials in the MFC system is presented. Finally, recent applications of the MFC systems are discussed.

Halobacterium salinarum NRC-1 Sustains Voltage Production in a Dual-Chambered Closed Microbial Fuel Cell.

Sustained bioenergy production from organisms that thrive in high salinity, low oxygen, and low nutrition levels is useful in monitoring hypersaline polluted environments. Microbial fuel cell (MFC) studies utilizing single species halophiles under salt concentrations higher than 1 M and as a closed microbial system are limited. The current study aimed to establish baseline voltage, current, and power density from a dual-chambered MFC utilizing the halophile Halobacterium salinarum NRC-1. MFC performance was determined with two different electrode sizes (5 cm2 and 10 cm2), under oscillating and nonoscillating conditions, as well as in a stacked series. A closed dual-chamber MFC system of 100 mL capacity was devised with Halobacterium media (4.3 M salt concentration) as both anolyte and catholyte, with H. salinarum NRC-1 being the anodic organism. The MFC measured electrical output over 7, 14, 28, and 42 days. MFC output increased with 5 cm2 sized electrodes under nonoscillating (p < 0.0001) relative to oscillating conditions. However, under oscillating conditions, doubling the electrode size increased MFC output significantly (p = 0.01). The stacked series MFC, with an electrode size of 10 cm2, produced the highest power density (1.2672 mW/m2) over 14 days under oscillation. Our results highlight the potentiality of H. salinarum as a viable anodic organism to produce sustained voltage in a closed-MFC system.

Comparative study of dihydroxybenzene isomers degradation and bioelectricity generation using CuO as cathodic catalyst in double chambered microbial fuel cell

A double chambered microbial fuel cell (MFC) showed enormous capacity in the simultaneous degradation of synthetic wastewater and dihydroxybenzene isomers (catechol, resorcinol and hydroquinone) and concurrently with bioelectricity generation. Operating parameter such as effect of catalyst on MFC system was evaluated using bare carbon plate and copper (II) oxide (CuO) loaded carbon plate as cathodes, respectively, in terms of chemical oxygen demand (COD) and dihydroxybenzene isomers removal efficiency, maximum voltage output and power density. Results revealed that the application of CuO loaded carbon plate was more effective in the COD removal of synthetic wastewater in the anodic chamber and degradation of dihydroxybenzene isomers in the cathodic chamber. Compared with the bare carbon plate as cathode, the COD removal efficiency of synthetic wastewater, removal rate of dihydroxybenzene isomers and maximum voltage output increased 20, 100 and 31 %, respectively, when CuO was applied as cathodic catalyst. Among the dihydroxybenzene isomers, hydroquinone exhibited the best performance in both absence and presence of catalyst in the MFC. The position of the substituent of hydroxyl groups possessed significant effect on the reaction rate, reactivity and conductivity of dihydroxybenzene isomers. Hydroquinone was more susceptible to be degraded than that of catechol and resorcinol due to its lower dipole moment which eased the bond cleavage. The intermediate products of degradation of catechol, resorcinol and hydroquinone were determined using gas chromatograph-mass spectrometer and the degradation pathways were proposed.

Electrical Characteristics of Chitosan-Carrageenan Membrane Implementation and Salt Bridge in Microbial Fuel Cell Using Yeast Fermented Cassava Waste Substrate

A Microbial Fuel Cell (MFC) is an electrochemical system that generates energy utilizing waste as a substrate and the results of microbial metabolism processes. This research utilizes yeast fermented cassava waste as a substrate to determine the electrical characteristics of PEM in the form of a chitosan-carrageenan membrane and salt bridge. The cassava waste is from the waste produced in the manufacture of tapioca flour. A dual-chamber MFC made of acrylic with a size of 8x8x10 cm is used. Cassava waste substrate with carbon electrodes would be in the anode compartment, and seawater electrolyte with Cu(Ag) fiber electrodes would be in the cathode compartment. Each measurement holds ±250 ml in each compartment. The MFC system consists of 10 cells and is analyzed every hour for 120 hours using a multitester. According to the results of the research, cassava waste (liquid and onggok) can be used as a substrate in the MFC system, which has the potential to produce alternative electrical energy. Compared to salt bridges, the use of PEM in the form of chitosan-carrageenan membranes produces more significant and better electrical characteristics. However, the chitosan-carrageenan membrane is still less suitable in the long term than the salt bridge.

Fabrication and characterization of hybrid poly (vinyl alcohol) based proton exchange membrane for energy generation from wastewater in microbial fuel cell system

Fabrication and characterization of hybrid poly (vinyl alcohol) based proton exchange membrane for energy generation from wastewater in microbial fuel cell system

Efficient organic contaminant and Cr (VI) synchronous removing by one-step modified molybdenite cathode microbial fuel cells.

As a novel technique with a wide range of applications, microbial fuel cell (MFC) could simultaneously remove organic contaminants and heavy metals in complex wastewater, despite striking differences in physicochemical properties of these contaminant. But its wastewater treatment efficiency is restricted by its lower generation performance. However, approaches for the modification of MFCs' cathode with appropriate catalyst could effectively overcome this limitation. Herein, a new-type efficient cathode catalyst was invented through modifying natural molybdenite via one-step oxidation method. In this case, molybdenite had many changes in morphology (wave-shaped bending, fragmentation and decrescent diameter) during oxidation modification process, and oxidation-modified molybdenite could provide much more active sites for the cathode. After applying this novel cathode catalyst, the electric generation capacity of MFC system increased by 5.08 times, and its simultaneous degradation efficiency of methyl blue (MB) and Cr (VI) increased by 3.35 times (compared with graphite cathode MFC). This study provides a novel low-carbon and environmentally friendly way to prepare high efficiency cathode catalyst materials and provides a new idea of simultaneous purification for organic and metallic pollutants from complex wastewater.