Sustainable power production in a membrane-less and mediator-less synthetic wastewater microbial fuel cell (original) (raw)
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Applied Biochemistry and Biotechnology, 2010
This objective of this study is to conduct a systematic investigation of the effects of configurations, electrolyte solutions, and electrode materials on the performance of microbial fuel cells (MFC). A comparison of voltage generation, power density, and acclimation period of electrogenic bacteria was performed for a variety of MFCs. In terms of MFC configuration, membrane-less two-chamber MFCs (ML-2CMFC) had lower internal resistance, shorter acclimation period, and higher voltage generation than the conventional two-chamber MFCs (2CMFC). In terms of anode solutions (as electron donors), the two-chamber MFCs fed with anaerobic treated wastewater (AF-2CMFCs) had the power density 19 times as the two-chamber MFCs fed with acetate (NO3−2CMFCs). In terms of cathode solutions (as electron acceptors), AF-2CMFCs with ferricyanide had higher voltage generation than that of ML-2CMFCs with nitrate (NO3−ML-2CMFCs). In terms of electrode materials, ML-2CMFCs with granular-activated carbon as the electrode (GAC-ML-2CMFCs) had a power density 2.5 times as ML-2CMFCs with carbon cloth as the electrode. GAC-ML-2CMFCs had the highest columbic efficiency and power output among all the MFCs tested, indicating that the high surface area of GAC facilitate the biofilm formation, accelerate the degradation of organic substrates, and improve power generation.
Energy, 2022
Bio-electrochemical systems, such as microbial fuel cells (MFCs), serve as greener alternatives to conventional fuel energy. Despite the burgeoning review works on MFCs, comprehensive discussions are lacking on MFC designs and applications. Thus, this review paper provides insights into MFC applications, substrates used in MFC, and the various design, technological, and chemical factors affecting MFC performance. MFCs have demonstrated efficacy in wastewater treatment of at least 50% and up to 98%. MFCs have been reported to produce ~30 W/m 2 electricity and ~1 m 3 /d of biohydrogen, depending on the design and feedstock. Electricity generation rates of up to 5.04 mW/m-2-3.6 mW/m-2 , 75-513 mW/m-2 , and 135.4 mW/m-2 have been found for SCMFCs, double chamber MFCs, and stacked MFCs, respectively, with the highest being produced by the single/hybrid single-chamber type using microalgae. Hybrid MFCs may emerge as financially promising technologies worth investigating due to their low operational costs, integrating low-cost proton exchange membranes such as PVA-Nafion-borosilicate, and electrodes made of natural materials, carbon, metal, and ceramic. MFCs are mostly used in laboratories due to their low power output and the difficulties in assessing the economic feasibility of the technology. However, MFCs can generate incomes of as much as $2498.77 x 10-2 /(W/m 2) annually through wastewater treatment and energy generation alone. The field application of MFC technology is also narrow due to its microbiological, electrochemical, and technological limitations, exacerbated by the gap in knowledge between laboratory and commercial-scale applications. Further research into novel and economically feasible electrode and membrane materials, the improvement of electrogenicity of the microbes used, and the potential of hybrid MFCs will provide opportunities to launch MFCs from the laboratory to the commercial-scale as a bid to improve the global energy security in an eco-friendly way.
Evaluation of hydrolysis and fermentation rates in microbial fuel cells
Applied Microbiology and Biotechnology, 2011
This study determined the influence of substrate degradation on power generation in microbial fuel cells (MFCs) and microbial community selection on the anode. Air cathode MFCs were fed synthetic medium containing different substrates (acetate, glucose and starch) using primary clarifier sewage as source of electroactive bacteria. The complexity of the substrate affected the MFC performance both for power generation and COD removal. Power output decreased with an increase in substrate complexity from 99±2 mW m −2 for acetate to 4±2 mW m −2 for starch. The organic matter removal and coulombic efficiency (CE) of MFCs with acetate and glucose (82% of COD removal and 26% CE) were greater than MFCs using starch (60% of COD removal and 19% of CE). The combined hydrolysisfermentation rate obtained (0.0024 h −1 ) was considerably lower than the fermentation rate (0.018 h −1 ), indicating that hydrolysis of complex compounds limits current output over fermentation. Statistical analysis of microbial community fingerprints, developed on the anode, showed that microbial communities were enriched according to the type of substrate used. Microbial communities producing high power outputs (fed acetate) clustered separately from bacterial communities producing low power outputs (fed complex compounds).
Factors affecting current production in microbial fuel cells using different industrial wastewaters
Bioresource Technology, 2011
This study evaluated how different types of industrial wastewaters (bakery, brewery, paper and dairy) affect the performance of identical microbial fuel cells (MFCs); and the microbial composition and electrochemistry of MFC anodes. MFCs fed with paper wastewater produced the highest current density (125 ± 2 mA/m 2 ) at least five times higher than dairy (25 ± 1 mA/m 2 ), brewery and bakery wastewaters (10 ± 1 mA/m 2 ). Such high current production was independent of substrate degradability. A comprehensive study was conducted to determine the factor driving current production when using the paper effluent. The microbial composition of anodic biofilms differed according to the type of wastewater used, and only MFC anodes fed with paper wastewater showed redox activity at À134 ± 5 mV vs NHE. Electrochemical analysis of this redox activity indicated that anodic bacteria produced a putative electron shuttling compound that increased the electron transfer rate through diffusion, and as a result the overall MFC performance.
Editorial In Focus: Microbial Fuel Cells, some considerations
Journal of Chemical Technology and Biotechnology, 2019
The discovery by M.C. Potter in 1911 that some bacteria can generate electricity in devices called microbial fuel cells (MFCs) opened up a new opportunity in exploitation of microbes' potential; but limited interest was shown for some time. However, since 1980's research in this area has intensified. MFCs work on the principle that electricigens can oxidise substrates in an anode chamber releasing electrons and protons. The electrons go through an external circuit to a cathode chamber, while protons travel from the anode to the cathode through a membrane that separates the two chambers. Recombination of electrons and protons in the cathodic chamber completes the circuit in presence of an oxidant, typically oxygen. MFCs have promise in a number of areas including bioremediation, electricity production, biosensing and water desalination. To enhance feasibility of MFC technology in biotechnology sectors, a number of challenges need to be overcome. These include selection/design of efficient microbes, electrodes, membranes and chambers; better understanding of the mechanism and improving the process of electron transfer from the microorganisms to the electrodes; integration of MFCs in the wastewater treatment train; extending potential of MFCs from applications in bioremediation to bioproduction; and cost-effective scale-up of the reactors. This 'In-focus' section of the Journal of Chemical Technology and Biotechnology (JCTB) covers a total of six manuscripts (two review papers 1,6 and four original research articles 2-4) in microbial fuel cells reporting recent developments in MFC technology. Alleviating the accumulation of xenobiotics in the environment, has been subject to extensive research. However, the use of bioelectrochemical systems (BES) in remediation is a relatively new endeavour. Fernando et al. 1 report in a comprehensive review, the history of electromicrobiology, contaminants treated by MFC, and types of BES used, addressing BES advantages. The review concludes that BES is promising for both in situ and ex situ environmental remediation applications in a sustainable manner. Gomaa et al. 2 address the mechanism of concomitant degradation of the dye Congo red and bioelectricity generation using a recombinant strain of E. coli. Their work shows that although there seems to exist a link between dye decolourisation and COD values in their reactor, the efficiency of the system for generation of electricity is low. This highlights the importance of appropriately engineered efficient strains for multiple desired outputs. In another study investigating multifunctional
Microbial Fuel Cell Construction Features and Application for Sustainable Wastewater Treatment
Membranes
A microbial fuel cell (MFC) is a system that can generate electricity by harnessing microorganisms’ metabolic activity. MFCs can be used in wastewater treatment plants since they can convert the organic matter in wastewater into electricity while also removing pollutants. The microorganisms in the anode electrode oxidize the organic matter, breaking down pollutants and generating electrons that flow through an electrical circuit to the cathode compartment. This process also generates clean water as a byproduct, which can be reused or released back into the environment. MFCs offer a more energy-efficient alternative to traditional wastewater treatment plants, as they can generate electricity from the organic matter in wastewater, offsetting the energy needs of the treatment plants. The energy requirements of conventional wastewater treatment plants can add to the overall cost of the treatment process and contribute to greenhouse gas emissions. MFCs in wastewater treatment plants can ...
Characterization of Microbial Fuel Cells at Microbially and Electrochemically Meaningful Time scales
2011
The variable biocatalyst density in a microbial fuel cell (MFC) anode biofilm is a unique feature of MFCs relative to other electrochemical systems, yet performance characterizations of MFCs typically involve analyses at electrochemically relevant time scales that are insufficient to account for these variable biocatalyst effects. This study investigated the electrochemical performance and the development of anode biofilm architecture under different external loadings, with duplicate acetate-fed singlechamber MFCs stabilized at each resistance for microbially relevant time scales. Power density curves from these steady-state reactors generally showed comparable profiles despite the fact that anode biofilm architectures and communities varied considerably, showing that steady-state biofilm differences had little influence on electrochemical performance until the steady-state external loading was much larger than the reactor internal resistance. Filamentous bacteria were dominant on the anodes under high external resistances (1000 and 5000 Ω), while more diverse rod-shaped cells formed dense biofilms under lower resistances (10, 50, and 265 Ω). Anode charge transfer resistance decreased with decreasing fixed external resistances, but was consistently 2 orders of magnitude higher than the resistance at the cathode. Cell counting showed an inverse exponential correlation between cell numbers and external resistances. This direct link of MFC anode biofilm evolution with external resistance and electricity production offers several operational strategies for system optimization.
Microbial fuel cell constructed with micro-organisms isolated from industry effluent
International Journal of Hydrogen Energy, 2011
Three types of aerobic bacteria such as Citrobacter freundii, Proteus mirabilis and Bacillus subtilis were evaluated in terms of bioelectricity production using double chambered microbial fuel cell (MFC) with graphite cloth as anode and cathode and Nafion membrane as proton exchange membrane (PEM). Performance of MFC was studied with addition of glucose. Cyclic voltammetry (CV) experiments showed the presence of peaks at À92 and À163 mV vs Ag/AgCl for C. freundii and P. mirabilis indicating their electrochemical activity without an external mediator. Potential time experiments showed the potential of MFC solely depend on change in anode potential rather than cathode potential. The internal resistance of MFC containing B. subtilis was lower than C. freundii and P. mirabilis. Fuel cell performance was evaluated employing polarization curve and power output along with cell potentials. MFC containing B. subtilis with neutral red mediator showed current output of 112 mA m À2 at external resistance of 0.3 kU which is higher than the current outputs from MFC containing C. freundii and P. mirabilis. The relative efficiency of power generation observed in aerobic microenvironment may be attributed to the effective substrate oxidation and good biofilm growth observed on the anodic surface.
Deleted Journal, 2023
Microbial Fuel Cell (MFC) is a dual-edged technology which combines wastewater treatment with power generation. The chemical energy present in the organic matter of wastewater is usually transformed into electricity in MFCs through the action of electroactive bacteria on electrodes which act as catalysts. The MFC technology has piqued the interest of numerous researchers since it has the unique capability for wastewater treatment while concurrently generating some bioelectricity. When compared with traditional energy sources, MFCs have various advantages over other wastewater treatment processes, such as the trickling filter method and the commonly employed activated sludge process. These advantages include but are not limited to low energy requirements, low or no production of hazardous products, and mild reaction conditions. As a result, this wastewater treatment process is both cost-effective and long-term. The various designs of MFCs, electrode materials, and various wastewaters (substrates) that electrogenic bacteria could utilize are discussed in this work. The review gave succinct information on the components of microbial fuel cells, their operations as well as the stability and sustainability of the fuel cell systems.