Performance of buffered ferric chloride as terminal electron acceptor in dual chamber microbial fuel cell (original) (raw)
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Journal of Chemical Technology & Biotechnology, 2014
BACKGROUND: Ferric chloride (FeCl 3) is widely used as a flocculating agent during wastewater treatment but can detrimentally lower pH and increase iron concentration. Microbial fuel cells (MFCs) are a promising technology for treating waste while concomitantly producing electricity and so were tested under the extreme conditions imposed by the addition of FeCl 3. MFCs were fed eight concentrations of FeCl 3 over two 8-week periods and the effects on power, pH, conductivity, metal content and COD were examined. RESULTS: MFCs generated highest power (3.58Wm-3) at 1.6 mmol L-1 FeCl 3 (pH 3.46), however cells reversed when fed 2 mmol L-1 (pH 3.29). During the second run, power almost doubled and MFCs were more resilient at higher loadings up to 2.8 mmol L-1 (pH 3.02). Conductivity and pH increased following treatment while soluble phosphorus, sulphur and iron levels decreased significantly in all feedstock up to 1.6 mmol L-1 FeCl 3. COD reduction was observed but efficiency may have been affected by the presence of alternative electron donors such as hydrogen sulphide. CONCLUSION: These findings demonstrate the robustness and versatility of MFCs in hostile conditions. They also confirm that MFCs can complement current wastewater treatment processes, even downstream from FeCl 3 dosing where conditions might be deemed unsuitable for operation.
Electrochemistry …, 2009
The performance of dual chambered microbial fuel cell (MFC, Nafion 117, non-catalyzed graphite electrodes) in concurrence with anodic pH microenvironment was evaluated based on bioelectricity generation and wastewater treatment efficiency. Experiments were carried out at different anodic pH microenvironments (acidophilic , neutral and alkaline ) using both aerated and ferricyanide catholytes with mixed consortia as anodic biocatalyst employing chemical wastewater. Acidophilic pH in anodic chamber showed effective performance with respect to power output compared to the corresponding neutral and alkaline operations. However, substrate degradation was observed to be higher at neutral condition followed by alkaline and acidophilic operations. Ferricyanide as catholyte showed positive influence on the power output parameters compared to aerated catholyte. Nature of the catholyte did not show any visible influence on the wastewater treatment efficiency.
Dual-chamber Microbial Fuel Cells (MFCs) were constructed using non-reactive polyacrylic containers of 1100ml with a working volume of 1000ml. 1000ml of the abattoir wastewater was fed into the anode chamber while equal volume 100mM Potassium Ferricyanide solution was fed into the cathode chamber. An Agar-salt Bridge (2% Agar and 1% NaCl) with dimension 10cm×3cm (length and radius) served as Proton Exchange Membrane. Rod-shaped carbon electrodes of length and diameter 12 cm × 1.2 cm were used. The Open circuit voltage, current, power density and physicochemical parameters were monitored. An initial Open circuit voltage of 459 mV, Current of 0.22 mA, and Power density of 22.10mW/m2 were recorded, which increased to give maximum Open Circuit Voltages of 736 mV, Current of 0.46mA, and Power density of 66.43mW/m2. The results also shows a 56.09%, 92.31%, 56.27%, 89.92%, 73.29% and 75.46% decrease for Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), Organic Carbon, Total Soluble solids (TSS), Total Dissolved Solids (TDS), Nitrate, and Nitrate-Nitrogen respectively, while a -3.58%, -3.51%, -4.21%, -228.76%, -226.07% and -226.16% increase was observed for Phosphates, Phosphorus, Orthophosphates, Ammonia, Ammonium-Nitrogen and Ammonium respectively. The bacterial isolates identified were Bacillus species, Streptococcus species, Escherichia coli and Staphylococcus aureus. Keywords: Abattoir wastewater treatment, Bioelectricity, Microbial Fuel Cell
Impact of salinity on cathode catalyst performance in microbial fuel cells (MFCs)
International Journal of Hydrogen Energy, 2011
Chloride Cathode a b s t r a c t Several alternative cathode catalysts have been proposed for microbial fuel cells (MFCs), but effects of salinity (sodium chloride) on catalyst performance, separate from those of conductivity on internal resistance, have not been previously examined. Three different types of cathode materials were tested here with increasingly saline solutions using singlechamber, air-cathode MFCs. The best MFC performance was obtained using a Co catalyst (cobalt tetramethoxyphenyl porphyrin; CoTMPP), with power increasing by 24 AE 1% to 1062 AE 9 mW/m 2 (normalized to the projected cathode surface area) when 250 mM NaCl (final conductivity of 31.3 mS/cm) was added (initial conductivity of 7.5 mS/cm). This power density was 25 AE 1% higher than that achieved with Pt on carbon cloth, and 27 AE 1% more than that produced using an activated carbon/nickel mesh (AC) cathode in the highest salinity solution. Linear sweep voltammetry (LSV) was used to separate changes in performance due to solution conductivity from those produced by reductions in ohmic resistance with the higher conductivity solutions. The potential of the cathode with CoTMPP increased by 17e20 mV in LSVs when the NaCl addition was increased from 0 to 250 mM independent of solution conductivity changes. Increases in current were observed with salinity increases in LSVs for AC, but not for Pt cathodes. Cathodes with CoTMPP had increased catalytic activity at higher salt concentrations in cyclic voltammograms compared to Pt and AC. These results suggest that special consideration should be given to the type of catalyst used with more saline wastewaters. While Pt oxygen reduction activity is reduced, CoTMPP cathode performance will be improved at higher salt concentrations expected for wastewaters containing seawater. (B.E. Logan).
Applications of Microbial Fuel Cell on Sewage Treatment by Using Electrogens
2015
Renewable and clean forms of energy are one of the major needs at present. Microbial Fuel Cells (MFC's) offers unambiguous advantages over other renewable energy conversion methods. Production of energy resources while minimizing waste is one of the best ways for sustainable energy resource management practices. The application of Microbial Fuel Cells (MFCs) may represent a completely new approach to wastewater treatment with the production of sustainable clean energy. The increase in energy demand can be fulfilled by Microbial Fuel Cell (MFC) in the future. In recent years, researchers have shown that MFCs can be used to produce electricity from water containing glucose, acetate, or lactate. Studies on electricity generation using organic matter from wastewater as substrate are in progress. Waste biomass is a cheap and relatively abundant source of electrons for microbes capable of producing electrical current outside the cell. Rapidly developing microbial electrochemical technologies, such as microbial fuel cells, are part of a diverse platform of future sustainable energy and chemical production technologies. In the present investigation to study the two wastewater samples, municipal wastewater from nearby areas of Guntur (A.P.) and Dairy waste from Guntur (A.P.) were used as substrates in Microbial Fuel Cells (MFCs) to generate electricity. Along with electricity generation, the MFCs can successfully help in treating the same sewage samples. The parameters like pH, TS, TSS, TDS, BOD, and COD were analyzed for all two samples. The COD removal efficiency of the MFCs was analyzed using the standard reflux method. All the MFCs were efficient in COD removal. 50%, 75%, and 85% COD removal was observed after 10, 15, and 30 days respectively of operation of MFCs with municipal waste as substrate.
Iranica Journal of Energy and Environment, 2013
A single chamber microbial fuel cell (SCMFC) was operated with distillery spent wash (DSW) wastewater and microorganisms in cow-dung as inoculum source from pH 4 to 9. MFC signifies maximum current in the sequence of pH 6 (0.46 mA) > pH 7 (0.4 mA) > pH 8-9 (0.16-0.19 mA); whereas the chemical oxygen demand (COD) removed in order of pH 8-9 (80-81%) > pH 7 (79%) > pH 6 (68%). The losses in coulombic yield were due to alternating electron acceptors and air diffusion through the reactor. The polarization curve yielded the maximum current density of 84 mA/m and maximum power density of 29 mW/m at an external resistance 2 2 of 820 (pH 6). The cyclic voltammetry (CV) demonstrated 3-electron transfer process with best electrochemical responses at pH 6 and 7. The MFC at desired operating conditions showed a positive response for bioelectricity generation.
Abattoir Wastewater Treatment and Energy Recovery Using a Ferricyanide-Catholyte Microbial Fuel Cell
International Letters of Natural Sciences
The capacity of Microbial fuel cells (MFCs) to produce voltage and concurrently treat abattoir waste water was investigated in MFCs that used 0.1M potassium ferricyanide (K 3 [Fe(CN) 6 ] as catholytes. Physicochemical, electrochemical and Microbiological properties of the MFCs were monitored. The open circuit voltage (OCV) readings were taken at 3 hours interval and maximum OCV of 965mV was recorded. Also, The physicochemical characteristics of the MFCs revealed that the pH decreased by 0.2 after treatment; Chemical Oxygen demand, biochemical oxygen demand, total suspended solids, ammonia, and total nitrogen reduced by 88.4%, 65.56%, 43.88%, 60% and 60% respectively. However, Phosphate increased by 54%. The bacterial isolates from the raw abattoir wastewater were Staphylococcus aureus, Bacillus cereus, Bacillus subtilis, Enterococcus faecalis, Enterobacter aerogenes, Escherichia coli and Micrococcus luteus while Enterococcus faecalis, Bacillus cereus and Escherichia coli were isolated from the biofilms on the anode. Microbial fuel cells therefore have capacities for simultaneous waste water treatment and electricity generation.
Enzyme and Microbial Technology, 2009
Four experimental columns were employed in this study to investigate their performance under wastewater treatment conditions. One column was set-up as a biological aerated filter and the remaining three were set-up as microbial fuel cells (MFCs), two of which were connected to an external load whereas the third was left open circuit. The performance of the columns under several flow rates and leachate strengths was studied in terms of BOD 5 removal efficiencies and electricity generation, when a fixed resistive load was connected. Results obtained demonstrated that it is possible to generate electricity and simultaneously treat landfill leachate in MFC columns. Energy generation in MFC columns improved with increasing flow rates from 24 to 192 mL/h, while BOD 5 removal efficiency levels reached a maximum at 48 mL/h and dropped to relatively low values at higher flow rates. The maximum removal efficiencies were obtained at a loading rate of 0.81 kg BOD 5 /m 3 d for columns C1, C2 and C4 and 1.81 kg BOD 5 /m 3 d for column C3. Electrical output levels and BOD 5 concentrations at the MFC columns showed a linear relationship, which allows the system to be used as a BOD 5 sensor. Part of the BOD removal was not associated with power generation and was attributed to the presence of alternative end terminal electron acceptors and volatilisation. The MFC columns could reach the same or even higher removal efficiencies than those from the biological aerated filter with the advantage of producing energy and saving cost of aeration. To the best of the authors' knowledge, this is the first study that compares the MFC technology with other conventional treatment systems for removing pollutants from wastewater.
Biosensors and …, 2009
Function of microbial fuel cell (MFC) as bio-electrochemical treatment system in concurrence with power generation was evaluated with composite chemical wastewater at high loading conditions (18.6 g COD/l; 56.8 g TDS/l). Two dual chambered MFCs [non-catalyzed graphite electrodes; mediatorless anode] were studied separately with aerated and potassium ferricyanide catholytes under similar anodic operating conditions [mixed consortia; pH 6]. Marked improvement in power output was observed at applied higher substrate loading rate for extended period of time without any process inhibition. Catholyte nature showed significant influence on power generation [ferricyanide-651 mV; 18.22 mA; 6230 mW/kg COD R (500 ); 2321.69 mA/m 2 (100 ); 11.80 mW/m 3 and aerated-578 mV; 10.23 mA; 2450 mW/kg COD R (400 ); 1220.68 mA/m 2 (100 ); 5.64 mW/m 3 ] but not on wastewater treatment efficiency. Along with enhanced substrate degradation, relatively good removal of color (31%) and TDS (51%) was also observed during MFC operation, which might be attributed to the diverse bio-electrochemical processes triggered due to substrate metabolism and subsequent in situ bio-potential (voltage) generation. Apart from power generation, various unit operations pertaining to wastewater treatment viz., biological (anaerobic) process, electrochemical decomposition and electrochemical oxidation were found to occur symbiotically in the anode chamber. Among them anaerobic metabolism is considered to be a crucial and important rate limiting step. In view of inherent advantages, function of MFC as integrated bio-electrochemical treatment system in the direction of various wastewater treatment operations can be exploited.