Separator Characteristics for Increasing Performance of Microbial Fuel Cells
KAUST Grant NumberKUS-I1-003-13
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AbstractTwo challenges for improving the performance of air cathode, single-chamber microbial fuel cells (MFCs) include increasing Coulombic efficiency (CE) and decreasing internal resistance. Nonbiodegradable glass fiber separators between the two electrodes were shown to increase power and CE, compared to cloth separators (J-cloth) that were degraded over time. MFCtestswereconductedusing glass fibermatswith thicknesses of 1.0mm (GF1) or 0.4 mm (GF0.4), a cation exchange membrane (CEM), and a J-cloth (JC), using reactors with different configurations. Higher power densities were obtained with either GF1 (46 ± 4 W/m3) or JC (46 ± 1 W/m3) in MFCs with a 2 cm electrode spacing, when the separator was placed against the cathode (S-configuration), rather than MFCs with GF0.4 (36 ± 1 W/m3) or CEM (14 ± 1 W/m3). Power was increased to 70 ± 2 W/m3 by placing the electrodes on either side of the GF1 separator (single separator electrode assembly, SSEA) and further to 150 ± 6 W/m3 using two sets of electrodes spaced 2 cm a part (double separator electrode assembly, DSEA). Reducing the DSEA electrode spacing to 0.3 cm increased power to 696 ± 26 W/m3 as a result of a decrease in the ohmic resistance from 5.9 to 2.2 Ω. The main advantages of a GF1 separator compared to JC were an improvement in the CE from 40% to 81% (S-configuration), compared to only 20-40% for JC under similar conditions, and the fact that GF1 was not biodegradable. The high CE for the GF1 separator was attributed to a low oxygen mass transfer coefficient (ko ) 5.0 x 10-5 cm/s). The GF1 andJCmaterials differed in the amount of biomass that accumulated on the separator and its biodegradability, which affected long-term power production and oxygen transport. These results show that materials and mass transfer properties of separators are important factors for improving power densities, CE, and long-term performance of MFCs. © 2009 American Chemical Society.
CitationZhang X, Cheng S, Wang X, Huang X, Logan BE (2009) Separator Characteristics for Increasing Performance of Microbial Fuel Cells. Environ Sci Technol 43: 8456–8461. Available: http://dx.doi.org/10.1021/es901631p.
SponsorsThis research was supported by Award KUS-I1-003-13 from the King Abdullah University of Science and Technology (KAUST), the U.S. National Science Foundation (CBET-0730359), the International Program of MOST (2006DFA91120) in China, and a scholarship from the China Scholarship Council (CSC).
PublisherAmerican Chemical Society (ACS)
CollectionsPublications Acknowledging KAUST Support
- Scalable air cathode microbial fuel cells using glass fiber separators, plastic mesh supporters, and graphite fiber brush anodes.
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- Power generation using different cation, anion, and ultrafiltration membranes in microbial fuel cells.
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- Air-cathode structure optimization in separator-coupled microbial fuel cells.
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- Membrane-less cloth cathode assembly (CCA) for scalable microbial fuel cells.
- Authors: Zhuang L, Zhou S, Wang Y, Liu C, Geng S
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- Power generation in fed-batch microbial fuel cells as a function of ionic strength, temperature, and reactor configuration.
- Authors: Liu H, Cheng S, Logan BE
- Issue date: 2005 Jul 15