Abstract
Tubular microbial fuel cells (MFC) with air cathode might be amenable to scale-up but with increasing volume a mechanically robust, cost-effective cathode structure is required. Membrane electrode assemblies (MEA) are investigated in a tubular MFC using cost-effective cation (CEM) or anion (AEM) exchange membrane. The MEA fabrication mechanically combines a cathode electrode with the membrane between a perforated cylindrical polypropylene shell and tube. Hydrogel application between membrane and cathode increases cathode potential by ~100mV over a 0-5.5mA range in a CEM-MEA. Consequently, 6.1Wm-3 based on reactor liquid volume (200 cm3) are generated compared with 5Wm-3 without hydrogel. Cathode potential is also improved in AEM-MEA using hydrogel. Electrochemical Impedance Spectroscopy (EIS) to compare MEA's performance suggests reduced impedance and enhanced membrane-cathode contact areawhenusing hydrogel. The maximum coulombic efficiency observed with CEM-MEA is 71% and 63% with AEM-MEA. Water loss through the membrane varies with external load resistance, indicating that total charge transfer in the MFC is related to electro-osmotic drag of water through the membrane. The MEA developed here has been shown to be mechanically robust, operating for more than six month at this scale without problem.
Original language | English |
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Pages (from-to) | 393 - 399 |
Number of pages | 6 |
Journal | Journal of Power Sources |
Volume | 187 |
Issue number | 2 |
DOIs | |
Publication status | E-pub ahead of print - 17 Nov 2008 |
Keywords
- microbial fuel cell
- membrane electrode assembly
- tubular
- impedance spectroscopy
- ion exchange membrane
- electro-osmotic drag