Microbes are able to create an electric potential as they undergo oxidation and reduction reactions. The optimal configuration that a Sediment Microbial Fuel Cell may be arranged in is therefore desirable. Three Sediment Microbial Fuel Cells were built in order to determine the ideal configuration for power generation. The configurations all consisted of: sediment contained within a reactor at a depth of 6 cm, a carbon cloth anode buried 1.5 cm beneath the sediment and a medium consisting of water for an overall reactor depth of 17.7 cm. Configurations differed in that: one reactor utilized a floating cathode coated in an activated carbon, isopropyl and nafion solution on the side in contact with water and polyvinylidene fluoride (PVDF) on the surface in contact with air, while the remaining reactors consisted of submerged cathodes coated in the same activated carbon, isopropyl and nafion solution on each side. These two reactors had their cathodes located at different depths in order to monitor how factors such as internal resistance and dissolved oxygen levels would affect power output. After monitoring the three reactors for two months it was seen that the two reactors with submerged cathodes consistently generated more power than the reactor with a floating cathode; furthermore there was not a significant difference in the power generated by the reactors with submerged cathodes regardless of the distance of the cathode in relation to the anode. From the results seen in this study the superior configuration of a Sediment Microbial Fuel Cell is one in which the cathode is completely submerged in the medium, but the depth of the cathode in the medium makes no substantial difference to power generation.
Future research that could result from the findings of this study could come from many different areas. The further optimization of power output is certainly possible through adjustment of parameters such as cathode and anode surface area, the identity of the medium used, the location of the electrode within a reactor, the materials used to construct the reactor and more. Research could also use a similar configuration to the one(s) used in this study in an effort to extract chemicals from a medium in the process known as bioremediation.
This research was supported by the Undergraduate Research Opportunities Program (UROP).
Bo Hu of the Department of Bioproducts & Biosystems Engineering was my faculty mentor.
Optimization of Sediment Microbial Fuel Cell for Power Generation.
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