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Continuous microbial fuel cells convert carbohydrates to electricity
I Rabaey1, W Ossieur, M Verhaege
1Laboratory for Microbial Ecology and Technology, Ghent University, Coupure Links 653, Ghent, Belgium.
Summary
Continuous microbial fuel cells (MFCs) show promise for practical applications. Research indicates that while batch systems yield higher power, continuous systems offer stability, with plant extract yielding optimal efficiency.
Area of Science:
- Environmental Science
- Biotechnology
- Electrochemistry
Background:
- Continuous mode microbial fuel cells (MFCs) are preferred for practical applications over fed batch systems.
- Optimizing anode reactor design and influent type is crucial for enhancing MFC performance.
Purpose of the Study:
- To evaluate the performance of continuous mode MFCs using different carbohydrate-rich influents.
- To investigate the impact of anode reactor configuration and bacterial redox mediators on MFC efficiency.
Main Methods:
- Testing three influent types: glucose medium, plant extract, and artificial wastewater.
- Utilizing a packed bed reactor with graphite granules as the anode compartment.
- Employing cyclic voltammetry to assess in-situ synthesized bacterial redox mediators.
Main Results:
- A packed bed reactor with graphite granules provided the best anode performance.
- Continuous mode MFCs achieved power outputs of 49 W m⁻³, significantly lower than batch systems (479 W m⁻³).
- Addition of soluble mediators did not substantially improve MFC power output in continuous mode.
Conclusions:
- Continuous MFCs are suitable for practical applications, though power output is lower than batch systems.
- Plant extract as influent, at a loading rate of 1 kg COD m⁻³ day⁻¹, yielded maximum coulombic (50.3%) and energy conversion (26.0%) efficiencies.
- Soluble mediators have a limited influence on the performance of continuous MFCs.