1. Microbial Fuel Cells for Renewable Energy - Characterization Study
University of Notre Dame
Civil Engineering and Geological Sciences Department
Microbial Fuel Cells for Renewable Energy - Characterization Study
Presented by:
Jesus M Garcia Figueroa
University of Puerto Rico at Mayaguez
Mentor: Susan Dahlheimer Advisor: Dr. Robert Nerenberg P.E.

2. Introduction 90% of world’s energy is supplied by fossil fuels
Non-sustainable
Negative environmental impacts
Need sustainable, environmentally-friendly energy sources
Fuel cells are a promising technology
Environmental Impacts: air pollution, acid rain, global warming)

3. Hydrogen Fuel Cell 2e-→ 2e- ↓ H2 H2O 2H+ + 2e- 2H+ ½O2 + 2H+ + 2e- H2M H2
H2O H2 O2
2H+ + 2e-
2H+
½O2 + 2H+ + 2e-
Chemical Reaction:
H2  2H+ + 2e-
½ O2 + 2H+ + 2e-  H2O
2H2 + O2 → 2H2O

4. Alternative Fuel Cells
H2 is not readily available
Organic wastes also contain energy:
Common catalysts not effective
Bacteria can catalyze electron transfer to anode
Chemical Reaction:
Wastewater + H2O  nH+ + yCO2 + ne-
½ O2 + 2H+ + 2e-  H2O
Wastewater + O2 → 2H2O + CO2

5. Our Experimental Setup
Voltmeter
Cathode
Anode
O2 Pumping
R Load
Proton Exchange Membrane (PEM)

7. Objectives MFC Qualitative Characterization
Proton Exchange Membrane (PEM) Characterization
Cathode Chamber Characterization
Anode Chamber Characterization

8. Cathode Characterization Experiments
Cathode Electrode Characterization
Cathode Oxidant
Surface Area Size
Electrode Thickness
Surface Area Form
Cathode Material
Original (Planar Electrode)
Rod Electrode
Original (6x10)cm2
Double
Half
Original (Thin)
Thick Electrode
Original (Carbon)
Platinum
Original (Oxygen)
Ferricyanide solution

9. Cathode Characterization Details
Experiments included loads of 10 Ω, 100 Ω, 1 kΩ, 10 kΩ, 100 kΩ and 1 MΩ
A data logger recorded V
With V and R, current and power were calculated using Ohm’s (V = IR) and Watt’s (P = VI) Laws.

10. Proton Exchange Membrane Characterization
Proton Exchange Membrane (PEM) Characterization
Nafion PEM
Ultrex PEM

11. PEM Characterization Details
Both chambers of the MFC contained a buffer solution, one chamber had no O2, other was saturated with O2.
Monitored O2 diffusion across two membranes with a dissolved O2 probe.
Compared how O2 concentration changed as a function of time for two membranes.

12. Anode Chamber Characterization
Anode and Anode Electrode Characterization
Attached Bacteria
Suspended Bacteria

13. Anode Characterization Details
Anode with biofilm was removed from operating MFC and placed in new MFC.
Fresh electrode placed in operating MFC with suspended growth
Compared the two systems.

14. Results and Discussion

15. Instability Region

18. General Results and Discussion
Open circuit voltage was not stable in all experiments.
Higher resistances resulted in unstable voltages, therefore the mid-range resistance of 10K Ohms is used for comparisons as it resulted in large power production in all experiments.
Voltage and current characterization show consistence with power characterization for all experimental comparison.

19. Cathode Results
Size: Double surface area better than half better than original.
Thickness: Thin is ~1.25x better than thick electrode.
Surface Area Form: Rod increased power ~1.1x greater the planar electrode surface.
Material: Pt electrode increased power ~5.5x.
Oxidant: Performance with ferricyanide ~12.6x better than with oxygen.

22. Conclusion Cathode parameters affect power production
Ultrex has lower O2 diffusion than Nafion
Both attached and suspended growth contribute to electron transfer
MFC technology a promising alternative energy source

23. Lab Pictures

24. Future Work
Make Anode MFC Experiments (such like Glucose and wastewater instead as a acetate feed) and more.
See other things such as bacteria growth and PEM Oxygen and Hydrogen diffusion coefficients.
Try to discover and explain how MFC Single Chamber works.

25. Acknowledgements Thanks for:
Susan Dahlheimer, Dr. Roberto Nerenberg P.E. and his Graduate students
Dr. Valli Sarveswaran, Jennifer Forsythe and EMSI-REU Program
University of Puerto Rico at Mayaguez
-Dr. Jose A. Colucci Rios P.E.
-Monica Ospinal Jimenez
-Juan Carlos Flores
Bryan Anderson