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Some Basic Concepts Related to Fuel Cells with a Focus on Microbial and Enzymatic Fuel Cells Nevin Longenecker John Adams High School. The PURPOSES of this investigation were to. examine and evaluate variables associated with increasing the efficiency of a microbial fuel cell .
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Some Basic ConceptsRelated to Fuel Cellswith a Focuson Microbial and EnzymaticFuel CellsNevin LongeneckerJohn Adams High School
The PURPOSES of this investigation were to examine and evaluate variables associated with increasing the efficiency of a microbial fuel cell . propose and construct a prototype enzymatic fuel cell based on the previous findings. describe in an educational science journal an inexpensive fuel cell which could be easily constructed and used in a classroom. The operation of such a cell would have diverse applications in many sciences and would integrate mathematical principles from calculus, statistics, algebra and geometry.
Advantages of Fuel Cellsvs.Internal Combustion Engines • Unlimited supply of fuel • No reliance on foreign oil • Little or no pollutants • Much higher energy conversion % • No moving parts • No noise
How does it work? How Does it Work? • Often Platinum Catalyst V V • Cathode Chamber • Exposed to air <-- • Anode Chamber • Stores fuel --> ^ • Membrane - Allows for H+ passage
Procedures • A prototype microbial fuel cell was designed and built. (next slide) • Factors affecting microbial fuel cell efficiency were measured and evaluated. • Surface area of electrodes • Bacterial conc. on anode/in solution • Aerobic vs anaerobic conditions • Supplemental O2 sources • Single and mixtures of enzymes were tested in the prototype cell to compare power output.
Significant Factors AffectingMicrobial Fuel Cell Operation • Type of electrodes • Surface area of electrodes • Use of catalysts on electrodes and PEM • Conc. of hydrocarbon in anode chamber • Agitation of hydrocarbon molecules • Rate of replacement of hydrocarbons • Types of microbes/enzymes • Conc. of microbes/enzymes
Significant Factors AffectingMicrobial Fuel Cell Operation • Types of mediators • Conc. of mediators • Distance between electrode and PEM • Type of proton exchange membrane(PEM) • Surface area of PEM • Source of oxygen • Temperature effects
Power Output of C rod Biofilm vs C rod Solution –anaerobic Ecoli
Proposed Advantages of Enzyme Use 1. Immediate contact with substrate 2. Elimination of metabolism of substrate by bacteria 3. Elimination of possible mixing of hazardous bacterial types 4. If immobilized on electrodes, no mediators are required.
Partial Composition of PEB Enzyme Solution • Lipase • Protease • Amylase • Hydrolase • Likely-dehydrogenases, lactase, decarboxylase, invertase • Supplied by Enzyme Solutions, Inc
PEB Investigation Trends and Conclusions 1. Optimum power output developed in 2hrs Whole Ecoli cells PEB solution 0.2 watts/m2 2.1 watts/m2 2. Prolonged power output at 24 hrs 0.14 watts/m2 2.05 watts/m2 3. Prolonged optimum power output continued for 5 days. 4. Pt. coating on the anode did not improve the efficiency of the enzymatic cell.
Uses forImplantable Enzymatic Fuel Cells (To utilize arterial glucose and oxygen with immobilized enzymes on electrodes in a noncompartmentalized cell) • Micropumps-insulin, pain meds, arthritis • Current for-nerve stimulation, hearing aids • Heart pacemaker (cells in series)
Additional Uses of Enzymatic Fuel Cells • Space-regeneration of human waste • Treatment of human waste in developing countries • Treatment of household wastes in place of landfills • Industry-detoxify chemical wastes • Portable units- power generation
Acknowledgments • University of Notre Dame • RET Program • Dr. Alex Hahn • Dr. Robert Nerenberg • Dr. Valli Sarveswaran