Bryan A. Reed Rising Senior : Manchester-Essex Regional High School NEB Summer Internship: Weigele...

Bryan A. ReedRising Senior: Manchester-Essex Regional High School

NEB Summer Internship: Weigele LabJune 23-Aug 15, 2008

Testing Microbial Fuel Cell Parameters:

Composition, Electrolyte, External Load, and Configuration.

August 5, 2008 Bryan A. Reed- NEB Summer InternSummary Presentation

biomass electricity

The goal


Create alternative to “baseline” off-grid lighting technologies

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

From the International Finance Corporation


Replace inefficient lighting with an LED powered by a Personal Bioreactor

From the International Finance Corporation, Photos: Evan Mills ©

Shoe sellers’ stalls in Tanzania

open flame lighting 1-Watt white LED


Electric Lighting

Fuel-Based Lighting

Source: Evan Mills, International Association of Energy Efficient Lighting and Lawrence Berkeley National Laboratory

$38 Billion

$185 Billion

Global Annual Spending on Lighting

From the International Finance Corporation

Fuel-based lighting is an $38 billion market


Biological basis of a microbial fuel cell

• Bacteria can respire (breathe) to insoluble electron acceptors (metal-oxide minerals) in natural anaerobic environments

• “Exocellular” respiration (transferring electrons out of the cell) yields more ATP and NADH per unit of substrate utilized than fermentation to ethanol, lactate, or acetate.

• Fuel cell anode material can substitute for native insoluble electron acceptors.


Core Technology: Microbial Fuel Cell (MFC)

2. Electrolyte

1. Anode

1. Anode: transfer of electrons to anode from electron donors is catalyzed by bacteria2. Electrolyte: transfer of protons (H+) to cathode3. Cathode: reduction of oxygen to form water (H2O): 4H+ + O2 + 4e- H2O

3. Cathode

A combination of cellulolytic and anode reducing bacteria couples oxidation of biomass to electrical power generation.

Biomass + bacteria H2O + CO2 + electricity


Lab scale MFC


Protocol

• 1:100 dilution of overnight culture of Shewanella oneidensis MR-1

• Rich broth or basal medium supplemented with 30 mM sodium lactate and 0.01% SDS

• Fuel cell attached to external load (an electronic resistor)

• Voltage measured using an analog-digital converter interfaced to a PC

• Data collected over time, imported and charted in Microsoft Excel

• Power calculated by: P=V2/R


Prior Data


How does an external load (resistance) affect power output?

• Greater load (more resistance) = less oxidizing anode

• Lower load (less resistance) = more oxidizing anode


Voltages Obtained Under Varying Resistances


Can we obtain power with different anode materials and microbial media?

• Tested carbon versus graphite felts

• Tested anode pretreatment (nitric acid soak)

• Tested basal mineral and seawater based media


Testing Anode and Medium Composition


Can we substitute the membrane electrolyte?

• Cation exchange membrane is CMI-7000S• CMI-7000S is $150/m2

•Tyvek is $0.26/m2

•Tyvek is a microporous material (Gore-tex for your house)


Power obtained without membrane electrolyte


Repeatability?


Repeatability?

• Looks like negative results are non-result

• Positive result is still positive result

• Potential leakage of O2 into anode compartment


Thank you!

Peter Weigele

Harriet Strimpel

Don Comb

( and OGL for seawater)


Just how much energy is in biomass?

1 watt = 1 joule/second1 watt hour = 3600 joules1 watt hour = 3.413 Btu1 Btu = 1055 joules

1 lb. agricultural residue = 4,300 - 7,300 BtuOr roughly 1.26 to 2.14 kWh, equivalent to the energy required to light between 12 and 21 100-Watt bulbs for one hour, or a 1 watt LED for between 52 and 89 days.

1 lb. switchgrass has 6.8 x 106 joules, or roughly 1.9 kWh


Electric genes: biological basis for anode reduction by Shewanella

Fe3+

Fe3+

Bryan A. Reed Rising Senior : Manchester-Essex Regional High School NEB Summer Internship: Weigele...

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