Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Microbial Fuel Cells: Optimization Of The Anode Compartment For Improved Electron Transfer

14.11.2003


A microbial fuel cell mimics a biological system, in which bacteria do not directly transfer the energy-rich electrons gained out of the feeding to their characteristic electron acceptor. Instead, the electrons are diverted towards an electrode (anode) and subsequently conducted over a resistance or power user, and a cathode (see figure). At the cathode, these electrons are used to reduce oxygen with the formation of water. This way, bacterial energy is directly converted to electrical energy.

Microbial fuel cells have so far known limited success because of the low output observed. The maximum attainable potential over a biofuel cell, based on the potential difference between the redox couple, is 1.15V. However, the real fuel cell potential is mostly lower due to the potential losses observed at both the anode and the cathode, and the internal resistance of the fuel cell. Lowering these losses at the anode can be obtained chemically through enlargement of the specific electrode surface or the use of redox mediators, and biologically by the selection of adapted bacteria.

The internal resistance is mainly caused by the resistance of the electrolytes and of the proton exchange membrane (PEM), and can be lowered by increasing the reactor turbulence and the electrolyte/PEM conductivity.



The Laboratory for Microbial Ecology and Technology (LabMET) and the Laboratory for Non-Ferrous Metallurgy cooperate to obtain chemical and biological anode optimization.

The biological optimisation has been performed through selection of suitable microbial consortia. Electrochemical active bacteria were selected from a bacterial culture originating from anaerobic sludge by repetitive bacterial transfer into new fuel cells. The culture was able to transfer electrons efficiently to the graphite electrodes, and could supply a considerably higher output than previously reported, up to 4,31W/m2 of electrode surface (664 mV, 30.9 mA). A series of tests was performed to elucidate the behaviour of the biofuel cell in relation to several glucose loading rates, clarifying operational parameters. Molecular analysis was performed to determine the nature of the bacteria present in the biofuel cell. The identified bacteria were mainly facultative anaerobic, capable of hydrogen production. Cyclic voltammetry showed an evolution towards an electrochemically more active mixed bacterial culture during the experimental period.

Chemical optimization is the next step in the research. The effect of chemical redox mediators, inserted into the electrode matrix, onto the electron transfer can be of significant importance to further boost up the biofuel cell output. Preliminary tests have indicated the viability of this approach.

The results obtained at LabMET open perspectives towards future applications. The first application will very likely involve the use of microbial fuel cells to generate electricity out of plant juices, obtained on site. This way, a forest can become a bio-power plant. Long term research will focus on low power mobile applications. Hence, the question at the restaurant might one day be: "Waiter, one sugar cube for my coffee, and one for my mobile phone..."

Korneel RABAEY | alfa

More articles from Power and Electrical Engineering:

nachricht Researchers pave the way for ionotronic nanodevices
23.02.2017 | Aalto University

nachricht Microhotplates for a smart gas sensor
22.02.2017 | Toyohashi University of Technology

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>