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 Multiregional brain on a chip
16.01.2017 | Harvard John A. Paulson School of Engineering and Applied Sciences

nachricht Researchers develop environmentally friendly soy air filter
16.01.2017 | Washington State University

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: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>