Microbial Fuel Cells
An Organic Way of Energy
The Use of Microbial Fuel Cells in Power Generation
Electricity is used everyday and everywhere in the modern world, but due to the cost of the production, it isn't common to have electricity in third world countries. About 1.5 billion people in the world do not have electric power. This problem is concentrated in Asia and Africa. The use of electricity is an necessity when it comes to having good medical care. Because MFCs can produce an electrical current while also cleaning wastewater (clean water is also not common to have in developing countries) MFCs are a good alternative to coal and other expensive electrical sources. (1)
Microbial fuel cells have a number of potential uses such as harvesting electricity produced for a power source. Because virtually any organic materical could be used to feed the MFCs including the materials found in wastewater, MFCs are good alternative for applications that require low power but have the potential for powering wireless sensor networks. (2) Microbial Fuel cells provide an insight to future technology to power motor vehicles, generators and portable electronic devices. As a result of the proton exchange membrane fuel cells ability operate at low temperatures it makes it optimal for use. PEM-FC contain electrocatalysts and a proton conducting membrane, the catalyst layer usually consists of dispersed Pt nanoparticles on a porous carbon support. H2 is oxidised at the anode and oxygen is reduced at the cathode. The protons from H2-oxidation pass through the membrane to the cathode and the electrons released from H2 travel along the circuit to generate electrical current. (3)
In Fig.1 TEM images of E. coli MFCs. A: biosorption only (before H2 addition). B: cells with Pd reduced and C: cells with precious metals from Degussa solution reduced after H2 exposure. (6.9)
In Fig. 2 The power output by the electrodes were made and tested. They are: Carbon powder; Commercial Fine Pd powder; Bio-PdE.coli MFCs; Bio- PME.coli MFCs. Each test was done more than 3 times using separate preparations. The variation was within 5% and representative data are shown. (6.9)
When we think about fuel for power plants, oil, coal and natural gas typically comes to mind. Professor Bruce E Logan from Pennsylvania State University shows us a microbial fuel cell, a device that can extract the energy from wastewater and turn it into electricity in the video to the right. (6.8)