BMFC · Biological and microbial fuel cells

Final Activity Report Summary - BMFC (Biological and microbial fuel cells)

The programme undertook the research and development of novel low cost, biological and microbial fuel cells. Biofuel cells convert readily available substrates from 'renewable' sources into electrical energy and also provide a means of simultaneously reducing waste treatment costs associated with many waste carbon sources- the potential fuels for the fuel cells. Microbial fuel cells (MFC) are a type of fuel cells that convert organic matter by using bacteria as biocatalyst rather than a chemical or metal catalyst. In MFC, bacteria do not transfer their electrons directly to their characteristic terminal electron acceptor, but rather to a solid electrode. The solid electrode then transfers the electrons to a second electrode in the cell at which oxygen from the air is reduced to water using a suitable electrocatalyst. The interest in MFC is increasing mainly because they offer the possibility of directly harvesting electricity from organic waste and renewable biomass. Microbial fuel cells seek to add the diversity of microbial catalytic abilities to the high-efficiency design of fuel cells, allowing the energy of mixed organic compounds to be converted into electricity. The potential advantages of biological systems over the conventional chemical systems were recognised. Firstly, it is feasible to develop biochemical fuel cells (biofuel cells) that can operate under very mild conditions. Secondly, a very wide range of organic and inorganic substances such as hydrocarbons, alcohols, carbohydrates, proteins, ammonia, H2, H2S (in fact, any material which can be oxidised by organisms) can serve as fuels. The conversion of waste materials (e.g. agricultural residues; municipal; food) into electrical energy is also possible and, of course, a very attractive option. The major targets of the Transfer of knowledge (ToK) activities were to increase the power density by enhanced bioelectrocatalysis, simplify fuel cell design and application with low cost high performance materials and identify and ultimately design appropriate microbial communities for the bio-fuel cell. The key objectives were: 1. to understand the Biocatalysis and optimisation of bacterial consortium; 2. to develop oxygen reduction electrocatalysts using high surface area, active carbons and other low cost materials; 3. to develop carbon electrode materials for MFCs with new advanced carbon materials and composites and identify biocompatible carbons; 4. - develop fuel cell concepts, designs and construct fuel cell for testing; 5. - fuel cell modelling research has led to fabrication of new high surface area biocompatible, carbons, carbon coated catalyst, composites for high electrical conductivity. A number of low cost cathode catalysts for oxygen reduction have been developed. The requirements for low cost, compact and high energy density bio-fuel cells was satisfied from the research of novel cell designs, including 'membraneless' cells and three dimensional structures. Development of mathematical models for microbial fuel cells (MFC) with cells suspended and attached to the anode have led to improved understanding of MFC behaviour. The models are based on mass balances in the bulk liquid and biofilm for several biomass metabolic types and dissolved chemical species. Multiple biological, chemical and electrochemical reactions can occur in the bulk liquid, in the end at the electrode surface. A general three-dimensional model setup is provided and has been implemented.

Data: CORDIS, © European Union