Fuel cell removes pollution to produce electricity Contamination of the aquatic environment by heavy metals and organic compounds can pose a threat to ecosystems and human health. An EU-funded initiative has developed technology that deals with pollution control as well as bioenergy production. Energy © Thinkstock Microbial fuel cells (MFCs) are a type of fuel cell that use bacteria to catalyse the oxidation of organic matter in order to produce electricity, thereby combining the clean-up of pollution with electricity production. The EU-funded SEFCUMPAQ project investigated a type of MFC known as a sediment fuel cell (SFC). The purpose was to develop a fuel cell that could couple waste water treatment with electricity production and so remediate heavy metal pollution of aquatic ecosystems. The main challenge facing SFC development was the enhancement of biofilm formation on the cell's anode electrode, which was tested in polluted freshwater and seawater environments using both pure and mixed microbial communities. A literature review on bioenergy was also conducted and a paper sent to a leading scientific journal. Electrochemical techniques were studied to gain a better understanding of how anode potential affected the diversity of microorganisms found in the electroactive biofilm. Researchers used single and dual-chambered microbial electrolysis cells to induce the biofilm to grow on graphite rod electrodes in the presence of acetate, which acted as an electron donor. Increased anodic currents for bioelectrocatalytic oxidation of acetate were obtained when the electrodes were incubated for longer periods with continuous electron donor feeding. Bioelectrochemical cell design was investigated to gain a better understanding of electron flow in biofilms. A study of the bacterium Geobacter sulfuredence provided additional information on how the anode influences power density in dual and single bioelectrical cells. Geobacter sulfurredence biofilm growth caused a bioelectrocatalytic response to acetate oxidation at different potentials in single electrochemical cells. In contrast, biofilms of dual-chambered bioelectrochemical cells show higher current densities at lower potential. Research also indicated that the potential of amine (NH2)-modified electrodes in electrochemical cells displayed higher current densities and kinetics, confirming amine as a significant prospect for biofuel application. The main scientific and technologically relevant achievement of the SEFCUMPAQ project was demonstration of the effect of anode potential on electron transfer. This was done through comparison with pure and mixed microbial communities and enhancing the current generation by surface-tailored electrode surfaces. SEFCUMPAQ has resulted in a number of technological spin-offs, which will contribute to European excellence and competitiveness in the field of bioenergy and pollution control.
