Electricity and hydrogen production using different types of microbial fuel cell technologies

Power density, electrode potential, Coulombic efficiency, and energy recovery in single-chamber microbial fuel cells (MFC) are strongly influenced by solution ionic strength, electrode spacing structure, and temperature. Power output was increased from 720 to 1330 mw/sq m by increasing ionic strength, and to 1210 mw/sq m by decreasing the distance between the anode and cathode from 4 to 2 cm. Decreasing the temperature from 32° to 20°C reduced power output by only 9%, primarily as a result of the reduction of the cathode potential. Coulombic efficiencies were a maximum of 61.4 and 15.1%. Electricity production is not the only product that can be achieved in this type of bio-catalytic system. By adapting the MFC to run under anaerobic conditions, hydrogen can directly be generated using a bio-electrochemically assisted process. This is an abstract of a paper presented at the 230th ACS National Meeting (Washington, DC 8/28/2005-9/1/2005).