The oxygen reduction due to microaerophilic biofilms grown on graphite cathodes (biocathodes) in Single Chamber Microbial Fuel Cells (SCMFCs) is proved and analysed in this paper. Pt-free cathode performances are compared with those of different platinum-loaded cathodes, before and after the biofilm growth. Membraneless SCMFCs were operating in batch-mode, filled with wastewater. A substrate (fuel) of sodium acetate (0.03. M) was periodically added and the experiment lasted more than six months.A maximum of power densities, up to 0.5Wm-2, were reached when biofilms developed on the electrodes and the cathodic potential decreased (open circuit potential of 50-200mV vs. SHE). The power output was almost constant with an acetate concentration of 0.01-0.05M and it fell down when the pH of the media exceeded 9.5, independently of the Pt-free/Pt-loading at the cathodes. Current densities varied in the range of 1-5Am-2 (cathode area of 5cm2). Quasi-stationary polarization curves performed with a three-electrode configuration on cathodic and anodic electrodes showed that the anodic overpotential, more than the cathodic one, may limit the current density in the SCMFCs for a long-term operation. © 2012 Elsevier B.V.
Cristiani, P., Carvalho, M., Guerrini, E., Daghio, M., Santoro, C., Li, B. (2013). Cathodic and anodic biofilms in single chamber microbial fuel cells. BIOELECTROCHEMISTRY, 92, 6-13 [10.1016/j.bioelechem.2013.01.005].
Cathodic and anodic biofilms in single chamber microbial fuel cells
DAGHIO, MATTEO;Santoro, C;
2013
Abstract
The oxygen reduction due to microaerophilic biofilms grown on graphite cathodes (biocathodes) in Single Chamber Microbial Fuel Cells (SCMFCs) is proved and analysed in this paper. Pt-free cathode performances are compared with those of different platinum-loaded cathodes, before and after the biofilm growth. Membraneless SCMFCs were operating in batch-mode, filled with wastewater. A substrate (fuel) of sodium acetate (0.03. M) was periodically added and the experiment lasted more than six months.A maximum of power densities, up to 0.5Wm-2, were reached when biofilms developed on the electrodes and the cathodic potential decreased (open circuit potential of 50-200mV vs. SHE). The power output was almost constant with an acetate concentration of 0.01-0.05M and it fell down when the pH of the media exceeded 9.5, independently of the Pt-free/Pt-loading at the cathodes. Current densities varied in the range of 1-5Am-2 (cathode area of 5cm2). Quasi-stationary polarization curves performed with a three-electrode configuration on cathodic and anodic electrodes showed that the anodic overpotential, more than the cathodic one, may limit the current density in the SCMFCs for a long-term operation. © 2012 Elsevier B.V.
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