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.
Cathodic and anodic biofilms in single chamber microbial fuel cells / Cristiani, P; Carvalho, M; Guerrini, E; DAGHIO, MATTEO; Santoro, C; Li, B.. - In: BIOELECTROCHEMISTRY. - ISSN 1567-5394. - 92:(2013), pp. 6-13. [10.1016/j.bioelechem.2013.01.005]
Cathodic and anodic biofilms in single chamber microbial fuel cells
DAGHIO, MATTEO;
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.I documenti in FLORE sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.