Optimization of anode current collector in microbial fuel cell for improved power output and bacterial development
Résumé
Microbial fuel cells (MFC) are among the most-studied bioelectrochemical systems (BES) over the last twenty years, and yet, still pose numerous difficulties when scale up is attempted at the laboratory scale. This study aimed at testing the hypothesis that external anode electrical connections play a major role in power output limitations during scale-up. At a small scale, these contacts are usually made by simple metal strip or wire connected at one point or one edge of the electrode. Scale-up strategies often do not take into account electrical contacts as possible reasons for power loss. Power losses arising due to the distance between remote anode points and single connections could appear when the anode size is increased without increasing the number of connections.We investigated the electricity production and bacterial anodic development in a 1L MFC with different electrical contact configurations on its 500 cm² carbon cloth anode. Ohmic resistance due to distance and electron charge transfer resistance due to potential drop distribution on the anode were thought to limit power production by shaping and restricting spatial development of microbes. Power output, electrochemical characterization by impedance spectroscopy and anodic biofilm structure through microscopy and molecular biology tools were used to examine the impact of current collector design on overall power production and microbial spatial distribution and community structure.