A 1D model for a single chamber microbial fuel cell

Abstract

A one dimensional (1D) model accounting for the charge and mass transfer, biofilm formation and the electrochemical reactions that occur in a single chamber microbial fuel cell (SCMFC) operated at batch mode was developed. As the authors are aware, this simplified and easy to implement model for this design and operating mode is unique. The assumptions performed on the model development and the set of parameters used in the model predictions were carefully considered and chosen based on the operating and design conditions and following recommendations from literature. Despite the simplifications and assumptions performed, the model predictions are in good agreement with the experimental data, with a maximum power density of 36.7 mW/cm2. The model predictions concerning the effect of the substrate concentration at the biofilm, anode and cathode overpotentials, cell voltage, current density and power density were also studied. The substrate concentration showed a higher impact on the anode overpotential for the medium to high current density values and predicted well the decrease in substrate availability for increasing current densities and higher anodic reaction rates. The model is rapidly implemented using simple numerical tools (like Excel and Matlab) being, therefore, suitable to seek for possibilities of optimizing the performance of a SCMFC by studying the impact of variations on the design parameters (such as membrane thickness, catalyst loading, electrodes type and thicknesses) and operating conditions (such as substrate concentration). This work demonstrated the value of the developed model in understanding the phenomena behind the MFC systems and on developing more efficient systems, towards an increase of their power output.