Evaluation of the Electrical Performance of a Soil-Type Microbial Fuel Cell Treated with a Substrate at Different Electrode Spacings

Abstract

The effect of electrode spacing on the performance of a microbial fuel cell (MFC) under batch treatment with a substrate was investigated with three single-chamber MFCs built with biologically active soil. The electrodes consisted of a stainless-steel mesh with layers of activated carbon catalyst. The MFCs were fed with artificial urine after reaching a stationary phase. After the initial treatment, the cell with the smallest electrode gap produced the maximum peak power under polarization. At 2 cm, 5 cm and 8 cm electrode spacing, the maximum power was 726.2 µW, 547 µW, and 520.3, respectively; while the average power of the MFCs from the first point of treatment with substrate to the last point was 297 + 259.2, 505.43+ 42.5, and 433.81+ 64, respectively. A significant decrease in internal resistance of the MFCs was observed during batch treatment. The impedance analysis of the MFCs showed that the reduction in internal resistance was largely due to a significant decrease in ohmic resistance compared to the charge transfer resistance.