Effect of Mechanical Polishing on the Performance of 3D-Printed Conductive PLA Electrodes in Soil Microbial Fuel Cells

Soil microbial fuel cells are a rising technology that relies on the interaction of microorganisms with organic matter merged with an electrochemical system to generate power. The advantages offered by the system, primarily, the simultaneous soil remediation and electricity generation, have attracted attention to its improvement. Thus, the study explored the potential usage of 3D printed electrodes where the performance of the stake without surface alteration (native) and with mechanical polishing are observed. Six systems were utilized, three being polished while the other three were unpolished. The systems were watered once a day at a different time where the normalized data showed that watering time and polishing do not provide significant improvement in the performance of SMFCs. Polarization studies generated a maximum power density of 4.72 µW/m<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and 5.46 µW/m<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> for native and polished electrodes, respectively. Both maximum power densities were recorded at high internal resistance which implies the limitation of polylactic acid (PLA) with additive carbon black as the conductive material. Moreover, notable damage and limestone deposits to the electrode were also observed. The findings of this study are recommended to be replicated with different electrode materials and different fuel cell fabrication methods. Additionally, it is recommended to include factors that could help the proliferation of the bacterial colony on the electrode surface.