Effect of nanowire conductive transfer on the performance of batch-microbial fuel cells

Microbial fuel cells (MFCs) are a promising technology that uses microorganisms to simultaneously generate bioelectricity while treating wastewater. To further improve the performance of the MFC, it is essential to understand and evaluate the electron transfer mechanism. However, redesigning the electron transfer mechanism of MFCs through an experimental approach is costly and time-consuming. Hence, in this study, a numerical modeling approach is implemented through the Nernst-Monod kinetic equation, which is validated by experimental results. A nanowire conductive transferring pathway is considered between the microorganisms and anode electrodes of a batch-type MFC. Moreover, two types of bacteria are utilized such as the Shewanella oneidensis MR-1 and Shewanella putrefacient with substrate concentrations of 0.5 M sodium lactate. The results have shown that the limiting current density of the MFC from the computational model is 1514 mA m(-2). On the other hand, the current density from the experimental approach for Shewanella oneidensis MR-1 is 497 mA m(-2) while for Shewanella putrefacient is 140 mA m(-2). The anode activation loss of 491 omega is lower than the cathode activation loss of 643 omega, which indicates the relative influence of the cathode activation loss on the bioelectricity generation of the MFC. In addition, the results revealed that the nanowire electron transfer mechanism in the anode biofilm was less affected by the concentration losses. This then indicates that the physical mechanism of the nanowire electron transfer can be effectively used to investigate the batch-type MFCs. In turn, the results of this study will contribute to the development of an improved MFC.

Automated summary

This study investigates the electron transfer mechanism in microbial fuel cells through numerical modeling and experimental validation using two types of bacteria and a nanowire conductive transferring pathway. Results show that the batch-type MFC with nanowire transfer pathway exhibits a higher limiting current density.