Optimizing Bioelectricity Generation from Plant-Microbial Fuel Cells Using Soil-Based Electrodes and Natural Substrates

Аңдатпа

Plant-assisted microbial fuel cells (P-MFCs) are a novel bio-electrochemical system that could convert solar energy into electricity through a mutually-beneficial association of plant roots and soil microbes. In the present study, P-MFC prototypes were constructed in soil with live plants, using metallic electrodes to serve as an anode and cathode conductor for the transformation of electrons in soil, to assess the potential of using P MFC. Continuous readings of voltage and current were collected to assess and compare the performance of different combinations of plant-soil, with a control MFC with no plants. In one design, the voltage achieved from a peak single cell was 0.75 V with a cumulative power density of 35 mW/m² of surface area, signifying that rhizodeposition from the plant assisted with microbial oxidation of root exudates to generate more electrons for the electrodes. Three P-MFCs combined in a series arrangement produced a total voltage of 2.1 V, with power density not significantly reduced, however any combination of more than three only provided minute changes in voltage (~10% increase). Again, this work suggests the importance of interaction with soil, plant species, and electrode design to optimize P-MFC operation. This work also supports a lower cost, environmental-friendly, offgrid, and easily scalable technology solution for energy generation in rural areas. This work provides implications for increasing bioelectricity outputs, as well as showcasing the ecological potential of plant microbial interactions in simple, engineered designs. Further, the capacity to improve bioelectricity density and efficiency related to electrode materials and stacking systems highlighted an agenda for novel developments for implementation of P-MFC technologies.