Direct electricity production from subaqueous wetland sediments and banana peels using membrane-less microbial fuel cells

Abstract

Subaqueous wetland sediments (SWSs) and banana peels (BPs), respectively used as anaerobic inoculums and raw materials, were valorized for electricity generation in membrane-less and biocathode-containing microbial fuel cells (MLBC-MFCs). The maximum current density was 78.2 mA/m2 for banana peel extracts (BPE) and 91.3 mA/m2 for anaerobically fermented banana peel extracts (ABPE). The polarization data indicated that Ohmic resistances were high that were 3.5, 4.2 and 9.3 kΩ when MLBC-MFCs were fed with ABPE, BPE and sodium acetate (SA), respectively. The ultraviolet-visible absorption spectroscopy coupled with three-dimensional fluorescence spectroscopy was used to explore the mechanisms of generating electricity. Results showed that SWSs provided functional microorganisms and a source of organic matter, while BPs were more helpful for the growth of microorganisms than SA and the microorganisms attached on the cathode primarily functioned as biocatalysts. Overall, this study highlights the simplicity and scalability of MLBC-MFCs equipped with SWSs and BPs.