Evaluation of Activated Carbon Electrodes as Anodes in a Microbial Fuel Cell Using Shewanella Putrefaciens

Abstract

In this work, three types of activated carbons were evaluated as electrodes in the anode chamber of a two-chamber microbial fuel cell (MFC). The evaluation was applied using a pure Shewanella Putrefaciens culture due to its gram-negative characteristics. In the cathode chamber, a platinum electrode was used, and a Nafion® 117 proton exchange membrane was selected as a separator of both chambers. The activated carbons were obtained from different precursors (coffee husk, commercial coal, and mineral coal), with different microporous and surface properties. From the voltage and current measurements, it was found that the cell power values ​​varied between 0.008 mW and 0.045 mW. The electrode obtained from chemical activation of coffee husk with H3PO4 at 450 °C (Q) showed the best electrochemical behaviour and highest power values. This result may be mainly related to the macroscopic morphology and mesopores that improve the wettability of the surface by the medium thought carbonaceous material. SEM images showed a better biofilm formation, larger filaments of the bacteria, and micro-beds formation over the surface of bio-anode Q, which improved the interaction with the microorganism, its metabolism, and electrons extracellular transfer. Therefore, activated carbon from coffee husk could be considered as a promising material for electrodes of microbial fuel cells.

Investigation of heavy metal removal from salty wastewater and voltage production using Shewanella oneidensisMR‐1 nanowires in a dual‐chamber microbial fuel cell

“…However, at 2 kΩ biofilm in carbon cloth showed a low number of cells, 49 but in our research a high number of cells were observed with lower resistance, due to presence of anaerobic conditions and the toxic environment due to the presence of heavy metals, sodium, and phenol. Additionally, biofilm acts as the mediator for easy electron transportation from the medium to the electrode, and the electrons are taken directly from the biofilm 50 …”

“…Additionally, biofilm acts as the mediator for easy electron transportation from the medium to the electrode, and the electrons are taken directly from the biofilm. 50 Bacterial nanowires demonstrate the connectivity between cells allowing higher electron transport between the medium and the electrode (Figure 1b). S. oneidensis produce nanowires with biofilm formation when added to a mixed culture with an o-xylene medium, 51 suggesting the adaptation of the bacteria to adverse conditions.…”