A comparative study of the performance of commercial carbon felt and the innovative carbon-coated Berl saddles as anode electrode in MFC

Microbial Fuel Cell (MFC) is a prospective technology that allows oxidizing organic and inorganic matter to generate current by the activity of bacteria with a high potential as portable remote energy generation. To render MFC as a cost-effective and energy sustainable technology, low-cost conductive materials can be employed as support for bacterial growth and proliferation. For this reason, in this work we performed a comparative study of the performance between commercial carbon felt and the innovative carbon-coated Berl saddles (C-Berl saddles) developed in our labs used as anode electrode in MFC. Both the experiments were conducted simultaneously using the same MFC configuration in continuous mode for more than 3 months at room temperature (22 ± 2 °C). In the anodic chamber, a mixed microbial population naturally present in sea water was employed as active microorganisms and sodium acetate (1 g.L-1 per day) with buffer solution was continuously fed as substrate. In the cathodic chamber, carbon felt was used as electrode material and potassium ferricyanide with buffer solution as an electron acceptor. A complete characterization of anodic solution was carried out with continuous measurement of pH, conductivity and redox potential. Electrochemical characterization were performed as a follow: (i) polarization curves including: Linear Sweet Voltammetry, Current Interrupt and Electrochemical Impedance Spectroscopy using a multi-channel VSP potentiostat by BioLogic and (ii) current and voltage under an external resistance of 1000 Ω using a Data Acquisition Unit by Agilent 34972A. Results showed that C-Berl saddles performed better than carbon felt showing an average maximum power density of 90 mW.m-2 and 60 mW.m-2 , respectively. In addition, from current vs. time data both cells were produced a comparable quantity of energy, linked to the good biocompatibility, conductibility and high mechanical stretching of electrode materials. Furthermore, C-Berl saddles helped to reduce the biofouling and favored the growth of biofilm as anode material for scaling-up MFC.