Characterization of oxidized carbon foil as a low-cost alternative to carbon felt-based electrodes in bioelectrochemical systems

The recent development of bioelectrochemical systems (BESs) is based on the growth of microorganisms on carbon electrode materials. Carbon felt and cloth are the most widely used electrode materials; however, less expensive alternative materials are required when BESs are used for wastewater treatment. In this work, graphite carbon foil was modified using chemical, thermal, and electrochemical oxidation methods to improve its surface characteristics, and the resulting material was compared with oxidized carbon felt. The materials were physically, chemically, and electrochemically characterized. The isotherms revealed that thermal oxidation increased the surface area of the carbon foil by 39 %, reaching a value of 26.2 m2 g−1. Electrochemical impedance spectroscopy showed that the charge transfer resistance of the untreated carbon foil was 445 Ω, which decreased to 34 Ω after electrochemical oxidation. Additionally, cyclic voltammetry revealed a 100-fold increase in current density for the foil and felt materials following electrochemical oxidation. Based on its large surface area, low charge transfer resistance, remarkable current density under polarization, and comparatively low cost, the graphite carbon foil was identified as a promising alternative that could be used for constructing bioelectrodes.