Enhanced performance of microbial fuel cells using electrochemically treated carbon felt anode

Abstract

The microbial fuel cell (MFC) technology is emerging as an effective technology for wastewater treatment to remove and detect many pollutants and simultaneously generate power. The anode is an essential component for bacterial attachment and extracellular electron transfer (EET). Thus, anode performance is critical for improving an MFC system's overall performance. Materials that are electronically conductive and provide favorable conditions for creating biofilm are good candidates for the anode. Carbon paper and carbon felt are the most used anode materials. However, the characteristics of these materials can be modified to increase their performance. This paper presents a modification of the conventional carbon anode by electrolyzing the carbon felt in a phosphate buffer and an experimental evaluation of the impact of the treatment. The tests were performed using an air cathode MFC, electrogenic bacteria Shewanella Baltica 20 fed on lactose-rich L-B. The treatment with phosphate buffer generates functional groups on the surface of the carbon felt, which establishes robust biofilm on the anode and offers lower charge-transfer resistance compared to the untreated carbon felt. This facilitates electron transfer from exoelectrogens to the anode, increasing the current density and power density output. Three times higher power density was observed in the cell with a modified anode than in an untreated carbon-felt anode.