Reduced graphene oxide and biofilms as cathode catalysts to enhance energy and metal recovery in microbial fuel cell

In this study, reduced graphene oxide (rGO) was developed and employed as cathode catalyst in a membrane-less microbial fuel cell (MFC) to improve energy and metal (copper) recovery in combined with biofilms. Results showed that rGO-based cathode exhibited better characterizations in structure and electron transfer than graphene oxide (GO)-based cathode. The voltage with rGO was about 67% increased, and Cu²⁺ removal efficiency was 43% improved as compared to GO. Cu species on cathode demonstrated the favorable Cu²⁺ reduction to Cu with the catalysis of rGO. Moreover, microbial community analysis indicated that rGO-based cathode exhibited better biocompatibility for functional bacteria that related to electron transfer and Cu²⁺ resistance, such as Geobacter and Pseudomonas, demonstrating the interspecific synergism of microorganisms for efficient energy and copper recovery. It will be of important significance for the heavy metal and energy recovery from low concentrations wastewater by using microbial fuel cell.