Enhancing bioelectricity production and copper remediation in constructed single-medium plant sediment microbial fuel cells

Abstract

A plant microbial fuel cell (PMFC) with a single-medium system suitable for in-situ treatment of contaminants was developed to treat copper (Cu) from sediment. The purpose is converting the toxic Cu2+ to be less harmful for the environment. Ipomoea aquatica was utilized to improve the generation of electricity and the removal of Cu by the PMFC through the existence of root exudates. The PMFC had a better average voltage output of 114 ± 5.89 mV, which was 1.84 times higher than that of the sediment MFC (SMFC). The remediation of Cu in sediment by SMFC and PMFC was 35.9 % and 71.2 %, respectively, showing that the PMFC was 1.98 times more effective in Cu removal than the SMFC as a result of a bioelectrochemical process and plant uptake. Cu nanoparticles were identified at the cathode as the final product, showing the successful Cu2+ reduction. Microbial community analysis revealed that Proteobacteria and Firmicutes were the dominant bacteria in the electricity production, abundantly found in PMFC due to the existence of root exudates, which also increased the voltage. This study successfully demonstrates that the PMFC is a promising technology for treating copper-contaminated sediment by supplying root exudates that promote microbial growth.