Anode‐modified sediment microbial fuel cell for simultaneous <scp>Cr</scp> ( <scp>VI</scp> ) removal and bioelectricity generation

Abstract BACKGROUND High concentrations of hexavalent chromium [Cr(VI)] in electroplating wastewater threaten ecosystems and human health, urging integrated technologies for simultaneous Cr(VI) removal and energy recovery. This study employs a hydrothermal method for the in situ synthesis of α‐manganese dioxide/carbon nanotubes (α‐MnO 2 /CNTs) composite to modify the carbon felt anode in sediment microbial fuel cell (SMFC), enabling concurrent electricity generation and Cr(VI) remediation. The effects of overlying water pH and initial Cr(VI) concentration on system performance are systematically investigated. RESULTS Under optimal conditions [pH 2, 100 mg L −1 Cr(VI)], the modified SMFC achieves an open‐circuit voltage of 0.546 V and a maximum power density of 29.94 mW m −2 , representing improvements of 42.6% and 62.2%, respectively, compared to the unmodified system. After 50 days of continuous operation, the Cr(VI) removal efficiency reaches 92.9%, representing a 1.47‐fold increase over the unmodified system. 16S rRNA gene sequencing reveals that Proteobacteria is the dominant phylum in anode‐associated sediment, with a relative abundance of 64.4%, representing a 1.98‐fold increase compared with the pre‐modification level. Functional microbial communities involved in electricity generation and Cr(VI) bioreduction are identified, including the genera Rhodoferax and Azospira , and the family Anaerolineaceae. CONCLUSION The α‐MnO 2 /CNTs‐modified SMFC demonstrates stable performance under high Cr(VI) concentrations and strongly acidic conditions, with the native sediment microbial community showing notable tolerance to these harsh conditions, thereby exhibiting great potential for in situ electroplating wastewater treatment and energy recovery. © 2026 Society of Chemical Industry (SCI).