In recent research, a novel approach has been employed to enhance the removal of Cu2+ from sediment using sediment microbial fuel cells (SMFCs). The study focused on integrating nano zero-valent iron (nZVI)-modified biochar into oxygen-releasing beads (ORBs), thereby improving the efficiency of SMFCs in copper removal and power generation. The traditional single-medium SMFCs, while capable of removing heavy metals like copper through electromigration, faced challenges such as high mass transfer resistance and limited oxygen availability at the cathode, hindering their performance. The introduction of ORBs, specifically designed for slow oxygen release, significantly increased the oxygen concentration at the cathode, improving sediment mass transfer properties and, consequently, copper removal efficiency.

Using response surface methodology, the research optimized the composition of nZVI-modified ORB (ORBm), achieving a notable copper removal efficiency of 95% and an oxygen release rate of 0.41 mg O2/d·g ORBm. The optimized ORBm, when added to the cathode area of a single-SMFC, resulted in a 4.6-fold increase in voltage output and a 2.1-fold increase in copper removal, compared to systems without ORBm. This improvement is attributed to the enhanced migration of Cu2+ in the sediment, facilitated by the optimal oxygen release and the presence of nZVI on the ORB surface, which participates actively in the reaction through changes in the Fe-O group.

The study’s implications extend beyond improving SMFCs’ operational efficiency. It offers a sustainable and energy-efficient method for remediating Cu-contaminated sediments, addressing the environmental and health hazards posed by long-term accumulation of heavy metals in aquatic ecosystems. This innovative approach exemplifies the potential of integrating nanotechnology with microbial fuel cell technologies for environmental remediation, showcasing a promising direction for future research in heavy metal removal from sediments.