Floating flexible microbial fuel cells for electricity generation and municipal wastewater treatment

A new design of floating flexible microbial fuel cell (FMFC) was constructed by combining the carbon nanoparticles modified titanium foil anode (CNPs/ TF), insulating cloth, and air–cathode loaded with Pt/ C catalyst. This FMFC can float on wastewater and generate a maximum power density of over 250 mW m⁻² whose power performance is higher than other reported floating MFCs. After 21 days of operating on municipal wastewater, the results showed that the chemical oxygen demand (COD) undertaken by this FMFC would decrease from 3845 mg L⁻¹ to 308 mg L⁻¹. It showed that the COD removal efficiency was 92.1% and it was better than a control without FMFC and whose COD removal efficiency was 61.5%. In addition, the cost of the FMFC is much lower than those traditional and common MFCs due to their membrane-free structure. Finally, it was also found that Geoalkalibacter was dominant exoelectrogens in anodic biofilm and benefited the power generation performance of FMFC. This study showed that this novel FMFC could polish the performance of municipal wastewater treatment and also produce electric power in future.