Construction of conductive modified polyethylene terephthalate-supported cathode in microbial fuel cell for nitrate removal

Polyethylene terephthalate (PET) has broad environmental applications, yet its inherent poor conductivity limits its utility in microbial fuel cell (MFC). This study addressed the need for cost-effective and conductive PET-supported materials. In this study, PET-supported three-dimensional materials were used as a substrate, introducing the conductive coating layer that enhanced hydrophilicity, electrochemically active surface area, and decreased charge transfer resistance. The PET-supported cathode modified with polypyrrole (PPy) and carbon nanotubes (CNTs) achieved a maximal power density (758.2 mW/m²) with long-term operational stability for 4 months. The PET/PPy/CNTs cathode exhibited 2.23-fold higher nitrate removal efficiency than carbon felt cathode. Notably, the average viability of biofilm on the internal surface of PET/PPy/CNTs (63.5%) was 2.89-fold higher than carbon felt. Furthermore, the PET/PPy/CNTs demonstrated significant cost-effectiveness with a cost of approximately $2.04/m². Considering the superior bioelectrochemical performance, low costs, and low life cycle environmental impacts, the PET-supported cathode demonstrates notable potential for enhancing MFC performance.