Iron-based anodes in CW-MFCs: mechanisms and performance enhancement for contaminant removal and sulfamethoxazole...

In recent years, the constructed wetland-microbial fuel cell (CW-MFC) had emerged as a promising technology for antibiotic removal from water, with anode material playing a critical role in system performance. This study investigated the effects of three anode materials-activated carbon (ACCW-MFC), iron-based biochar (FCW-MFC), and pyrite (PCW-MFC)-on the removal of conventional pollutants and sulfamethoxazole (SMX), power generation, and microbial community composition. Results demonstrated that FCW-MFC achieved exceptional removal rates for COD (96.4 ± 0.68 %), TP (100 %), and SMX (100 %). FCW-MFC exhibited superior resilience to shock loads, while PCW-MFC displayed peak voltages of 402 and 399 mV before and after SMX addition, respectively. Pseudomonadota was the dominant bacterial phylum in all three MFCs (ACCW-MFC, FCW-MFC, and PCW-MFC), with relative abundances of 71.34 %, 67.26 %, and 63.35 %, respectively. Notably, FCW-MFC and PCW-MFC supported substantial populations of the denitrifying genus Thauera (27.96 % and 15.58 %, respectively). The study demonstrated that iron amendment in the anode significantly enriches the electroactive microbial community and enhanced the comprehensive performance of CW-MFCs, providing an effective strategy for simultaneous wastewater treatment and energy recovery.