Long-term operational characteristics of microbial fuel cells based on novel biofilm-separated membrane

The high cost of conventional separators limits their widespread use in microbial fuel cells (MFCs). In this study, polyurethane sponges and pyrite were used as carriers for biofilm separators, and their potential for long-term application in MFCs was evaluated. The performance of MFCs constructed based on polyurethane sponge (PSMFC), pyrite (Py-MFC), and commercial cation exchange membrane (CEM, CEM-MFC) was compared over 90 days. Biofilm separators demonstrated superior substrate blocking capacity, while their dissolved oxygen (DO) blocking capacity approached that of CEM-MFC over time. The redox properties of pyrite enhanced pH balance during long-term operation between the anode and cathode chambers, for which PS-MFC (36.91 Omega) and Py-MFC (30.33 Omega) introduced lower internal resistance to the systems compared to CEM-MFC (43.84 Omega). The average output voltage of PS-MFC and Py-MFC reached 369 mV and 328 mV, respectively, close to that of CEM-MFC in long-term operation. Additionally, both biofilm-separated MFCs achieved comparable electricity generation (maximum output power density > 8.01 W/m3) to CEM-MFC. Furthermore, biofilm-separated MFCs achieved higher nitrogen removal loads (>33.94 mg/(L & sdot;d)) and exhibited increasing advantages in COD removal as the operational time increased. The long-term advantages of biofilm separators primarily stemmed from the progressive maturation of the biofilms and the sustained stability of the microbial community. Cost analysis further revealed that biofilm separators presented economic advantages over CEM. These findings suggest that biofilm separators offer an efficient alternative to CEM, with significant potential for scaling up MFC technology.