Coupled Effects of Nanomaterial-Modified Anodes on Temperature, pH Stability, and COD Removal in Microbial Fuel Cells

Microbial fuel cells (MFCs) are a very promising method for wastewater treatment along with energy generation. But one of their biggest factors that affect their functioning is the environmental conditions such as temperature and pH, which regulate microbial activity and electron transfer as well. This work dealt with the effects of nanomaterial-modified anodes and exposure to temperature change, pH fluctuations, and voltage production of the single-chamber MFCs treating real domestic wastewater. Nine MFC systems, with a control one and eight nanomaterial-coated anodes (CNT, Al₂O₃, TiO₂, Fe₂O₃, CeO₂, ZnO, activated carbon, and boron nitride), were run for 14 days under the same conditions. Modification to the MFC system with nanoparticles led to different temperature patterns of the MFC systems and the BN-modified system showed the highest temperature values. Temperature and voltage output showed a strong positive relationship, which was identified through correlation analysis (r ≈ 0.81), and on the other hand, a moderate negative relationship was reported between pH and voltage (r ≈ -0.41). These relationships represent statistical associations under the tested conditions and do not establish direct causation. The BN-modified system combined a comparatively small pH decrease with favorable voltage output during the 14-day operation. Overall, the results indicate that MFC performance was associated with the combined responses of temperature, pH, COD removal, and electrochemical output under the tested conditions. Among the tested materials, the BN-modified system showed the most favorable overall combination of these measured responses.