Coupling microbial fuel cell with the sulfidated zerovalent iron for efficient uranium(VI) recovery in low-carbon...

The resource recovery treatment of uranium-containing wastewater presents a significant challenge for both nuclear energy and environmental sustainability. This study develops the system of coupling microbial fuel cells with sulfidated zero-valent iron (MFC@S-ZVI) to enhance U(VI) removal and facilitate resource recovery from low-carbon wastewater. Sulfidation significantly improves electron transfer, thereby enhancing the removal of U(VI) by ZVI under various reaction conditions, including different pH levels and coexisting ions, with the removal rate increasing by a factor of 1.29-20.90 depending on the specific conditions. In the MFC@S-ZVI system, a U(VI) removal rate of 98.8% is achieved within 36 h, surpassing other configurations such as MFC@ZVI (82.0%) and MFC (57.6%). The synergistic effect of S-ZVI and microbial activity optimizes electron flow, resulting in a 2.7-fold improvement in U(VI) removal efficiency compared to single MFC systems. Additionally, XPS and SEM-EDS analyses confirm that U(VI) is predominantly reduced to U(IV) and adsorbed on the S-ZVI surface as high-purity crystalline UO₂, offering a promising method for uranium recovery. Moreover, the MFC@S-ZVI system maintains enhanced reactivity toward U(VI) across multiple cycles, ensuring long-term sustainability for wastewater treatment. In general, this study underscores the potential of the MFC@S-ZVI system for treating uranium-contaminated wastewater and highlights its broader applicability in resource recovery, particularly in wastewater treatment systems with low carbon source.