In situ fabrication of ultrathin δ-MnO2 nanosheet-decorated MWCNTs for efficient electrochemical uranium extraction

Uranium is a critical resource for nuclear energy, but the radioactive wastewater generated during its processing and use poses significant environmental and health risks. Recently, electrochemical uranium extraction technology has attracted significant interest, with the primary challenge being the development of efficient electrode materials. In this study, a one-step in situ synthesis of δ-MnO 2 nanosheets anchored on multi-walled carbon nanotubes (denoted C@M) was developed for efficient electrochemical uranium extraction. This heterostructure leverages the high conductivity and structural robustness of MWCNTs, while the δ-MnO 2 nanosheets provide abundant active sites and further augment the specific surface area, which significantly improves uranium removal efficiency. Benefiting from the unique heterostructure, the saturated adsorption capacity of C@M reached 1216.32 mg g −1 (at 1.2 V, pH 4, based on the Langmuir model). Moreover, the C@M electrode exhibited >70 % retention after 7 cycles and good interference resistance in multi-ion solutions ( e.g. , coexisting K + , Na + , Ca 2+ , Mg 2+ , and Al 3+ ). This work presents an efficient and stable electrode material design strategy for uranium recovery from complex wastewater streams.