Insights into enhanced immobilization of uranyl carbonate from seawater by Fe-doped MXene

Extracting uranium from seawater not only reduces radioactive contamination in seawater but also provides a source of uranium energy. However, due to the low concentration of uranium in seawater and the high salinity of seawater, extraction of uranium from seawater is challenging. In this work, we demonstrated a simple strategy to synthesize Fe-doped MXene (Fe@Ti₃C₂T_x) via a hydrothermal method and applied for uranium enrichment in seawater. The Fe@Ti₃C₂T_x exhibited excellent adsorption performance in high salinity environments. The removal capacity of Fe@Ti₃C₂T_x was determined to be 526.6 mg/g for UO₂(CO₃)₂^2- at 328 K with quick reaction equilibrium (∼ 30 min). Kinetic and thermodynamic analyses of UO₂(CO₃)₂^2- elimination process on Fe@Ti₃C₂T_x surface revealed it to be a spontaneous and endothermic single-phase elimination process. FT-IR and XPS analyses further indicated that the removal mechanism of UO₂(CO₃)₂^2- by Fe@Ti₃C₂T_x was surface complexation. Our study suggests that Fe@Ti₃C₂T_x can provide a feasible solution for uranium enrichment in seawater.