Highly selective uranium separation using magnetic N-doped Co/C-decorated Ti₃C₂T_x MXene: Response surface optimization

To efficiently separate U(VI) from liquid radioactive waste, magnetic N-doped Co/C-decorated Ti₃C₂T_x MXene (MNC-MX) composites were synthesized via coprecipitation and calcination. The physicochemical properties and morphology of the composites were systematically analyzed using various characterization techniques. The U(VI) adsorption performance of the composites was evaluated through batch adsorption experiments by investigating the effects of adsorbent dosage, pH, temperature, contact time, initial U(VI) concentration, and the presence of coexisting ions. The adsorption behavior was best described by the pseudo-second-order kinetic model and the Langmuir isotherm. The maximum adsorption capacity was 686.9 mg/g at pH 6, 25 °C, an initial U(VI) concentration of 400 mg/L, and an adsorbent dosage of 0.1 g/L. Response surface methodology revealed the optimal U(VI) removal efficiency to be 99.76% at a contact time of 1.24 h, an adsorbent dosage of 0.084 g/L, and pH 6.5. Under these optimized conditions, MNC-MX enabled the rapid and efficient separation of uranium from liquid radioactive waste via magnetic separation. The primary U(VI) adsorption mechanisms were identified as surface complexation and electrostatic attraction. These results highlight the strong potential of MNC-MX composites for the selective extraction of U(VI) from liquid radioactive waste through magnetic separation.