Pseudocapacitive deionization of uranium(VI) with WO3/C electrode

Decontamination and recovery of uranium(VI) [U(VI)] from radioactive wastewater is vital to sustainable nuclear power production and reclamation of radioactive waste. As a promising technology of water treatment, capacitive deionization for adsorption of U(VI) started to attract attention. Herein, for the first time, a floriform WO3/C composite was developed as a pseudocapacitive electrode material for electrosorption of U(VI) from water. The as-prepared WO3/C composite was constructed from dozens of 2D nanosheets with a thin amorphous carbon layer, resulting in uniform flower-like particles with hierarchical nanostructure and superior open pore network. The charge/discharge process of WO3/C was demonstrated as prominent capacitive controlled behavior by quantization of capacitance contributions. As a result, the WO3/C electrodes achieved a maximum U(VI) electrosorption capacity of 449.9 mg g−1 at 1.2 V and good cycling stability after consecutive adsorption-desorption, which is superior to the conventional physical adsorption processes. The superior CDI performance of the WO3/C electrode is credited to the synergistic effect of EDLs and pseudocapacitance based on the combination of WO3 and carbon layer with hierarchical nanostructure. Overall, the facile preparation strategy, the superior electrosorption performances, and the high cycling stability, endow the floriform WO3/C electrodes to be a promising electrode material for electrosorption of U(VI) from wastewater.