In uranium mining and smelting, a significant amount of uranium-containing wastewater is generated, which can easily cause groundwater pollution. In polluted groundwater, uranium often combines with carbonates to form more diffusive and migratory uranyl carbonate complexes, making uranium removal more difficult.

This study aims to consider the performance of a three-dimensional electrochemical system of rGO/BB hydrogel particle electrodes on uranyl carbonate, and implement an efficient method for removing uranium-containing solutions.

Firstly, graphene oxide (go) samples were prepared by modified Hummers method, then, the effects of electrolyte (sodium nitrate) concentration, applied voltage, electrode spacing, pH value, particle electrode dosage, and initial uranium concentration on the adsorption performance of uranyl carbonate ions by a three-dimensional electrochemical system were investigated, and the recycling performance of the system was studied. Finally, the adsorption mechanism of uranium was analyzed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS).

Experimental results show that under the conditions of pH value of 4~8, electrode spacing of 4 cm, voltage of 5 V, and rGO/BB hydrogel dosage of 90 mg, 200 mL of uranyl carbonate with a concentration of 1~1 000 mg?L^-1 exhibits good adsorption efficiency. Even when the uranyl carbonate concentration is 1 000 mg?L^-1, the adsorption rate can reach 87.56% in 14 h. After five cycles of adsorption and desorption, the adsorption rate remains above 87%, thus showing good recycling performance. The addition and use of rGO/BB hydrogel particle electrodes significantly improves the adsorption capacity of the electrochemical system for uranium, in which carboxyl and hydroxyl groups play a major role in uranium adsorption.

The results of this study show that the three-dimensional electrochemical system based on rGO/BB hydrogel particle electrodes has great application potential for removing uranyl carbonate ions.