Ion pair sites for efficient electrochemical extraction of uranium in real nuclear wastewater.

Lin, Tao; Chen, Tao; Jiao, Chi; Zhang, Haoyu; Hou, Kai; Jin, Hongxiang; Liu, Yan; Zhu, Wenkun et al. · Nat Commun · 2024

basic_science · Level V

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Abstract

Electrochemical uranium extraction from nuclear wastewater represents an emerging strategy for recycling uranium resources. However, in nuclear fuel production which generates the majority of uranium-containing nuclear wastewater, fluoride ion (F<sup>-</sup>) co-exists with uranyl (UO<sub>2</sub><sup>2+</sup>), resulting in the complex species of UO<sub>2</sub>F<sub>x</sub> and thus decreasing extraction efficiency. Herein, we construct Ti<sup>δ+</sup>-PO<sub>4</sub><sup>3-</sup> ion pair extraction sites in Ti(OH)PO<sub>4</sub> for efficient electrochemical uranium extraction in wastewater from nuclear fuel production. These sites selectively bind with UO<sub>2</sub>F<sub>x</sub> through the combined Ti-F and multiple O-U-O bonds. In the uranium extraction, the uranium species undergo a crystalline transition from U<sub>3</sub>O<sub>7</sub> to K<sub>3</sub>UO<sub>2</sub>F<sub>5</sub>. In real nuclear wastewater, the uranium is electrochemically extracted with a high efficiency of 99.6% and finally purified as uranium oxide powder, corresponding to an extraction capacity of 6829 mg g<sup>-1</sup> without saturation. This work paves an efficient way for electrochemical uranium recycling in real wastewater of nuclear production.