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(-)) co-exists with uranyl (UO(2)(2+)), resulting in the complex species of UO(2)F(x) and thus decreasing extraction efficiency. Herein, we construct Ti(δ+)-PO(4)(3-) ion pair extraction sites in Ti(OH)PO(4) for efficient electrochemical uranium extraction in wastewater from nuclear fuel production. These sites selectively bind with UO(2)F(x) through the combined Ti-F and multiple O-U-O bonds. In the uranium extraction, the uranium species undergo a crystalline transition from U(3)O(7) to K(3)UO(2)F(5). 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(-1) without saturation. This work paves an efficient way for electrochemical uranium recycling in real wastewater of nuclear production.