Self-oxidation cycle of oxidized red phosphorus for regeneration of binding sites enables efficient uranium extraction in tributylphosphate-kerosene system

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2023-03, Vol.460, p.141834, Article 141834
• Main Authors: Lv, Yingtong, Cheng, Ru, Yang, Guolin, Liu, Wang, Zhang, Jingye, Yu, Xiaofang, Bai, Wencai, He, Rong, Zhu, Wenkun
• Format: Article
• Language: English
• Subjects: Photocatalytic; Self-oxidation; TBP-kerosene; U(VI) extraction
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2023.141834

[Display omitted] •Self-oxidation strategy enables efficient uranium extraction in 30 %TBP-kerosene system.•Binding sites for U(VI) in DO-CRP are regenerated during self-oxidation process.•The defect sites are exposed for the next cycle of self-oxidation in desorption process.•DO-CRP exhibits an impressive capacity of 580.8 mg/g in 30 %TBP-kerosene system. Photocatalytic extraction of hexavalent uranium (U(VI)) is challenging in organic phase, especially the widely used tributylphosphate (TBP)-kerosene system in the nuclear fuel cycle process. Organic components in TBP-kerosene system are difficult to be oxidized, which limits the reduction of U(VI). Herein, we demonstrated a self-oxidation strategy to enable the photocatalytic cycle of U(VI) reduction in TBP-kerosene system by the deeply oxidized commercial red phosphorus (DO-CRP). In the 30 %TBP-kerosene solution, the DO-CRP exhibited 88.0 % of extraction efficiency with 580.8 mg/g of capacity for U(VI) within 120 min. In this process, PO43− groups generated at the defects were used as the binding sites to capture and reduce U(VI). Following desorption process involved in the cleavage of uranium and PO43− groups, which released defect sites for self-oxidation in the next cycle. Mechanistic study revealed that such regeneration of self-oxidation and U(VI) binding sites achieved the continuous photocatalytic extraction of U(VI) in TBP-kerosene system.