Tailored covalent organic framework with phosphorylation for boosting typical actinide adsorption under acidic conditions

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2023-05, Vol.463, p.142408, Article 142408
• Main Authors: Zhang, Huidi, Wang, Shuai, Yu, Jipan, Li, Zijie, Lan, Jianhui, Zheng, Lirong, Liu, Siyan, Yuan, Liyong, Xiu, Taoyuan, Wang, Jindong, Wang, Xinpeng, Shi, Weiqun
• Format: Article
• Language: English
• Subjects: Adsorption; Covalent organic frameworks (COFs); High acidity; Phosphonic group; Plutonium; Uranium
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2023.142408

[Display omitted] •Phosphorylated TzDa-Phos fabricated for the U(VI) and Pu(IV) adsorption.•qm(U) at pH 4.0 and 3 M HNO3: 394 and 56 mg/g, respectively; Kd(Pu): 9.7 × 103 mL/g.•Phosphonic group P–O− responsible for the coordination with U at pH 4.0.•Nonprotonated PO maintains the removal capacity for U and Pu from 3 M HNO3. Uranium and plutonium are typical actinides tightly associated with nuclear fuel cycle. In this work we rationally design and fabricate a phosphonic group-decorated covalent organic framework, TzDa-Phos, for highly selective removal of uranium [U(VI)] and plutonium [Pu(IV)]. The saturation adsorption capacity for U(VI) can reach 394 mg/g at pH 4.0, and even maintains 40 mg/g in 1–4 M HNO3 solutions. The distribution coefficient of Pu(IV) with TzDa-Phos is recorded up to 9.7 × 103 mL/g at 3 M HNO3. The excellent adsorption performance of TzDa-Phos for U(VI) and Pu(IV) is reasonably attributed to phosphonic groups decorated in TzDa. Specifically, the strong complexation of PO with uranium nitrate species (e.g., UO2(NO3)+, UO2(NO3)20) is indicated at high acidities, in contrary to the coordination of P-O− with uranium at pH 4.0 as evidenced by FT-IR, XPS and EXAFS analyses. This work provides a promising adsorbent to recover uranium and plutonium from various wastewaters via a solid-phase extraction approach.