1. A sustainable strategy for targeted extraction of thorium from radioactive waste leachate based on hydrophobic deep eutectic solvent.
- Author
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Ni, Shuainan, Gao, Yun, Yu, Guisu, Zhang, Sijia, Zeng, Zhiyuan, and Sun, Xiaoqi
- Subjects
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RADIOACTIVE wastes , *LEACHATE , *EUTECTICS , *THORIUM , *WASTE recycling , *RARE earth metals , *EXCHANGE reactions , *SOLVENTS - Abstract
In this work, the new hydrophobic deep eutectic solvents (HDESs) based on 2-hexyldecanoic acid (HDA) as a hydrogen bond donor (HBD) were used to selectively enrich trace Th from radioactive waste leach solution. These HDESs are characterized by low toxicity, bio-friendliness, low viscosity and sufficient hydrophobicity. Compared with Al, Mg, Ca and RE, HDESs exhibited exceptional selectivity for Th extraction, along with high loading capacity, easy stripping and stable reusability. The mechanism of Th extraction by the HDES is a cation exchange reaction. Based on the thymol (TL):HDA (1:3) HDES, a short flow closed-loop recovery process of Th in the leach solution of radioactive waste residue was developed. After a single-step extraction, the extraction percentage (E%) of Th exceeded 98.0%, while the E% of other elements was less than 0.14%. After stripping, the concentration of Th in the concentrated solution reached 2.16 × 103 mg/L with a purity of 74.2%, which could be directly used for subsequent purification. By adjusting the pH to 4.00, the raffinate was used as a feed solution for RE elements recovery. The HDES-based extraction strategy for Th is simple, safe, efficient and environmentally friendly, providing a new idea for the recovery of radioactive waste residues. [Display omitted] • HDESs based on 2-hexyldecanoic acid were prepared and characterized. • The separation factor between Th and rare earths is much greater than 1000. • A closed-loop thorium recovery process based on HDES was developed. • The extraction percentage of Th by HDES is more than 98%. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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