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Li P, He T, Wang J, Ou N, Liang J, Wang G, Fan Q. Realizing Direct Uranium Extraction from Seawater Using a Carboxyl-g-C 3N 4/CdS Hydrogel. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2404417. [PMID: 39039986 DOI: 10.1002/smll.202404417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 07/11/2024] [Indexed: 07/24/2024]
Abstract
The photocatalytic U(VI) reduction is regarded as an effective strategy for recovering uranium. However, its application in seawater uranium extraction poses challenges due to limited reactivity in the presence of carbonate and under atmospheric conditions. In the present study, a photoactive hydrogel made of carboxyl-functionalized g-C3N4/CdS (CCN/CdS) is designed for extracting uranium. The carboxyl groups on g-C3N4 enhance the affinity toward uranyl ions while CdS facilitates the activation of dissolved oxygen. Under atmospheric conditions, the prepared hydrogel catalyst achieves over 80% reduction rate of 0.1 mM U(VI) within 150 min in the presence of carbonate, without the assistance of any electron donors. During the photocatalytic process, U(VI) is reduced to form UO2+x. The hydrogel catalyst exhibits a high uranium extraction capacity of >434.5 mg g⁻1 and the products can be effectively eluted using a 0.1 M NaCO3 solution. Furthermore, this hydrogel catalyst offers excellent stability, good recyclability, outstanding antifouling activity, and ease of separation, all of which are desirable for seawater uranium extraction. Finally, the test in real seawater demonstrates the successful extraction of uranium from seawater using the prepared hydrogel catalyst.
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Affiliation(s)
- Ping Li
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
- Key Laboratory of Petroleum Resources Exploration and Evaluation, Lanzhou, Gansu, 730000, China
- Changyi Marine Ecology and Engineering Research Station, Changyi, 261300, China
- Key Laboratory of Strategic Mineral Resources of the Upper Yellow River, Ministry of Natural Resources, Lanzhou, 730000, China
| | - Teng He
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Jingjing Wang
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Niya Ou
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Jianjun Liang
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
- Key Laboratory of Petroleum Resources Exploration and Evaluation, Lanzhou, Gansu, 730000, China
- Key Laboratory of Strategic Mineral Resources of the Upper Yellow River, Ministry of Natural Resources, Lanzhou, 730000, China
| | - Gen Wang
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
- Key Laboratory of Petroleum Resources Exploration and Evaluation, Lanzhou, Gansu, 730000, China
| | - Qiaohui Fan
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
- Key Laboratory of Petroleum Resources Exploration and Evaluation, Lanzhou, Gansu, 730000, China
- Key Laboratory of Strategic Mineral Resources of the Upper Yellow River, Ministry of Natural Resources, Lanzhou, 730000, China
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Shu Z, Liu Q, Liu E, Pan Z, Yan S, Zhang L, Song W, Wang Z. Overlooked role of aqueous chromate (VI) as a photosensitizer in enhancing the photochemical reactivity of ferrihydrite and production of hydroxyl radical. JOURNAL OF HAZARDOUS MATERIALS 2024; 466:133557. [PMID: 38309168 DOI: 10.1016/j.jhazmat.2024.133557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/26/2023] [Accepted: 01/16/2024] [Indexed: 02/05/2024]
Abstract
The reactive oxygen species (ROS) photochemically generated from natural iron minerals have gained significant attention. Amidst the previous studies on the impact of heavy metal ions on ROS generation, our study addresses the role of the anion Cr(VI), with its intrinsic photoactivity, in influencing ROS photochemical generation with the co-presence of minerals. We investigated the transformation of inorganic/organic pollutants (Cr(VI) and benzoic acid) at the ferrihydrite interface, considering sunlight-mediated conversion processes (300-1000 nm). Increased photochemical reactivity of ferrihydrite was observed in the presence of aqueous Cr(VI), acting as a photosensitizer. Meanwhile, a positive correlation between hydroxyl radical (•OH) production and concentrations of aqueous Cr(VI) was observed, with a 650% increase of •OH generation at 50 mg L-1 Cr(VI) compared to systems without Cr(VI). Our photochemical batch experiments elucidated three potential pathways for •OH photochemical production under varying wet chemistry conditions: (1) ferrihydrite hole-mediated pathway, (2) chromium intermediate O-I-mediated pathway, and (3) chromium intermediates CrIV/V-mediated pathway. Notably, even in the visible region (> 425 nm), the promotion of aqueous Cr(VI) on •OH accumulation was observed in the presence of ferrihydrite and TiO2 suspensions, attributed to Cr(VI) photosensitization at the mineral interface. This study sheds light on the overlooked role of aqueous Cr(VI) in the photochemical reactivity of minerals, thereby enhancing our understanding of pollutant fate in acid mining-impacted environments.
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Affiliation(s)
- Zhipeng Shu
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Qiuyao Liu
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Enyang Liu
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Zezhen Pan
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China; National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Institute of Eco-Chongming, Fudan University, Shanghai 200062, China.
| | - Shuwen Yan
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Liwu Zhang
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Weihua Song
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Zimeng Wang
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China; National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Institute of Eco-Chongming, Fudan University, Shanghai 200062, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
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Synthesis of a New Chelating Iminophosphorane Derivative (Phosphazene) for U(VI) Recovery. Polymers (Basel) 2022; 14:polym14091687. [PMID: 35566857 PMCID: PMC9099652 DOI: 10.3390/polym14091687] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Revised: 04/12/2022] [Accepted: 04/15/2022] [Indexed: 12/21/2022] Open
Abstract
A new synthetic chelating N–hydroxy–N–trioctyl iminophosphorane (HTIP) was prepared through the reaction of trioctylphosphine oxide (TOPO) with N–hydroxylamine hydrochloride in the presence of a Lewis acid (AlCl3). Specifications for the HTIP chelating ligand were successfully determined using many analytical techniques, 13C–NMR, 1H–NMR, FTIR, EDX, and GC–MS analyses, which assured a reasonable synthesis of the HTIP ligand. The ability of HTIP to retain U(VI) ions was investigated. The optimum experimental factors, pH value, experimental time, initial U(VI) ion concentration, HTIP dosage, ambient temperature, and eluents, were attained with solvent extraction techniques. The utmost retention capacity of HTIP/CHCl3 was 247.5 mg/g; it was achieved at pH = 3.0, 25 °C, with 30 min of shaking and 0.99 × 10−3 mol/L. From the stoichiometric calculations, approximately 1.5 hydrogen atoms are released during the extraction at pH 3.0, and 4.0 moles of HTIP ligand were responsible for chelation of one mole of uranyl ions. According to kinetic studies, the pseudo–first order model accurately predicted the kinetics of U(VI) extraction by HTIP ligand with a retention power of 245.47 mg/g. The thermodynamic parameters ΔS°, ΔH°, and ΔG° were also calculated; the extraction process was predicted as an exothermic, spontaneous, and advantageous extraction at low temperatures. As the temperature increased, the value of ∆G° increased. The elution of uranium ions from the loaded HTIP/CHCl3 was achieved using 2.0 mol of H2SO4 with a 99.0% efficiency rate. Finally, the extended variables were used to obtain a uranium concentrate (Na2U2O7, Y.C) with a uranium grade of 69.93% and purity of 93.24%.
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