Key Takeaways & Executive Findings
- •• • H-Nb2O5−x achieves 99.1% uranium extraction efficiency in 30 g L−1 fluoride solution, outperforming conventional adsorbents that suffer from competitive fluoride complexation. • • In a 10-L real nuclear wastewater trial, the electrode maintained stable operation for 40 days, reducing uranium from 1372.3 mg L−1 to 0.93 mg L−1 (99.93% removal), demonstrating industrial viability. • • The material is synthesized from commercial bulk niobium oxide via rapid reconstruction, enabling cost-effective scale-up compared to complex nanostructured electrodes. • • The intrinsic Nb4+ active sites and compact oxygen structure provide strong binding to uranyl fluoride species, ensuring high selectivity and long-term stability under harsh fluorine conditions.
Abstract
Electrochemical uranium extraction from fluorine-containing nuclear wastewater is critical for nuclear fuel recovery, yet current electrode materials suffer from limited scalability and insufficient long-term stability. Here, we report a bulk monoclinic Nb2O5−x (H-Nb2O5−x) derived from commercial bulk niobium oxide via rapid reconstruction, exhibiting exceptional activity and robustness for electrochemical uranium extraction in fluorine-rich environments. The intrinsic active pairs of low-valent Nb4+ and compact oxygen structure strongly bind with dominant uranyl fluoride species (UO2F+, UO2F2, UO2F3−, UO2F4^2−), facilitating efficient separation. In a 30 g L−1 fluoride solution, H-Nb2O5−x achieved a uranium extraction efficiency of 99.1%. Notably, in a 10-L real nuclear wastewater test, the bulk material maintained stable performance over 40 days, reducing uranium concentration from 1372.3 mg L−1 to 0.93 mg L−1. This work demonstrates a scalable, durable electrode material for industrial electrochemical uranium extraction, addressing the bottlenecks of complexation and stability in fluoride-containing waste streams.
1. Introduction
Fluorine-containing nuclear wastewater, generated during uranium enrichment and conversion processes, presents a formidable challenge for uranium recovery. The presence of fluoride ions leads to the formation of stable uranyl fluoride complexes (e.g., UO2F+, UO2F2, UO2F3−, UO2F4^2−), which severely impede conventional adsorption and ion-exchange methods. These methods suffer from low selectivity and capacity due to competitive binding by fluoride. Electrochemical extraction offers a promising alternative, as the reduction of uranyl species can disrupt the uranium-fluorine interaction, enabling efficient separation. However, existing electrode materials often require complex synthesis routes, limiting scalability, and exhibit insufficient long-term stability in aggressive fluoride environments, hindering practical deployment.
This study addresses these bottlenecks by engineering a bulk monoclinic Nb2O5−x (H-Nb2O5−x) directly from commercial bulk niobium oxide via a rapid reconstruction process. The material leverages intrinsic Nb4+ active sites and a compact oxygen lattice to strongly bind uranyl fluoride species, achieving high extraction efficiency and exceptional durability. The scalable synthesis and demonstrated 40-day stability in real wastewater underscore its potential for industrial application, offering a robust solution to the longstanding challenge of uranium recovery from fluorine-containing streams.
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Kai Hou, Guo Li, Xiaochuan Deng, Honghao Zhang, Xue Jiang, Wenli Zhou, Rong He, Wenkun Zhu (2026). Rapid Reconstruction of Commercial Bulk Niobium Oxide for Highly Stable Electrochemical Uranium Extraction in the Presence of Fluorine. SCIENCE CHINA Materials. https://doi.org/10.1007/s40843-025-4185-6
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Frequently Asked Questions
What is the maximum fluoride concentration that H-Nb2O5−x can tolerate while maintaining high uranium extraction efficiency?
The material achieved 99.1% uranium extraction efficiency in a solution containing 30 g L−1 fluoride, indicating high tolerance to fluoride interference. This is particularly relevant for industrial wastewater streams where fluoride concentrations can be elevated.
How does the long-term stability of H-Nb2O5−x compare to conventional electrode materials in real nuclear wastewater?
In a 10-L real nuclear wastewater test, H-Nb2O5−x maintained stable electrochemical performance over 40 days, reducing uranium from 1372.3 mg L−1 to 0.93 mg L−1. This demonstrates superior durability compared to many reported electrodes that degrade within days due to fluoride corrosion or fouling.
What is the synthesis scalability of H-Nb2O5−x from commercial bulk niobium oxide?
The rapid reconstruction process starts from commercial bulk niobium oxide, which is inexpensive and readily available. This approach avoids complex, multi-step nanostructuring, enabling cost-effective scale-up for industrial electrodes.
What is the mechanistic basis for the high selectivity of H-Nb2O5−x towards uranyl fluoride species?
The intrinsic Nb4+ active sites and compact oxygen structure form synergistic coordination bonds with F, O, and U atoms, strongly binding to uranyl fluoride complexes. This facilitates electron transfer and reduction, effectively separating uranium from fluoride.
What is the energy consumption or current efficiency of the electrochemical extraction process using H-Nb2O5−x?
The provided text does not specify energy consumption or current efficiency. However, the high extraction efficiency (99.1%) and long-term stability suggest favorable operational economics, though detailed energy metrics would require further analysis.
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