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The development and exploration of uranium decorporation agents with straightforward synthesis, high removal ability, and low toxicity are crucial guarantees for the safety of workers in the nuclear industry and the public. Herein, we report the use of traditional Chinese medicine licorice for uranium decorporation. Licorice has good adsorption performance and excellent selectivity for uranium in the simulated human environment. Glycyrrhizic acid (GL) has a high affinity for uranium (p(UO2) = 13.67) and will complex with uranium at the carbonyl site. Both licorice and GL exhibit lower cytotoxicity compared to the commercial clinical decorporation agent diethylenetriamine pentaacetate sodium salts (CaNa3-DTPA). Notably, at the cellular level, the uranium removal efficiency of GL is eight times higher than that of CaNa3-DTPA. Administration of GL by prophylactic intraperitoneal injection demonstrates that its uranium removal efficiency from kidneys and bones is 55.2 and 23.9%, while CaNa3-DTPA shows an insignificant effect. The density functional theory calculation of the bonding energy between GL and uranium demonstrates that GL exhibits a higher binding affinity (−2.01 vs −1.15 eV) to uranium compared to DTPA. These findings support the potential of licorice and its active ingredient, GL, as promising candidates for uranium decorporation agents.

The capture of the radionuclides strontium and cesium is of great importance to the environment, human health, and the sustainable development of nuclear energy, and zirconium phosphate with excellent ion exchange capacity has potential application in this field. In this work, we organically granulated zirconium phosphate to induce the formation of composite bead materials (CA@ZrP) with a calcium-containing phase with selectivity for Sr2+and Cs+higher than that of pure ZrP in low-pH environments and competing ionic environments. The adsorption performance of the material was systematically investigated. It was concluded that the adsorption performance of CA@ZrP improved with an increase in temperature, and under the dynamic adsorption experimental conditions, the treatment capacity of CA@ZrP for Sr2+and Cs+reached 404.79 and 302.2 bed volumes, respectively. The systematic study and characterization showed that the generation of the calcium-containing phase [Ca0.55ZrH0.9(PO4)2] promoted the exchange of Ca2+with Sr2+and Cs+, thus improving the selectivity of the composite beads. The highly selective composite bead material can be prepared in batches and easily recycled, providing a new idea for practical engineering applications.

Nitrogen enrichment and increased nitrogen content is an effective strategy for enhancing adsorption of uranium by carbon nitride polymers. Herein, we reported the uranium absorption by using a structurally well-defined and nitrogen-rich carbon nitride polymer with C3N5stoichiometry for the first time. In comparison with the adsorption performance of g-C3N4for U(VI), the conjugation system of the material was increased by connecting the heptazine unit through the azo bridge in the structure of C3N5, so that C3N5exhibited several times higher adsorption performance than that of g-C3N4. The C3N5has high kinetics for uranyl ions, which can adsorb 100 mg/g U(VI) in only 10 min and reach complete adsorption equilibrium in 60 min; the theoretical maximum adsorption capacity is 207 mg/g, meanwhile, the material exhibits high selectivity. The results of spectral analysis and theoretical calculations indicate that the process of uranyl ion capture by C3N5is a combination of physical and chemical adsorption, and its higher density of electronic states makes the electrostatic binding ability enhanced, which is favorable to the adsorption of uranyl ions by C3N5. This work indicates that C3N5has great promise and application in the separation and enrichment of uranyl ions, and also provides a reference for the systematic investigation of the adsorption ability of nitrogen-rich carbon nitrogen polymers on uranyl ions.

Not only a critical matter in the nuclear fuel cycle but uranium is also a global contaminant with both radioactive and chemical toxicity. Reducing soluble hexavalent uranium [U(VI)] to relatively nonimmigrated tetravalent uranium [U(IV)] by photocatalytic technologies is recognized as a highly promising strategy for avoiding environmental pollution and re-extracting uranium resources from nuclear wastewater. Herein, we have designed a heterojunction photocatalyst constructed from the carbon aerogels (CA) and the CdS nanoflowers with an S-vacancy (CA@CdS-SV). With the S-vacancy and heterojunction being synergized, the U(VI) removal rate exceeded 97% in 40 min without the addition of any sacrificial agents. As impacted by the synergistic effects of the S-vacancy and heterojunction, thermodynamics and kinetics revealed that photogenerated electrons were first captured via shallow traps generated by vacancies on CdS-SV and then transferred to the CA surfaces through the heterojunction to realize the spatial separation of carriers, thereby achieving a satisfactory performance. This work is considered to underpin the improvement of U(VI) immobilization by exploiting the synergistic effect of vacancy engineering and the Schottky heterojunction from the perspective of thermodynamics and kinetics.

Large quantities of uranium-containing radioactive wastewater are typically generated during nuclear fuel cycle processes. Despite significant efforts, efficient capture of migratable hexavalent uranium U(VI) is still a huge challenge due to its acidity, radioactivity, coexisting organics, and high impurity cation abundance in wastewater. Herein, we have fabricated all-polymer-based 0D/2D C4N/C6N7homostructure hybrids with an S-scheme electronic configuration by coordinating the band engineering of semiconductors to enrich uranium species from the complex wastewater environment. The sample can capture over 97% of U(VI) in the actual concentration of nuclear industrial reprocessing wastewater; also, the U(VI) enrichment ratio still exceeds 95% when the irradiation dose (including α, β, and γ) is up to 100 kGy. Density functional theory and X-ray absorption spectroscopy demonstrate that the aggregation of charge carriers on the surface of the sample regulates the electron-rich microenvironment, thus accelerating the reduction conversion of single electron reaction uranium disproportionation. It is expected that this work can provide more insight into other functional materials, thereby promoting uranium removal advancements in nuclear wastewater.

Uranium accumulation in the kidneys and bones following internal contamination results in severe damage, emphasizing the pressing need for the discovery of actinide decorporation agents with efficient removal of uranium and low toxicity. In this work, cinnamic acid (3-phenyl-2-propenoic acid, CD), a natural aromatic carboxylic acid, is investigated as a potential uranium decorporation ligand. CD demonstrates markedly lower cytotoxicity than that of diethylenetriaminepentaacetic acid (DTPA), an actinide decorporation agent approved by the FDA, and effectively removes approximately 44.5% of uranyl from NRK-52E cells. More importantly, the results of the prompt administration of the CD solution remove 48.2 and 27.3% of uranyl from the kidneys and femurs of mice, respectively. Assessments of serum renal function reveal the potential of CD to ameliorate uranyl-induced renal injury. Furthermore, the single crystal of CD and uranyl compound (C9H7O2)2·UO2(denoted as UO2–CD) reveals the formation of uranyl dimers as secondary building units. Thermodynamic analysis of the solution shows that CD coordinates with uranyl to form a 2:1 molar ratio complex at a physiological pH of 7.4. Density functional theory (DFT) calculations further show that CD exhibits a significant 7-fold heightened affinity for uranyl binding in comparison to DTPA.

The low efficient transfer of photogenerated electrons to an active catalytic site is a pivotal problem for the photoreduction of highly soluble hexavalent uranium [U(VI)] to low soluble tetravalent uranium [U(IV)]. Herein, we successfully synthesized a TiO2–x/1T-MoS2/reduced graphene oxide heterojunction (T2–xTMR) with dual charge-transfer channels by exploiting the difference in Fermi levels between the heterojunction interfaces, which induced multilevel separation of photogenerated carriers. Theoretical and experimental results demonstrate that the presence of the electron buffer layer promoted the efficient migration of photogenerated electrons between the dual charge-transfer channels, which achieved effective separation of photogenerated carriers in physical/spatial dimensions and significantly extended the lifetime of photogenerated electrons. The migration of photogenerated electrons to the active catalytic site after multilevel spatial separation enabled the T2–xTMR dual co-photocatalyst to remove 97.4% of the high concentration of U(VI) from the liquid-phase system within 80 min. This work provides a practical reference for utilizing multiple co-catalysts to accomplish directed spatial separation of photogenerated carriers.