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An agent for actinide sequestration with fast uranium uptake kinetics and efficient in vivo uranium removal using a nanoscale metal-organic framework (nano-MOF) is proposed. UiO-66 nanoparticles post-synthetically functionalized with carboxyl groups, UiO-66-(COOH) 4 -180, exhibit the fastest uranium uptake kinetics reported with more than 65 % of uranyl in fetal bovine serum (FBS) removed within 5 min. Moreover, the in vivo bio-distribution studies show that the material partially accumulates in kidneys and femurs where uranium mainly deposits facilitating the in vivo sequestration of uranium. The results of the in vivo uranium decorporation assays with mice show that UiO-66-(COOH) 4 -180 could successfully reduce the amounts of uranyl deposited in kidneys and femurs by up to 55.4 % and 36.5 %, respectively, and is significantly more efficient than the commercial actinide decorporation agent, ZnNa 3 -DTPA., (© 2020 Wiley-VCH GmbH.)

Searching for actinide decorporation agents with advantages of high decorporation efficiency, minimal biological toxicity, and high oral efficiency is crucial for nuclear safety and the sustainable development of nuclear energy. Removing actinides deposited in bones after intake is one of the most significant challenges remaining in this field because of the instantaneous formation of highly stable actinide phosphate complexes upon contact with hydroxyapatite. Here we report a hydroxypyridinone-based ligand (5LIO-1-Cm-3,2-HOPO) exhibiting stronger affinity for U(VI) compared with the reported tetradentate hydroxypyridinone ligands. This is further revealed by the first principles calculation analysis on bonding between the ligand and uranium. Both in vitro uranium removal assay and in vivo decorporation experiments with mice show that 5LIO-1-Cm-3,2-HOPO can remove uranium from kidneys and bones with high efficiencies, while the decorporation efficiency is nearly independent of the treatment time. Moreover, this ligand shows a high oral decorporation efficiency, making it attractive for practical applications.

Most of the key radionuclides in the nuclear fuel cycle, such as actinides, possess a combination of heavy metal chemotoxicity and radiotoxicity and therefore represent a severe threat to the ecological environment and public safety. The radiotoxicity originates from direct radiation-induced organ damage and indirect damage, mostly through radiation-induced reactive oxygen species (ROS). Although effective chelating agents that can accelerate the excretion of actinides, such as uranium, have been developed in the past several decades, very few of them can reduce radiation-induced damage from internal contamination. In fact, the strategy of simultaneous removal of actinides and their induced-ROS in vivo has scarcely been considered. Here, we report a 3,2-hydroxypyridinone-grafted chitosan oligosaccharide nanoparticle (COS-HOPO) as a new type of decorporation agent that is effective for the removal of both uranium and ROS in vivo. The cytotoxicity and decorporation assays indicate that the marriage of chitosan oligosaccharide (COS) and hydroxypyridinone (HOPO) gives rise to a remarkable decrease in toxicity and promotion of the uranium removal capability from both kidneys and femurs. The decorporation efficacy can reach up to 43% in rat proximal tubular epithelial cells (NRK-52E), 44% in kidneys, and 32% in femurs. Moreover, the ROS levels of the cells treated with COS-HOPO are significantly lower than those of the control group, implying a promising radiation protection effect. The detoxification mechanism of COS-HOPO is closely related to both chelating U(VI)- and scavenging U(VI)-induced intracellular ROS.

The Kunduleng granite hosts one of several significant uranium anomalies within the southern Great Xing'an Range, NE China. Whole-rock geochemistry and mineral chemistry data, along with the zircon U-Pb-Hf isotope have been used to constrain the petrogenesis of this granitic intrusion and the origin of the uranium anomaly. Microscopically, quartz, alkali-feldspar, and plagioclase are the essential mineral constituents of the granite, with minor biotite, while monazite, apatite, xenotime, and zircon are accessory minerals. Geochemically, the silica- and alkali-rich granites show a highly fractionated character with "seagull-shaped" REE patterns and significant negative anomalies of Ba and Sr, along with low Zr/Hf and Nb/Ta ratios. The granite has positive zircon εHf(t) values ranging from +12.7 to +14.5 and crustal model ages (TDM2) of 259–376 Ma, indicating a Paleozoic juvenile crustal source. Uraninite and brannerite are the main radioactive minerals responsible for the uranium anomaly within the Kunduleng granite. Uraninite presents well-developed cubic crystals and occurs as tiny inclusions in quartz and K-feldspar with magmatic characteristics (e.g., elevated ThO2, Y2O3, and REE2O3 contents and low CaO, FeO, and SiO2 concentrations). The calculated U-Th-Pb chemical ages (135.4 Ma) are contemporaneous with the U-Pb zircon age (135.4–135.6 Ma) of the granite, indicating a magmatic genesis for uraninite. The granites are highly differentiated, and extreme magmatic fractionation might be the main mechanism for the initial uranium enrichment. Brannerite is relatively less abundant and typically forms crusts on ilmenite and rutile or it cements them, representing the local redistribution and accumulation of uranium. [ABSTRACT FROM AUTHOR]

We disclose the intrinsic semiconducting properties of one of the largest mixed‐valent uranium clusters, [H3O+][UV(UVIO2)8(μ3‐O)6(PhCOO)2(Py(CH2O)2)4(DMF)4] (Ph=phenyl, Py=pyridyl, DMF=N,N‐dimethylformamide) (1). Single‐crystal X‐ray crystallography demonstrates that UV center is stabilized within a tetraoxo core surrounded by eight uranyl(VI) pentagonal bipyramidal centers. The oxidation states of uranium are substantiated by spectroscopic data and magnetic susceptibility measurement. Electronic spectroscopy and theory corroborate that UV species serve as electron donors and thus facilitate 1 being a n‐type semiconductor. With the largest effective atomic number among all reported radiation‐detection semiconductor materials, charge transport properties and photoconductivity were investigated under X‐ray excitation for 1: a large on‐off ratio of 500 and considerable charge mobility lifetime product of 2.3×10−4 cm2 V−1, as well as a high detection sensitivity of 23.4 μC Gyair−1 cm−2. [ABSTRACT FROM AUTHOR]

An agent for actinide sequestration with fast uranium uptake kinetics and efficient in vivo uranium removal using a nanoscale metal–organic framework (nano‐MOF) is proposed. UiO‐66 nanoparticles post‐synthetically functionalized with carboxyl groups, UiO‐66‐(COOH)4‐180, exhibit the fastest uranium uptake kinetics reported with more than 65 % of uranyl in fetal bovine serum (FBS) removed within 5 min. Moreover, the in vivo bio‐distribution studies show that the material partially accumulates in kidneys and femurs where uranium mainly deposits facilitating the in vivo sequestration of uranium. The results of the in vivo uranium decorporation assays with mice show that UiO‐66‐(COOH)4‐180 could successfully reduce the amounts of uranyl deposited in kidneys and femurs by up to 55.4 % and 36.5 %, respectively, and is significantly more efficient than the commercial actinide decorporation agent, ZnNa3‐DTPA. [ABSTRACT FROM AUTHOR]

The design and synthesis of uranium sorbent materials with high uptake efficiency, capacity and selectivity, as well as excellent hydrolytic stability and radiation resistance remains a challenge. Herein, a polyoxometalate (POM)–organic framework material (SCU‐19) with a rare inclined polycatenation structure was designed, synthesized through a solvothermal method, and tested for uranium separation. Under dark conditions, SCU‐19 can efficiently capture uranium through ligand complexation using its exposed oxo atoms and partial chemical reduction from UVI to UIV by the low‐valent Mo atoms in the POM. An additional UVI photocatalytic reduction mechanism can occur under visible light irradiation, leading to a higher uranium removal without saturation and faster sorption kinetics. SCU‐19 is the only uranium sorbent material with three distinct sorption mechanisms, as further demonstrated by X‐ray photoelectron spectroscopy (XPS) and X‐ray absorption near edge structure (XANES) analysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel Zr(IV)-based MOF with high-density free carboxylic groups was constructed. • The MOF demonstrates high stability and excellent uranium removal performance. • Dynamic sorption tests highlight its potential for treating radioactive wastewater. • The mechanism for its excellent ability to adsorb U(VI) was investigated. The extraction of uranium from aqueous environments, including the ocean and radioactive wastewater, represents a significant challenge with profound implications for energy resources and environmental remediation. This work presents the design and synthesis of a novel highly stable carboxylated metal–organic framework, BUT-12-3COOH, which achieves excellent U(VI) extraction ability from water. BUT-12-3COOH features high-density free carboxylic groups, exceptional chemical stability, fast kinetics, and high adsorption capacity for U(VI). Dynamic sorption experiments further demonstrated the potential of BUT-12-3COOH in treating real radioactive wastewater. The mechanisms for the U(VI) capture of BUT-12-3COOH are investigated through the combination of EDS, FT-IR, and XPS analysis. The results of this study underscore the promising utility of BUT-12-3COOH as an effective sorbent for extracting radionuclides from environmental specimens and liquid nuclear waste streams. [ABSTRACT FROM AUTHOR]

• New uranyl uptake strategy with combined complexation and photoreduction is shown. • An ultrahigh uranyl uptake capacity not limited by the sorption site is achieved. • Uranyl can be removed completely regardless of its initial concentration. • Uranyl extraction is not affected by the coexisting metal cations. Uranium enrichment is perhaps the most critical chemical process throughout the nuclear fuel cycle including uranium mining, uranium extraction from seawater, used fuel reprocessing and disposal, and environmental contamination remediation. New uranium extraction technology is still highly desirable at current stage, although a variety of extraction methods have been established and developed in the past several decades but all with clear demerits. Herein we present a new uranium extraction strategy with combined ligand complexation and photocatalytic reduction based on postsynthetically functionalized metal-organic frameworks (MOFs). The highly robust and photoactive MOF PCN-222 is modified with phosphono- and amino groups that can capture U(VI) from solution. Upon visible light irradiation, the photo-induced electrons from the MOF host can efficiently reduce U(VI) pre-enriched in MOF, affording neutral uranium species that evacuate the MOF structure and regenerating the active site readily for capturing additional U(VI). This auto-recycled process offers an ultrahigh uranium extraction capacity not limited by the number of adsorption sites and more importantly an extra uranium uptake selectivity over these non-redox-active competing metal cations, and can be utilized for uranium separation over extremely wide uranium concentrations and pH ranges, showing a powerful application potential. [ABSTRACT FROM AUTHOR]