Micro-structural analysis of aqueous uranyl ions (UO22+) during the course of forward and back extraction in A biphasic system using all atom atomistic simulations.

Development of a micro separation and analysis system for uranyl ions composed of microplug extraction and liquid scintillation detection.

Polyphenolic polymers for uranium decorporation with radiation protection effect.

This paper reports stability constants for complexes formed between uranyl ions and benzoate, as well as 12 anions of various hydroxybenzoates, determined at T = 298.2 K, p = 0.1 MPa, and ionic strength I = 0.05 M (NaClO4). The relationship between the protolytic properties of the corresponding acids and complex stability is established through analysis of both our experimental data and literature values. A simple incremental approach quantifies the contribution of hydroxyl groups in ortho-, meta-, and para-positions to the stability constants. 13C NMR spectroscopy was employed to identify the functional groups of hydroxybenzoates participating in complexation. Additionally, the crystal structure of [UO2(2,6-DHBA)2(H2O)2]·1.5H2O was refined using X-ray diffraction analysis.

Nanoflower-like covalent organic framework/indium sulfide step scheme heterojunction for selective electrochemical uranium extraction.

Tetradentate phenanthroline-based ligands have demonstrated ability to efficiently extract uranium(VI) from nitric acid solutions. While their coordination with U(VI) has been extensively studied, their behavior toward tetravalent actinides under conditions relevant to spent nuclear fuel reprocessing remains poorly understood. Here, we investigated the extraction and coordination chemistry of Th(IV) in the presence of excess U(VI). Using a combination of solvent extraction, UV-Vis and Raman, we demonstrated that when the organic phase is pre-loaded with the uranyl ion pair [UO2L(NO3)]+[UO2(NO3)3]-, Th(IV) undergoes a selective anion-exchange reaction with the trinitratouranyl anion, forming the mixed ion pair [UO2L(NO3)]+[Th(H2O)2(NO3)5]-. Single-crystal X-ray diffraction further confirms the formation of heterometallic U-Th complexes, including ([UO2L(NO3)]+)2[Th(NO3)6]2-, providing direct structural evidence for mixed-metal ion pairing. These results revealed a previously unrecognized mechanism of Th(IV) uptake driven by anion exchange rather than direct ligand coordination.

Efficient and complete uranium removal from aqueous solution holds immense importance in protecting humans from harmful effects of uranium contamination. Herein, an ultrathin two-dimensional MOF nanosheet with cavity structures was elaborately constructed for uranium removal. The cavity, decorated with extensive adsorption sites (azo groups) inside, can fully utilize the structural advantages of MOF nanosheets in pollutant removal, including significantly exposed surfaces and readily accessible sites. Such features enhanced interactions with uranium, ultimately leading to an exceptionally high adsorption capacity (482.77 mg/g). Moreover, the MOF nanosheets were able to preconcentrate and extract uranium from aqueous solution, owing to the functionalized cavity structure, which achieved ultrahigh removal efficiency (>97%) in the low concentration range of 145-1169 ppb. Even for the ultralow concentration of 21 ppb, 94.29% uranium still can be removed, with an ultralow residual concentration of 1.2 ppb. The MOF nanosheets also exhibited high anti-interference ability, which could efficiently remove low-level uranium from various real samples, with residual uranium well below the WHO limit (30 ppb). Investigations on adsorption mechanism revealed that the synergistic effect between the cage-like cavities and the internal sufficient azo groups with uranyl ions can be responsible for the excellent uranium extraction performance.

Geobacter bacteria use conductive pili and redox-active outer membrane vesicles to mediate metal transformations critical to the effectiveness of bioremediation and energy technologies. Mechanistic knowledge into these processes primarily comes from studies with Geobacter sulfurreducens grown in media closely formulated to mirror the mineral chemistry of contaminated sites. Here we show that, although subtle differences in the media's cationic strength did not measurably change permeability, they reprogrammed outer membrane-peptidoglycan crosslinks tomodulate vesiculation and envelope functions impacting growth efficiency and mineralization. Cations that strongly bind and neutralize peptidoglycan carboxylates to prevent cell wall distortions, such as sodium and uranyl ions, controlled the extent of envelope remodeling and cell bias toward pili-driven uraniummineralization or membrane adsorption and release in vesicles. These findings identify cation chemistry as a key regulator of outer membrane vesiculation and the reprogramming of envelope functions ultimately determining the reproducibility of laboratory studies and effectiveness of bioremediation and energy-harvesting applications.

A synergistic ligand complexation and photocatalytic precipitation strategy for efficient uranium extraction from salt lake.

Photocatalytic uranium extraction can surpass the intrinsic capacity limits of adsorption by converting soluble uranyl into insoluble uranium peroxides via H2O2 generation. However, this process requires simultaneous local enrichment of H2O2 and UO22+ beyond the solubility product constant, which is difficult to achieve in continuously flowing and ultra-dilute seawater. Here we report a hollow hierarchical covalent organic framework (COF) microcavity reactor, HH-COF-(CN/AO)x, that spatially decouples H2O2 generation from uranyl capture to overcome this thermodynamic barrier via a bidirectional reactant flux coupling strategy. A cyano-functionalized inner layer produces and stores H2O2 in a central cavity, whereas an amidoxime-rich outer layer selectively enriches uranyl ions. The convergence of outward H2O2 flux and inward uranyl adsorption establishes a persistent high-concentration interface that supports continuous formation of insoluble uranium peroxide. The optimized HH-COF-(CN/AO)0.35 achieves 25.1 mg g-1 uranium uptake in natural seawater, 3.9 times that of the non-hollow analog, which demonstrates a generalizable strategy for manipulating reactant fluxes in ultra-dilute environments for realizing effective resource extraction from water environment.

Given the high difficulty and poor controllability associated with the direct synthesis of uranium-based metal-organic frameworks (U-MOFs), this study took an alternative approach by utilizing a host-guest chemistry strategy to construct novel uranium-based luminescent materials. A uranyl-functionalized metal-organic framework was synthesized by introducing uranyl ions (UO22+) into the channels of a stable MOF host via a solution impregnation method. Characterization results demonstrated that the as-prepared material fully retained the host framework structure while exhibiting the characteristic luminescence of uranyl and displaying excellent water stability. Luminescence sensing experiments demonstrated the exceptional selectivity and sensitivity of MOF-76(Y)@U toward acetone in aqueous solutions, achieving a directly measured limit of detection (LOD) of 6.75 × 10-6 mol/L via luminescence spectroscopy upon the addition of trace acetone. This study not only provides a facile and efficient approach for the synthesis of novel uranium-based luminescent metal-organic frameworks, but also offers a practical and feasible new method for the low-cost, highly sensitive detection of acetone.

Selective uranium recovery from rare earth leaching solutions is hindered by competing ions and similar chemistry. Herein we propose a "framework-embedded hard base sites" strategy that simultaneously resolves selectivity and charge separation bottlenecks. By anchoring oxygen atoms as hard bases into 1D covalent organic frameworks (COFs), we create a dual-function platform where oxygen sites selectively capture uranyl ions while delocalizing excitons, lowering the exciton binding energy to 56.2 meV. The optimal COF-PODA with the highest density of oxygen sites achieves a high adsorption capacity of 1205 mg g-1 and reduction kinetics of 0.079 min-1. In actual rare earth leaching solution, it removes 99.5% of uranium with outstanding selectivity over lanthanides and retains more than 95% activity after six cycles. This work uncovers an unforeseen synergy between hard-base coordination and electronic modulation, establishing a new design route for advanced radionuclide photocatalysts.

Uranyl ion (UO22+) pollution in marine environments poses a serious threat to human health and aquatic ecosystems. To overcome the dependence of traditional detection methods on large-scale instruments, a portable smartphone-integrated hydrogel kit was reported for on-site quantitative detection of UO22+ with nanozyme technology. Spindle-shaped FeOOH/MnO2 nanozymes with intrinsic oxidase-like activity were fabricated within an agarose hydrogel matrix in a 96-well plate. FeOOH/MnO2 catalyzes the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) without the need of unstable hydrogen peroxide (H2O2). UO22+ causes a distinct blue-to-colorless transition by forming a complex with OX-TMB. Quantification of UO22+ was achieved using either a microplate reader or a smartphone by analyzing the RGB values extracted from the hydrogel wells. The detection limit was 5.53 ppb, which is below the drinking water safety standard of 30 ppb stipulated by the World Health Organization (WHO). To the best of our knowledge, it is the first example of a portable oxidase-like hydrogel kit for UO22+ detection. By merging nanozyme catalysis, hydrogel encapsulation, and smartphone-based readout, this platform provides a reliable, high-throughput, and field-deployable strategy for monitoring uranium contamination and may inspire the development of detection strategies for other marine pollutants.

Spider-web-inspired phosphorylated aerogel engineered via Schiff base linkages for efficient uranium capture.

The uranyl dication ([UO2]2+) is a highly active photocatalyst for the functionalization of inert Csp3-H bonds by direct hydrogen atom abstraction (HAA). However, photocatalysis by the uranyl ion remains underexplored. Most reports are limited to reactions catalyzed by simple uranyl salts, such as uranyl nitrate [UO2(NO3)2·6H2O] (UNO3). We report a set of uranyl tris(benzoate) complexes 1-R containing strongly coordinating and tunable equatorial ligands that resist photodamage and control access to the oxo groups. These catalyst variants with appropriate aryl substituents undergo catalytic reactions at C-H bonds by HAA. The selectivity and reactivity of this step depend on the ligand framework and are distinct from that of UNO3 or other photoactive oxo complexes, such as decatungstate, that lack ancillary ligands. Finally, consistent with the strong, stable axial U-O bond, reaction with exogenous radical acceptors outcompetes radical rebound, enabling C-C and C-N bond formation from the alkyl radical intermediate. Regioselective alkylation and functionalization of a broad range of substrates results, and this photocatalysis shows that modulation of equatorial ligands on [UO2]2+ can influence the reactivity and selectivity of photocatalytic C-H bond functionalization.

Organic frameworks-based optical sensors for uranyl ions: Unveiling mechanisms and applications

Crab pincer-inspired bionic porphyrin-based adsorbent to achieve capture-co-reduction of uranyl ions by dinitrogen chelation

Photocatalytic uranium extraction from wastewater is of great significance for environmental remediation and resource recycling, yet conventional photocatalysts for this purpose suffer from insufficient active sites and low carrier separation efficiency. To address these challenges, we report a rational strategy of constructing sulfur-vacancy-rich Lewis acid sites on two-dimensional 3R-phase ZnIn2S4 nanosheets. The sulfur vacancies, acting as electron-deficient centers, serve as robust Lewis acid sites that can preferentially adsorb uranyl ions. Meanwhile, the synergistic effect between the sulfur vacancies and the 3R-phase crystal structure facilitates charge separation and transfer to drive uranyl photoreduction. This integrated strategy achieves a remarkable enhancement in uranium extraction capacity, increasing from 133 (bulk) to 1320mg/g (sulfur-vacancy-rich nanosheets). Notably, the sample maintains outstanding selectivity for uranium even in the presence of multiple competing ions (each at 100ppm, K+, Ca2+, Mg2+, Zn2+, Co2+, Ni2+, Pb2+, Cu2+, Fe3+, and V5+). Furthermore, the material exhibits inherent anti-biofouling performance (≈100% after 3h) and excellent cycling stability over 10 cycles. Our findings reveal the dual role of sulfur vacancies in photocatalysis as a binding site for uranium and an electronic modulator for charge dynamics, thereby proposing a "phase-defect synergy" design principle for the development of advanced environmental remediation materials.

Heteropore covalent organic framework membranes are predicted to exhibit excellent uranium extraction capabilities due to their combination of rapid transport and strong affinity. However, the growth orientation of covalent organic framework networks is susceptible to disturbance when a supporting substrate is introduced, posing a major challenge to the fabrication of covalent organic framework membranes with well-defined hierarchical pores. Here, a general synthetic method is introduced for the preparation of heteropore covalent organic framework membranes. By pre-coating covalent organic framework nanoparticles onto a nylon substrate, the subsequent covalent organic framework network grows following the orientation of the nanoparticles under solvothermal conditions. This method demonstrates remarkable versatility across a broad range of covalent organic framework systems, including single-pore (with sql net) and dual-pore (with kgm net) networks. Several heteropore covalent organic framework membranes are fabricated with pore sizes ranging from 7.1/26.9 Å to 11.2/34.3 Å and 14.0/42.1 Å. The covalent organic framework membrane with 7.1/26.9 Å dual-pores exhibits the fastest uranyl ion transport rate among all Schiff-base porous membranes, which is 4.3 times faster than that of typical covalent organic framework membranes with single-pore channels. After irradiation treatment, the covalent organic framework membrane enables the conversion of uranium (VI) ions from seawater into insoluble precipitates, which suggests a versatile design paradigm for heteropore covalent organic framework membranes with synthetically engineered functionalities.

ABSTRACT Tributyl phosphate (TBP)-impregnated styrene-divinylbenzene (STY-DVB)-SiO2 composite resins with controlled cross-linking degree (CL = 34, 56, 68, and 90%) were evaluated for U(VI) uptake in acidic media (5 M HNO3 and 9 M HCl) using a feed containing U, Th, Sr, Ag, and Cs. Selectivity tests showed dominant U(VI) adsorption, with negligible uptake of Sr and Cs and only trace Ag; Th exhibited moderate adsorption in HNO3. Kinetic profiles (1–240 min) were analyzed by pseudo-first-order and pseudo-second-order models, and PSO provided the better fit within the linearized analysis used here. The intermediate CL resin (CL = 56%) showed the fastest uptake. Apparent equilibrium isotherms (0.1–10 mg L−1) were well described by both linearized Langmuir and Freundlich models; Langmuir R L values (0–1) indicated favorable uptake. Overall, the results indicate that CL strongly influences the accessibility and uptake rate of TBP-containing domains under the present conditions.