Photoreduced Ag+/sodium alginate supramolecular hydrogel as a sensitive SERS membrane substrate for rapid detection of uranyl ions.

BACKGROUND: In the fields of environmental monitoring and nuclear emergency, in order to obtain the relevant information of uranyl-induced environmental pollution and nuclear accident, it is necessary to establish a rapid quantitative analytical technique for uranyl ions. As a new promising technique, surface-enhanced Raman scattering (SERS) is hopeful to achieve this goal. However, uranyl ions are easily desorbed from SERS substrates under acidic conditions, and the structures of SERS substrates will be destroyed in the strong acidic aqueous solutions. Besides, the quantitative detection ability of SERS for uranyl ions needs to be promoted. Hence, it is necessary to develop new SERS substrates for accurate quantitative detection of trace uranyl in environmental water samples, especially in acidic solutions. RESULTS: In this work, we prepared silver ions/sodium alginate supramolecular hydrogel membrane (Ag+/SA SMH membrane), and the Ag+ ions from the membrane were transformed into Ag/Ag2O complex nanoparticles under laser irradiation. The Raman signal of uranyl was strongly enhanced under the synergistic interaction of electromagnetic enhancement derived from the Ag nanoparticles and charge transfer enhancement between uranyl and Ag2O. Utilizing the peak of SA (550 cm-1) as an internal standard, a quantitative detection with a LOD of 6.7 × 10-9 mol L-1 was achieved due to a good linear relation of uranyl concentrations from 1.0 × 10-8 mol L-1 to 2 × 10-6 mol L-1. Furthermore, foreign metal ions hardly affected the SERS detection of uranyl, and the substrate could determine trace uranyl in natural water samples. Particularly, the acidity had no obvious effect on SERS signals of uranyl ions. Therefore, in addition to the detection of uranyl ions in natural water samples, the proposed strategy could also detect uranyl ions in strong acidic solutions. SIGNIFICANCE AND NOVELTY: A simple one-step method was used to prepare an Ag+/SA SMH membrane for rapid quantitative detection of uranyl ions for the first time. The proposed substrate successfully detected uranyl ions under acidic conditions by immobilizing uranyl ion in hydrogel structure. In comparison with the previous studies, a more accurate quantitative analysis for uranyl ions was achieved by using an internal standard, and the proposed strategy could determine trace uranyl in either natural water samples or strong acidic solutions.

Extraction of uranyl from spent nuclear fuel wastewater via complexation-a local vibrational mode study.

CONTEXT: The efficient extraction of uranyl from spent nuclear fuel wastewater for subsequent reprocessing and reuse is an essential effort toward minimization of long-lived radioactive waste. N-substituted amides and Schiff base ligands are propitious candidates, where extraction occurs via complexation with the uranyl moiety. In this study, we extensively probed chemical bonding in various uranyl complexes, utilizing the local vibrational modes theory alongside QTAIM and NBO analyses. We focused on (i) the assessment of the equatorial O-U and N-U bonding, including the question of chelation, and (ii) how the strength of the axial U = O bonds of the uranyl moiety changes upon complexation. Our results reveal that the strength of the equatorial uranium-ligand interactions correlates with their covalent character and with charge donation from O and N lone pairs into the vacant uranium orbitals. We also found an inverse relationship between the covalent character of the equatorial ligand bonds and the strength of the axial uranium-oxygen bond. In summary, our study provides valuable data for a strategic modulation of N-substituted amide and Schiff base ligands towards the maximization of uranyl extraction. METHOD: Quantum chemistry calculations were performed under the PBE0 level of theory, paired with the relativistic NESCau Hamiltonian, currently implemented in Cologne2020 (interfaced with Gaussian16). Wave functions were expanded in the cc-pwCVTZ-X2C basis set for uranium and Dunning's cc-pVTZ for the remaining atoms. For the bonding properties, we utilized the package LModeA in the local modes analyses, AIMALL in the QTAIM calculations, and NBO 7.0 for the NBO analyses.

Highly sensitive and selective determination of uranyl ions based on Ag/Ag2O-COF composite SERS substrate.

Uranium is an essential nuclear material in civilian and military areas; however, its extensive application raises concerns about the potential safety issues in the fields of environmental protection and nuclear industry. In this study, we developed an Ag/Ag2O-COF (covalent-organic framework) composite SERS substrate to detect uranyl ions (UO22+) in environmental aqueous solutions. Herein, the strong SERS effect of uranyl adsorbed in Ag/Ag2O composite and the high adsorption efficiency of COF TpPa-1 were combined to realize the trace detection of uranyl ions. This method displayed a linear range of 10-8 mol L-1 to 10-6 mol L-1 with the detection limit of 8.9 × 10-10 mol L-1 for uranyl ions. Furthermore, common metal cations and oxo-ions hardly affected the SERS detection of uranyl, which is helpful for the trace analysis of uranyl in natural water samples. Although the proposed strategy is deployed for uranyl detection, the reusable and high-efficiency system may be expanded to trace detection of other substance with Raman activity.

U(V) Stabilization via Aliovalent Incorporation of Ln(III) into Oxo-salt Framework.

Pentavalent uranium compounds are key components of uranium's redox chemistry and play important roles in environmental transport. Despite this, well-characterized U(V) compounds are scarce primarily because of their instability with respect to disproportionation to U(IV) and U(VI). In this work, we provide an alternate route to incorporation of U(V) into a crystalline lattice where different oxidation states of uranium can be stabilized through the incorporation of secondary cations with different sizes and charges. We show that iriginite-based crystalline layers allow for systematically replacing U(VI) with U(V) through aliovalent substitution of 2+ alkaline-earth or 3+ rare-earth cations as dopant ions under high-temperature conditions, specifically Ca(UVIO2)W4O14 and Ln(UVO2)W4O14 (Ln=Nd, Sm, Eu, Gd, Yb). Evidence for the existence of U(V) and U(VI) is supported by single-crystal X-ray diffraction, high energy resolution X-ray absorption near edge structure, X-ray photoelectron spectroscopy, and optical absorption spectroscopy. In contrast with other reported U(V) materials, the U(V) single crystals obtained using this route are relatively large (several centimeters) and easily reproducible, and thus provide a substantial improvement in the facile synthesis and stabilization of U(V).

Novel Olefin-Linked Covalent Organic Framework with Multifunctional Group Modification for the Fluorescence/Smartphone Detection of Uranyl Ion.

Monitoring and purification of uranium contamination are of great importance for the rational utilization of uranium resources and maintaining the environment. In this work, an olefin-linked covalent organic framework (GC-TFPB) and its amidoxime-modified product (GC-TFPB-AO) are synthesized with 3-cyano-4,6-dimethyl-2-hydroxypyridine (GC) and 1,3,5-tris(4-formylphenyl) benzene (TFPB) by Knoevenagel condensation. GC-TFPB-AO results in specificity for rapid fluorescent/smartphone uranyl ion (UO22+) detection based on the synergistic effect of multifunctional groups (amidoxime, pyridine, and hydroxyl groups). GC-TFPB-AO features a rapid and highly sensitive detection and adsorption of UO22+ with a detection limit of 21.25 nM. In addition, it has a good recovery (100-111%) for fluorescence detection in real samples, demonstrating an excellent potential of predesigned olefin-linked fluorescent COFs in nuclear contaminated wastewater detection and removal.

Spatially Resolved Raman Spectroscopic Investigation of Uranyl Fluoride: A Case Study in the Importance of Instrument Optimization.

Raman spectroscopy is an emerging technique for rapid and nondestructive analysis of nuclear materials for forensic and nonproliferation applications as it is a powerful tool for distinguishing multiple chemical forms of materials with similar stoichiometries. Recent developments in spectroscopic software have enabled rapid data collection with high-speed Raman spectroscopic mapping capabilities. However, some uranium-rich materials are susceptible to degradation in humid air and/or laser-induced phase transformations. To mitigate environmental or measurement-related sample degradation of potential samples of interest, we have taken a systematic approach to define optimized data collection parameters for high-throughput measurements of uranyl fluoride (UO2F2), which is an important intermediate material in the nuclear fuel cycle. First, we systematically describe the influence of optical magnification (5× to 100×), laser power, and exposure time on obtained signal for identical particles of UO2F2 and find that at low laser power and exposure times, comparable signal is obtained regardless of optical magnification. Second, we ensure sample integrity during data collection, and third, collect spectroscopic maps that employ optimized parameters to reduce the time required to obtain spatially resolved spectroscopic information. Reductions of 90% and 99% in measurement times are discussed as they relate to differences in resolving spectroscopic features of particles in identical mapping areas. During this work, we found that additional data processing options were needed and thus developed a customized Python script for importing, processing, analyzing, and visualizing Raman spectroscopic map data.

Open-Framework Vanadate as Efficient Ion Exchanger for Uranyl Removal.

The elimination of uranium from radioactive wastewater is crucial for the safe management and operation of environmental remediation. Here, we present a layered vanadate with high acid/base stability, [Me2NH2]V3O7, as an excellent ion exchanger capturing uranyl from highly complex aqueous solutions. The material possesses an indirect band gap, ferromagnetic characteristic and a flower-like morphology comprising parallel nanosheets. The layered structure of [Me2NH2]V3O7 is predominantly upheld by the H-bond interaction between anionic framework [V3O7]nn- and intercalated [Me2NH2]+. The [Me2NH2]+ within [Me2NH2]V3O7 can be readily exchanged with UO22+. [Me2NH2]V3O7 exhibits high exchange capacity (qm = 176.19 mg/g), fast kinetics (within 15 min), high removal efficiencies (>99%), and good selectivity against an excess of interfering ions. It also displays activity for UO22+ ion exchange over a wide pH range (2.00-7.12). More importantly, [Me2NH2]V3O7 has the capability to effectively remove low-concentration uranium, yielding a residual U concentration of 13 ppb, which falls below the EPA-defined acceptable limit of 30 ppb in typical drinking water. [Me2NH2]V3O7 can also efficiently separate UO22+ from Cs+ or Sr2+ achieving the highest separation factors (SFU/Cs of 589 and SFU/Sr of 227) to date. The BOMD and DFT calculations reveal that the driving force of ion exchange is dominated by the interaction between UO22+ and [V3O7]nn-, whereas the ion exchange rate is influenced by the mobility of UO22+ and [Me2NH2]+. Our experimental findings indicate that [Me2NH2]V3O7 can be considered as a promising uranium scavenger for environmental remediation. Additionally, the simulation results provide valuable mechanistic interpretations for ion exchange and serve as a reference for designing novel ion exchangers.

The Role of Alkalis in Orchestrating Uranyl-Peroxide Reactivity Leading to Direct Air Capture of Carbon Dioxide.

Spectator ions have known and emerging roles in aqueous metal-cation chemistry, respectively directing solubility, speciation, and reactivity. Here, we isolate and structurally characterize the last two metastable members of the alkali uranyl triperoxide series, the Rb+ and Cs+ salts (Cs-U1 and Rb-U1). We document their rapid solution polymerization via small-angle X-ray scattering, which is compared to the more stable Li+, Na+ and K+ analogues. To understand the role of the alkalis, we also quantify alkali-hydroxide promoted peroxide deprotonation and decomposition, which generally exhibits increasing reactivity with increasing alkali size. Cs-U1, the most unstable of the uranyl triperoxide monomers, undergoes ambient direct air capture of CO2 in the solid-state, converting to Cs4[UVIO2(CO3)3], evidenced by single-crystal X-ray diffraction, transmission electron microscopy, and Raman spectroscopy. We have attempted to benchmark the evolution of Cs-U1 to uranyl tricarbonate, which involves a transient, unstable hygroscopic solid that contains predominantly pentavalent uranium, quantified by X-ray photoelectron spectroscopy. Powder X-ray diffraction suggests this intermediate state contains a hydrous derivative of CsUVO3, where the parent phase has been computationally predicted, but not yet synthesized.

Electron Microscopy Methods for Phage-Based Study.

Electron microscopy (EM) techniques play a vital role in virology research including phage discovery and their identification. The use of different staining protocols based on the concept of negative staining is one of the most important steps in the EM processing. This chapter will summarize the widely used EM protocols in phage research, their advantages, and limitations. Phage-based therapy, especially recently developed nanoparticle-phage conjugates, are expected to find clinical significance in the antimicrobial resistance (AMR) epidemic. EM techniques are important to characterize these conjugates and we will also discuss the methods here.

Interlayer manipulation of bio-inspired Ti3C2Tx nanocontainer through intercalation of amino acid molecules to dramatically boosting uranyl hijacking capability from seawater.

More than 4.5 billion tons of unconventional uranium resources [UO2(CO3)3]4- are uniformly dissolved in seawater, providing a sustainable and abundant fuel source for the development of nuclear energy. Herein, we presented a rational design and development of Ti3C2Tx nanocontainer inspired by the exceptional selectivity and affinity exhibited by superb-uranyl proteins through amino acid intercalation. The amino acid intercalation of Ti3C2Tx demonstrated exceptional UO22+ capture capacity (Arg-Ti3C2Tx, His-Ti3C2Tx, and Lys-Ti3C2Tx with qmax values of 594.46, 846.04, and 1030.17 mg/g). Furthermore, these intercalated materials exhibited remarkable sequestration efficiency and selectivity (Uinitial = ∼45.2 ∼7636 µg/L; ∼84.45% ∼98.08%; and ∼2.72 ×104 ∼1.28 ×105 KdU value), despite the presence of an overwhelming surplus of Na+, Ca2+, Mg2+, and Co2+ ions. Significantly, even in the 0.3 M NaHCO3 solution and surpassing 103-fold of the Na3VO4 system, the adsorption efficiency of Lys-Ti3C2Tx still achieved a remarkable 63.73% and 65.05%. Moreover, the Lys-Ti3C2Tx can extract ∼30.23 ∼8664.03 µg/g uranium after 24 h contact in ∼13.3 ∼5000 µg/L concentration from uranium-spiked natural seawater. The mechanism analysis revealed that the high binding capability can be attributed to the chelation of carboxyl and amino groups with uranyl ions. This innovative state-of-the-art approach in regulating uranium harvesting capability through intercalation of amino acid molecules provides novel insights for extracting uranium from seawater.

Superoxide Radicals in Uranyl Peroxide Solids: Lasting Signatures Identified by Electron Paramagnetic Resonance Spectroscopy.

U(VI) peroxide phases (studtite and meta-studtite) are found throughout the nuclear fuel cycle and exist as corrosion products in high radiation fields. Peroxides are part of a family of reactive oxygen species (ROS) that include hydroperoxyl and superoxide species and are produced during alpha radiolysis of water. While U(VI) peroxides have been thoroughly investigated, the incorporation and stability of ROS species within studtite have not been validated. In the current study, electron paramagnetic resonance (EPR) spectroscopy was used to identify the presence of free radicals within a series of U(VI) peroxide samples containing depleted, highly enriched, and natural uranium. Density functional theory calculations indicated that the predicted EPR signals matched well with a superoxide (O2 -⋅) species incorporated into the studtite structure, confirming the presence of ROS in the material. Further analysis of samples that were synthesized between 1945 and 2023 indicated that there is a correlation between the radical signal and the product of specific activity multiplied by age of the sample.

Fluorescent Eu-MOF@nanocellulose-based nanopaper for rapid and sensitive detection of uranium (â ¥).

Radioactive uranium leaks into natural water bodies mainly in the form of uranyl ions (UO22+), posing ecological and human health risks. Fluorescent europium-based metal-organic frameworks (Eu-MOFs) have been demonstrated to be effective fluorescent sensors for UO22+, but the large size, powder state and poor dispersity limit their further application. In this work, fluorescent Eu-MOFs were in-situ grown on TEMPO-oxidized cellulose nanofibers (TOCNFs), which is the first time that spherical Eu-MOF crystals with sizes below 10 nm were prepared. Fluorescence spectral analysis revealed a nine-fold increase in the fluorescence intensity of TOCNF@Eu-MOF compared to Eu-MOF. The nanocomposites achieved rapid and sensitive fluorescence quenching to UO22+ through the "antenna effect" and unsaturated Lewis basic sites on the ligands binding with UO22+. Moreover, TOCNF@Eu-MOF demonstrated excellent selectivity and anti-interference for UO22+ detection. For the nanopaper-based sensor made from TOCNF@Eu-MOF, the Stern-Volmer quenching constant (KSV) was calculated as 8.21 × 104 M-1, and the lowest limit of detection (LOD) was 6.6 × 10-7 M, significantly lower than the 1.32 × 10-6 M of Eu-MOFs. In addition, the nanopaper exhibited good fluorescence stability and cyclic detection performance, enabling the rapid and convenient detection of UO22+ in the aqueous phase within 30 s by simple dipping.

Research on the Formation Conditions and Preventive Measures of Uranium Precipitates during the Service Process of Medical Isotope Production Reactors.

This study focuses on the Medical Isotope Production Reactor (MIPR), an aqueous homogeneous reactor utilized for synthesizing medical isotopes like 99Mo. A pivotal aspect of MIPR's functionality involves the fuel solution's complex chemical interactions, particularly during reactor operation. These interactions result in the formation of precipitates, notably water filamentous uranium ore and columnar uranium ore, which can impact reactor performance. The research presented here delves into the reactions between liquid fuel uranyl nitrate and key radiolytic products, employing simulation calculations complemented by experimental validation. This approach facilitates the identification of uranium precipitate types and their formation conditions under operational reactor settings. Additionally, the article explores strategies to mitigate the formation of specific uranium precipitates, thereby contributing to the efficient and stable operation of MIPR.

Uranyl ammonium carbonate precipitation and conversion into triuranium octaoxide.

Uranyl ammonium carbonate (AUC), with the chemical formula UO2CO3·2(NH4)2CO3, plays a crucial role in the wet conversion of uranium hexafluoride (UF6) into uranium dioxide (UO2) or triuranium octaoxide (U3O8) for nuclear fuel production, and is used in commercial and research reactors. In this study, the precipitation of AUC from uranyl fluoride (UO2F2) solution and its subsequent conversion into U3O8 powder were investigated. AUC precipitation was performed at uranium concentrations in UO2F2 solution of 80-120 gL-1, ammonium carbonate (NH4)2CO3 concentrations of 200-400 gL-1, and (NH4)2CO3 to U (C/U) ratios of 5-9. The conversion of AUC into U3O8 powder was studied and sintering of the U3O8 nuclear material derived from ammonium uranyl carbonate (ex-AUC U3O8) was conducted at temperatures of 1000-1800 °C. The kinetics of AUC precipitation from the UO2F2 solution were studied using fundamental kinetic equations, and the kinetics of AUC conversion into UO3 were examined using an isoconversion method based on the thermogravimetric analysis of AUC. The final product of U3O8 nuclear material was characterized using typical techniques, such as thermogravimetric analysis, X-ray diffraction, and scanning electron microscopy. This study provides valuable insights into the production and characterization of AUC and U3O8 nuclear materials, which are key materials in the nuclear fuel industry.

Insights into enhanced immobilization of uranyl carbonate from seawater by Fe-doped MXene.

Extracting uranium from seawater not only reduces radioactive contamination in seawater but also provides a source of uranium energy. However, due to the low concentration of uranium in seawater and the high salinity of seawater, extraction of uranium from seawater is challenging. In this work, we demonstrated a simple strategy to synthesize Fe-doped MXene (Fe@Ti3C2Tx) via a hydrothermal method and applied for uranium enrichment in seawater. The Fe@Ti3C2Tx exhibited excellent adsorption performance in high salinity environments. The removal capacity of Fe@Ti3C2Tx was determined to be 526.6 mg/g for UO2(CO3)22- at 328 K with quick reaction equilibrium (∼ 30 min). Kinetic and thermodynamic analyses of UO2(CO3)22- elimination process on Fe@Ti3C2Tx surface revealed it to be a spontaneous and endothermic single-phase elimination process. FT-IR and XPS analyses further indicated that the removal mechanism of UO2(CO3)22- by Fe@Ti3C2Tx was surface complexation. Our study suggests that Fe@Ti3C2Tx can provide a feasible solution for uranium enrichment in seawater.

Design of Promising Uranyl(VI) Complexes Thin Films with Potential Applications in Molecular Electronics.

In this work, it is proposed the development of organic semiconductors (OS) based on uranyl(VI) complexes. The above by means of the synthesis and the characterization of the complexes by Infrared spectroscopy, Nuclear magnetic resonance spectroscopy, mass spectrometry, and X-ray diffraction. Films of these complexes were deposited and subsequently, topographic and structural characterization was carried out by Scanning Electron Microscopy, X-ray diffraction, and Atomic Force Microscopy. Additionally, the nanomechanical evaluation was performed to know the stiffness of uranyl films using their modulus of elasticity. Also, the optical characterization took place in the devices and their bandgap value ranges between 2.40 and 2.93 eV being the minor for the film of the uranyl complex with the N on pyridine in position 4 (2 c). Finally, the electrical behavior of the uranyl(VI) films was evaluated, and important differences were obtained: the uranyl complex with the N on pyridine in position 2 (2 a) film is not influenced by changes in lighting and its current density is in the order of 10-3 A/cm2. The film with uranyl complex with the N on pyridine in position 3 (2 b) and 2 c presents a greater current flow under lighting conditions and two orders of magnitude larger than in film 2 a. In these films 2 b and 2 c, ohmic behavior occurs at low voltages, while at high voltages the charge transport changes to space-charge limited current behavior.

Plant polyphenol surfactant construction with strong surface activity and chelation properties as efficient decontamination of UO22+ on cotton fabric.

Chemically synthesized surfactants have promising applications in the treatment of uranium, however, their hazardous environmental effects, non-biodegradability, and numerous drawbacks prevent them from being widely used in practice. Herein, we successfully synthesized a green chelating and foaming integrated surfactant (BTBS) by Mannich reaction and acylation of bayberry tannin for the effective removal of UO22+ from aqueous environments or solid surfaces. The as-prepared surfactant was systematically characterized by FT-IR, showing that the hydrophobic groups were successfully grafted onto tannin. The modified material showed better foaming and emulsifying properties, which proved this method could improve the amphiphilicity of tannin. Moreover, for the first time, a foam fractionation method in conjunction with a tannin-based surfactant was applied for UO22+ removal from water. This surfactant was used as a co-surfactant and could readily remove 90 % of UO22+ (20 mg L-1) from water. The removal of UO22+ could be completed in a short time (30 min), and the maximum adsorption capacity was determined as 175.9 mg g-1. This surfactant can also be used for efficient decontamination of uranium-contaminated cotton cloth with a high removal rate of 94.55 %. In addition, the mechanism studies show that the adsorption of BTBS for UO22+ can be mainly attributed to a chelating mechanism between UO22+ and the adjacent phenolic hydroxyls. The novel biomass-derived BTBS with advantages such as high capture capacity, environmental friendliness, and cost-effectiveness suggests that it plays an important role in the remediation of radionuclide pollution.

Adsorption of uranium (VI) complexes with polymer-based spherical activated carbon.

Adsorption processes with carbon-based adsorbents have received substantial attention as a solution to remove uranium from drinking water. This study investigated uranium adsorption by a polymer-based spherical activated carbon (PBSAC) characterised by a uniformly smooth exterior and an extended surface of internal cavities accessible via mesopores. The static adsorption of uranium was investigated applying varying PBSAC properties and relevant solution chemistry. Spatial time-of-flight secondary ion mass spectrometry (ToF-SIMS) was employed to visualise the distribution of the different uranium species in the PBSAC. The isotherms and thermodynamics calculations revealed monolayer adsorption capacities of 28-667 mg/g and physical adsorption energies of 13-21 kJ/mol. Increasing the surface oxygen content of the PBSAC to 10 % enhanced the adsorption and reduced the equilibrium time to 2 h, while the WHO drinking water guideline of 30 µgU/L could be achieved for an initial concentration of 250 µgU/L. Uranium adsorption with PBSAC was favourable at the pH 6-8. At this pH range, uranyl carbonate complexes (UO2CO3(aq), UO2(CO3)22-, (UO2)2CO3(OH)3-) predominated in the solution, and the ToF-SIMS analysis revealed that the adsorption of these complexes occurred on the surface and inside the PBSAC due to intra-particle diffusion. For the uranyl cations (UO22+, UO2OH+) at pH 2-4, only shallow adsorption in the outermost PBSAC layers was observed. The work demonstrated the effective removal of uranium from contaminated natural water (67 µgU/L) and meeting both German (10 µgU/L) and WHO guideline concentrations. These findings also open opportunities to consider PBSAC in hybrid treatment technologies for uranium removal, for instance, from high-level radioactive waste.

Crystal structures of three uranyl-acetate-bipyridine complexes crystallized from hydraulic fracking fluid.

Hydraulic fracking exposes shale plays to acidic hydraulic fracking fluid (HFF), releasing toxic uranium (U) along with the desired oil and gas. With no existing methods to ensure U remains sequestered in the shale, this study sought to add organic ligands to HFF to explore potential U retention in shale plays. To test this possibility, incubations were set up in which uranyl acetate and one organic bipyridine ligand (either 2,2'-, 2,3'-, 2,4'-, or 4,4'-bipyridine) were added to pristine HFF as the crystallization medium. After several months and complete evaporation of all volatiles, bulk yellow crystalline material was obtained from the incubations, three of which yielded crystals suitable for single-crystal analysis, resulting in two novel structures and a high-quality structure of a previously described compound. The UO2VI acetate complexes bis(acetato-κ2O,O')(2,2'-bipyridine-κ2N,N')dioxidouranium(VI), [U(C2H3O2)2O2(C10H8N2)2] or [2,2'-bipyridine]UVIO2(CH3CO2)2, (I), and bis(acetato-κ2O,O')(2,4'-bipyridine-κN1')dioxidouranium(VI), [U(C2H3O2)2O2(C10H8N2)2] or [2,4'-bipyridine]2UVIO2(CH3CO2)2, (III), contain eight-coordinate UVI in a pseudo-hexagonal bipyramidal coordination geometry and are molecular, packing via weak C-H...O/N interactions, whereas catena-poly[bis(2,3'-bipyridinium) [di-µ-acetato-µ3-hydroxido-µ-hydroxido-di-µ3-oxido-hexaoxidotriuranium(VI)]-2,3'-bipyridine-water (1/1/1)], (C10H9N2)2[U3(C2H3O2)2O8(OH)2]·C10H8N2·H2O or {[2,3'-bipyridinium]2[2,3'-bipyridine][(UVIO2)3(O)2(OH)2(CH3CO2)2·H2O]}n, (II), forms an ionic one-dimensional polymer with seven-coordinate pentagonal bipyramidal UVI centers and hydrogen-bonding interactions within each chain. The formation of these crystals could indicate the potential for bipyridine to bind with U in shale during fracking, which will be explored in a future study via ICP-MS (inductively coupled plasma mass spectrometry) analyses of U concentration in HFF/bipyridine/shale incubations. The variation seen here between the molecular structures may indicate variance in the ability of bipyridine isomers to form complexes with U, which could impact their ability to retain U within shale in the context of fracking.

Perilla frutescens: A new strategy for uranium decorporation.

Radionuclide uranium is a great threat to human health, due to its high chemical toxicity and radioactivity. Finding suitable uranium decorporation to reduce damage caused by uranium internal contamination is an important aspect of nuclear emergency response. However, the poor selectivity and/or high toxicity of the only excretory promoter approved by Food and Drug Administration (FDA) is an obvious disadvantage. Herein, we choose an edible natural product, the traditional Chinese medicine called Perilla frutescens (PF), which has wide sources and can be used as an excellent and effective uranyl decorporation. In vivo uranium decorporation assays illustrate the removal efficiency of uranium in kidney were 68.87% and 43.26%, in femur were 56.66% and 54.53%, by the test of prophylactic and immediate administration, respectively. Cell level experiments confirmed that it had better biocompatibility than CaNa3-DTPA (CaNa3-diethylenetriamine pentaacetate, a commercial actinide excretion agent). In vitro static adsorption experiments exhibited that its excellent selectivity sorption for uranyl. All those results findings would provide new research insights about natural product for uranyl decorporation.