In Vivo Uranium Sequestration using a Nanoscale Metal-Organic Framework

Self-Aggregated Nanoscale Metal-Organic Framework for Targeted Pulmonary Decorporation of Uranium

The limited availability of effective agents for removing actinides from the lungs significantly restricts the effectiveness of medical treatments for nuclear emergencies. Inhalation is the primary route of internal contamination in 44.3% of actinide-related accidents, leading to the accumulation of radionuclides in the lungs and resulting in infections and potential tumor formation (tumorigenesis). This study focuses on the synthesis of a nanometal-organic framework (nMOF) material called ZIF-71-COOH, which is achieved by post-synthetic carboxyl functionalization of ZIF-71. The material demonstrates high and selective adsorption of uranyl, while also exhibiting increased particle size (≈2100 nm) when it aggregates in the blood, enabling passive targeting of the lungs through mechanical filtration. This unique property facilitates the rapid enrichment and selective recognition of uranyl, making nano ZIF-71-COOH highly effective in removing uranyl from the lungs. The findings of this study highlight the potential of self-aggregated nMOFs as a promising drug delivery system for targeted uranium decorporation in the lungs.

Boosting Simultaneous Uranium Decorporation and Reactive Oxygen Species Scavenging Efficiency by Lacunary Polyoxometalates

The chemical toxicity and the oxidative stress induced by the internal exposure of uranium is responsible for the long-term adverse effect of in vivo contamination of uranium. An agent with simultaneous removal capability of uranium and excess reactive oxygen species (ROS) is highly desired. Herein, the lacunary Keggin-type polyoxometalate (POM) is demonstrated to selectively bind with uranyl ions in the presence of excess essential divalent ions and exhibits a compelling ROS scavenging efficiency of 78.8%. In vivo uranium decorporation assays illustrate the uranium sequestration efficiencies of 74.0%, 49.4%, and 37.1% from kidneys by prophylactic, prompt, and delayed administration of lacunary POM solution, respectively. The superior ROS quenching and uranium removal performance in comparison with all reported bifunctional agents endow lacunary polyoxometalates as novel agents to effectively protect people from injuries caused by the internal exposure of actinides.

Metal-Organic Frameworks and Their Composites for Environmental Applications

From the point of view of the ecological environment, contaminants such as heavy metal ions or toxic gases have caused harmful impacts on the environment and human health, and overcoming these adverse effects remains a serious and important task. Very recent, highly crystalline porous metal-organic frameworks (MOFs), with tailorable chemistry and excellent chemical stability, have shown promising properties in the field of removing various hazardous pollutants. This review concentrates on the recent progress of MOFs and MOF-based materials and their exploit in environmental applications, mainly including water treatment and gas storage and separation. Finally, challenges and trends of MOFs and MOF-based materials for future developments are discussed and explored.

Highly efficient immobilization of environmental uranium contamination with Pseudomonas stutzeri by biosorption, biomineralization, and bioreduction

Uranium is a heavy metal with both chemotoxicity and radiotoxicity. Due to the increasing consumption of uranium, the remediation of uranium contamination and recovery of uranium from non-conventional approach is highly needed. Microorganism exhibits high potential for immobilization of uranium. This study for the first time isolated a marine Pseudomonas stutzeri strain MRU-UE1 with high uranium immobilization capacity of 308.72 mg/g, which is attributed to the synergetic mechanisms of biosorption, biomineralization, and bioreduction. The uranium is found to be immobilized in forms of tetragonal chernikovite (H₂(UO₂)₂(PO₄)₂·8H₂O) by biomineralization and CaU(PO₄)₂ by bioreduction under aerobic environment, which is rarely observed and would broaden the application of this strain in aerobic condition. The protein, phosphate group, and carboxyl group are found to be essential for the biosorption of uranium. In response to the stress of uranium, the strain produces inorganic phosphate group, which transformed soluble uranyl ion to insoluble uranium-containing precipitates, and poly-β-hydroxybutyrate (PHB), which is observed for the first time during the interaction between microorganism and uranium. In summary, P. stutzeri strain MRU-UE1 would be a promising alternative for environmental uranium contamination remediation and uranium extraction from seawater.

Synthesis of core-shell magnetic metal organic frameworks composite for efficient uranium (VI) removal

The combination of magnetic nanoparticles and metal-organic frameworks (MOFs) has demonstrated their prospective for pollutant sequestration. In this work, Fe3O4@SiO2@UiO-66 core-shell magnetic microspheres were synthesized and used for the removal...

Confinement effect of layered double hydroxide on intercalated pyromellitic acidic anions and highly selective uranium extraction from simulated seawater

The oxygen-rich pyromellitic acidic anions (PMA4-) have been intercalated into MgAl-layered double hydroxide to fabricate the MgAl-PMA-LDH (abbr. PMA-LDH) composite, exhibiting excellent adsorption performance toward uranium (U(VI)). Benefiting from the...

Rationally Tailoring Pore and Surface Properties of Metal-Organic Frameworks for Boosting Adsorption of Dy3

The adsorption and recovery of dysprosium ions (Dy³⁺) from industrial wastewater are necessary but still challenging. Herein, we constructed a series of defect-containing metal-organic frameworks (MOFs) [UiO-66-(COOH)₂] using sodium benzoate (BCNa) as a modulator. Upon the formation of defects, the porosity and surface charge properties of the MOFs were improved, leading to a higher utilization ratio of active groups and higher adsorption capacities for Dy³⁺. The synthesized UiO-66-(COOH)₂-B10 with an optimal addition of BCNa exhibited a superior adsorption capacity of 150.6 mg g^-1. Fast adsorption occurred at ∼5 min, and equilibrium was reached at ∼60 min. Higher pH and temperature were found to be beneficial for boosting Dy³⁺ adsorption, and selective adsorption over other metal ions was achieved in a multicomponent solution. Further, FTIR spectroscopy and XPS investigations indicate that free carboxyl contributes to the capture of Dy³⁺. Thus, this work provides a promising strategy to enhance the utilization ratio of active groups and further adsorption performance.

Anti-bacterial and super-hydrophilic bamboo charcoal with amidoxime modified for efficient and selective uranium extraction from seawater

With the growing demand for nuclear energy, uranium extraction from seawater (UES) is becoming increasingly important due to the ocean reserves 4.5 billion tons for uranium(VI) [U(VI)]. Herein, two kinds of amidoxime modified bamboo charcoal (AOOBCS and AOOBCH) with porous structure, anti-bacterial, and super-hydrophilic properties were successfully synthetized by two etching methods (soaking and hydrothermal). The super-hydrophilic property of AOOBCH accelerated the contact between the amidoxime group and uranyl ions (UO₂²⁺), and promoted the action of anti-bacterial substances (bamboo-quinone) on bacteria to restrain the form of bacterial membrane. In addition, the amidoxime groups not only didn't destroy the super-hydrophilic surface, but also adjusted the adsorbents' pK_a by changing the amidoxime grafting rate. Under PH = 7, the adsorption capacity of AOOBCH was about 1.97 times that of AOOBCS and 2.95 times that of BC. Importantly, the AOOBCH exhibited ultra-high uptake capacity (6.37 mg g^-1) and exceptional selectivity for U(VI) in 100-fold interfering ions simulated seawater system due to the chelation between C(NH₂)NOH and UO₂²⁺ to form a more stable coordination structure (E_ads = -36.56 eV). Benefiting from the superior performance and selectivity, the AOOBCH is a potential candidate for UES.

Metal-Organic-Framework Based Functional Materials for Uranium Recovery: Performance Optimization and Structure/Functionality-Activity Relationships

Uranium recovery has profound significance in both uranium resource acquisition and pollution treatment. In recent years, metal-organic frameworks (MOFs) have attracted much attention as potential uranium adsorbents owing to their tunable structural topology and designable functionalities. This review explores the research progress in representative classic MOFs (MIL-101, UiO-66, ZIF-8/ZIF-67) and other advanced MOF-based materials for efficient uranium extraction in aqueous or seawater environments. The uranium uptake mechanism of the MOF-based materials is refined, and the structure/functionality-property relationship is further systematically elucidated. By summarizing the typical functionalization and structure design methods, the performance improvement strategies for MOF-based adsorbents are emphasized. Finally, the present challenges and potential opportunities are proposed for the breakthrough of high-performance MOF-based materials in uranium extraction.

Melanin nanoparticles as an actinide in vivo sequestration agent with radiation protection effect

PEG grafted melanin nanoparticles exhibit codecorporation effect of U and Th as well as good ROS scavenging ability.