Uranium extraction from seawater provides an opportunity for sustainable fuel supply to nuclear power plants. Herein, an adsorption–electrocatalysis strategy is demonstrated for efficient uranium ...extraction from seawater using a functionalized iron–nitrogen–carbon (Fe–Nx–C–R) catalyst, comprising N‐doped carbon capsules supporting FeNx single‐atom sites and surface chelating amidoxime groups (R). The amidoxime groups bring hydrophilicity to the adsorbent and offer surface‐specific binding sites for UO22+ capture. The site‐isolated FeNx centres reduce adsorbed UO22+ to UO2+. Subsequently, through electrochemical reduction of the FeNx sites, unstable U(V) ions are reoxidized to U(VI) in the presence of Na+ resulting in the generation of solid Na2O(UO3·H2O)x, which can easily be collected. Fe–Nx–C–R reduced the uranium concentration in seawater from ≈3.5 ppb to below 0.5 ppb with a calculated capacity of ≈1.2 mg g‐1 within 24 h. To the best of the knowledge, the developed system is the first to use the adsorption of uranyl ions and electrodeposition of solid Na2O(UO3.H2O)x for the extraction of uranium from seawater. The important discoveries guide technology development for the efficient extraction of uranium from seawater.
A novel adsorption–electrocatalysis system is developed for efficiently extracting uranium from seawater. Amidoxime groups impart Fe–Nx–C–R with hydrophilicity and a high binding affinity for uranyl ions, whilst the iron sites provides a reversible electron‐transfer platform for the eventual production of Na2O(UO3·H2O)x in the presence of Na+, thus allowing facile uranium recovery and Fe–Nx–C–R reuse.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Covalent organic frameworks (COFs) represent an emerging class of organic photocatalysts. However, their complicated structures lead to indeterminacy about photocatalytic active sites and reaction ...mechanisms. Herein, we use reticular chemistry to construct a family of isoreticular crystalline hydrazide-based COF photocatalysts, with the optoelectronic properties and local pore characteristics of the COFs modulated using different linkers. The excited state electronic distribution and transport pathways in the COFs are probed using a host of experimental methods and theoretical calculations at a molecular level. One of our developed COFs (denoted as COF-4) exhibits a remarkable excited state electron utilization efficiency and charge transfer properties, achieving a record-high photocatalytic uranium extraction performance of ~6.84 mg/g/day in natural seawater among all techniques reported so far. This study brings a new understanding about the operation of COF-based photocatalysts, guiding the design of improved COF photocatalysts for many applications.
Seawater contains uranium at a concentration of ≈3.3 ppb, thus representing a rich and sustainable nuclear fuel source. Herein, an adsorption–electrocatalytic platform is developed for uranium ...extraction from seawater, comprising atomically dispersed indium anchored on hollow nitrogen‐doped carbon capsules functionalized with flexible amidoxime moieties (In–Nx–C–R, where R denotes amidoxime groups). In–Nx–C–R exhibits excellent uranyl capture properties, enabling a uranium removal rate of 6.35 mg g−1 in 24 h, representing one of the best uranium extractants reported to date. Importantly, In–Nx–C–R demonstrates exceptional selectivity for uranium extraction relative to vanadium in seawater (8.75 times more selective for the former). X‐ray absorption spectroscopy (XAS) reveals that the amidoxime groups serve as uranyl chelating sites, thus allowing selective adsorption over other ions. XAS and in situ Raman results directly indicate that the absorbed uranyl can be electrocatalytically reduced to an unstable U(V) intermediate, then re‐oxidizes to U(VI) in the form of insoluble Na2O(UO3·H2O)x for collection, through reversible single electron transfer processes involving InNx sites. These results provide detailed mechanistic understanding of the uranium extraction process at a molecular level. This work provides a roadmap for the adsorption–electrocatalytic extraction of uranium from seawater, adding to the growing suite of technologies for harvesting valuable metals from the earth's oceans.
Porous indium−nitrogen−carbon capsules functionalized with flexible amidoxime groups enable highly efficient uranium extraction from seawater. The flexible amidoxime groups allow selective uranyl adsorption, while the InNx single atom sites provide a reversible single electron transfer platform for uranyl conversion to a harvestable Na2O(UO3·H2O)x precipitate via a U(V) intermediate.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
This letter presents an adaptive synchronization scheme between two different kinds of delayed chaotic neural networks (NNs) with partly unknown parameters. An adaptive controller is designed to ...guarantee the global asymptotic synchronization of state trajectories for two different chaotic NNs with time delay. An illustrative example is given to demonstrate the effectiveness of the present method.
Radioiodine capture from nuclear fuel waste and contaminated water sources is of enormous environmental importance, but remains technically challenging. Herein, we demonstrate robust covalent organic ...frameworks (COFs) with antiparallel stacked structures, excellent radiation resistance, and high binding affinities toward I
, CH
I, and I
under various conditions. A neutral framework (ACOF-1) achieves a high affinity through the cooperative functions of pyridine-N and hydrazine groups from antiparallel stacking layers, resulting in a high capacity of ~2.16 g/g for I
and ~0.74 g/g for CH
I at 25 °C under dynamic adsorption conditions. Subsequently, post-synthetic methylation of ACOF-1 converted pyridine-N sites to cationic pyridinium moieties, yielding a cationic framework (namely ACOF-1R) with enhanced capacity for triiodide ion capture from contaminated water. ACOF-1R can rapidly decontaminate iodine polluted groundwater to drinking levels with a high uptake capacity of ~4.46 g/g established through column breakthrough tests. The cooperative functions of specific binding moieties make ACOF-1 and ACOF-1R promising adsorbents for radioiodine pollutants treatment under practical conditions.
Fudan University (FDU)-type mesoporous polymer (FDU-15) was sulfonated by fuming sulfuric acid. The application of FDU-15 and sulfonated FDU-15 (FDU-15-SO
3
H/t, t = 9 h, 18 h, or 27 h) in removing ...of U(VI) was explored comprehensively. The adsorbents were characterized by various techniques. The effects of sulfonation time, initial pH values, shaking time, initial concentrations, and temperature on adsorption were optimized. Besides, the desorption and reusability, as well as adsorptive selectivity were investigated. The results indicated high adsorption (43.65 ± 2.11 mg g
−1
) was achieved under weak acid condition (pH 2.0) for FDU-15-SO
3
H/9 h. In short, FDU-15-SO
3
H/9 h may be a superior adsorbent to remove the U(VI) in wastewater.
In this work, hexadecyltrimethylammonium-bromide (HTAB)-modified polythiophene (PTh)/TiO
2
nanocomposite (HTAB/PTh/TiO
2
) was applied to remove uranyl ions (UO
2
2+
). FT-IR, XRD, ζ potential, TGA, ...SEM, and XPS were utilized to obtain the chemical and physical properties of HTAB/PTh/TiO
2
. The effects of HTAB content, preparation temperature, and adsorption conditions on UO
2
2+
removal were investigated comprehensively. And the UO
2
2+
adsorption process on HTAB/PTh/TiO
2
was fitted to the Sips model with a saturated adsorption capacity of 234.74 mg/g, which was 6 times over TiO
2
. The results suggested that the surfactant of HTAB can significantly improve the adsorption ability of TiO
2
for UO
2
2+
ions. This work provides a strategy of surfactant modification for enhancing the separation and recovery ability of adsorbent toward UO
2
2+
in the radioactive wastewater.
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CEKLJ, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Hereditary primary hyperparathyroidism (PHPT) accounts for 5-10% of all PHPT cases, necessitating genetic testing for diagnosis and management. Among these, hyperparathyroidism-jaw tumor syndrome ...(HPT-JT) is an autosomal dominant disorder caused by
mutations with variable clinical presentations and incomplete symptoms.
The proband, diagnosed with PHPT, underwent parathyroidectomy at the age of 41 with pathological examination of parathyroid carcinoma (PC). Hereditary PHPT was initially suspected due to the early-onset PHPT and family history. Genetic testing identified a heterozygous
mutation, NM_024529.4: c. 687_688delAG (p. Arg229Serfs*37). Even in the absence of jaw tumors, the diagnosis of HPT-JT was confirmed based on the discovery of renal cysts. A secondary thyroidectomy was performed to reduce the risk of recurrence.
Genetic testing is strongly recommended in cases of early-onset PHPT, family history, jaw tumors, renal and uterine involvement, atypical parathyroid tumors, and PC. This testing provides valuable information for personalized management, and counseling is available for affected families.
The rice stalk (RS) was pretreated using torrefaction in a fixed-bed reactor at 200, 240, and 280 °C, respectively. The torrefied rice stalk (TRS) was liquefied in a batch autoclave with ...supercritical ethanol as the medium at 325 °C and 14–15 MPa for a residence time of 60 min to obtain bio-oil. The TRS was analyzed via Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). It was observed from SEM results that the compact, uniform, and lamellar structure of RS was broken down, whereas the FTIR and chemical composition analysis results showed that the thermal decomposition of hemicellulose was the main reaction that occurred between 200 and 280 °C. Gas chromatography–mass spectrometry (GC–MS) results showed that the bio-oil obtained from TRS at a temperature of 200 °C had the highest ester content of 30.60% and the lowest acid content of 0.35% and also the alcohols of bio-oil reached the maximum value of 20.56% at a temperature of 240 °C. The water content slightly decreased from 2.23 to 1.31% when the torrefaction temperature was increased from 200 to 280 °C, and the heating value reached a maximum value of 32.53 MJ/kg at a temperature of 200 °C; however, the bio-oil yield gradually decreased from 55.03% of non-torrefied RS to 49.80% of TRS at 200 °C to 38.56% of TRS at 280 °C.
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IJS, KILJ, NUK, PNG, UL, UM
Optimizing the electronic structure of covalent organic framework (COF) photocatalysts is essential for maximizing photocatalytic activity. Herein, we report an isoreticular family of multivariate ...COFs containing chromenoquinoline rings in the COF structure and electron‐donating or withdrawing groups in the pores. Intramolecular donor‐acceptor (D‐A) interactions in the COFs allowed tuning of local charge distributions and charge carrier separation under visible light irradiation, resulting in enhanced photocatalytic performance. By optimizing the optoelectronic properties of the COFs, a photocatalytic uranium extraction efficiency of 8.02 mg/g/day was achieved using a nitro‐functionalized multicomponent COF in natural seawater, exceeding the performance of all COFs reported to date. Results demonstrate an effective design strategy towards high‐activity COF photocatalysts with intramolecular D‐A structures not easily accessible using traditional synthetic approaches.
A strategy is reported to regulate local charge distributions and intramolecular donor‐acceptor interactions in multivariate covalent organic frameworks (COFs). By fine‐tuning the donor‐acceptor (D‐A) interactions, a COF with a record‐high uranium extraction efficiency of 8.02 mg/g/day in natural seawater under visible light was realized.
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