Detection Of Uranium Research Articles

Economical amidoxime-functionalized non-porous β-cyclodextrin polymer for selective detection and extraction of uranium

Herein, a dual-functional adsorbent (amidoxime-functionalized non-porous β-cyclodextrin polymer (AO-NPCDP)) with simultaneous detection and adsorption of U(VI) is developed. Fascinatingly, the luminescence intensity of AO-NPCDP could be selectively and efficiently quenched by U(VI) with a quenching rate of 80.5 % in 30 s. The adsorption of U(VI) on AO-NPCDP results in fluorescence quenching with an ultra-low detection limit (10.3 nM) in deionized water, which is much lower than the maximum contamination standard in drinking water of the World Health Organization contamination limit for U(VI) in drinking water (63 nM). More importantly, AO-NPCDP exhibits high sensitivity in detecting U(VI) ions in natural water systems such as lake water, seawater and tap water with the calculated detection limits of 63.5 nM, 22.2 nM and 17.6 nM, respectively. Moreover, the AO-NPCDP can be easily regenerated using a gentle washing procedure and maintains a high reusability of 95.8 % after 7 adsorption–desorption cycles. Density functional theory (DFT) calculation shows that the fluorescence mechanism between AO-NPCDP and U(VI) is photo-induced electron transfer. The sensitivity and selectivity as well as the economy and high reusability reveal the promise of AO-NPCDP for on-site, real-time monitoring and adsorption of U(VI).

“Two-in-one” dual-function luminescent MOF hydrogel for onsite ultra-sensitive detection and efficient enrichment of radioactive uranium in water

In consideration of the severe hazards of radioactive uranium pollution and the growing demand of uranium resources, the novel sensor/adsorbent composite was creatively developed to integrate the dual functions for on-site detection of uranium contamination and efficient recovery of uranium resources. By hybridizing the luminescent 3D terbium (III) metal–organic framework (Tb–MOF) with sodium alginate (SA) gel using terbium (III) as cross-linker, the Tb-MOF/Tb-AG was fabricated with multi-luminescence centers and sufficient binding sites for uranium. Notably, the ultra-high sensitivity with detection limit as low as 1.2 ppt was achieved, which was 4 orders of magnitude lower than the uranium contamination standard in drinking water (USEPA) and even comparable to the sensitivity of the ICP-MS. Furthermore, the very wide quantification range (1.0 ×10−9-5.0 ×10−4 mol/L), remarkable adsorption capacity (549.0 mg/g) and outstanding anti-interference ability have been achieved without sophisticated sample preparation procedures. Applied in complex natural water samples from Uranium Tailings and the Pearl River, this method has shown good detection accuracy. The ultra high sensitivity and great adsorption capacity for uranium could be ascribed to the synergistic coordination, hydrogen bonding and ion exchange between uranium and Tb-MOF/Tb-AG. The mechanisms were explored by infrared spectroscopy, batch experiments, X-ray photoelectron studies and energy dispersive spectroscopic studies. In addition, the Tb-MOF/Tb-AG can be reused for uranium adsorption.

A fluorescent N-doped carbon dot-hydrogel composite for concurrent selective detection and local hot spot promoted adsorption of uranium(vi)

N-doped carbon dot-embedded cellulose-based fluorescent hydrogel composite (CMH–NCDs) with 3D hydrophilic hierarchical pore network and confined convection exhibited concurrent selective detection and adsorption of uranium(vi) from nuclear water.

Simultaneous detection and separation of uranium based on a fluorescent amidoxime-functionalized covalent organic polymer

To ensure the long-term sustainable development of nuclear energy as well as the prevention and control of uranium pollution, new materials that can simultaneously detect and separate uranium are still urgently needed. Herein, a new fluorescent covalent organic polymer (COP), namely HT-COP-AO, was synthesized andemployed as both the fluorescent probe and absorbent for simultaneous uranium detection and separationconsidering its excellent fluorescence property and strong uranium coordination ability. The results showed that the fluorescence of HT-COP-AO was quickly quenched by uranium within 2 min, and the limit of detection was 0.23 µM (3σ/K). Further studies implied that uranium was coordinated with the amidoxime groups of HT-COP-AO through U-N and O = U = O bonds, which resulted in electron transfer from uranium to HT-COP-AO and quenching the fluorescence of HT-COP-AO consequently. Meanwhile, HT-COP-AO exhibited excellent absorption ability towards uranium, and the maximum absorption capacity (qmax = 401.3 mg/g) was higher than most reported amidoxime modified materials. The HT-COP-AO also showed high selectivity for both uranium detection and separation which makes it a great promising for uranium monitoring in real water samples.

Total reflection X-ray spectroscopy based detection of uranium and thorium in phosphogypsum simulated by Monte Carlo method

Detection of trace amounts of uranium and thorium in phosphogypsum using total reflection X-ray fluorescence (TXRF) was addressed by Monte Carlo method (MCNP code, version 6.2). The simulated samples contained average concentrations of 238U (120 Bq/kg) and 232Th (40 Bq/kg), as well as 7 major components in oxide forms and other 11 heavy metals in trace amounts, commonly found in PG. It was found that, for a molybdenum target X-ray tube operating under total reflection condition and equipped with an SDD detector, the detection limit for uranium and thorium in the simulated multi-elemental sample are (1.42±0.04)ng and (1.03±0.02)ng, respectively. Based on parameters of certified solutions for uranium and thorium, and adding gallium as an internal standard element, calibration plots provided mass recovery from the multi-component sample with relative errors of 4.56% for uranium and 2.74% for thorium. Our results show that TXRF technique can accurately detect and quantify trace amounts of uranium and thorium in the presence of matrix effects without any pre-treatment of PG samples.

Membrane-Based Electrochemical Detection of Uranium: A Review

The determination of uranium in environmental samples has always been a crucial environmental issue due to its adverse impacts on human life. Electrochemical detection is one of the most suitable methods for directly determining uranium because of its portable instrument and quick response characteristics. The ion-selective membrane in the working electrodes is selectively responsible for uranium transport and separation. This mini-review provides a general overview of the membrane-based ion-selective electrodes in detecting uranium ions reported in the literature. The ion-selective membranes are classified according to their ionophore categories. Furthermore, the limits and outlook are also discussed to provide a reference for further developing membrane-based electrochemical uranium sensors.

A three-dimensional luminescent covalent organic framework for rapid, selective, and reversible uranium detection and extraction

Uranium is a key fuel for nuclear reactions, but it also causes serious public health concerns to human beings when leaked into the environment. Exploring new strategies for simultaneous uranium detection and extraction is highly desirable for public health and environmental protection. Herein, a hydroxyl-functionalized 3D covalent organic framework (termed TAPM-DHBD) with strong fluorescence and 3D interconnected pore channels is synthesized and evaluated for uranium detection and extraction. TAPM-DHBD exhibits an exceptional uranium extraction capacity of 955.3 mg g−1 as well as fast kinetics due to the plentiful selective binding sites on the extremely accessible pore channels of 3D interconnected micropore skeleton. Interestingly, due to the signal amplification of the 3D conjugated skeleton, it has a rapid-response time of 2 s and an ultra-low detection limit of 4.08 nM UO22+ suitable for sensitive and on-site monitoring the radioactive uranium contamination of the extracted water. Furthermore, TAPM-DHBD exhibits excellent regenerable performance at least six cycles. This study provides a new strategy for constructing high-performance 3D COFs for radioactive contamination monitoring and strategic nuclides extraction.

Raw signal improvement using beam shaping plasma modulation for uranium detection in ore using laser-induced breakdown spectroscopy

Real-time quantitative detection of uranium in ores is one of the major challenges for uranium exploration. Laser-induced breakdown spectroscopy (LIBS) has been regarded as a most promising technique for this application. However, due to the matrix complexity as well as low uranium concentration of ore, the detection sensitivity of LIBS for uranium in ores is still unsatisfactory. This work explored the potential of a beam-shaping plasma modulation method to improve the limit of detection of uranium in ores. By shaping the profile of laser beam from normally Gaussian distribution to flat-top, the plasma was modulated to be more excited with reduced peak electron density at the laser-plasma interaction point for plasma shielding reduction especially at high laser energy as well as to be more morphologically stable for LIBS signal repeatability improvement. It was further found that this method enhanced LIBS signal intensity mainly by increasing the plasma temperature, while the electron density was almost unchanged, which was very attractive for uranium detection in ore since one of the major problem for uranium detection was that it is hard to find clear uranium spectral lines for analysis due to the high dense emission lines of ore samples in real cases and lower electron density, indicated less line broadening and less line overlap or interferences. A clear uranium emission line has been found in crowded ore spectra, and the intensity of U II 409.013 nm based on flat-top beam was about 5 times higher than that of Gaussian beam, and the relative standard deviation (RSD) of the signal was reduced by about 50%. Moreover, the LOD of uranium in ores was estimated to be 21.2 ppm with flat-top beam, indicating that beam shaping is a promising method for rapid and accurate detection of uranium in ores.

Novel biocompatible and sensitive visual sensor based on aggregation-induced emission for on-site detection of radioactive uranium in water and live cell imaging

In consideration of the severe hazards of radioactive uranium pollution, the rapid assessment of uranium in field and in vivo are urgently needed. In this work a novel biocompatible and sensitive visual fluorescent sensor based on aggregation-induced emission (AIE) was designed for onsite detection of UO22+ in complex environmental samples, including wastewater from Uranium Plant, river water and living cell. The AIE-active sensor (named as TPA-SP) was prepared with a “bottom-up” strategy by introducing a trianiline group (TPA) with a single-bond rotatable helix structure into the salicylaldehyde Schiff-base molecule. The photophysical properties, cytotoxicity test, recognition mechanism and the analytical performance for the detection of UO22+ in actual water samples and cell imaging were systematically investigated. TPA-SP exhibited high sensitivity and selectivity toward UO22+ as well as outstanding anti-interference ability against large equivalent of different ions in a wide effective pH range. A good linear relationship in the UO22+ concentration range of 0.05–1 μM was obtained with a low limit of detection (LOD) of 39.4 nM (9.38 ppb) for uranium detection. The prepared visual sensor showed great potential for fast risk assessment of uranium pollution in environmental systems. In addition, our results also indicated that the TPA-SP exhibited very low cytotoxicity in cells and demonstrated great potential for uranium detection in vivo.

An Optical Fiber Sensor for Uranium Detection in Water.

An optical sensor for uranyl has been prepared based on a gold-plated D-shaped plastic optical fiber (POF) combined with a receptor consisting of a bifunctional synthetic molecule, 11-mercaptoundecylphosphonic acid (MUPA), with a phosphonic group for complexing the considered ion, and a sulfide moiety through which the molecule is fixed at the gold resonant surface as a molecular layer in an easy and reproducible way. The sensor is characterized by evaluating the response in function of the uranyl concentration in aqueous solutions of different compositions and real-life samples, such as tap water and seawater. The mechanism of the uranyl/MUPA interaction was investigated. Two different kinds of interactions of uranyl with the MUPA layer on gold from water are observed: a strong one and a weak one. In the presence of competing metal ions as Ca2+ and Mg2+, only the strong interaction takes place, with a high affinity constant (around 107 M−1), while a somewhat lower constant (i.e., around 106 M−1) is obtained in the presence of Mg2+ which forms stronger complexes with MUPA than Ca2+. Due to the high affinity and the good selectivity of the recognition element MUPA, a detection limit of a few μg L−1 is reached directly in natural water samples without any time-consuming sample pretreatment, making it possible for rapid, in situ controls of uranyl by the proposed sensor.

Ultra-sensitive and stable N-doped carbon dots for selective detection of uranium through electron transfer induced UO2+(V) sensing mechanism

Unintended leakage of toxic and radioactive uranyl ion (UO22+) ions poses high harmful to human health and environment, hence its monitoring and detection is of utmost significance. Here, we developed a mild synthetic route to prepare stable N-doped carbon nanodots (CDs) with special hydrophilicity functional groups and graphitic N by polymerization and carbonization of novel norfloxacin precursor with nitrogen heterocyclic structure. The morphology, chemical structure, fluorescent properties, sensing competition and selectivity behaviors of CDs-UO22+ were systematically analyzed. Controllable experiments including low and high concentration CDs-UO22+ and another type of carbon dots (TEA-CDs) with low graphitic N amount using triethanolamine (TEA) precursor without nitrogen heterocyclic structure were designed, which further confirmed the effective coordination and interaction mechanism between CDs and UO22+ that graphitic N in CDs induced the formation UO2+(V) by electron transfer. It is very suitable for on-site and real-time monitoring of UO22+ with an ultra-fast response time (∼20 s) and low detection limit of 20.38 nM (4.7 μg L−1), which is lower than the permissible limits (30 μg L−1) defined by the United States Environmental Protection Agency (EPA). More importantly, different form the liquid sensor, solid sensors (printed test strip and hydrogel) were also successfully employed to monitor UO22+ targets quickly, broadening the potential application for the advanced image encryptions.

Insertion of Hemin into Metal-Organic Frameworks: Mimicking Natural Peroxidase Microenvironment for the Rapid Ultrasensitive Detection of Uranium.

Constructing enzyme-like active sites in mimic enzyme systems is critical for achieving catalytic performances comparable to natural enzymes and can shed light on the natural development of enzymes. In this study, we described a specific hemin-based mimetic enzyme, which was facilely synthesized by the assembly of zeolitic imidazolate framework-l (ZIF-l) and hemin. The obtained hemin-based mimetic enzyme (denoted as ZIF-l-hemin) displayed enhanced peroxidase activity compared to free hemin in solution. Such excellent activity originated from the ZIF-l framework mimicking the active site cavity microenvironment of horseradish peroxidase in terms of axially coordinated histidine and distal histidine. Additionally, the constructed peroxidase mimetic was extremely resistant to a variety of severe circumstances that would normally denature natural enzymes. These characteristics made ZIF-l-hemin a potential platform for the colorimetric sensor of uranium (UO22+) with wide linear ranges (0.25-40 μM) and low limits of detection (0.079 μM). Moreover, the detection mechanism demonstrated that the coordination of uranyl ion with imidazole of ZIF-l-hemin reduced the catalytic efficiency of ZIF-l-hemin. The current work not only proposed a novel approach for fabricating artificial peroxidase but also offered facile colorimetric methods for selective radionuclide detection.

Recent Advances on DNAzyme-Based Biosensors for Detection of Uranyl

Nuclear facilities are widely used in fields such as national defense, industry, scientific research, and medicine, which play a huge role in military and civilian use. However, in the process of widespread application of nuclear technology, uranium and its compounds with high carcinogenic and biologically toxic cause a lot of environmental problems, such as pollutions of water, atmosphere, soil, or ecosystem. Bioensors with sensitivity and specificity for the detection of uranium are highly demand. Nucleic acid enzymes (DNAzyme) with merits of high sensitivity and selectivity for targets as excellent molecular recognition elements are commonly used for uranium sensor development. In this perspective review, we summarize DNAzyme-based biosensors for the quantitative detection of uranyl ions by integrating with diverse signal outputting strategies, such as fluorescent, colorimetry, surface-enhanced Raman scattering, and electrochemistry. Different design methods, limit of detection, and practical applications are fully discussed. Finally, the challenges, potential solutions, and future prospects of such DNAzyme-based sensors are also presented.

Photo-induced graft (co)polymerization of glycidyl methacrylate and acrylonitrile on PET ion-track membranes for electrochemical detection of uranyl ions

Uranium and their compounds are harmful to human health and with rapid development of nuclear industry, development of fast and reliable method of detection of uranium in the environment has become relevant task. In this article, we present the results of preparation of electrochemical sensor based on poly(ethylene terephthalate) ion-track membranes (PET TMs) for sensing of uranium in water. Graft (co)polymerization of glycidyl methacrylate (GMA) and acrylonitrile (AN) and subsequent polymer analogous reactions of grafted chains with formation of amino and amidoxime groups allow us to obtain sensors with LOD of up to 5.45 μg/L (R2 = 0.9981, linear relationship in in concentration range from 1 to 100 μg/L) for PET TMs-g-PAN/PGMA using square wave anodic stripping voltammetry (SW-ASV). The influence of the type of grafted polymer on the sensitivity of sensors was also studied. Optimal parameters that led to functionalization of the surface by photo-induced grafting with preservation of the pore structure were found. Morphology and pore size of the membranes were evaluated by scanning electron microscopy (SEM) and atomic force microscopy (AFM), gas permeability test. Chemical changes on the membrane were proven by infrared spectroscopy (FTIR).

Metal-Organic Framework-Based Materials for Adsorption and Detection of Uranium(VI) from Aqueous Solution.

The steady supply of uranium resources and the reduction or elimination of the ecological and human health hazards of wastewater containing uranium make the recovery and detection of uranium in water greatly important. Thus, the development of effective adsorbents and sensors has received growing attention. Metal–organic frameworks (MOFs) possessing fascinating characteristics such as high surface area, high porosity, adjustable pore size, and luminescence have been widely used for either uranium adsorption or sensing. Now pertinent research has transited slowly into simultaneous uranium adsorption and detection. In this review, the progress on the research of MOF-based materials used for both adsorption and detection of uranium in water is first summarized. The adsorption mechanisms between uranium species in aqueous solution and MOF-based materials are elaborated by macroscopic batch experiments combined with microscopic spectral technology. Moreover, the application of MOF-based materials as uranium sensors is focused on their typical structures, sensing mechanisms, and the representative examples. Furthermore, the bifunctional MOF-based materials used for simultaneous detection and adsorption of U(VI) from aqueous solution are introduced. Finally, we also discuss the challenges and perspectives of MOF-based materials for uranium adsorption and detection to provide a useful inspiration and significant reference for further developing better adsorbents and sensors for uranium containment and detection.

Screening of uranium contamination on waste surfaces using X-ray fluorescence analysis

X-ray fluorescence (XRF) analysis is useful for detecting radionuclides with long half-lives, such as most isotopes of uranium (234U, 235U, and 238U), as the detection of uranium by radiation measurements can be difficult. Therefore, we propose energy dispersive X-ray fluorescence (EDXRF) analysis as a method for the rapid screening of pollution from substances that are contaminated with uranium-containing water droplets. Sealed uranium-containing filter paper, which was used as the contaminated area model, was layered on top of a rubber plate to simulate a rubber plate whose surface was contaminated with uranium. The measured EDXRF spectra revealed a U Lα peak at the tail of a strong Br Kβ peak, and the contribution of this U Lα peak was extracted by peak fitting. The obtained results suggested a linear relationship between the uranium concentration of the filter paper and the signal intensity of the U Lα peak. The proposed method is more sensitive than the α-particle counting method for long half-life radionuclides, and can be used at uranium handling facilities.

An innovative strategy for construction of pH-responsive supramolecular hydrogel from graphene quantum dots clusters toward integration of detection and removal of uranium

A novel supramolecular hydrogel (GQDs-GSH), generated from self-assembly between the reduced graphene oxide (RGO) and in-situ formed graphene quantum dots (GQDs), was fabricated by using one-step hydrothermal route. In the hydrogel, the GQDs clusters that produced by the aggregation of GQDs acted as the good cross-linkers, pillars and surface stabilizers to bind RGO building blocks via multiple hydrogen bonding to construct interconnected 3D porous network. Otherwise, the as-prepared hydrogel exhibited special pH-responsive on-off switchable fluorescence behavior, which means that the reversible process referred to stripping and reloading of GQDs in the hydrogel was regulated by the pH stimulation. Sequentially, GQDs-GSH was applied for U(VI) detection with a good linear relationship (R2 = 0.999) and high selectivity, followed by effective U(VI) removal and feasible GQDs recovery from aqueous solution. These exciting findings reveal good promises of GQDs for the preparation of 3D architectures and provide a potential platform for integrated detection and treatment of pollutants.

Remote Optical Detection of Uranium and Plant Response to Uranium Exposure

Remote Optical Detection of Uranium and Plant Response to Uranium Exposure

Laser Device for Lowering the Uranium Detection Limit in Technological Environments of NPP

Laser Device for Lowering the Uranium Detection Limit in Technological Environments of NPP

A conveniently synthesized redox-active fluorescent covalent organic framework for selective detection and adsorption of uranium

Uranium is a key element in the nuclear industry and also a global environmental contaminant with combined highly toxic and radioactive. Currently, the materials based on post-modification of amidoxime have been developed for uranium detection and adsorption. However, the affinity of amidoxime group for vanadium is stronger than that of uranium, which is the main challenge hindering the practical application of amidoxime-based adsorbents. Herein, we synthesized a fluorescent covalent organic framework (TFPPy-BDOH) through integrating biphenyl diamine and pyrene unit into the π-conjugated framework. TFPPy-BDOH has an excellent selectivity to uranium due to the synergistic effect of nitrogen atom in the imine bond and hydroxyl groups in conjugated framework. It can achieve ultra-fast fluorescence response time (2 s) and ultra-low detection limit (8.8 nM), which may be attributed to its intrinsic regular porous channel structures and excellent hydrophilicity. More excitingly, TFPPy-BDOH can chemically reduce soluble U (VI) to insoluble U (IV), and release the binding site to adsorb additional U (VI), achieving high adsorption capacity of 982.6 ± 49.1 mg g−1. Therefore, TFPPy-BDOH can overcome the challenges faced by current amidoxime-based adsorbents, making it as a potential adsorbent in practical applications.