Rapid Determination of Uranium in Water Samples by Adsorptive Cathodic Stripping Voltammetry Using a Tin-Bismuth Alloy Electrode

Understanding electrocatalytic mechanisms and ultra-trace uranyl detection with Pd nanoparticles electrodeposited in deep eutectic solvents

This research paper investigates the electrocatalytic mechanisms and ultra-trace detection abilities of uranyl ions (UO22+) using palladium nanoparticles (PdNPs) electrodeposited in deep eutectic solvents (DESs). The unique properties of DESs, such as their adjustable viscosity and ionic conductivity, offer an advantageous and environmentally friendly medium for Pd nanoparticle electrodeposition, resulting in highly active and stable electrocatalysts. Various characterization techniques, including scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD), were used to examine the morphology, size distribution, and crystallographic structure of the Pd nanoparticles. Electrochemical tests revealed that the Pd-modified electrodes show exceptional electrocatalytic activity and current sensitivity towards uranyl ions, with detection limits as low as 3.4 nM. Density functional theory (DFT) calculations were conducted to elucidate the mechanism of the electrocatalytic reduction of UO22+ by the PdNPs, providing a plausible explanation for the high sensitivity of PdNPs in detecting uranyl ions based on the calculated structural parameters and reaction energetics. This study underscores the potential of Pd nanoparticles electrodeposited in DESs as a promising method for sensitive uranyl ion detection, contributing to advancements in environmental monitoring and nuclear safety.

Bismuth-based liquid metals: advances, applications, and prospects

Bismuth-based liquid metals (LMs) are a large group of alloys with melting points slightly above room temperature. They are associated with fewer encapsulation constraints than room temperature LMs such as mercury, sodium-potassium alloys, and gallium-based alloys and are more likely to remain stable in the natural environment. In addition, their low melting point properties enable them to soften and melt via easy control. Bismuth-based alloys can also be modified with metal-based, carbon-based, and ceramic-based micro/nano particles as well as polymeric materials to create a series of novel composites owing to their outstanding functions. Based on these considerations, this review provides a comprehensive overview of bismuth-based LMs. The categories of bismuth and bismuth-based LMs are first briefly introduced to better systematize the physical and chemical properties of bismuth-based LMs. Based on these properties, bismuth-based LMs have been prepared using various methods, and this review briefly categorizes these preparation methods based on their finished forms (lumps, powders, and films). In addition, this review details the research progress of bismuth-based LMs in the fields of printed electronics, 3D printing, thermal management, biomedicine, chemical engineering, and deformable robotics. Finally, the challenges and future opportunities of bismuth-based LMs in the development process are discussed and visualized from different perspectives.

Application of a solid lead microelectrode as a new voltammetric sensor for adsorptive stripping voltammetry of U(VI)

For the first time solid lead microelectrode was utilized for analytical purposes: the article reports on its application for adsorptive stripping voltammetric determination of U(VI) ions. The proposed solid metal microelectrode of a diameter of 25 μm contains about 30 μg of metallic lead that significantly restricts amount of toxic lead introduced into the environment in comparison to lead film equivalents. The potential window of the proposed sensor was checked by means of cyclic voltammetry. The optimization of the analytical procedure of determination of U(VI) ions complexed with cupferron was performed. The experimental parameters (potential of microelectrode activation, pH of supporting electrolyte, complexing agent concentration, potential and time of accumulation and effects of possible interferences) were studied. A linear calibration graph for U(VI) determination was linear in the range from 2 × 10^-9 to 1 × 10^-7 mol L^-1 (accumulation time of 120 s). The obtained detection limit for uranium ions determination following accumulation time of 120 s was 5.5 × 10^-10 mol L^-1. Repeatability of the method calculated as RSD % for U(VI) concentration of 2 × 10^-8 mol L^-1 was 4.7% (n = 5). The proposed procedure was successfully applied for U(VI) ions determination in lake water certified reference material that confirms analytical application.

Determination of trace uranium by resonance fluorescence method coupled with photo-catalytic technology and dual cloud point extraction

In this paper, two kinds of salophens (Sal) with different solubilities, Sal1 and Sal2, have been respectively synthesized, and they all can combine with uranyl to form stable complexes: [UO2(2+)-Sal1] and [UO2(2+)-Sal2]. Among them, [UO2(2+)-Sal1] was used as ligand to extract uranium in complex samples by dual cloud point extraction (dCPE), and [UO2(2+)-Sal2] was used as catalyst for the determination of uranium by photocatalytic resonance fluorescence (RF) method. The photocatalytic characteristic of [UO2(2+)-Sal2] on the oxidized pyronine Y (PRY) by potassium bromate which leads to the decrease of RF intensity of PRY were studied. The reduced value of RF intensity of reaction system (ΔF) is in proportional to the concentration of uranium (c), and a novel photo-catalytic RF method was developed for the determination of trace uranium (VI) after dCPE. The combination of photo-catalytic RF techniques and dCPE procedure endows the presented methods with enhanced sensitivity and selectivity. Under optimal conditions, the linear calibration curves range for 0.067 to 6.57ngmL(-1), the linear regression equation was ΔF=438.0 c (ngmL(-1))+175.6 with the correlation coefficient r=0.9981. The limit of detection was 0.066ngmL(-1). The proposed method was successfully applied for the separation and determination of uranium in real samples with the recoveries of 95.0-103.5%. The mechanisms of the indicator reaction and dCPE are discussed.

Highly selective and sensitive fluorescence optode membrane for uranyl ion based on 5-(9-anthracenylmethyl)-5-aza-2,8-dithia[9],(2,9)-1,10-phenanthrolinophane

A highly sensitive and selective fluorimetric optode membrane based on the enhancement in fluorescence emission of 5-(9-anthracenylmethyl)-5-aza-2,8-dithia[9],(2,9)-1,10-phenanthrolinophane (L) for subnanomolar detection of uranyl ion is presented.