Efficient preparation of UCl3 by ZnCl2 mediated chlorination

Journal of Radioanalytical and Nuclear Chemistry - U chlorination is demonstrated using electrochemical and chemical reactions with ZnCl2 in LiCl–KCl molten salts. Voltammetric studies...     

Development of the anode-liquid cathode module (ALCM) for a high-throughput electrowinner

The employment of multiple electrode pairs is one of the ways to achieve a high-throughput electrowinner. In order to improve the U/TRU recovery rate and also to obtain economic advantages for a molten salt electrowinning process, which is a major step in pyroprocessing, the development of an electrode module having a compact structure is required. Here, we designed an anode-liquid cathode module (ALCM), where two graphite anodes are symmetrically arranged centering on a liquid Cd cathode with a mesh stirrer to prevent the growth of U dendrites, to be applied to the electrowinning process. As a preliminary study, basic electrochemical characterization of the designed electrode module was conducted and its capability for U recovery was evaluated in the ALCM-employed lab-scale electrowinner including LiCl–KCl-UCl₃ at 500 °C. Also, the morphology and component of the recovered U residue by distillation of the cathode product was examined by FE-SEM and EDS analyses.     

Development and characterization of a magnetic bead-quantum dot nanoparticles based assay capable of Escherichia coli O157:H7 quantification

The development and characterization of a magnetic bead (MB)-quantum dot (QD) nanoparticles based assay capable of quantifying pathogenic bacteria is presented here. The MB-QD assay operates by having a capturing probe DNA selectively linked to the signaling probe DNA via the target genomic DNA (gDNA) during DNA hybridization. The signaling probe DNA is labeled with fluorescent QD₅₆₅ which serves as a reporter. The capturing probe DNA is conjugated simultaneously to a MB and another QD₆₅₅, which serve as a carrier and an internal standard, respectively. Successfully captured target gDNA is separated using a magnetic field and is quantified via a spectrofluorometer. The use of QDs (i.e., QD₅₆₅/QD₆₅₅) as both a fluorescence label and an internal standard increased the sensitivity of the assay. The passivation effect and the molar ratio between QD and DNA were optimized. The MB-QD assay demonstrated a detection limit of 890 zeptomolar (i.e., 10⁻²¹ mol L⁻¹) concentration for the linear single stranded DNA (ssDNA). It also demonstrated a detection limit of 87 gene copies for double stranded DNA (dsDNA) eaeA gene extracted from pure Escherichia coli (E. coli) O157:H7 culture. Its corresponding dynamic range, sensitivity, and selectivity were also presented. Finally, the bacterial gDNA of E. coli O157:H7 was used to highlight the MB-QD assay's ability to detect below the minimum infective dose (i.e., 100 organisms) of E. coli O157:H7 in water environment.     

Uranium recovery with zinc distillation from a liquid zinc cathode for pyroprocessing

Journal of Radioanalytical and Nuclear Chemistry - U recovery test was performed on a Zn-U alloy to confirm the feasibility of Zn as an alternative cathode material. An evaporation test of pure Zn...     

Uranium recovery via melt separation of rare earth elements and chemical oxidation

Journal of Radioanalytical and Nuclear Chemistry - Pyroprocessing of spent fuels, especially the recovery of U, improves the overall efficiency of nuclear recycling. The recovery of U/Transuranic...     

An integrated passive micromixer-magnetic separation-capillary electrophoresis microdevice for rapid and multiplex pathogen detection at the single-cell level

Here we report an integrated microdevice consisting of an efficient passive mixer, a magnetic separation chamber, and a capillary electrophoretic microchannel in which DNA barcode assay, target pathogen separation, and barcode DNA capillary electrophoretic analysis were performed sequentially within 30 min for multiplex pathogen detection at the single-cell level. The intestine-shaped serpentine 3D micromixer provides a high mixing rate to generate magnetic particle-pathogenic bacteria-DNA barcode labelled AuNP complexes quantitatively. After magnetic separation and purification of those complexes, the barcode DNA strands were released and analyzed by the microfluidic capillary electrophoresis within 5 min. The size of the barcode DNA strand was controlled depending on the target bacteria (Staphylococcus aureus, Escherichia coli O157:H7, and Salmonella typhimurium), and the different elution time of the barcode DNA peak in the electropherogram allows us to recognize the target pathogen with ease in the monoplex as well as in the multiplex analysis. In addition, the quantity of the DNA barcode strand (～10(4)) per AuNP is enough to be observed in the laser-induced confocal fluorescence detector, thereby making single-cell analysis possible. This novel integrated microdevice enables us to perform rapid, sensitive, and multiplex pathogen detection with sample-in-answer-out capability to be applied for biosafety testing, environmental screening, and clinical trials.     

Removal of rare earth elements from a U/RE ingot via a reaction with UCl3

Journal of Radioanalytical and Nuclear Chemistry - A chemical equilibrium experiment was conducted to remove rare earth (RE) elements from a U/RE ingot using UCl3 as an oxidant. Upon analysis, the...     

A preparation of a single-layered enzyme-membrane using asymmetric pBPPO base film for development of pesticide detecting biosensor

A novel single-layered enzyme-membrane using BPPO film which was pore-filled with cross-linked PVA containing TYR was prepared to develop a pesticide biosensor with an increased stability. The prepared enzyme-membrane was assembled on a glassy carbon electrode to detect pesticides. The voltammetric measurements revealed a coupled reaction, an enzymatic oxidation and an electrochemical reduction of catechol transported through the prepared membrane. A detection range of parathion and carbaryl was 0.01–1 ppb and 0.01–10 ppb, respectively. The activity in the enzyme-membrane was maintained for 1 month due to favorable aqueous environment of PVA for enzyme activity while BPPO film provided structural stability.     

Development of an anode structure consisting of graphite tubes and a SiC shroud for the electrowinning process in molten salt

In a molten chloride salt-based electrolysis, chloride evolution at an anode needs to be considered in terms of potential fluctuation, capture, and corrosion problems. Here, we demonstrate an anode structure consisting of graphite tubes and a SiC shroud to be applied to the electrowinning process. A large surface area as well as high corrosion resistivity was achieved through the use of inert graphite tubes. The Cl₂ (g) capture was enhanced by the employment of a porous SiC shroud. It also allows an efficient contact of the electrode surface to the LiCl–KCl eutectic melt for an anodic evolution. No significant effects of the use of a SiC shroud on the anode overpotential and cell potential were found during the U deposition test.