Studying Thermochemical Conversion of Sm2O3 to SmCl3 using AlCl3 in LiCl-KCl Eutectic Melt

Electrochemical and spectroscopic analysis of thermochemical conversion of UO2 to UCl3 using AlCl3 and Al in LiCl–KCl eutectic

Analysis of Antarctic Marine Sediment by Inductively Coupled Plasma Atomic Emission and Total Reflection X-Ray Fluorescence Spectrometry

The co-reduction process of Th(IV) and Al(III) ions in the LiCl-KCl-AlCl3-ThO2 molten salts with different concentrations of AlCl3 was investigated at 800 K on the tungsten electrode. Cyclic voltammetry, square wave voltammetry and open-circuit chronopotentiometry techniques were used to study electrochemical behaviors of Al(III), Th(IV) and Al-Th alloy formation processes. The results showed that five kinds of Al-Th intermetallic compounds could be formed in the AlCl3 poor system, whereas only one kind of Al-Th compound formed in the AlCl3 rich system. Al-Th alloys were obtained by potentiostatic electrolysis on aluminum electrodes and by galvanostatic electrolysis on a tungsten electrode. All the Al-Th alloys were characterized by scanning electron microscopy ( SEM) with energy dispersive spectrometry (EDS), X-ray diffraction (XRD) and inductively coupled plasma atomic emission spectrometry (ICP-AES). The XRD results showed that the Al-Th compound prepared in the AlCl3 rich system was

In order to remove impurity AlCl3 from LiCl-KCl melts before Li electrolysis, the Al3+ reduction potential on a tungsten electrode and the relation between Al3+ reduction peak current and AlCl3 concentration in LiCl-KCl-AlCl3 melts were determined by cyclic voltammetry (CV). Constant potential electrolysis at –1.6 V vs Cl2/Cl– on both solid Fe and liquid Zn cathodes was performed to remove AlCl3 impurity from the LiCl-KCl-AlCl3 melts. The removal rate of Al3+ from the melts was analyzed by both electrochemical methods and inductively coupled plasma–atomic emission spectrometry (ICP-AES) analysis. The results showed that 96.11 wt pct of Al were removed on a Fe cathode and 99.90 wt pct on a Zn cathode through 10 hours electrolysis, respectively. While stirring the melts by argon gas, 99.21 wt pct of Al3+ was separated from the melts by 4 hours of electrolysis at 723 K (450 °C), which effectively expedited the Al3+ electrochemical reduction rate and shortened the electrolysis time.

Separation of lanthanides erbium and ytterbium on indium electrodes by modulated potential selective extraction in molten salts and a thermodynamic and kinetic analysis of the process

Electrochemical reduction of Tm ions in LiCl-KCl melt at liquid Zn electrodes

The electrochemical behaviors of Pr(III) and Er(III) in LiCl-KCl melts were studied on inert tungsten and reactive magnesium electrodes by cyclic voltammetry, square wave voltammetry, and open-circuit chronopotentiometry at 823 K. On a W electrode, the reduction of Pr(III) and Er(III) were found to be through a one-step process: Pr(III) + 3 e− → Pr, Er(III) + 3e − → Er. On a Mg electrode, the reduction potentials of Pr(III)/Pr and Er(III)/Er were observed at more positive potential values than those on W electrode, due to the formation of Mg-Pr and Mg-Er intermetallic compounds when Pr(III) and Er(III) ions were reduced to Pr and Er metal and then react with the Mg substrate, respectively. The extraction of Pr(III) and Er(III) in LiCl-KCl melts were performed by galvanostatic electrolysis on Mg electrode, respectively. The Mg3Pr and Mg24Er5 intermetallic compounds were obtained, which characterized by X-ray diffraction (XRD) and scanning electron microscopy equipped with energy-dispersive spectrometry (SEM-EDS). In order to separate the Pr(III) and Er(III), potentiostatic electrolysis was performed at −1.9 V in LiCl-KCl-PrCl3-ErCl3 melts on a Mg electrode, only one Mg-Pr intermetallic compound, Mg12Pr, was found in the deposit. The separation efficiency was evaluated via inductively coupled plasma atomic emission spectrometer (ICP-AES) analysis at different electrolysis time during potentiostatic electrolysis at −1.9 V. The separation efficiency of Pr(III) was about 95.3 % from the mixture of PrCl3-ErCl3 in LiCl-KCl melts.

The objectives of this study were to simplify sample preparation and validate mercury detection in soil and plant samples using inductively coupled plasma atomic emission spectroscopy (ICP-AES). A set of mercury contaminated and mercury free soil and plant samples were digested and analyzed by ICP-AES, inductively coupled plasma mass spectrometry (ICP-MS), and cold vapor atomic absorption spectroscopy (CVAAS). Results show that mercury measurements in soil and plant samples using ICP-AES were in agreement with those analyzed using ICP-MS and CVAAS. The concentrations of mercury in soils and plant tissues determined by ICP-AES were 92.2% and 90.5% of those determined by CVAAS and ICP-MS, respectively. Digestion of soil samples with 4 M HNO3 and direct measurement by ICP-AES without reduction of Hg2+ to Hg0 gave a reasonable and acceptable recovery (92%) for determining Hg in soils. We conclude that ICP-AES with optimized conditions (addition of gold chloride, extension of washing time, linear working range, and selection of wavelength – 194 nm) resulted in reliable detection of mercury in environmental samples.

Underpotential deposition on an active Al cathode plays an increasingly important role in pyroprocessing of used nuclear fuel, but most of the developed models are applied to simulate underpotential deposition at atomic level without considering electron transfer process which is a critical step in electrochemical reactions. In this work, a novel finite-element model for the underpotential deposition of Ce(III) in LiCl–KCl melts is developed with the consideration of Ce(III) activity in the Al electrode and the electron transfer process which is described by Butler-Volmer equation. This model was applied to investigate cyclic voltammetry(CV), square wave voltammetry(SWV) and electrodeposition behaviors of Ce(III) on an Al/Mo electrode. Additionally, the effect of temperature and electrode surface area on the electrodeposition thickness was investigated. Simulated CV and SWV curves are obtained and compared with our pervious experimental data. The results also provide the distribution diagrams of current density, electrostatic potential, Ce(III) concentration and electrodeposition thickness. Furthermore, the electrodeposition thickness is found to be linearly proportional to temperature and the inverse of cathode’s area, respectively. This work proposes a new pathway for the further study of underpotential deposition process.

Comparison of a portable micro-X-ray fluorescence spectrometry with inductively coupled plasma atomic emission spectrometry for the ancient ceramics analysis

A major aspect of lead hazard control is the evaluation of soil lead hazards around housing coated with lead‐based paint. The use of field‐portable X‐ray fluorescence (FPXRF) to do detailed surveying, with limited laboratory confirmation, can provide lead measurements in soil (especially for planning abatement activities) in a far more cost‐efficient and timely manner than laboratory analysis. To date, one obstacle to the acceptance of FPXRF as an approved method of measuring lead in soil has been a lack of correspondence between field and laboratory results. In order to minimize the differences between field and laboratory results, RTI International (RTI) has developed a new protocol for field drying and sieving soil samples for field measurement by FPXRF. To evaluate this new protocol, composite samples were collected in the field following both U.S. Department of Housing and Urban Development (HUD) guidelines and ASTM International (ASTM) protocols, measured after drying by FPXRF, and returned to the laboratory for confirmatory inductively coupled plasma atomic emission spectroscopy (ICP‐AES) analysis. Evaluation of study data from several diverse sites revealed no statistical difference between paired FPXRF and ICP‐AES measurements using the new method. © 2008 Wiley Periodicals, Inc.

Coupling dispersive liquid-liquid microextraction to inductively coupled plasma atomic emission spectrometry: An oxymoron?

Shellfish samples (clams, oysters and mussels) were analysed for Pb, Cd, Cu, Cr, Zn and Ni by flame atomic absorption spectrometry (FAAS) and inductively coupled plasma atomic emission spectrometry (ICP-AES) following wet-ash digestion. Split samples were taken for both FAAS and ICP-AES analysis. Vanadium was used as the internal standard for ICP-AES whereas 1.25% NaCl was added to the FAAS standards to correct for the high salt background associated with shellfish.The methods were compared for statistical significance using regression analysis, the F-test and Student's t-test. Precision and accuracy were determined by replicate analyses, recovery of added heavy metals and National Bureau of Standards (NBS) reference materials. Results obtained from regression analysis for the coefficient of determination or “goodness of fit” were all above the acceptable 0.80 level. The t-test showed that the methods were statistically similar for all metals tested at the 95% confidence level. Average percentage recoveries ranged from 80.2 to 100.7%. Heavy metals were added at approximate expected levels normally found in the shellfish.Accuracy, based on heavy metal levels determined by FAAS and ICP-AES versus certified values for NBS reference materials, varied with the individual reference materials tested. The over-all data obtained indicated that FAAS and ICP-AES showed good agreement for the determination of the heavy metals tested, ICP-AES providing a drastic reduction in analysis time following initial sample work-up.

Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), a modern technique with high sensitivity, accuracy and low matrix effect, is applied extensively in multielement analysis of serum and other biological materials. The objective of this study has been to develop a reliable and practical method for ICP-AES to estimate the serum concentrations of Zn, Cu, Fe, Mg, Ca, Na and K. 60 serum specimens were analyzed by both ICP-AES and Atomic Absorption Spectroscopy (AAS). The results were compared by the t-test and linear regression analysis. In comparison to the AAS method, the ICP-AES yields slightly higher Cu, Mg, Ca and K, and lower Zn, Fe and Na values. Except for Zn (r= 0.612), the correlation between the results is very high (³0.942), indicating that the ICP-AES results are equally satisfactory. In conclusion, ICP-AES is a reliable technique with the advantages of minimal sample volume and analysis time.

Alignment of sequences of vertebrate beta-carotene 15,15'-monooxygenase-1 (BCMO1) and related oxygenases revealed four perfectly conserved histidines and five acidic residues (His172, His237, His308, His514, Asp52, Glu140, Glu314, Glu405, and Glu457 in mouse BCMO1). Because BCMO1 activity is iron-dependent, we propose that these residues participate in iron coordination and therefore are essential for catalytic activity. To test this hypothesis, we produced mutant forms of mouse BCMO1 by replacing the conserved histidines and acidic residues as well as four histidines and one glutamate non-conserved in the overall family with alanines by site-directed mutagenesis. Our in vitro and in vivo data showed that mutation of any of the four conserved histidines and Glu405 caused total loss of activity. However, mutations of non-conserved histidines or any of the other conserved acidic residues produced impaired although enzymatically active proteins, with a decrease in activity mostly due to changes in V(max). The iron bound to protein was determined by inductively coupled plasma atomic emission spectrometry. Bound iron was much lower in preparations of inactive mutants than in the wild-type protein. Therefore, the conserved histidines and Glu405 are absolutely required for the catalytic mechanism of BCMO1. Because the mutant proteins are impaired in iron binding, these residues are concluded to coordinate iron required for catalytic activity. These data are discussed in the context of the predicted structure for the related eubacterial apocarotenal oxygenase.