Determination Of Thorium Research Articles

A New Spectrophotometric Method for Thorium Determination Using 1,4-Dihydroxyanthraquinone

A new reagent, 1,4-dihydroxyanthraquinone (1,4-DHA), is described for the spectrophotometric determination of thorium(IV). Optimization of the formed thorium−1,4-DHA complex was performed by studying several parameters such as methanol concentration, suitable pH, dye concentration, temporal stability of the formed complex and thorium concentration (calibration curve). The optimized method was applied to different rock types bearing thorium with good accuracy results. This reagent is highly sensitive toward thorium; thorium complex has a molar absorptivity of 1.82 × 104 L/(mol cm) at 600 nm and pH 3.25. Beer’s law was obeyed in the range from 0.9 to 20 µg/mL for Th(IV). The tolerance limits for several metal ions were calculated and gave high tolerance limit especially for uranium. Details are given for the estimation of thorium in standard reference and natural rocks.

An innovative spectrophotometric method for determination of uranium and thorium using 3-aminomethylalizarn-N-N diacetic acid in some geological samples

3-aminomethylalizarn-N-N diacetic acid chromogenic dye (AMADA) was used for the first time in uranium and thorium spectrophotometric estimation with accurate and sensitive result, their complexes having a maximum absorbance at 575 nm for U and at 510 nm for Th. This system allows uranium and thorium content to be calculated with a detection limit (LOD) of 0.16 µg L−1 and 0.14 µg L−1, respectively. The first-derivative spectra and EDTA were investigated to eliminate interference and provide selective estimation of uranium and thorium in presence of each other. This new spectrophotometric method was applied for the determination of U(VI) and Th(IV) in the standard reference materials (granite and Syenite) and some cataclastic rock samples with accurate results.

On-line ultrasound-assisted dispersive micro-solid phase extraction using graphitic carbon nitride microparticles combined with ICP-OES for the preconcentration and determination of thorium

In this study, on-line ultrasound-assisted dispersive micro-solid phase extraction technique is introduced for the separation and ICP-OES determination of thorium in aqueous samples. In this method, microparticles of g-C3N4 were dispersed into the sample using ultrasonic radiation and Th(IV) ions were directly adsorbed by the sorbent. The sample solution was then passed through a membrane filter and the adsorbed Th(IV) ions were subsequently eluted directly into the ICP-OES nebulizer. The Limit of detection of developed method was 0.05 μg L−1. The developed on-line technique eliminates the centrifugation step in order to simplify and speed up the extraction procedure.

Study of thorium and uranium isotopes activity concentration after percolation or agitation leaching, in mining lixiviation liquor samples

This work refers to determination of thorium and uranium isotopes in the mining lixiviation liquor samples. The analytical procedure involves sample preparation steps for rare earth elements, thorium and uranium separation, besides alpha spectrometry analysis of the isolated radionuclides. An isotopic tracer is used to determine the overall chemical yield and to ensure traceability to a standard sample from NIST. The paper presents and discusses that the chemical yield of thorium and uranium depends on the leaching method used, that is, column leaching or agitated leaching. We improved the method looking for reproducibility and isotopes isolation as required by alpha spectrometry and the method showing effective in analysis of mining liquor

Концентрирование органических реагентов и их комплексов с ионами металлов в системах на основе смесей анионных и катионных ПАВ

The work investigates the distribution patterns of organic complexing reagents in the potassium bis (alkylpolyoxyethylene)phosphate (oxyphos B) – alkylbenzyldimethylammonium chloride (catamine AB) –water and oxyphos B – tertiary oxyethylated amine of coconut oil acids (ethomeen C / 15) – water systems, and also proposed a method for the extraction-spectrophotometric determination of thorium with arsenazo III. The composition of resulting complex compound and its stability have been determined.

Trace Determination of Thorium with 6-Chloro-3-hydroxy-2- (2′-furyl)-4H-chromen-4-one as an Analytical Reagent

A simple, rapid, highly sensitive and selective method for the spectrophotometric determination of micro amounts of thorium(IV) has been worked out using 6-chloro-3-hydroxy-2-(2′-furyl)-4H-chromen-4-one (CHFC) as a complexing agents in a acidified (CH3COOH, pH 3.5) medium. The yellow complex shows a maximum absorbance at 425-435 nm. The method obeys Beer′s law upto 3.5 μg Th cm-2. As many as 31 cations and 11 anions and/or complexing agents do not interfere. The method has good reproducibility and can be satis-factorily applied to the determination of thorium in samples corresponding to Australian monazite in composition.

Cloud Point Extraction and Spectrophotometric Determination of Thorium(IV) Ions and their Application in Silicate Rock Samples

Cloud Point Extraction and Spectrophotometric Determination of Thorium(IV) Ions and their Application in Silicate Rock Samples

Amberlite XAD-2010 Impregnated with Chrome Azurol S for Separation and Spectrophotometric Determination of Uranium and Thorium

A new extractant-impregnated resin (EIR), chrome azurol S-impregnated on XAD-2010, is used as an adsorbent to separate and preconcentrate U(VI) and Th(IV) ions prior to their spectrophotometric determination. Various instrumental techniques such as elemental analysis, FTIR, and SEM analysis were employed for full characterization of the synthetic extractant. Optimization of the adsorption and elution conditions of U(VI) and Th(IV) ions using synthesized chrome azurol S-impregnated XAD-2010 were studied. Langmuir isotherm model has the best fitting experimental data with a maximum adsorption capacity of 23.8 mg g−1 for U(VI) and 25.4 mg g−1 for Th(IV). The adsorption process of each metal ion using synthesized chrome azurol S-impregnated XAD-2010 showed an exothermic pseudo-second-order adsorption process. High tolerance limits for several studied metal ions on chrome azurol S-impregnated XAD-2010 were observed. The optimized method was applied on an international certified samples and different rock types bearing thorium and uranium with accurate results.

Determination of uranium and thorium in sediments from Cananéia-Iguape system, Brazil

The Cananeia-Iguape system is a complex of lagoon and estuarine channels located in the south of state of Sao Paulo. This system received the waters of Ribeira de Iguape River, after the construction of a channel in 1852, which changed its original characteristic. This study evaluated the uranium and thorium concentrations in superficial bottom sediments samples from this system by spectrophotometric determination. The mean uranium concentration found was 2.9 mg kg−1 and 6.6 mg kg−1 for thorium. Geo-accumulation index classified the sediments as “unpolluted to moderately polluted”. Statistical analysis showed that uranium and thorium presented a non-homogeneous behavior along the system.

Micro-funnel magnetic stirring-assisted liquid–liquid microextraction technique combined with UV–Vis spectrophotometry for determination of thorium in aqueous samples with the aid of experimental design

In this study, trace amounts of thorium ions were extracted using a highly sensitive, selective, rapid and simple micro-funnel magnetic stirring-assisted liquid–liquid microextraction method, and determined by UV–Vis spectrophotometry. Tri-n-octylphosphine oxide was used as the complexing agent during the microextraction process, and Arsenazo III was applied as the chromogenic reagent through spectrophotometric determination. The effective parameters on extraction efficiency were optimized by experimental design methods. Under the optimum conditions, detection limit, relative standard deviation and the enrichment factor were 0.98 μg L−1, 0.69% and 152, respectively. The calibration graph was linear over the range of 5–250 μg L−1.

Development of separation procedures for determination of uranium and thorium in the 82Se source of the SuperNEMO experiment: first steps

Two methods have been tested for separation of uranium and thorium from selenium using UTEVA and anion exchange resins. The average yield for separation of uranium, thorium and selenium was determined to be for the UTEVA method 91 ± 9%, 79 ± 8% and 96 ± 8%, respectively, and 96 ± 10%, 88 ± 9% and 94 ± 8%, respectively, in the case of the anion exchange resin. The methods will be used in consequent development of analytical procedures for determination of 238U and 232Th content with mass spectrometric techniques in 82Se source materials of the SuperNEMO experiment.

Moving window partial least squares after orthogonal signal correction as a coupling method for determination of uranium and thorium by ultrasound‐assisted emulsification microextraction

AbstractThis study, a fast, simple, and efficient ultrasound‐assisted emulsification microextraction coupled with orthogonal signal correction‐moving window partial least squares (OSC‐MWPLS) was successfully used to preconcentration and simultaneous spectrophotometric determination of uranium and thorium in water samples. Response surface methodology based on a Box‐Behnken design was used to optimize the extraction conditions. The analysis of variance and some statistical tests such as lack‐of‐fit and coefficient of determination (R2) showed good fit of the experimental data with the second‐order polynomial model. Under the optimum conditions, the calibration graphs were linear in the range of 10.0 to 230.0 and 10.0 to 250.0 ng mL−1 with detection limits of 3.11 and 3.56 ng mL−1 (3Sb/m) for uranium and thorium, respectively. The preconcentration factor of this method for uranium and thorium reached 192. Repeatability (intra‐day) and reproducibility (inter‐day) were obtained 1.23% and 2.18% for uranium and 1.34% and 1.95% for thorium, respectively. The OSC was used for preprocessing of data matrices, and also MWPLS regression has been proposed for the selection of informative spectral intervals. In this paper, ultrasound‐assisted emulsification microextraction coupled with OSC‐MWPLS method was presented for the first time. The root mean square error of prediction for uranium and thorium with PLS, OSC‐PLS, and OSC‐MWPLS were 11.755, 10.335 and 5.301, 5.399 and 0.974, 0.986 ng mL−1, respectively. The results indicated that practical and environmentally friendly proposed method could be successfully used to the simultaneous determination of uranium and thorium in different environmental water samples.

A novel combined countercurrent chromatography – inductively coupled plasma mass spectrometry method for the determination of ultra trace uranium and thorium in Roman lead

The concentration of uranium and thorium in lead shields, which are used in underground particle physics research, should be monitored at sub-ppt levels. A combination of extraction chromatography and inductively coupled plasma mass spectrometry can resolve this analytical task. However, a multi-step complicated separation procedure and clean room are required. Besides, the recovery yields for U and Th do not exceed 80% and 60%, correspondingly. We propose an alternative approach. U and Th were pre-concentrated and separated from Pb by countercurrent chromatography, which is a support-free liquid-liquid chromatography. A series of two-phase extraction systems were tested. Under the optimized conditions, U and Th were extracted using a system 1 M HNO3/0.01 M tetraphenylmethylenediphosphine dioxide in chloroform and then eluted by 0.01 M aqueous solution of etidronic acid and determined by inductively coupled plasma mass spectrometry. The separation is performed in one chromatographic run, takes less than 1 h, and provides the quantitative recovery of U and Th. The limits of detection are 3 and 1 ppt for U and Th, correspondingly. The concentrations of U and Th in Roman lead, which was raised from the sea bottom, were lower than the limits of detection. It sounds unbelievable, nevertheless, the antique lead manufactured by Romans can indeed serve as a high-purity low-background material for the construction of Pb shields. Apart from the analysis of antique lead, the proposed approach can be easily extended to the determination of ultra trace impurities in different materials due to a very wide variety of two-phase extraction systems, which can be used in countercurrent chromatography.

Determination of Thorium and Uranium in Nickel-based Alloys by ICP-MS After Matrix Separation Using Novel Co-polymer of Ethylene Glycol Methacrylate and Bis[2-methacryloyloxy)ethyl] Phosphate

Determination of Thorium and Uranium in Nickel-based Alloys by ICP-MS After Matrix Separation Using Novel Co-polymer of Ethylene Glycol Methacrylate and Bis[2-methacryloyloxy)ethyl] Phosphate

Extraction conductometric determination of scandium and thorium in kaolins

Extraction conductometric determination of scandium and thorium in kaolins

CONCENTRATION OF THORIUM (IV) BY CHELATING SORBENT

The paper analyses complexation of thorium(IV) with 2,3,4-trihydroxy-4’-fluoroazobenzene. A complex is formed immediately after mixing the components. Their molar ratio (1:2) was established using the methods of Starik–Barbanel relative yield, equilibrium shift and isomolar series. The maximum light absorption of the complex is observed at 440 nm, with the molar absorption coefficient being equal to 1.80×10 4 . In this work, we synthesised a new sorbent containing fragments of para-aminosalicylic acid. Identification of sorbents was carried out using IR spectroscopy. Sorption was studied in static and dynamic modes. The optimal conditions for concentration were investigated. The magnitude of the sorption and the degree of metal extraction was calculated from its residual concentration in the solution using a spectrophotometric method. Our results show that the maximum sorption is observed at pH = 4. In the course of preliminary kinetic experiments, it was found that the maximum sorption of cadmium is attained within 2 hours, remaining practically at the same level thereafter. The effect of the ionic strength of the solution was studied using the photometric method. Thorium(IV) was sorbed from solutions having an ionic strength of 0.1–1.4. It is shown that a significant decrease in the sorption of thorium(IV) occurs in solutions with an ionic strength of more than 0.2 M. The effect of metal concentration on sorption was also investigated. An isotherm of thorium sorption by the synthesised sorbent was constructed. An increased concentration of thorium(IV) in the solution leads to an increase in the amount of sorbed metal, with the maximum concentration being reached at 1856 mg/l. We also studied the effect of various acids (HClО 4 , H2SО 4 , HNО 3 , HCl) on the desorption of thorium(IV) from the sorbent: thorium(IV) was quantitatively desorbed by 2 M nitric acid. The degree of extraction of thorium ions (IV) under optimal conditions exceeds 95%. The study has revealed the possibility of using the matrix of a copolymer of maleic anhydride and styrene modified by para-aminosalicylic acid for sorption-photometric determination of thorium(IV). Following regeneration, this sorbent can be reused.

Synthesis of UiO-66-OH zirconium metal-organic framework and its application for selective extraction and trace determination of thorium in water samples by spectrophotometry

In this study, a zirconium-based metal-organic framework (Zr-MOF), named UiO-66-OH, was synthesized by the solvo-thermal method and characterized by Fourier transform-infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), and scanning electron microscopy (SEM). This Zr-MOF was then employed as a sorbent for selective extraction and preconcentration of thorium ions after their complexation with 2‑(2,4‑dihydroxyphenyl)‑3,5,7‑trihydroxychromen‑4‑one (morin) from environmental water samples prior to its spectrophotometrical determination. The experimental parameters affecting extraction, such as pH of sample solution, amount of Zr-MOF, type and volume of eluting solvent, adsorption and desorption time, and concentration of complexing agent were evaluated and optimized. Under the optimized conditions, an enrichment factor of 250 was achieved. The limit of detection was calculated to be 0.35μg·L−1 with a linear range between 10 and 2000μg·L−1of thorium. The maximum sorption capacity of MOF toward thorium was found to be 47.5mg·g−1. The proposed procedure was successfully applied to the analysis of real water samples.

Correction to Mass Spectrometric Determination of Uranium and Thorium in High Radiopurity Polymers Using Ultra Low Background Electroformed Copper Crucibles for Dry Ashing.

Correction to Mass Spectrometric Determination of Uranium and Thorium in High Radiopurity Polymers Using Ultra Low Background Electroformed Copper Crucibles for Dry Ashing.

A new optical sensor for spectrophotometric determination of uranium (VI) and thorium (IV) in acidic medium

Abstract A spectrophotometric method was developed for U(VI) and Th(IV) determination in acidic medium by using proposed optical sensor. This sensor is base on the complexation reaction of the ionophore midodrine hydrochloride (L) with U(VI)/Th(IV) in plasticized (o-NPOE) high molecular weight (PVC). Several parameters such as effect of acidic medium, response time and sensor compositions were studied. The determination of the complexes stoichiometry was also studied using Job’s method. The complexes stoichiometry were measured at the absorbance spectra 302 nm and the results were found to be 1:1 for both complexes U(VI)-L and Th(IV)-L. The complexation reaction was extremely rapid at room temperature; it takes 5, 10 min to complete the complexation reaction in U(VI) and Th(IV), respectively. Under the optimum conditions the calibration curves of U(VI)/Th(IV) determination, have good linearity at different acidic medium nitric, sulfuric, and phosphoric acids with low detection and quantification limits. The accuracy and precision studies proved that the proposed optical sensor is valid and qualified for U(VI)/Th(IV) spectrophotometric determination in different acidic medium. The selectivity of the proposed optical sensor was studied. The proposed optical sensor was applied successfully for U(VI)/Th(IV) determination in research and development (R&D) nuclear waste samples with satisfactory results. A comparative study of the proposed optical sensor with other previous spectrophotometric sensors for U(VI)/Th(IV) determination, proved the high efficiency of the proposed optical sensor, that it presents wide linear range and low detection limit. The proposed optical sensor could be applied for a quantitative determination of U(VI)/Th(IV) in acidic waste samples.

Determination of thorium (IV) using isophthalaldehyde-tetrapyrrole as probe by resonance light scattering, second-order scattering and frequency-doubling scattering spectra

The coordination reaction of thorium (IV) with a ditopic bidentate ligand to form supramolecular polymer was studied by resonance light scattering (RLS) spectra, second-order scattering (SOS) spectra and frequency-doubling scattering (FDS) spectra, respectively. The ditopic bidentate ligand is isophthalaldehyde-tetrapyrrole (IPTP). It was synthesized through a condensation reaction of isophthalaldehyde with pyrrole. The formation of supramolecular polymer results in remarkable intensity enhancements of the three light scattering signals. The maximum scattering wavelengths of RLS, FDS and SOS were 290, 568 and 340nm, respectively. The reaction was used to establish new light scattering methods for the determination of thorium (IV) by using IPTP as probe. Under optimum conditions, the intensity enhancements of RLS, SOS and FDS were directly proportional to the concentration of thorium (IV) in the ranges of 0.01 to 1.2μgmL−1, 0.05 to 1.2μgmL−1 and 0.05 to 1.2μgmL−1, respectively. The detection limits were 0.003μgmL−1, 0.012μgmL−1 and 0.021μgmL−1, respectively. The methods were suitable for analyzing thorium (IV) in actual samples. The results show acceptable recoveries and precision compared with a reference method.