Analytical use of arsenazo III Determination of thorium, zirconium, uranium and rare earth elements

Саввин, С. Б.

doi:10.1016/0039-9140(61)80164-1

Cited by 539 publications

(159 citation statements)

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“…[31] The pH value was measured by combination glass electrodes (WTW Co., Germany). The electrode were calibrated with five standards following a multi-point calibration protocol [Meinrath & Spitzer 2000] and in agreement with the new IUPAC recommendation [Buck et al 2002] .…”

Section: Methodsmentioning

confidence: 99%

Investigating the Mechanism of Uranium Removal by Zerovalent Iron

Noubactep¹,

Meinrath

Merkel

2005

Environ. Chem.

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Environmental ContextGroundwater remediation is mostly a costly long-term process. In-situ remediation by permeable reactive barriers is a potential solution. For pollution by halogenated hydrocarbons, nitrate, and chromium, zerovalent iron (ZVI) has been found to induce a chemical reduction.ZVI remediation technology has been extended to metal pollution, where one of the major removal mechanisms seems to be co-precipitation with the products of iron corrosion. Due to difficulties of identifying reaction products in the matrix of corrosion products, investigation methods for characterising the contaminant removal with respect to interactions between contaminant and corrosion products need to be developed. AbstractZerovalent iron (ZVI) has been proposed as a reactive material in permeable in-situ walls for groundwater contaminated by metal pollutants. For such pollutants which interact with corrosion products, the determination of the actual mechanism of their removal is very important to predict the long-term stability of reactive walls. From a study of the effects of pyrite (FeS 2 ) and manganese nodules (MnO 2 ) on the uranium removal potential of a selected ZVI material, a test methodology (FeS 2 -MnO 2 -method) is suggested to follow the pathway of contaminant removal by ZVI materials. An interpretation of the removal potential of ZVI for uranium in presence of both additives corroborates coprecipitation with iron corrosion products as a major removal mechanism for uranium.

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Section: Methodsmentioning

confidence: 99%

Investigating the Mechanism of Uranium Removal by Zerovalent Iron

Noubactep¹,

Meinrath

Merkel

2005

Environ. Chem.

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“…e centrifuged (pure) bentonite samples were dried in an oven at 105 ∘ C for 4 hours and stored in polyethylene bottles. (Figure 1) was used as a spectrophotometric reagent in the determination of thorium(IV) and uranium(VI) ion concentration [15].…”

Section: Puri�cation Of Al-azra�mentioning

confidence: 99%

Sorption of Uranium(VI) and Thorium(IV) by Jordanian Bentonite

Khalili

Salameh

Shaybe

2012

Journal of Chemistry

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Puri�cation of raw bentonite was done to remove quartz. is includes mixing the raw bentonite with water and then centrifuge it at �50 rpm; this process is repeated until white puri�ed bentonite is obtained. �RD, �RF, FTIR, and SEM techniques will be used for the characterization of puri�ed bentonite. e sorption behavior of puri�ed Jordanian bentonite towards UO 2 2+and  4+ metal ions in aqueous solutions was studied by batch experiment as a function of pH, contact time, temperature, and column techniques at 25.0 ∘ C and pH = 3. e highest rate of metal ions uptake was observed aer 18 h of shaking, and the uptake has increased with increasing pH and reached a maximum at pH = 3. Bentonite has shown high metal ion uptake capacity toward uranium(VI) than thorium(IV). Sorption data were evaluated according to the pseudo-second-order reaction kinetic. Sorption isotherms were studied at temperatures 25.0 ∘ C, 35.0 ∘ C, and 45.0 ∘ C. e Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) sorption models equations were applied and the proper constants were derived. It was found that the sorption process is enthalpy driven for uranium(VI) and thorium(IV). Recovery of uranium(VI) and thorium(IV) ions aer sorption was carried out by treatment of the loaded bentonite with different concentrations of HNO 3 1.0 M, 0.5 M, 0.1 M, and 0.01 M. e best percent recovery for uranium(VI) and thorium(IV) was obtained when 1.0 M HNO 3 was used.

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“…[26] Analysis for uranium was performed after reduction to U(IV) with the Asernazo III method. [27,28] Uranium was tested as redox-labile pollutant, that may be reduced by ZVI from soluble U(VI) species to less soluble U(IV) phases. In general, the solubility of U(IV) phases is lower than that of U(VI) phases and U(IV) phases are stable over a wider range of pH.…”

Section: Uranium Removal Experimentsmentioning

confidence: 99%

Testing the Suitability of Zerovalent Iron Materials for Reactive Walls

et al. 2005

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Environmental ContextGroundwater remediation is mostly a costly long-term process. In-situ remediation by permeable reactive barriers is a potential solution. For pollution by various redox sensitive contaminants, zerovalent iron (ZVI) has been proposed to immobilise or degrade dissolved pollutants in groundwater. Scrap iron materials are considered as an effective low-cost ZVI material. Due to the wide variation of scrap metal compositions, testing methods for characterising the corrosion behaviour need to be developed. AbstractZerovalent iron (ZVI) has been proposed as reactive material in permeable in-situ walls for contaminated groundwater. An economically feasible ZVI reactive wall requires cheap but efficient iron materials. From an uranium treatability study and results of iron dissolution in 0.002 M EDTA by five selected ZVI materials, it is shown that current research and field implementation is not based on a rational selection of application-specific iron metal sources.An experimental procedure is proposed which could enable a better material characterization.This procedure consists in mixing ZVI materials and reactive additives including contaminant 2 releasing materials (CRM) in long term batch experiments and characterise the contaminant concentration over the time.

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Analytical use of arsenazo III Determination of thorium, zirconium, uranium and rare earth elements

Cited by 539 publications

References 0 publications

Investigating the Mechanism of Uranium Removal by Zerovalent Iron

Investigating the Mechanism of Uranium Removal by Zerovalent Iron

Sorption of Uranium(VI) and Thorium(IV) by Jordanian Bentonite

Testing the Suitability of Zerovalent Iron Materials for Reactive Walls

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