Preparation of U(VI) and Th(IV) alpha-sources from sea and fresh water samples by combining coprecipitation, solvent extraction and electrodeposition procedures

Abstract

Uranium / Thorium / Sea water / Fresh water / Coprecipitation / Iron hydroxides / Solvent extraction / Electrodeposition / α-particle spectrometry Summary. A simple method combining coprecipitation, solvent extraction and electrodeposition for determining uranium and thorium in sea water and fresh water samples is developed. It offers a considerable saving in time, minimising chemical treatment and costs. The analytical procedure consists of enrichment of U and Th by coprecipitation with iron(III) hydroxides and subsequent extraction by diethylether solution and electrodeposition of each actinide in the extracting organic phase in which it was separated.The dependence of the coprecipitation, the extractionelectrodeposition and the overall yields of the above mentioned elements is examined in relation to the initial aqueous solution acidity and various amounts of iron carrier. At an initial pH between 6 and 10, quantitative coprecipitation of U and Th requires use of an Fe(III) quantity which depends on the acidity of these solutions. This quantity varies, under explored conditions, between 10 and 110 mg/L. At a starting pH of 11, this coprecipitation becomes almost independent of Fe(III) amounts.The proposed procedure was used to analyse the content of U and Th isotopes in water samples. Recoveries of 60%-93% are obtained for uranium and 63%-86% for thorium. Good resolutions (37-56.5 keV) are also achieved under optimum conditions. These resolutions allow to make accurate determination of U and Th isotopes in various water samples.

Determination of U, Th and Pu in natural waters, biological materials and clinical samples by ETV-ICP-MS

“…This same value is used by WHO, 7 but a 20-fold higher limit is set by EURATOM. 8 Although these elements have been traditionally measured by radiometric techniques such as alpha spectroscopy, [9][10][11][12][13] gamma spectroscopy, [14][15][16] liquid scintillation [17][18][19] and neutron activation analysis (NAA), [20][21][22][23][24] they are not ideally suited to rapid and /or accurate determination as they generally require large sample volumes, complex sample pre-treatment, extensive time necessary for detection and suffer from poor detection limits.…”

Determination of Thorium and Uranium in Ultrapure Lead by Inductively Coupled Plasma Mass Spectrometry

“…Although these elements have been traditionally measured by radiometric techniques, such as α spectroscopy, − γ spectroscopy, − and neutron activation analysis, − these are not ideally suited to rapid or accurate determinations.…”

27 Radiochemistry and radiopharmaceuticals

“…The general principles for soil sampling for radioactive contamination 270 have been reviewed. More specifically the transport of actinide elements in the Irish Sea has been subject to theoretical modelling 271 whilst practical details have been described 272 for the preparation of an alpha source for the analysis of uranium and thorium in aqueous solution and the determination 273 of air-born plutonium contamination. Other methods for the analysis of trace amounts of technetium, 274 of polonium, 275 of uranium isotopes, 276 of thorium, 277 or of plutonium and americium 278,279 have all depended on pre-concentration using particular exchange resins, or anion exchange chromatography.…”