PRECONCENTRATION, SOLVENT SUBLATION AND SPECTROMETRIC DETERMINATION OF URANIUM(VI) IN WATER SAMPLES USING ARSENAZO III AND TRI N-OCTYL AMINE

摘要

Objective: Preconcentration and solvent sublation has been studied for the separation and determination of trace uranium (VI) in various spiked water samples. Me thods: A strongly red colored anionic [UO2(Ar-III)]2 -complex was formed at pH 1.0 upon adding arsenazo III (Ar-III) to the sample solution. Tri n-octyl amine (TOA) was added in the solution to form the (TOA)2[UO2(Ar-III)] ion pair, and an oleic acid (HOL) surfactant was added. Then, the (TOA)2[UO2(Ar-III)] ion pairs were floated by vigorous shaking in the flotation cell and extracted into methyl isobutyl ketone (MIBK)on the surface of the aqueous solutio n. The uranium collected in the MIBK layer was measured directly by spectrophotometry. Different experimental variables that may affect the sublation efficiency were thoroughly investigated. Results: The molar absorptivity of the (TOA)2[UO2(Ar-III)] ion pair was 3.28 x 104and 1.24 × 106L mol– 1cm– 1 in the aqueous and organic layers, respectively. Beer's law held up to 0.01-1.0 mgL- 1o f U(VI) in the aqueous as well as in the organic layers. Conclusion: The adopted solvent sublation method was successfully applied for the determination of U(VI) in various kinds of water samples with a preconcentration factor of 250