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  • Author or Editor: Sevda Ayata x
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Abstract  

This paper reports silica gel loaded with p-tert-butylcalix[8]arene as a new solid phase extractor for determination of trace level of uranium. Effective extraction conditions were optimized in column methods prior to determination by spectrophotometry using arsenazo(III). The results showed that U(VI) ions can be sorbed at pH 6 in a mini-column and quantitative recovery of U(VI) (>95–98%) was achieved by stripping 0.4 mol L−1 HCl. The sorption capacity of the functionalized sorbent is 0.072 mmol uranium(VI) g−1 modified silica gel. The relative standard deviation and detection limit were 1.2% (n = 10) for 1 μg uranium(VI) mL−1 solution and 0.038 μg L−1, respectively. The method was employed to the preconcentration of U(VI) ions from spiked ground water samples.

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Abstract  

Benzoylthiourea derivatives (N,N-diphenyl-N′-(3-methylbenzoyl)thiourea and diphenyl-N′-(4-methylbenzoyl)thiourea) were impregnated onto silica gel. The preconcentration of uranium(VI) from aqueous solution was investigated. Extraction conditions were optimized in batch method prior to determination by uv–visible absorption spectrometry using arsenazo(III). The optimum pH for quantitative adsorption was found as 3–7. Quantitative recovery of uranium (VI) was achieved by stripping with 0.1 mol L−1 HCl. Equilibration time was determined as 30 min for 99% sorption of U(VI). Under optimal conditions, dynamic linear range of for U(VI) was found as 0.25–10 μg mL−1. The relative standard deviation as percentage and detection limit were 5.0% (n = 10) for 10 μg mL−1 U(VI) solution and 8.7 ng mL−1, respectively. The method was employed to the preconcentration of U(VI) ions in soil and tap water samples.

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