Sorption of uranium using silica gel with benzoylthiourea derivatives

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 mu g mL(-1). The relative standard deviation as percentage and detection limit were 5.0% (n = 10) for 10 mu g 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.