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.