Solid phase extraction using silica gel functionalized with Sulfasalazine for preconcentration of uranium(VI) ions from water samples

Silica gel surface was chemically functionalized by reaction the silanol from the silica surface with 3-chloropropyltrimethoxysilane followed by reaction with Sulfasalazine. This new sorbent has been used for the preconcentration of low levels of U(VI) ions from an aqueous phase. Parameters involved in extraction efficiency such as pH, weight of the sorbent, volume of sample and eluent were optimized in batch and column methods prior to determination by spectrophotometry using arsenazo(III) reagent. The results showed that U(VI) ions can be sorbed at pH range of 5.0-6.0 in a minicolumn and quantitative recovery of U(VI) (> 98.0 +/- 1.6%) was achieved by stripping with 2.5 mL of 0.1 mol L-1 HCl. The sorption capacity of the functionalized silica gel was 1.15 mmol g(-1) of U(VI). A linear calibration graph was obtained over the concentration range of 0.02-27.0 mu g mL(-1) with a limit of detection of 1 mu g L-1 in treatment with 1000 mL of the U(VI) solution in which the preconcentration factor was as high as 400. The method was employed to the preconcentration of U(VI) ions from spiked ground water and synthetic sea water samples.