Solid phase extractive preconcentration of uranium(VI) onto diarylazobisphenol modified activated carbon

Diarylazobisphenol (DAB) I and diarylazobisphenol modified carbon 2 were synthesized and characterised. The latter has been used for solid phase extractive preconcentration and separation of trace amounts Of uranium(VI) from other inorganics. In this, a column mode preconcentration of uranium(VI) was carried Out in the pH range 4.0-5.0, eluted with 1.0 mol l(-1) HCl and determined by an Arsenazo III spectrophotometric procedure. Calibration graphs were rectilinear over the Uranium(VI) concentrations in the range 5-200 mug l(-1). Five replicate determinations of 25 mug of uranium(VI) present in I I solution gave a mean absorbance of 0.032 with a relative standard deviation of 2.52%. The detection limit corresponding to three times the standard deviation of the blank was found to be 5 mug l(-1). The accuracy of the developed preconcentration method in conjunction with the Arsenazo III procedure was tested by analysing MESS-3, a marine sediment certified reference material. Further, the above procedure has been successfully employed for analysis of uranium(VI) in soil and sediment samples. (C) 2003 Elsevier B.V. All rights reserved.