On-line extraction and determination of uranium in aqueous samples using multi-walled carbon nanotubes-coated cellulose acetate membrane

In this work, multi-walled carbon nanotubes (MWCNTs)-coated cellulose acetate membrane was used for on-line extraction and pre-concentration of uranium from aqueous samples prior to inductively coupled plasma optical emission spectrometry (ICP-OES) determination. Sample solutions containing the U(VI)-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (Br-PADAP) complex were passed through the membrane. The adsorbed analyte was subsequently eluted from the membrane with acid, which was directly introduced into the ICP-OES nebuliser. The main variables affecting the pre-concentration and determination steps of uranium were studied and optimised. Under the optimised conditions, the enrichment factor of 150 and the detection limit of 0.16 μg L^–1 were obtained. This method was successfully used for determination of uranium in environmental water samples.