m.a salehi - Faculty of Engineering, University of Guilan, P. O. Box ۳۷۵۶, Rasht- Iran
s.a milani - Nuclear Fuel Cycle Research School, Nuclear Science and Technology Research Institute, AEOI, P.O. Box:۱۴۸۹۳-۸۳۶, Tehran – Iran
n rahgozar - Faculty of Engineering, University of Guilan, P. O. Box ۳۷۵۶, Rasht- Iran

In this article cloud-point extraction (CPE) was used with chelating agent to extract uranium from aqueous solutions. The methodology used is based on the formation of metal complexes soluble in a micellar phase of surfactant. The metal ions complexes are then extracted into the surfactantrichphase at a temperature above the cloud-point temperature. The effect of type of surfactants and ligands on extraction efficiency at constant condition (pH =6, surfactant concentration of 0.5 % (w/v), chelating agent concentration of 1.5 × 10-3 M, incubation time of 20 min, equilibrium temperature of 50°C , centrifugation time of 10 min) were studied and the best surfactant and ligand was identified.Then optimum concentration of surfactant and ligand and also the other optimal conditions of extraction was determined. By using CPE method and obtained optimal conditions, determination of uranium in water samples with a detection limit of 0.15μg L-1 was conducted

Cloud-point extraction, Uranium, Triton X-114, Triton X-100, CTAB, 8-HQ, SDS,PAN, DBM, Br-PADAP