Studies on the removal of uranyl ions from aqueous solutions by micellar-enhanced ultrafiltration

Ultrafiltration (UF) is one of the most effective techniques of concentrating or removing water-soluble solutes, mainly organic molecules as small as 1000 Da from aqueous streams. In the present investigations, UF of uranium(VI) in the presence of a micelle - solubilized hydrophobic ligand has been studied using sodium dodecyl sulfate (SDS) and 2-ethylhexyl phosphonic acid mono - 2-ethylhexyl ester as an anionic surfactant and an extractant, respectively. In aqueous media, the uranyl ions are entrapped within the surfactant micelles containing the extractant, and are effectively rejected by UF membranes with their consequent concentration in the retentate solution. The rejection of U(VI) enhanced with the lowering an acidity of the aqueous solution. The effect of surfactant concentration and applied pressure on the rejection of U(VI) from aqueous solutions were examined. The results showed potential application of UF for the separation of U(VI) from aqueous solutions. (author)