Separation of uranium(vi) from soils by extraction in aqueous peg (1550) na2so4 na2co3 two-phase systems. i. preliminary results
1 Al.I.Cuza University of Iasi, Faculty of geography and Geology, Department of Geology and Geochemistry, 20A, Carol I Blvd., 700506, Iasi, Romania
2 Romanian Academy, Branch of Iasi Collective of Geography, 18, Carol I Blvd., 700506, Iasi, Romania
3 Gh. Asachi Technical University of Iasi, Faculty of Chemical Engineering and Environmental Protection, Department of Environmental Engineering and Management, 71 Mangeron Blvd., 700050 Iasi, Romania
2 Romanian Academy, Branch of Iasi Collective of Geography, 18, Carol I Blvd., 700506, Iasi, Romania
3 Gh. Asachi Technical University of Iasi, Faculty of Chemical Engineering and Environmental Protection, Department of Environmental Engineering and Management, 71 Mangeron Blvd., 700050 Iasi, Romania
Abstract
In this paper preliminary results of studies concerning the extraction of uranium(VI) from soils in aqueous PEG (1550) 20 % - Na2SO4 20 % - Na2CO3 10-2-10-3 M two-phase systems are presented, as well as the spectrophotometric determination of extracted uranium with pirocatechol violet (PV). A special attention was given to the experimental factors (pH, redox potential, CO32- anion concentration and initial uranium concentration), which was found to influence both the formation and stability of aqueous two-phase extraction system, and the values of extraction parameters. The experimental values of distribution coefficients, extraction degree and enrichment coefficients for U(VI) extraction indicate an acceptable separation at pH=4-5, and at pH=8-9, respectively. Under certain work conditions, the increasing of U(VI) concentration in initial solution and of CO32anion concentration determined an increase of extraction degree and of enrichment coefficient.
Keywords
aqueous two-phase systems; extraction; spectrophotometry; uranium(VI)