Thermodynamic parameters and sorption of U(VI) on ACSD
- 106 Downloads
This paper discusses the sorption properties for U(VI) by alginate coated CaSO4·2H2O sepiolite and calcined diatomite earth (Kieselguhr) (ACSD). The removal of U(VI) from aqueous solution by sorption onto ACSF in a single component system with various contact times, pH, temperatures, and initial concentrations of U(VI) was investigated. The sorption patterns of uranium on the composite adsorbent followed the Langmuir, Freundlich and Dubinin-Radushkhevic (D-R) isotherms. The Freundlich, Langmuir, and D-R models have been applied and the data correlated well with Freundlich model and that the sorption was physical in nature (sorption energy, E a = 17.05 kJ/mol). The thermodynamic parameters such as variation of enthalpy ΔH, variation of entropy ΔS and variation of Gibbs free energy ΔG were calculated from the slope and intercept of lnK 0 vs. 1/T plots. Thermodynamic parameters (ΔH ads = 31.83 kJ/mol, ΔS ads = 167 J/mol·K, ΔG o ads (293.15 K) = −17.94 kJ/mol) showed the endothermic heat of sorption and the feasibility of the process. The thermodynamics of U(VI) ion/ACSD system indicates the spontaneous and endothermic nature of the process. It was noted that an increase in temperature resulted in a higher uranium loading per unit weight of the adsorbent.
KeywordsUranium Alginate Thermodynamic Parameter Sepiolite Versus Initial
Unable to display preview. Download preview PDF.
- 2.R. Qadeer, J. Hanif, M. Khan, M. Saleem, Radiochim. Acta, 68 (1995) 197.Google Scholar
- 3.R. Qadeer, J. Hanif, Radiochim. Acta, 65 (1994) 259.Google Scholar
- 7.A. Alvarez, Sepiolite: properties and uses, in: Developments in Sedimentology, A. Singer and E. Galan (Eds), Elsevier, Amsterdam, 1984, p. 253.Google Scholar
- 18.M. A. Hashim, K. H. Chu, Modelling the batch adsorption of copper by the microalga Chlorella vulgaris, in: Proc. of the 6th World Congress of Chemical Engineering, Melbourne, Australia, September, 2001, p. 23.Google Scholar
- 19.Analysis Reports of Diatomite, Turkish Sugar Fact. Inc., Kieselguhr Factory, Etimesgut- Ankara/Turkey, 1986.Google Scholar
- 21.T. M. Florence, AAEC/TM552, 1970, Paper 5.Google Scholar
- 22.A. Singer, Palygorskite and sepiolite group minerals, in: Minerals in Soil Environment, J. B. Dixon, S. B. Weed (Eds), Soil Science Society of America, Madison, WI, USA, 1989, p. 829.Google Scholar
- 25.J. Paquette, R. J. Lemire, Nucl. Sci. Eng., 79 (1981) 26.Google Scholar
- 27.T. J. Sorg, Removal of uranium from drinking water by conventional treatment methods, in: Radon, Radium and Uranium in Drinking Water, Vol. 2, Cothern and Rebers (Eds), Lewis Publishers, Michigan, ISBN 0 87371, 1991, p. 173.Google Scholar