Browsing by Author "Hiçsönmez, Ü"

Now showing 1 - 3 of 3
  • No Thumbnail Available
    Item
    Use of extraction chromatography for thorium purification from Eskisehir-Beylikahir thorium-REEs ore deposit
    Hiçsönmez, Ü; Eral, M
    The extraction chromatography method was used to separate thorium from acidic leach solution. The separation of thorium was realized on silica gel column coated with tri-octlyphosphine oxide (TOPO). The extraction yield of thorium on this column from nitric acid leach solution is 91.9%. Then thorium was eluted by using 0-5 M H2SO4 solution, and elution yield was determined as 96.5%. The chemical analysis of H2SO4 fractions indicated that thorium was concentrated and purified succesfully by this method. As a result, thorium was recovered in dilute leach solution with a yield of 81.0 +/- 6.8%.
  • No Thumbnail Available
    Item
    Sorption of uranium(VI) from aqueous solutions by DEEA organo-volcanic: isotherms, kinetic and thermodynamic studies
    Kaynar, ÜH; Hiçsönmez, Ü; Kaynar, SÇ; Koçak, S
    The sorption of the uranium(VI) ions from aqueous solutions by diethylethanolammonium organo-volcanics (Kula-TURKEY) was investigated under different experimental conditions. DEEA was used to modify the surface of basaltic volcanics. The characteristic of basaltic volcanic was analyzed by XRF, SEM-EDS, FTIR, and XRD. The BET surface areas of unmodified volcanics and DEEA-modified volcanics were found as 2.265 and 3.689 m(2)/g, respectively. The volcanic samples were treated by using different concentrations of DEEA. The adsorption of U(VI) on natural and modified volcanics was examined as a function of the contact time, initial pH of the solution, initial U(VI) concentration, and temperature. Langmuir, Freundlich, and D-R adsorption isotherms were used to describe the adsorption. While examining the adsorption percentage and distribution coefficient, these values for unmodified volcanics were found to be 25% +/- 0.76 and 10.08 mL/g, while the values for the DEEA-modified volcanics were 88% +/- 1.04 and 220 mL/g, respectively. The pseudo-first-order and pseudo-second-order kinetic models were used to describe the kinetic data. In this study, it can be seen that the adsorption process is suitable for the pseudo-second-order kinetic model. Various thermodynamic parameters (Delta G degrees, Delta H degrees, and Delta S degrees) were calculated with the thermodynamic distribution coefficients obtained at different temperatures. The sorption process was a chemical adsorption process. The results indicated that the processes are spontaneous and endothermic.
  • No Thumbnail Available
    Item
    Removal of uranium(VI) from aqueous solutions using nanoporous ZnO prepared with microwave-assisted combustion synthesis
    Kaynar, ÜH; Ayvacikli, M; Kaynar, SÇ; Hiçsönmez, Ü
    The adsorption of the uranyl ions from aqueous solutions on the nanoporous ZnO powders has been investigated under different experimental conditions. The adsorption of uranyl on nanoporous ZnO powders were examined as a function of the contact times, pH of the solution, concentration of uranium(VI) and temperature. The ability of this material to remove U(VI) from aqueous solution was followed by a series of Langmuir and Freunlinch adsorption isotherms. The adsorption percent and distribution coefficient for nanoporous ZnO powders were 98.65 % +/- 1.05 and 7,304 mL g(-1), respectively. The optimum conditions were found as at pH 5.0, contact time 1 h, at 1/5 Zn2+/urea ratio, 50 ppm U(VI) concentration and 303 K. The monomolecular adsorption capacity of nanoporous ZnO powders for U(VI) was found to be 1,111 mg g(-1) at 303 K. Using the thermodynamic equilibrium constants obtained at different temperatures, various thermodynamic parameters, such as Delta G degrees, Delta H degrees and Delta S degrees , have been calculated. Thermodynamic parameters (Delta H degrees = 28.1 kJ mol(-1), Delta S degrees = 160.30 J mol(-1) K-1, Delta G degrees = -48.54 kJ mol(-1)) showed the endothermic and spontaneous of the process. The results suggested that nanoporous ZnO powders was suitable as sorbent material for recovery and adsorption of U(VI) ions from aqueous solutions.