Browsing by Author "Turkozu, Dogukan Alkim"

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Determination of Optimum Conditions for the Extraction and Separation of Lanthanum, Cerium, Yttrium and Thorium Using Taguchi Method
(Springer, 2023) Yacouba, Abdoul-Rachid Chaibou; Oral, Alparslan Enes; Bawa, Ali Sanda; Sert, Senol; Kaptanoglu, Ikbal Gozde; Turkozu, Dogukan Alkim; Aytas, Sule
Taguchi method was applied to determine the optimum conditions for the extraction and separation of some lanthanides using three organic extractants. It was found that the optimum results were obtained with trioctylphosphine oxide (TOPO). The extraction efficiency and distribution coefficient of La(III), Ce(III), Y(III) and Th(IV) increased by increasing the salt concentration. Under these conditions 1 M HNO3, 0.1 M TOPO and 10(-1) M KSCN, the extraction efficiency of all metals reached 85%. Based to the Pourbaix diagrams La3+, Ce3+, Y3+ and Th4+ were formed and the stoichiometry of the extracted complexes were [Ln(NO3)(3) center dot 2TOPO](org) and [Th(NO3)(4) center dot TOPO](org).
Removal of Th(Iv) Ions From Aqueous Solution Using Bi-Functionalized Algae-Yeast Biosorbent
(Springer, 2011) Gok, Cem; Turkozu, Dogukan Alkim; Aytas, Sule
Composites could be more effective adsorbents than inorganic and organic components individually. In the present study, the red macro marine algae, Jania Rubens and yeast, Saccharomyces cerevisiae immobilized on silica gel were used as a constituent of bi-functionalized biosorbent to remove thorium ions from aqueous solution. Optimum biosorption conditions were determined as a function of pH, initial Th(IV) concentration, contact time, temperature, volume/mass ratio and co-ion effect. The morphological analysis of the biocomposite was performed by the scanning electron microscopy and functional groups in the biosorbent were determined by FT-IR spectroscopy. In order to find the adsorption characteristics, Langmuir, Freundlich, and Dubinin-Radushkevich adsorption isotherms were applied to the adsorption data. The data were well described by Langmuir adsorption isotherms while the fit of Freundlich adsorption isotherms and Dubinin-Radushkevich equation to adsorption data was poor. Using the equilibrium constant value obtained at different temperature, the thermodynamics properties of the biosorption (Delta GA degrees, Delta HA degrees and Delta SA degrees) were also determined. The results show that biosorption of Th(IV) ions onto biocomposite was exothermic nature, spontaneous and more favorable at lower temperature under examined conditions.