Browsing by Author "Erenturk S.A."

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    Removal of 209Po from aquatic environment and its equilibrium and thermodynamic parameters
    (Elsevier Ltd, 2020) Hicsonmez U.; Erenturk S.A.; Gorgun A.U.; Aslani M.A.A.
    In this study, removal of 209Po from aqueous media using a natural zeolite as an adsorbent material was investigated. The adsorption experiments were performed by batch technique. The influence of specific process parameters such as initial concentration, pH of solution, contact time and temperature was studied to predict the optimum conditions for effective removing of 210Po. Initial and equilibrium activity concentration of 209Po in solutions was counted by a ZnS(Ag) alpha scintillation counter. Adsorption yield of 209Po onto the zeolite was determined as 90 ± 2% at pH: <3 and 25 °C for 40 min of contact time. The applications of the isotherm models such as Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms were studied to evaluate adsorption characteristics of 209Po onto natural zeolite. Results indicated that the Dubinin-Radushkevich and Freundlich models gave a better fit to the experimental data than Langmuir isotherm models. The thermodynamic parameters such as Gibbs free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) of adsorption process were calculated. The change in entropy (ΔSo) and enthalpy (ΔHo) were estimated to be −0.0003 J nmol−1 K−1 and 0.1008 kJ nmol−1, respectively. © 2020 Elsevier Ltd
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    Use of zeolite in reducing environmental risk of polonium: kinetic models
    (Akademiai Kiado ZRt., 2025) Hicsonmez U.; Erenturk S.A.; Gorgun A.U.; Aslani M.A.A.
    A study was conducted to understand the mechanism of adsorption kinetic that is effective in removal of 209Po by clinoptilolite, a natural zeolite, from aquatic environments. Studies of the adsorption kinetics of 209Po were carried out by interacting zeolite with 209Po at different time intervals. Experimental polonium adsorption data obtained in our previous article were applied to some known kinetic models such as pseudo-first order, pseudo-second order, Elowich, Bangham, Homogeneous particle diffusion and Shell step models. The data obtained from the models revealed that the rate-limiting step is more compatible with the pseudo-second order model, which is based on the assumption that chemical sorption. According to the results obtained, the calculated the amount of 209Po adsorbed at equilibrium (qe) and the equilibrium rate constant of pseudo-second-order sorption (k2) were found to be 0.3302 ng g−1, − 4.4 × 10–5 ng g−1 min−1, respectively. © The Author(s) 2025.