Browsing by Author "Kaynar S.Ç."

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    Determination of radioactivity levels in Akhisar, Gördes, Gölmarmara and Sindirgi regions, Western Turkey
    (2014) Kaynar S.Ç.; Saç M.M.; Ereeş F.S.
    In this study, radioactivity measurements in the environment of Akhisar, Gölmarmara, Gördes and Sindirgi regions in Western Turkey were investigated in order to evaluate the implications of any excess radioactivity in the environment of geological formation. The radioactivity concentrations of 40K, 238U and 232Th radionuclides in the soil samples were measured by a NaI(Tl) gamma spectrometer system, and the radium activity concentrations in the water samples were also analyzed by an ZnS(Ag) alpha counter by the collector chamber method. The radioactivity of 40K, 238U and 232Th in soils ranged 2.80-2,347.77, 9.90-256.19 and 9.66-106.53 Bq kg-1, respectively. The activity of 226Ra in the water samples ranged from 0.03 Bq L-1 (0.89pCi/L) to 0.80 Bq L-1 (21.58pCi/L). In addition, the external terrestrial gamma dose rate in air (nGy h-1), annual effective dose rate (mSv year-1) and radium equivalent activity (Bq kg-1) were calculated and compared with international standard values. © 2013 Springer-Verlag Berlin Heidelberg.
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    Modeling of thorium (IV) ions adsorption onto a novel adsorbent material silicon dioxide nano-balls using response surface methodology
    (Elsevier Ltd, 2016) Kaynar Ü.H.; Şabikoğlu I.; Kaynar S.Ç.; Eral M.
    The silicon dioxide nano-balls (nano-SiO2) were prepared for the adsorption of thorium (IV) ions from aqueous solution. The synthesized silicon dioxide nano-balls were characterized by Scanning Electron Microscopy/Energy Dispersive X-ray, X-ray Diffraction, Fourier Transform Infrared and BET surface area measurement spectroscopy. The effects of pH, concentration, temperature and the solid–liquid ratio on the adsorption of thorium by nano-balls were optimized using central composite design of response surface methodology. The interaction between four variables was studied and modelled. Furthermore, the statistical analysis of the results was done. Analysis of variance revealed that all of the single effects found statistically significant on the sorption of Th(IV). Probability F-values (F=4.64–14) and correlation coefficients (R2=0.99 for Th(IV)) indicate that model fit the experimental data well. The ability of this material to remove Th(IV) from aqueous solution was characterized by Langmuir, Freunlinch and Temkin adsorption isotherms. The adsorption capacity of thorium (IV) achieved 188.2 mg g−1. Thermodynamic parameters were determined and discussed. The batch adsorption condition with respect to interfering ions was tested. The results indicated that silicon dioxide nano-balls were suitable as sorbent material for adsorption and recovery of Th(IV) ions from aqueous solutions. © 2016 Elsevier Ltd