Browsing by Author "Hiçsönmez, U"

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    Studying of 210Po and 210Pb Deposition in Some Lichen Species in Manisa, Turkey
    Kaynar, SÇ; Kaynar, UH; Sevinç, OS; Hiçsönmez, U
    Lichens are very useful for monitoring of the radionuclide deposition because having a high efficiency capturing the radionuclides from the atmospheric fallout. In the present work, Po-210 and Pb-210 deposition in some lichen species were determined using an alpha spectrometer. Different lichens were collected around Demirci-Manisa and investigated their uses as biomonitor for Po-210 and Pb-210 deposition. The highest activity concentrations for Po-210 and Pb-210 were detected in Neofuscelia pulla (898Bq kg(-1) and 1207Bq kg(-1), respectively). The mean activities in the lichen species ranged from 164 to 584Bq kg(-1) for Po-210 and from 175 to 671Bq kg(-1) for Pb-210. The activity ratios for Po-210/Pb-210 ranged from 0.75 to 1.57.
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    Determination of 210Po and 210Pb depositions in lichen and soil samples collected from Koprubasi-Manisa, Turkey
    Kaynar, SÇ; Kaynar, UH; Hiçsönmez, U; Sevinç, OS
    In this study, we aimed to determine the accumulations of Po-210 and Pb-210 in soil and lichen samples in Koprubasi. The Koprubasi district is home to the largest uranium deposits in Turkey. To date, there has been no study recorded in the literature related to Po-210 and Pb-210 depositions in lichens in Koprubasi. Six different lichen species (Cladonia convoluta, Parmelina tiliacea, Physcia stellaris, Pleurosticta acetabulum, Xanthoparmelia conspersa, and Xanthoria parietina) as well as soil samples were collected from seven sampling locations around Koprubasi. Lichens were used as biomonitors for Po-210 and Pb-210 deposition. The Po-210 and Pb-210 activity concentrations were measured in all the samples by alpha spectrometry. The activity concentrations in the lichen samples ranged from 64 to 577 Bq kg(-1) with an average of 266 Bq kg(-1) for Po-210 and from 78 to 565 Bq kg(-1) with an average of 333 Bq kg(-1) for 210 Pb. The activity ratios of Po-210/Pb-210 ranged from 0.80 to 1.99. In the lichen species, the mean 210 Po activity values varied from 154 Bq kg(-1) in Pleurosticta acetabulum to 390 Bq kg(-1) in Xanthoparmelia conspersa. The range of the mean Pb-210 activity was between 153 Bq kg(-1) in Cladonia convoluta and 378 Bq kg(-1) in Parmelina tiliacea. In the soil samples, Po-210 and Pb-210 activity concentrations were ranged from 14 to 1268 Bq kg(-1) and from 19 to 1113 Bq kg(-1), respectively. While the values of Po-210 and Pb-210 measured in the lichen samples are comparable with those of the literature, the results of Po-210 and Pb-210 in the soil taken from the uranium mine are higher than the results of the literature studies.
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    Preliminary Cesium Adsorption Study with a Unique Iron(III) Ferrocyanide/Vermiculite Nanocomposite via One-Pot Hydrothermal Synthesis
    Akalin, HA; Hiçsönmez, U
    A novel iron(III) ferrocyanide (Prussian blue)/vermiculite nanocomposite was synthesized, characterized and the cesium removal efficiency of the nanoadsorbent was investigated in this study. Characterization studies revealed that the nanocomposite was successfully produced and the saturation magnetization value was found as 0.15 emu/g. Low magnetization value was due to the low amount of Fe3O4 (magnetite). Adsorption isotherm studies confirmed that the process was in accordance with Langmuir, Freundlich, and D-R (Dubinin-Radushkevich) isotherm models, suggesting that the reaction mechanism was both monolayer and multilayer, also had a physical sorption character with 0.0906 kJ/mol adsorption energy. Higher linear regression values obtained from Langmuir and D-R isotherms proved that chemical adsorption mechanism was more favorable than physical adsorption and the nanoadsorbent had 49.50 mg/g maximum adsorption capacity.
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    Removal of thorium (IV) ions from aqueous solution by a novel nanoporous ZnO: Isotherms, kinetic and thermodynamic studies
    Kaynar, ÜH; Ayvacikli, M; Hiçsönmez, U; Kaynar, SC
    The adsorption of thorium (IV) from aqueous solutions onto a novel nanoporous ZnO particles prepared by microwave assisted combustion was studied using batch methods under different experimental conditions. The effect of contact time, solution pH, initial concentration and temperature on adsorption process was studied. The ability of this material to remove Th (IV) from aqueous solution was characterises by Langmuir, Freunlinch and Temkin adsorption isotherms. The adsorption percent and distribution coefficient for nanoporous ZnO powders in optimum conditions Were 97% +/- 1.02; 8080 L kg(-1) for Th (IV), respectively. Based on the Langmuir model, the maximum adsorption capacity of nanoporous ZnO for Th (IV) was found to be 1500 g kg(-1). Thermodynamic parameters were determined and discussed. The results indicated that nanoporous ZnO was suitable as sorbent material for recovery and adsorption of Th (IV) ions from aqueous solutions. The radioactive Th (VI) in surface water, sea water and waste waters from technologies producing nuclear fuels, mining (uranium and thorium) and laboratories working with radioactive materials (uranium and thorium) can be removed with this nanoporous ZnO. (C) 2015 Elsevier Ltd. All rights reserved.