Yazar "Ceyhan A.A." seçeneğine göre listele

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    The crystallization kinetics of potassium chloride in the presence of additives with common ions
    (2013) Ceyhan A.A.; Bulutcu A.N.
    In this study, the growth and dissolution rates of closely sized KCl crystals that were classified with respect to their separation voltages in an electrostatic separator were investigated in the presence of K 2SO4, CH3COOK, NH4Cl and BaCl 2 additives, having common cations or anions. Separation voltages were taken as a measure of surface potential. The experiments were carried out in a typical stagnant medium type single crystal measurement system. From experimental results it is observed that thread-like growth behaviors resulting from surface nucleation were dominant and dead zones where there was no growth or dissolution did always exist. For additives having common cation, it was found that the growth in the thread-like structure increases with the increase of surface potential. It was also found that, additives having common anions, initially led to decrease and neutralize the surface potential, then oppositely charged the crystal surface, when the crystal growth/dissolution behavior changes were considered. This study obviously proved that, crystal growth and dissolution behaviors can be controlled by changing the surface potentials of crystals by using additives having common ions. © 2013 Elsevier B.V. All rights reserved.
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    Effect of heavy metals impurities upon nucleation kinetics of NaCl [Nacl' ün çeki?rdeklenme ki?neti??i?ne a?ir metal safsizliklarinin etki?si?]
    (Gazi Universitesi Muhendislik-Mimarlik, 2014) Ceyhan A.A.; Baytar O.; Gülce A.
    In this study, effects of heavy metal's impurities (Pb2+, Fe3+) on nucleation kinetics of NaCl in crystallizationmedium were investigated. The tests were conducted by taking into account industrial production conditions ofthe salt (NaCl) and taking measurements of the setting period of the solution. In the study, where the tests werecarried out in both pure medium and in the presence of impurities, it was observed that the stirring processincreases the nucleation rate of NaCl. It was found that heavy metal impurities significantly reduce thenucleation rate and that this effect becomes more vivid with lead ions impurities (Pb2+). The study also foundthat the presence of seed crystal increases the nucleation rate. However; it was also clear that the negative effectsimposed by the heavy metal impurities on nucleation still kept persisting.
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    Surface and porous characterization of activated carbon prepared from pyrolysis of biomass by two-stage procedure at low activation temperature and it's the adsorption of iodine
    (Elsevier B.V., 2013) Ceyhan A.A.; Şahin Ö.; Baytar O.; Saka C.
    The textural characteristics of activated carbon prepared from biomass (Elaeagnus angustifolia seeds) activated with zinc chloride and two-stage pyrolysis in air was studied in this paper. The effect of activation temperature, duration time, impregnation concentration of agent and impregnation time was examined. Adsorption capacity was demonstrated with BET and iodine number. The highest iodine number was achieved as 1009 mg/g. The Dubinin-Astakhov approach was used to study the pore size diameter of activated carbon. The Dubinin-Radushkevich method was used to evaluate the micropore volume of activated carbon. The structural morphology of activated carbons were evaluated by SEM. The surface chemical characteristics of activated carbons were determined by FTIR spectroscopic method. © 2013 Elsevier B.V. All rights reserved.