Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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  • Article
    Citation - WoS: 7
    Citation - Scopus: 7
    Contributory Roles of Concentration and Ph in Caco3 Growth Inhibition for Submicron Particles Synthesis With Additive Ca2+
    (Elsevier B.V., 2024) Majekodunmi,O.T.; Kilic,S.; Ozdemir,E.
    Excessive growth of CaCO3 precipitates is inhibited by additive Ca2+. Here, we report the influence of concentration and solution pH on the extent of growth inhibition. Equal volumes of equimolar CaCl2 and Na2CO3 solutions were mixed and continuously dispersed in Ca(OH)2 solution, where Ca2+ irreversibly adsorb on the precipitates. Compared to conditions where additive Ca2+ are absent, this method can produce more than 90% decrease in particle size. We observe the degree of growth inhibition increases as the concentration of additive Ca2+, relative to the volume of precipitates, increases. An unusual role of pH is also revealed: growth inhibition that leads to the synthesis of monodisperse submicron CaCO3 particles is only observed in high alkaline pH conditions. Additive Ca2+ adsorb on CaCO3 precipitates in pH conditions above the isoelectric point (pH ≈ 9), but their ability to limit CaCO3 growth diminishes when pH < 12. © 2024 Elsevier B.V.
  • Article
    Citation - WoS: 14
    Citation - Scopus: 15
    Effect of Carbonic Anhydrase on Caco3 Crystallization in Alkaline Solution
    (American Chemical Society, 2016) Molva, Murat; Kılıç, Sevgi; Özdemir, Ekrem
    The effect of bovine carbonic anhydrase (CA) on calcium carbonate (CaCO3) crystallization was investigated. A new method was developed to estimate the biocatalytic activity of CA in alkaline solution. The CA was immobilized within polyurethane (PU) foam, and compared its biocatalytic activity with the free-CA and bare-PU foam. A minireactor was created in a calcium hydroxide (Ca(OH)2) solution in order to control the CO2 transfer rate, and reproducible results were obtained. It was found that the free-CA lost its activity in less than 6 min at pH 12.5 in alkaline Ca(OH)2 solution. The CaCO3 crystallization rates for the immobilized-CA were found to be a U-shape, relatively lower at lower immobilized-CA amounts compared to those for the free-CA and bare-PU foam and higher when the amount of immobilized-CA increased. It was concluded that a higher immobilized-CA amount is required to accelerate the CaCO3 crystallization rates in Ca(OH)2 solution.