Sürdürülebilir Yeşil Kampüs Koleksiyonu / Sustainable Green Campus Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7755

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Institution Author: search.filters.institutionAuthor.Shahwan, Talal

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  • Article
    Citation - WoS: 211
    Citation - Scopus: 246
    A Radiotracer Study of the Adsorption Behavior of Aqueous Ba2+ Ions on Nanoparticles of Zero-Valent Iron
    (Elsevier Ltd., 2007) Çelebi, O.; Üzüm, Çağrı; Shahwan, Talal.; Erten, Hasan N
    Recently, iron nanoparticles are increasingly being tested as adsorbents for various types of organic and inorganic pollutants. In this study, nanoparticles of zero-valent iron (NZVI) synthesized under atmospheric conditions were employed for the removal of Ba2+ ions in a concentration range 10-3 to 10-6 M. Throughout the study, 133Ba was used as a tracer to study the effects of time, concentration, and temperature. The obtained data was analyzed using various kinetic models and adsorption isotherms. Pseudo-second-order kinetics and Dubinin-Radushkevich isotherm model provided the best correlation with the obtained data. Observed thermodynamic parameters showed that the process is exothermic and hence enthalpy-driven.
  • Article
    Citation - WoS: 120
    Citation - Scopus: 127
    Equilibrium, Thermodynamic and Kinetic Studies for the Biosorption of Aqueous Lead(ii), Cadmium(ii) and Nickel(ii) Ions on Spirulina Platensis
    (Elsevier Ltd., 2008) Şeker, Ayşegül; Shahwan, Talal; Eroğlu, Ahmet Emin; Yılmaz, Sinan; Demirel, Zeliha; Conk Dalay, Meltem
    The biosorption of lead(II), cadmium(II) and nickel(II) ions from aqueous solution by Spirulina platensis was studied as a function of time, concentration, temperature, repetitive reactivity, and ionic competition. The kinetic results obeyed well the pseudo second-order model. Freundlich, Dubinin Radushkevich and Temkin isotherm models were applied in describing the equilibrium partition of the ions. Freundlich isotherm was applied to describe the design of a single-stage batch sorption system. According to the thermodynamic parameters such as ΔG°, ΔH°and ΔS° calculated, the sorption process was endothermic and largely driven towards the products. Sorption activities in a three metal ion system were studied which indicated that there is a relative selectivity of the biosorbent towards Pb2+ ions. The measurements of the repetitive reusability of S. platensis indicated a large capacity towards the three metal ions.