PubMed İndeksli Yayınlar Koleksiyonu / PubMed Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7645

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End date: 2009Subject: search.filters.subject.Adsorption

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  • Article
    Citation - WoS: 262
    Citation - Scopus: 286
    Dye Adsorption Behavior of Luffa Cylindrica Fibers
    (Elsevier Ltd., 2008) Demir, Hasan; Top, Ayben; Balköse, Devrim; Ülkü, Semra
    Using natural Luffa cylindrica fibers as adsorbent removal of methylene blue dye from aqueous solutions at different temperatures and dye concentrations was investigated in this study. Thermodynamics and kinetics of adsorption were also investigated. The adsorption isotherms could be well defined with Langmuir model instead of Freundlich model. The thermodynamic parameters of methylene blue (MB) adsorption indicated that the adsorption is exothermic and spontaneous. The average MB adsorption capacity was found out as 49 mg/g and average BET surface area of fibers was calculated as 123 m2/g.
  • Letter
    Citation - WoS: 46
    Citation - Scopus: 53
    A Characterization Study of Some Aspects of the Adsorption of Aqueous Co2+ Ions on a Natural Bentonite Clay
    (Elsevier Ltd., 2006) Shahwan, Talal; Erten, Hasan N.; Ünügür, S.
    The natural bentonite used in this study contained montmorillonite in addition to low cristobalite. The uptake of aqueous Co2+ ions was investigated as a function of time, concentration, and temperature. In addition, the change in the interlayer space of montmorillonite was analyzed using XRPD, and the distribution of fixed Co2+ ions on the heterogeneous clay surface was recorded using EDS mapping. The sorbed amount of Co2+ appeared to closely follow Freundlich isotherm, with the sorption process showing apparent endothermic behavior. The relevance of the apparent Δ Ho values is briefly discussed. Analysis of the Co-sorbed bentonite samples using SEM/EDS showed that the montmorillonite fraction in the mineral was more effective in Co2+ fixation than the cristobalite fraction. XRPD analysis demonstrated that the interlayer space of montmorillonite was slightly modified at the end of sorption.
  • Article
    Citation - WoS: 1
    Citation - Scopus: 2
    Kinetic Estimation of the Adsorbate Distribution on the Surface From Adsorbed Amounts
    (Elsevier Ltd., 2006) Polat, Mehmet
    A phenomenological multilayer adsorption model for a well-dispersed, homogeneous, nonporous adsorbent and a molecular adsorbate is presented. The model provides explicit kinetic expressions associating the adsorbed amounts to the fraction of the surface occupied and reduces to the first- and second-order adsorption models for special cases. Parameters of the model are a pair of true rate constants related to the adsorbate-adsorbent and adsorbate-surface adsorbate affinities. A general graphical procedure and analytical equations for special cases are provided to estimate the rate constants from kinetic adsorption data. Data from the adsorption of sodium stearate onto α-alumina from water were used to test the model. The predicted values of the rate constants suggested that the stearate was distributed homogeneously on the alumina surface and essentially adsorbed as a monolayer before starting to form the second layer.
  • 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.