WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7150

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Author: search.filters.author.Hallam, Keith R.Institution Author: search.filters.institutionAuthor.Shahwan, Talal

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  • Article
    Citation - WoS: 119
    Citation - Scopus: 151
    Batch Removal of Aqueous Cu2+ Ions Using Nanoparticles of Zero-Valent Iron: a Study of the Capacity and Mechanism of Uptake
    (American Chemical Society, 2008) Karabelli, Duygu; Üzüm, Çağrı; Shahwan, Talal; Eroğlu, Ahmet Emin; Scott, Tom B.; Hallam, Keith R.; Lieberwirth, Ingo
    In this study, nZVI prepared by borohydride reduction was applied for the removal of Cu2+ ions under a variety of experimental conditions. The uptake experiments investigated the effects of initial concentration, contact time, pH, and repetitive loading on the extent of retardation of Cu2+ ions. Within the applied conditions, the sorbent demonstrated fast uptake kinetics and outstanding fixation abilities up to an initial Cu2+ concentration of 200.0 mg/L. Partitioning of Cu2+ ions between liquid and solid phases demonstrated an isotherm of L-type. Within the studied conditions, the capacity of uptake was found to be 250 mg of Cu2+ per g of nZVI. According to X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) results, Cu2+ ions were sorbed primarily via a redox mechanism that resulted in the formation of Cu2O and Cu0. The contact of iron nanoparticles with aqueous media caused extensive formation of iron oxide. However, the material did not completely lose its removal capacity and was repeatedly applied at low concentrations for further uptake trials.
  • Article
    Citation - WoS: 163
    Citation - Scopus: 187
    Application of Zero-Valent Iron Nanoparticles for the Removal of Aqueous Co2+ Ions Under Various Experimental Conditions
    (Elsevier Ltd., 2008) Üzüm, Çağrı; Shahwan, Talal; Eroğlu, Ahmet Emin; Lieberwirth, Ingo; Scott, Thomas B.; Hallam, Keith R.
    Nanosized zero-valent iron (nZVI) is increasingly gaining interest as an efficient sorbent for various types of aqueous pollutants. In this study, nZVI was synthesised by the borohydride reduction method, characterised and then examined for the removal of aqueous Co2+ ions over a wide range of concentrations, from 1 to 1000 mg/L. The size of nZVI particles was predominantly within the range of 20–80 nm, and only limited oxidation was observed in samples aged for a period of 2 months. The experiments investigated the effects of V/m ratio, concentration, contact time, repetitive loading, pH and aging on the extent of retardation of Co2+ ions. Iron nanoparticles demonstrated very rapid uptake and large capacity for the removal of Co2+ ions. Effective uptake was observed even after a number of repetitive trials. The extent of Co2+ uptake increased with the increasing pH. X-ray photoelectron spectroscopy (XPS) indicate that the fixation of Co2+ ions takes place through the interaction of these ions with the oxohydroxyl groups on the iron nanoparticle surfaces in addition to spontaneous precipitate formation at high loadings.