Chemistry / Kimya

Permanent URI for this collectionhttps://hdl.handle.net/11147/4072

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Author: search.filters.author.Lieberwirth, IngoSubject: search.filters.subject.Uptake

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  • Article
    Citation - WoS: 83
    Citation - Scopus: 97
    Characterization of the Uptake of Aqueous Ni2+ Ions on Nanoparticles of Zero-Valent Iron (nzvi)
    (Elsevier Ltd., 2009) Efecan, Nazlı; Shahwan, Talal; Eroğlu, Ahmet Emin; Lieberwirth, Ingo
    This study investigates the fixation of aqueous Ni2+ ions by nanoparticles of zero-valent iron (nZVI) prepared using the borohydride reduction method. The uptake of Ni2+ was tested under various experimental conditions like initial concentration, time, pH, and repetitive application of nZVI. Part of the experiments was devoted to comparing the extent of uptake of Ni2+ ions with those of Cu2+, Cd2+, Zn2+, and Sr2+ ions, which belong to a wide range of standard reduction potentials. Particle size analysis of nZVI in aqueous solution indicated that the material suffered extensive aggregation, much above the extent of aggregation known for dry nZVI. Nevertheless, nZVI showed fast uptake kinetics and very high uptake capacity. The overall results demonstrated the high fixation capability of nZVI towards the studied transition metal ions in aqueous solution. The same conclusion is, however, not valid for the removal of Sr2+ ions.
  • Article
    Citation - WoS: 306
    Citation - Scopus: 345
    Synthesis and Characterization of Kaolinite-Supported Zero-Valent Iron Nanoparticles and Their Application for the Removal of Aqueous Cu2+ and Co2+ Ions
    (Elsevier Ltd., 2009) Üzüm, Çağrı; Shahwan, Talal; Eroğlu, Ahmet Emin; Hallam, Keith R.; Scott, Thomas B.; Lieberwirth, Ingo
    This study reports the synthesis and characterization of nano-scale zero-valent iron in the presence of kaolinite clay (nZVI-kaol). The adsorbent, nZVI-kaol, was produced at initial Fe:kaolinite mass ratios of 1:1, 0.5:1, and 0.2:1. The presence of kaolinite resulted in decreased aggregation of iron nanoparticles, yielding composites with iso-electric points (IEPs) around 6.7–7.0. The reduction in Fe2+ precursor concentration appeared to decrease further the extent of aggregation and the size of individual nZVI particles. The synthesized nZVI-kaol materials were then tested for the removal of aqueous Cu2+ and Co2+ ions. The investigated parameters in the uptake experiments included volume/mass (V/M) ratio, initial concentrations of Cu2+ and Co2+ ions, contact time, pH, and repetitive application of the adsorbent. The adsorbents demonstrated high removal abilities towards both cations under the investigated conditions. Repetitive loading tests showed that significant removal could still be achieved at small concentrations by samples reused several times. X-ray photoelectron spectroscopy (XPS) analysis showed that while Co2+ was mainly fixed by the oxyhydroxyl groups of iron nanoparticles, Cu2+ ions were fixed by a redox mechanism, leading to the formation of Cu2O and Cu0.