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: 119Citation - Scopus: 151Batch 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, IngoIn 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: 306Citation - Scopus: 345Synthesis 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, IngoThis 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.Article Citation - WoS: 654Citation - Scopus: 786Green Synthesis of Iron Nanoparticles and Their Application as a Fenton-Like Catalyst for the Degradation of Aqueous Cationic and Anionic Dyes(Elsevier Ltd., 2011) Shahwan, Talal; Abu-Sirriah, Sadieh; Nairat, Muath; Boyacı, Ezel; Eroğlu, Ahmet Emin; Scott, Thomas B.; Hallam, Keith R.Iron nanoparticles were produced using extracts of green tea leaves (GT-Fe NPs). The materials were characterized using TEM, SEM/EDX, XPS, XRD, and FTIR techniques and were shown to contain mainly iron oxide and iron oxohydroxide. The obtained nanoparticles were then utilized as a Fenton-like catalyst for decolorization of aqueous solutions containing methylene blue (MB) and methyl orange (MO) dyes. The related experiments investigated the removal kinetics and the effect of concentration for both MB and MO. The concentrations of dyes in aqueous solution were monitored using ultraviolet–visible (UV–vis) spectroscopy. The results indicated fast removal of the dyes with the kinetic data of MB following a second order removal rate, while those of MO were closer to a first order removal rate. The loading experiments indicated almost complete removal of both dyes from water over a wide range of concentration, 10–200 mg L−1. Compared with iron nanoparticles produced by borohydride reduction, GT-Fe nanoparticles demonstrated more effective capability as a Fenton-like catalyst, both in terms of kinetics and percentage removal.Article Citation - WoS: 163Citation - Scopus: 187Application 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.