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: 8Citation - Scopus: 10Trypsin-Immobilized Silica: a Novel Adsorbent for V(iv) and V(v) Removal From Water(Water Environment Federation, 2018) Erdem Yayayürük, Aslı; Eroğlu, Ahmet Emin; Shahwan, Talal; Shahwan, Talal; Şanlı Mohamed, Gülşah; Şanlı Mohamed, Gülşah; Eroğlu, Ahmet Emin; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of TechnologyIn the present study, trypsin-immobilized silica was employed for the removal of V(IV) and V(V) ions from water. The synthesized sorbent was first characterized and then investigated for the removal of V(IV) and V(V) under various experimental conditions. The adsorption performance of the sorbent was tested as a function of pli, sorbent amount, initial vanadium concentration, contact time, and temperature. The sorption process was then investigated, both from a kinetic perspective and also in terms of isotherm models. The Langmuir adsorption isotherm was the best model to describe the sorption process. Sorption thermodynamics were spontaneous and exothermic. The proposed method was successfully applied to real samples for the removal of V(IV)and V(V) with sufficient accuracy and precision.Article Citation - WoS: 47Determination of Technetium in Sea-Water Using Ion Exchange and Inductively Coupled Plasma Mass Spectrometry With Ultrasonic Nebulisation(Royal Society of Chemistry, 1998) Eroğlu, Ahmet Emin; Eroğlu, Ahmet Emin; Leonard, Kinson S.; McCubbin, David; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of TechnologyAn enrichment–separation scheme employing a strong-base type anion-exchange resin was developed for the determination of99Tc in sea-water by inductively coupled plasma mass spectrometry utilising ultrasonic nebulisation with membrane desolvation. Samples were processed through an anion-exchange column to enrich Tc and to eliminate sea-water matrix ions. The limit of detection for 99Tc in sea-water based on processing a 14 ml sample was 0.03 ng l–1. Accuracy was verified with spike recovery experiments. The potential for rapid on-line sample processing via a microcolumn–flow injection system was demonstrated.Article Citation - WoS: 50Synthesis of Aminopropyl Triethoxysilane-Functionalized Silica and Its Application in Speciation Studies of Vanadium(iv) and Vanadium(v)(Elsevier Ltd., 2011) Erdem, Aslı; Shahwan, Talal; Çağır, Ali; Eroğlu, Ahmet Emin; Shahwan, Talal; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of TechnologyA solid phase extraction sorbent, aminopropyl triethoxysilane-functionalized silica was prepared and used for vanadium speciation prior to inductively coupled plasma mass spectrometric determination. The necessary sorption parameters such as sorption pH, reaction temperature, sorbent amount and sample volume were optimized. The sorption for V(V) and V(IV) under the optimized conditions was 98% (±1) and was lower than 10%, respectively. The sorption process was investigated both from a kinetic perspective and also in terms of Freundlich, Dubinin-Radushkevich and Langmuir isotherm models to characterize the uptake of vanadate ion by the functionalized silica. Desorption from the sorbent was realized with 0.5 mol L−1 thiourea prepared in 0.2 mol L−1 HCl. Among the possible interfering species tested, Te(IV), Se(IV), Se(VI) and Fe(III) showed interference effects with V(V) signal. The validity of the method was first checked via spike recovery experiments with four different types of water; namely ultra pure, bottled drinking, tap, and sea water for different concentrations of V(V). The percent recovery values changed between 87 and 108 for all water types. The accuracy of the proposed methodology was also checked by analyzing a standard reference material (NIST, SRM 1643e) and a good agreement was found between the determined and the certified value. The proposed methodology has also been shown to be applicable for the separate sorption of V(V) in the absence/presence of V(IV) and for the sorption of both V(IV) and V(V) in waters. The amount of V(IV) can then be determined from the difference.Article Citation - WoS: 46Synthesis, Characterization and Application of a Novel Mercapto- and Amine-Bifunctionalized Silica for Speciation/Sorption of Inorganic Arsenic Prior To Inductively Coupled Plasma Mass Spectrometric Determination(Elsevier Ltd., 2011) Shahwan, Talal; Çağır, Ali; Shahwan, Talal; Eroğlu, Ahmet Emin; Çağır, Ali; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of TechnologyA bifunctional sorbent, (NH2 + SH)silica, containing both amine and mercapto functionalities was prepared by modification of silica gel with 3-(triethoxysilyl)propylamine and (3-mercaptopropyl)trimethoxysilane. In addition to the bifunctional sorbent, silica gel was modified individually with the functional mercapto- and amino-silanes, and the mono-functional sorbents, namely (SH)silica and (NH2)silica, were also mechanically mixed ((NH2)silica + (SH)silica) for the sake of comparison of sorption performances. It has been demonstrated that (SH)silica shows quantitative sorption only to As(III) at two pH values, 1.0 and 9.0, while (NH2)silica displays selectivity only towards As(V) at pH 3.0. On the other hand, the bifunctional (NH2 + SH)silica possesses the efficient features of the two mono-functionalized sorbents; for example, it retains As(III) at a wider pH range, from 1.0 to at least 9.0 with the exception at pH 2.0, and it also shows quantitative sorption to As(V) at pH 3.0. This property gives the bifunctional (NH2 + SH)silica a better flexibility in terms of sorption performance as a function of solution pH. The mechanically mixed (NH2)silica + (SH)silica exhibits a similar but less efficient sorption behavior compared to the bifunctional sorbent. Desorption of both As(III) and As(V) species can be realized using 0.5 M NaOH. The validity of the proposed method was checked through the analysis of a standard reference material and a good correlation was obtained between the certified (26.67 μg L−1) and determined (27.53 ± 0.37 μg L−1) values. Spike recovery tests realized with ultrapure water (93.0 ± 2.3%) and drinking water (86.9 ± 1.2%) also confirmed the applicability of the method.