Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Author: search.filters.author.Shahwan, TalalInstitution Author: search.filters.institutionAuthor.Eroğlu, Ahmet Emin

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Now showing 1 - 10 of 26
  • Article
    Citation - WoS: 1
    Citation - Scopus: 2
    A Molecularly Imprinted Polymer as Solid Phase Extraction Sorbent for Ketoprofen Determination in Water and Artificial Serum Prior To Hplc
    (TÜBİTAK - Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, 2022) Shahwan, Talal; Gürel Özyurt, Elif; Shahwan, Talal; Ölçer, Yekta Arya; Eroğlu, Ahmet Emin; Eroğlu, Ahmet Emin; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of Technology
    Ketoprofen (KET) is an active pharmaceutical compound that has pain relieving and antipyretic effects. Its determination in body fluids and environmental waters is important due to widespread use of the compound. In this study, a selective and reliable method has been developed for the determination of ketoprofen in water and artificial serum using molecularly imprinted polymers (MIPs) as a solid phase extraction sorbent prior to HPLC-DAD detection. The MIP was synthesized by copolymerization of methacrylic acid (MAA) and trimethylpropane trimethacrylate (TRIM) in the presence of ketoprofen as the template. For the sake of comparison, nonimprinted polymer (NIP) was also synthesized under the same experimental conditions without the addition of ketoprofen under the same experimental conditions. Critical extraction parameters such as sample pH, shaking time and sorbent amount were optimized and adjusted to 8.0, 24 h, and 10.0 mg, respectively, for a sample volume of 10.0 mL. MIP showed higher selectivity than NIP towards ketoprofen in an artificial matrix containing another pain relieving drug, ibuprofen, and a cardiovascular drug, metoprolol. The proposed method was successfully applied for the detection of ketoprofen in spiked drinking water, tap water, and artificial serum samples, and showed satisfactory results with respective recoveries of 96.8 % (± 0.8), 93.7% (± 0.6), 62.2% (± 0.6), and 69.9% (± 0.6).
  • Article
    Citation - WoS: 8
    Citation - Scopus: 10
    Trypsin-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 Technology
    In 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: 1
    Citation - Scopus: 1
    Amalgamation Performances of Gold-Coated Quartz Wool, Alumina, Silica, Sand and Carbon Fiber for the Determination of Inorganic Mercury in Waters by Cold Vapor Atomic Absorption Spectrometry
    (Pleiades Publishing, 2017) Erdem Şimşek, Arzu; Erdem Yayayürük, Aslı; Shahwan, Talal; Eroğlu, Ahmet Emin; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of Technology
    Different gold-coated sorbents for amalgamation were applied for the determination of inorganic mercury in waters using a home-made cold vapor generation unit coupled to atomic absorption spectrometry. Among the gold-coated materials investigated (quartz wool, alumina, silica, sand and carbon fiber) quartz wool was found to give the most efficient results in terms of sorption and release. Analytical performance of the system without and with amalgamation was investigated and it was found that when amalgamation was applied, the linearity and slope of the calibration plots were independent on the sample volume for 1.0, 5.0 and 10.0 mL. Method validation was realized through the analysis of a sample of spring water spiked with 1.0 μg/L inorganic mercury and the spike recoveries were found to be 95 ± 1, 91 ± 3, and 99 ± 5% for 1.0, 5.0, and 10.0 mL, respectively. The results demonstrated that the methodology can be applied to these types of samples directly or after amalgamation, depending on the mercury concentration.
  • Article
    Citation - WoS: 41
    Citation - Scopus: 40
    Biosorption of Cu(ii) and Pb(ii) Ions From Aqueous Solution by Natural Spider Silk
    (Elsevier Ltd., 2011) Shahwan, Talal; Ertaş, Fatma Nil; Eroğlu, Ahmet Emin; Shahwan, Talal; Tural, H.; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of Technology
    Aside from its excellent mechanical properties, spider silk (SS) would offer an active surface for heavy metal interaction due to its rich protein structure. The present study describes the potential use of natural (SS) as a sorbent of heavy metals from aqueous solutions. Single and multi-species biosorption experiments of heavy metals by natural SS were conducted using batch and column experiments. The biosorption kinetics, in general, was found to follow the second-order rate expression, and the experimental equilibrium biosorption data fitted reasonably well to Freundlich isotherm. From the Freundlich isotherm, the biosorption capacities of Cu(II) and Pb(II) ions onto SS were found as 0.20 and 0.007mmolg -1, respectively. The results showed a decrease in the extent of metal ion uptake with lowering the pH.
  • Article
    Citation - WoS: 45
    Citation - Scopus: 55
    Incorporation of Iron Nanoparticles Into Clinoptilolite and Its Application for the Removal of Cationic and Anionic Dyes
    (Korean Society of Industrial Engineering Chemistry, 2015) Eroğlu, Ahmet Emin; Shahwan, Talal; Shahwan, Talal; Fuchs, Harald; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of Technology
    This study reports the preparation of composite sorbents of iron nanoparticles (nZVI) and clinoptilolite at various iron/clinoptilolite ratios. The composites were characterized using various characterization techniques. The material was used for the removal of methylene blue (MB) and methyl orange (MO) as model cationic and anionic dyes. The experiments investigated the effects of time, loading, initial pH, reusability, and temperature on the removal process. According to the results, Cl-nZVI showed fast and quantitative removal over a wide range of concentrations. The removal process was endothermic in nature, and the composite demonstrated reusability for several trials.
  • Article
    Citation - WoS: 21
    Citation - Scopus: 21
    Retention of Aqueous Ba2+ Ions by Calcite and Aragonite Over a Wide Range of Concentrations: Characterization of the Uptake Capacity, and Kinetics of Sorption and Precipitate Formation
    (The Geochemical Society of Japan, 2007) Tunusoğlu, Özge; Shahwan, Talal; Eroğlu, Ahmet Emin; Shahwan, Talal; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of Technology
    The uptake of aqueous Ba2+, ions by abiogenic calcite and aragonite was studied over a wide range of concentration; 1.0 × 101, 5.0 × 101, 1.0 × 102 5.0 × 102, 1.0 × 103, 5.0 × 104, and 1.0 × 104 mg/L. The uptake process was characterized using ICP-AES, XRPD, SEM/EDS, and FTIR techniques. Up to the initial concentration of 5.0 × 102 mg/L, the uptake of Ba2+ ions was fast and obeyed Lagergren's kinetic model. The equilibrium data were adequately described using Freundlich isotherm model. The overgrowth of BaCO3 (witherite) took place at higher concentrations, in a kinetically slow process and enhanced the uptake of Ba2+ ions. Quantitative XRPD was used to evaluate the fractions of precipitated BaCO3 on calcite and aragonite minerals and monitor their variation with time. At all the studied concentrations, aragonite showed higher removal capacity of Ba2+ and faster uptake kinetics than did calcite. The precipitated crystals appeared to predominantly possess olivary-like morphology with an average particle size of 1-2 μm. EDS was used to reveal the elemental quantities of Ba and Ca after BaCO3 formation on calcite and aragonite surfaces. FTIR spectroscopy was employed to analyze the vibrational modes in carbonate mixtures upon incorporation of Ba2+ by sorption and precipitation mechanisms.
  • Article
    Citation - WoS: 19
    Citation - Scopus: 21
    Kinetic and Thermodynamic Investigations of Strontium Ions Retention by Natural Kaolinite and Clinoptilolite Minerals
    (Walter De Gruyter Gmbh, 2005) Akar, Dilek; Shahwan, Talal; Shahwan, Talal; Eroğlu, Ahmet Emin; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of Technology
    The current study was devoted to the determination of various thermodynamic and kinetic parameters resulting from the fixation of Sr2+ by natural samples of kaolinite and clinoptilolite minerals. The sorption process followed pseudo second order kinetics, with faster sorption on kaolinite compared to clinoptilolite, where the uptake is affected by intraparticle diffusion. Freundlich and Dubinin-Radushkevich isotherm models described the data more adequately than Langmuir model, and clinoptilolite showed a higher strontium sorption capacity than kaolinite. Thermodynamically, the activation energy of Sr2+ sorption by kaolinite and clinoptilolite were respectively, -8.5 and -18.4 kJ/mol. The sorption process on both minerals was spontaneous and endothermic at all the studied concentrations, with ΔH° being 11.3 and 9.8 kJ/mol, for sorption on kaolinite and clinoptilolite, respectively. The findings of this study were compared with those of an earlier study on the uptake of Cs+ by the same minerals.
  • Article
    Citation - WoS: 87
    Citation - Scopus: 108
    Synthesis and Characterization of Bentonite/Iron Nanoparticles and Their Application as Adsorbent of Cobalt Ions
    (Elsevier Ltd., 2010) Shahwan, Talal; Üzüm, Çağrı; Eroğlu, Ahmet Emin; Shahwan, Talal; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of Technology
    This study reports the synthesis and characterization of iron nanoparticles in the presence of K10 bentonite. Introducing K10 during synthesis of iron nanoparticles resulted in a partial decrease in the aggregation of the nanoparticles. The dispersed nanoparticles showed a typical core–shell structure and were predominantly within the 10–60 nm size range. The composite adsorbent was tested for the removal of Co2+ ions in aqueous solution at various contact times, concentrations, pH, and repetitive loadings. The rate of adsorption was evaluated using first and second order rate equations. The adsorption was described by the Freundlich model. The adsorbent showed effective removal after re-use and the adsorption increased with increasing initial pH.
  • Article
    Citation - WoS: 17
    Citation - Scopus: 17
    Separation of Trace Antimony and Arsenic Prior To Hydride Generation Atomic Absorption Spectrometric Determination
    (Elsevier Ltd., 2005) Ural, Müşerref Yersel; Erdem, Aslı; Eroğlu, Ahmet Emin; Shahwan, Talal; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of Technology
    A separation method utilizing a synthetic zeolite (mordenite) was developed in order to eliminate the gas phase interference of Sb(III) on As(III) during quartz furnace hydride generation atomic absorption spectrometric (HGAAS) determination. The efficiency of the proposed separation method in the reduction of suppression effects of transition metal ions on As(III) signal was also investigated. Among the volatile hydride-forming elements and their different oxidation states tested (Sb(III), Sb(V), Se(IV), Se(VI), Te(IV), and Te(VI)), only Sb(III) was found to have a signal depression effect even at low (μg l−1) concentrations under the experimental conditions employed. It has been shown that mordenite adsorbs Sb(III) quantitatively, even at a concentration of 1000 μg l−1, at pHs greater than two, and also, it reduces the initial concentrations of the transition metal ions to lower levels which can be tolerated in many studies. The adsorption of Sb(III) on mordenite follows the Freundlich isotherm and is endothermic in nature.
  • Article
    Citation - WoS: 70
    Citation - Scopus: 82
    Sorption Efficiency of Chitosan Nanofibers Toward Metal Ions at Low Concentrations
    (American Chemical Society, 2010) Horzum Polat, Nesrin; Boyacı, Ezel; Shahwan, Talal; Shahwan, Talal; Demir, Mustafa Muammer; Demir, Mustafa Muammer; Eroğlu, Ahmet Emin; 04.01. Department of Chemistry; 03.09. Department of Materials Science and Engineering; 03. Faculty of Engineering; 04. Faculty of Science; 01. Izmir Institute of Technology
    Chitosan fibers showing narrow diameter distribution with a mean of 42 nm were produced by electrospinning and utilized for the sorption of Fe(III), Cu(II), Ag(I), and Cd(II) ions from aqueous solutions. The ion concentrations in the supernatant solutions were determined using inductively coupled plasma-mass spectrometry (ICP-MS). The filtration efficiency of the fibers toward these ions was studied by both batch and microcolumn methods. High efficiency in sorption of the metal ions was obtained in the both methods. The effects of sorbent amount (0.10−0.50 mg), shaking time (15−120 min), initial metal ion concentration (10.0−1000.0 μg·L−1), and temperature (25 and 50 °C) on the extent of sorption were examined. The sorbent amount did not significantly alter the efficiency of sorption; however, shaking time, temperature, and metal ion concentration were found to have a strong influence on sorption. By virtue of its mechanical integrity, the applicability of the chitosan mat in solid phase extraction under continuous flow looks promising.