Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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2003 - 20086

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Author: search.filters.author.Eroğlu, Ahmet EminSubject: search.filters.subject.Atomic absorption spectroscopy

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Now showing 1 - 6 of 6
  • Master Thesis
    Biosorption of Aqueus Pb2+, Cd2+, and Ni2+ Ions by Dunaliella Salina, Oocystis Sp., Porphyridium Cruentum, and Scenedesmus Protuberans Prior To Atomic Spectrometric Determination
    (Izmir Institute of Technology, 2008) Karaca, Meral; Eroğlu, Ahmet Emin
    In this study, the possibility of using four different algae for the sorption of heavy metals, namely, Pb, Cd, and Ni, from waters was investigated. Dunaliella salina, Oocystis sp., Porphyridium cruentum, and Scenedesmus protuberans were shown to be good candidates for the sorption/removal of the metals from waters prior to atomic spectrometric determination. Characterization of the algae was carried out by scanning electron microscopy, FTIR, elemental analysis, and thermogravimetric analysis.All biomasses behaved similarly in the optimization of sorption parameters.Solution pH of 6.0, sorbent amount of 10.0 mg for 10.0 mL sample volume, shaking time of 60 min, and reaction temperature of 25C were used in the sorption experiments. It was demonstrated that the primary sorption mechanism is the electrostatic attraction between the negatively charged functional groups on the surface of the biomass and the positively (+2) charged metal ions in the solution. Among the biomasses investigated, Dunaliella salina has shown the highest sorption capacity for all the metal ions. It was followed by Oocystis sp., Scenedesmus protuberans and Porphyridium cruentum. Additionally, the biomasses examined have demonstrated the highest affinity towards Pb2+ which was followed by Cd2+ and Ni2+.The competitive biosorption experiments have shown that the uptake of Pb2+ ions was not influenced by the presence of other ions for all the algae studied.However, the general trend for the other biomasses was a decrease in their sorption efficiency towards Cd2+ and Ni2+ ions with the increase in the concentration of the competitive ions.It can be proposed that the algal biomasses investigated in this study can be utilized successfully in the sorption and selective removal of the studied heavy metal ions from waters.
  • Master Thesis
    Speciation of Chromium in Waters Via Sol-Gel Preconcentration Prior To Atomic Spectrometric Determination
    (Izmir Institute of Technology, 2007) Kumral, Elif; Eroğlu, Ahmet Emin
    Chromium occurs in natural samples in two relatively stable valence states, i.e. in the form of Cr(III) and Cr(VI) species. Their concentration in natural waters is usually very low, in the order of a few .g/L. This low concentration necessitates either the use of very sensitive analytical techniques or the application of suitable preconcentration methods prior to instrumental determination. In the present study, a resin having immobilized mercapto or amino functional groups was prepared by reacting silica gel with 3-mercaptopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, L-glutamic acid dimethyl ester, aminophenol, aminothiophenol and aminobenzothiazol for the preconcentration of Cr(III) and Cr(VI) species in waters prior to their determination by flame atomic absorption spectrometry (FAAS). Characterization of the novel sorbents were performed using scanning electron microscopy (SEM/EDS), thermo gravimetric analysis (TGA) and elemental analysis. Among the sorbents synthesized, amino sol-gel and silica amino have been shown to be efficient in terms of sorption capacity. The applicability of the new sorbents for the preconcentration of Cr(III) and Cr(VI) species in waters was examined by batch method. After pH 4, silica amino could quantitatively sorb both Cr(III) and Cr(VI) whereas amino sol-gel sorbed only Cr(III). Effect of the amount of silica amino and amino sol-gel was examined at the optimum pH. The optimum amount of silica amino for quantitative sorption was found to be 0.1 g for 20.0 mL of 1.0 mg/L Cr(III) and Cr(VI) solutions whereas that of amino sol-gel was 0.05 g for 20.0 mL of 1.0 mg/L for both species. The effect of Cr(III) and Cr(VI) concentrations on amino sol-gel and silica amino were investigated at the initial concentrations of 1.0, 10.0, 25.0 and 50.0 mg/L. Elution was realized with 2.0 M HCl, and the percent recovery values changed between 60 and 80%.
  • Master Thesis
    Speciation and Preconcentration of Inorganic Antimony and Manganese in Waters Using Microcolumn-Flow Injection System and Determination by Atomic Absorption Spectrometry
    (Izmir Institute of Technology, 2003) Erdem, Aslı; Eroğlu, Ahmet Emin
    A selective separation/preconcentration method utilizing microcolumn of a chelating resin with -SH functional groups (Duolite GT-73) was proposed for the determination of Sb(III) in waters by segmented flow injection HGAAS. The selectivity of the resin towards Sb(III) and Sb(V) was not dependent on the pH of the solution; Sb(III) was retained by the resin quantitatively in a broad pH and acidity range whereas Sb(V) was not retained at all and could be determined after a pre-reduction step with L-cysteine.Spike recoveries were tested at various concentration levels in different water types and were found to vary between 80-110 %. Accuracy of the proposed methodology was checked by analyzing a standard reference material and a good correlation was found between the determined and the certified values. The method was applied to several bottled drinking water samples for antimony determination. The samples were found to contain no antimony above the permissible level (5 ug/L). The applicability of the microcolumn separation/preconcentration method for flow injection systems was also demonstrated.A similar separation system was proposed for Mn determination in waters. A macroporous resin with no functional groups (Amberlite XAD-7HP) was employed for the speciation of Mn(II) and Mn(VII) and was found to retain Mn(VII) at pH values from 4.0 to 12.0. Mn(II) was retained at a pH of 12.0, possibly due to MnO2 precipitation rather than adsorption by the resin.
  • Master Thesis
    Sorption of as (v) From Waters by Use of Novel Amine-Containing Sorbents Prior To Hgaas and Icp-Ms Determination
    (Izmir Institute of Technology, 2008) Boyacı, Ezel; Eroğlu, Ahmet Emin
    A novel sorption method utilizing several amine-containing sorbents was developed for arsenic determination in waters by hydride generation atomic absorption spectrometry (HGAAS) and inductively coupled plasma mass spectrometry (ICP-MS).Chitosan, chitosan-immobilized sodium silicate, chitosan-modified macroporous silicate, and aminopropyl triethoxysilane-treated macroporous silicate were among the sorbents investigated for As(V) sorption.Sorption parameters were optimized for As(V) using chitosan and chitosanimmobilized sodium silicate and were then applied in all sorption studies. These parameters, namely, sorption pH, amount of sorbent, reaction temperature, and shaking time were 3.0, 50.0 mg, 25 .C, and 30 min, respectively. The sorption for chitosan under the optimized conditions was 89% (±1) while that for As(III) was lower than 10% at all pHs. In addition, chitosan-modified and amine-modified macroporous silicate demonstrated 88% (±3) and 68% (±12) sorption, respectively. After the sorption, the release of arsenate from chitosan and chitosan-immobilized sodium silicate was realized using two eluents; namely, 2.0% (v/v) acetic acid which dissolved chitosan, and 1.0% (w/v) L-cysteine solution having a pH of 3.0 adjusted with HCl which eluted arsenate by reducing to arsenite. Their respective desorption percentages were 90% (±1) and 100% (±4) for chitosan, and 67% (±2) and 100% (±1) for chitosan-immobilized sodium silicate.The preconcentration study performed using an absolute amount of 150.0 ng As(V) in bottled drinking water at the enrichment factors of 1, 2, and 10 has given 98% (±3), 95% (±2), and 78% (±4) recoveries, respectively. The accuracy of the proposed methodology with chitosan was verified with spike recovery tests for various water types at a concentration of 10.0 .g/L As(V). With matrix-matched calibration, the percentage spike recovery values were determined to be 114 (±4), 112 (±2), 43 (±4), and 0 (±1), for ultrapure, bottled, tap and sea water, respectively. These results have shown the strong suppression effect of the tap and the sea water matrixes.
  • Master Thesis
    Separation of Trace Antimony and Arsenic Prior To Hydride Generation Atomic Absortion Spectrometric Determination
    (Izmir Institute of Technology, 2005) Yersel, Müşerref; Eroğlu, Ahmet Emin
    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 several 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 2, and also, it reduces the initial concentrations of the 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.
  • Master Thesis
    Use of Different Gold Amalgamation Techniques in Mercury Determination by Cold Vapor Atomic Absorption Spectrometry
    (Izmir Institute of Technology, 2005) Erdem, Arzu; Eroğlu, Ahmet Emin
    A novel amalgamation/cold vapor atomic absorption spectrometric system was developed for the determination of Hg(II) concentration in water samples. In the next part, an amalgamation unit utilizing various Au-coated sorbents was constructed and tested in the determination of mercury. Among the new amalgamation materials suggested, gold-coated quartz wool was found to be the most efficient although gold sputter-coated carbon fiber gave also very promising results. Analytical performance of the CVAAS system in terms of sample volume, limit of detection, and without/with amalgamation was also investigated. It was observed that the mercury signal increased with increasing sample volume, as expected. On the other hand, provided that the absolute amount of Hg(II) was kept constant while changing the sample volume, use of amalgamation unit resulted in similar calibration sensitivities. With amalgamation, the linearity and the slope of the calibration plots were not dependant on the sample volume and this property is expected to offer an important advantage since it makes the volume adjustment unnecessary. The limit of detection was also improved with amalgamation. The highest improvement was obtained with 2.0 ml sample volume; the limit of detection was 3.5 times lower (3.5 times better) than that of without amalgamation when 5-times trapping was employed. The results demonstrated that the methodology can be applied to these types of samples directly or after amalgamation, depending on Hg(II) concentration.