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Preconcentration of Heavy Metals in Environmental Samples by Biosorption and Determination by Atomic Spectrometry
(Izmir Institute of Technology, 2007) Şeker, Ayşegül; Eroğlu, Ahmet Emin; Eroğlu, Ahmet Emin; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of Technology
In the assessment of environmental quality, one of the priorities must be given to the determination of heavy metals. In the present study, Spirulina platensis, a cyanobacteria (or blue-green alga) was suggested to be used as a biosorbent prior to the atomic spectrometric determination of Pb, Cd and Ni in some environmental samples. For this purpose, the parameters which might be effective on the biosorption were investigated such as pH, time, initial metal ion concentration, biosorbent amount, temperature, kinetics of sorption, repetitive reactivity and ionic competition. According to the sorption kinetics, results obeyed well the pseudo second-order model. Freundlich, Dubinin Radushkevich and Temkin isotherm models were applied in describing the equilibrium partition of the ions. Freundlich isotherm was applied to describe the design of a single-stage batch sorption system. Thermodynamic parameters (.G0, .H0 and .S0) were calculated and the sorption process was found to be largely driven towards the products and it had an endothermic nature. Faster adsorption kinetics was observed for Pb2+ ions in comparison to Cd2+ and Ni2+ ions. Based on kinetic modeling, the apparent activation energy, Ea, was calculated to be 44 kJmol-1, -16 kJmol-1 and 54 kJmol-1 for Pb2+, Cd2+and Ni2+, respectively. The measurements of the repetitive reusability of Spirulina platensis indicated a large capacity towards the three metal ions. Sorption activities in a three metal ion system were studied and at an initial metal concentration of 100.0 mgL-1, % Pb2+ was found to be still high (85%).However, it decreased to less than 20% for Cd2+ and Ni2+ indicating the relative selectivity of the biosorbent towards Pb2+. Finally, the use of Spirulina platensis, in its natural form or after be immobilized onto various matrices (alginate, silicate, carboxymethylcellulose and polysulfone) was planned for the separation of heavy metals from the sample matrix.
A Novel Sorbent (mcm-41 Immobilized With N-Methylglucamine) for Removal/Preconcentration of Boron From Waters. Synthesis, Characterization and Applications To Water Samples
(Izmir Institute of Technology, 2005) Kaftan, Öznur; Eroğlu, Ahmet Emin; Eroğlu, Ahmet Emin; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of Technology
Determination of boron has become an important task in a variety of analytical applications because of the increasing use of boron compounds in various industrial fields. Its concentration is generally low in many samples and this 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 novel sorbent was prepared by the functionalization of an inorganic support material, MCM-41, with N-methylglucamine for the uptake of boron from aqueous solutions prior to its determination by ICP-OES. Characterization of the newly synthesized material was performed using elemental analysis, XRD, DRIFTS, and BET analysis. Sorption behavior of the novel sorbent for boron was also investigated and found to obey Freundlich and Dubinin-Radushkevich (D-R) isotherm models. The maximum amount of B (as H3BO3) that can be sorbed by the sorbent was calculated from the D-R isotherm and was found to be 0.8 mmol of B per gram of sorbent. The applicability of the new sorbent for the removal/preconcentration of boron from aqueous samples was examined by batch method. It was found that the sorbent can take up 85 % of boron in 5 minutes whereas quantitative sorption is obtained in 30 minutes. Any pH greater than 6 can be used for sorption. The desorption from the sorbent was carried out with 1.0 M HNO3. For method validation, spike recovery tests were performed at various concentration levels in different water types and were found to be between 85-95 and 75-90 percent for ultra pure water and geothermal water, respectively.
Preconcentration and Atomic Spectrometric Determination of Rare Earth Elements (rees) in Environmental Samples
(Izmir Institute of Technology, 2004) Pasinli, Türker; Eroğlu, Ahmet Emin; Eroğlu, Ahmet Emin; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of Technology
Determination of rare earth elements (REEs) in environmental samples is usually performed by the plasma techniques, inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS). Due to low concentrations of REEs and usually the presence of heavy matrix, an efficient separation and preconcentration technique is required prior to instrumental measurements in order to achieve accurate and reliable results. In this study, different types of zeolites (Clinoptilolite, Mordenite, Zeolite Y, Zeolite Beta), ion exchangers (Amberlite CG-120, Amberlite IR-120, Rexyn 101, Dowex 50W X18) and chelating resins (Muromac, Chelex 100, Amberlite IRC-718) were proposed as adsorbent materials for the preconcentration of REEs in environmental waters prior to their determination by ICP-OES. It was shown that REEs can be retained by these adsorbents quantitatively in a broad pH range (pH>4) and their desorptions from the adsorbents can be realized with acidic eluents. Of the sorbents investigated, clinoptilolite was chosen for the subsequent studies. Spike recovery tests were performed at various concentration levels in different water types including pure water, bottled drinking water, river water, sea water, and tap water, and were found to change between 85-90%.

Sürdürülebilir Yeşil Kampüs Koleksiyonu / Sustainable Green Campus Collection

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