Person: KAHRAMAN, MEMET VEZİR
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KAHRAMAN
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MEMET VEZİR
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Publication Metadata only Removal of Ag(I) from Aqueous Solutions by Thiol-ene-Based Hydrogel and Its Application to Radiographic Films(SPRINGER, 2014) KÖK YETİMOĞLU, ECE; Firlak, Melike; Kahraman, Memet Vezir; Yetimoglu, Ece KokThe thiol-ene-based P(Penta3MP4/PEGDA/AAc) hydrogels were prepared by UV curing technique, then characterized and used as adsorbents for the investigation of the effect of process parameters such as pH of solution, contact time, and initial concentration of solution, on the removal of Ag(I) from aqueous solution. The results indicate that the adsorption of Ag(I) ions from aqueous solutions is strongly dependent on pH under experimental conditions. Both Langmuir and Freundlich isotherm models were applied to experimental data, and the results show that the adsorption process is well fitted to the Langmuir isotherm model. Selectivity, reusability, and applicability of hydrogels to radiographic film waste were investigated.Publication Metadata only Removal of Lead and Cadmium Ions from Aqueous Solutions Using Sulphur and Oxygen Donor Ligand Bearing Hydrogels(TAYLOR & FRANCIS INC, 2010) KÖK YETİMOĞLU, ECE; Firlak, Melike; Yetimoglu, Ece Koek; Kahraman, Memet Vezir; Apohan, Nilhan Kayaman; Deniz, SabahattinA new thiourea and urea functional monomers were synthesized. A series of hydrogels were prepared by photopolymerization. The hydrogels were used for the removal of Pb(II) and Cd(II) ions from aqueous solutions. The influence of the uptake conditions such as the pH, the time, and the initial feed concentration on the metal ion binding capacity of hydrogel was tested. The selectivity of the hydrogels towards the different metal ions was also tested. The adsorption isotherm models were applied. The limits of detection and quantification were calculated. The usability of the hydrogels for preconcentration studies were also investigated.Publication Metadata only Removal of Pb2+ and Cd2+ ions from aqueous solutions using guanidine modified hydrogels(WILEY-BLACKWELL, 2011) KÖK YETİMOĞLU, ECE; Yetimoglu, Ece Kok; Firlak, Melike; Kahraman, Memet Vezir; Deniz, SabahattinIn this study, experimental measurements have been made on the batch adsorption of cadmium and lead ions from aqueous solutions using poly(guanidine modified 2-acrylamido-2-methylpropan sulfonic acid/acrylic acid/N-vinylpyrrolidone/2-Hydroxyethyl methacrylate), P(AMPSG/AAc/NVP/HEMA) hydrogels. The guanidyl end group bearing AMPSG monomer was synthesized from the reaction of AMPS and guanidine. The hydrogels were prepared by UV-curing technique. The morphology of the dry H10-hydrogel sample was examined by SEM. The influence of the uptake conditions, such as pH, functional monomer per cent, contact time, initial feed concentration, and foreign metal ions on the metal ion binding capacity of hydrogel, was also tested. The selectivity of the hydrogel toward the different metal ions tested was Hg(II) > Pb(II) > Au(III) > Cd(II). The adsorption isotherm models were applied to the experimental data, and it was seen that the Langmuir isotherm model was the best fit for the adsorption of Cd(II) and Pb(II) ions on P(AMPSG/AAc/NVP/HEMA) hydrogel. It was found that adsorbed lead and cadmium ions on P(AMPSG/AAc/NVP/HEMA) hydrogel can be effectively desorbed by acid leaching and the regenerated P(AMPSG/AAc/NVP/HEMA) hydrogel can be reused almost five times less without any loss of adsorption capacity. Copyright (C) 2009 John Wiley & Sons, Ltd.Publication Metadata only Uptake of Pb2+ Using N-Vinyl Imidazole Based Uniform Porous Hydrogels(TAYLOR & FRANCIS INC, 2011) KÖK YETİMOĞLU, ECE; Firlak, Melike; Cubuk, Soner; Yetimoglu, Ece Kok; Kahraman, Memet VezirThe uniform porous and continuous phase lead (II) adsorbent hydrogel, was prepared by copolymerizing 2-hydroxyethyl methacrylate (HEMA), acrylic acid (AAc), and N,N'-methylenebisacrylamide (MBAAm), with n-vinyl imidazole (VIM). A series of hydrogels, including different ratios of VIM, were prepared by photopolymerization and characterized. The influence of the uptake conditions such as pH, functional monomer percent, contact time, initial feed concentration, and foreign metal ions on the metal ion binding capacity of hydrogel, were also tested. The selective chelation of heavy metal ions from synthetic wastewater was also studied. The affinity order on molar basis was observed as follows: Pb (II) > Zn (II) > Cd (II). Chelation behavior of heavy metal ions could be modelled using both the Langmuir and Freundlich isotherms and it was seen that the Langmuir isotherm model was the best fit for the adsorption of Pb (II) ions in P(VIM/AAc/HEMA) hydrogel. Moreover, the limits of detection and the quantification values were determined. Regeneration of the hydrogels was easily performed with 1M HCl and the same hydrogel can be reused five times almost without any loss of adsorption capacity. All these features make P(VIM/AAc/HEMA) hydrogels potential candidate adsorbent for heavy metal removal.Publication Metadata only N-vinylpyrrolidone/acrylic acid/2-acrylamido-2-methylpropane sulfonic acid based hydrogels: Synthesis, characterization and their application in the removal of heavy metals(ELSEVIER, 2007) KÖK YETİMOĞLU, ECE; Yetimoglu, E. Kok; Kahraman, M. V.; Ercan, O.; Akdemir, Z. S.; Apohan, N. KayamanIn this work, the synthesis of N-vinylpyrrolidone/acrylic acid/2-acryl amido-2-methylpropane sulfonic acid (NVP/AAc/ AMPS) based hydrogels by UV-curing technique was studied and their swelling behavior, heavy metal ion recovery capabilities were investigated. The structures of hydrogels were characterized by FT-IR analysis and the results were consistent with the expected structures. Thermal gravimetric analysis of hydrogels showed that the thermal stability of hydrogel decreases slightly with incorporation of AMPS units into the structure. In addition, the morphology of the dry hydrogel sample was examined by SEM. According to swelling experiments, hydrogels with higher AMPS content gave relatively higher swelling ratio compared to neat hydrogel. These hydrogels were used for the separation of Cd(II), Cu(II) and Fe(III) ions from their aqueous solutions. The influence of the uptake conditions such as pH, time and initial feed concentration on the metal ion binding capacity of hydrogel was also tested. The selectivity of the hydrogel towards the different metal ions tested was Cd(II) > Cu(II) > Fe(III). It was observed that the specific interaction between metal ions and ionic comonomers in the hydrogel affected the metal binding capacity of the hydrogel. The recovery of metal ions was also investigated in acid media. (c) 2007 Elsevier Ltd. All rights reserved.