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KAHRAMAN, MEMET VEZİR

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KAHRAMAN

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MEMET VEZİR

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Now showing 1 - 4 of 4
  • Publication
    Recovery of Au(III) ions by Au(III)-imprinted hydrogel
    (SPRINGER INTERNATIONAL PUBLISHING AG, 2016) KÖK YETİMOĞLU, ECE; Firlak, Melike; Cubuk, Soner; Yetimoglu, Ece Kok; Kahraman, Memet V.
    A new Au(III)-imprinted hydrogel (Au(III)-Imp) was prepared by the photopolymerisation of 4-acryloylmorpholine (AcM), 2-hydroxyethyl acrylate (HEA), and poly(ethylene glycol) diacrylate (cross-linking monomer, PEG-DA) in the presence of gold ions. In addition, non-imprinted hydrogel (N-Imp) was similarly prepared without Au(III) ions The Au(III)-Imp hydrogel was characterised by several techniques. To achieve the optimal conditions, effect of pH, time, and initial metal ion concentrations were investigated using a batch system. The pre-concentration factor for Au(III) ions was found to be at least 100. The analytical parameters of the method were determined and the method was also successfully applied to computer circuit board scrap samples. The reusability of the Au(III)-Imp hydrogel was also determined. (C) 2016 Institute of Chemistry, Slovak Academy of Sciences
  • Publication
    Photocured thiol-ene based optical fluorescence sensor for determination of gold(III)
    (ELSEVIER SCIENCE BV, 2014) KÖK YETİMOĞLU, ECE; Cubuk, Soner; Kahraman, Memet Vezir; Yetimoglu, Ece Kok; Kenan, Sibel
    This study describes the preparation and the characterization of a new thiol-ene based polymeric fluorescence sensor by photo initiated polymerization of trimethylolpropane tris(3-mercaptopropionate), 2-hydroxyethylacrylate, and 2,4,6-triallyloxy-1,3,5-triazine which are used as monomers and also a photo initiator (2,2-dimethoxy-2-phenylacetophenone) for its usage as optical sensor for gold ions. The thiolene based polymeric membrane sensor was characterized by using attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy (SEM). The response characteristics of the sensors including dynamic range, pH effect, response time, and the effect of foreign ions were investigated. Fluorescence spectra showed that the excitation/emission maxima of the membrane were at 3791425 nm, respectively (C) 2014 Elsevier B.V. All rights reserved.
  • Publication
    UV photocrosslinked polymeric fluorescent sensor for bisphenol A
    (ELSEVIER SCIENCE BV, 2018) KÖK YETİMOĞLU, ECE; Tasci, Nese; Cubuk, Soner; Firlak, Melike; Yetimoglu, Ece Kok; Kahraman, Memet Vezir
    Bisphenol A (BPA) is known as endocrine disrupting compound and it is widely used as an intermediate in manufacturing of polycarbonate and epoxy resins. These resins are used to manufacture inner surface of food cans or directly contact with food and can release BPA into food. It is known that BPA poses health risk, but how risky is a matter of debate. In this study, selective and sensitive fluorescent polymeric membrane sensor for detection of BPA was developed based on fluorescence quenching (lambda ex/lambda em = 272/295 nm). Working concentration range was linear between 4.4 x 10(-9) mol L-1 and 1.1 x 10(-7) mol L-1 with a detection limit of 1.58 x 10(-9) mol L-1. Optimization of sensor was done and the sensor exhibited satisfactory results for being used as a fluorescent sensor for determination of BPA. Additionally, the proposed method was successfully applied to plastic food containers real samples. The developed sensor was shown to be more sensitive than other methods currently in use, and was able to provide results in a matter of seconds, opening up the possibility of a rapid tool for BPA detection.
  • Publication
    Statistical optimization and selective uptake of Au(III) from aqueous solution using carbon nanotube-cellulose based adsorbent
    (ELSEVIER, 2022) BİRTANE, HATİCE; Birtane, Hatice; Urucu, Oya Aydin; Yildiz, Nilgun; Cigil, Asli Beyler; Kahraman, Memet Vezir
    In this study, a carbon nanotube cellulose-based UV-curable nanocomposite was prepared as an adsorbent to selectively separate Au (III) ions from an aqueous medium. For this purpose, thiol-functionalized carbon nanotube and acrylate-functionalized hydroxyethyl cellulose were synthesized and the photo-curable adsorbent was obtained using the thiol-ene click reaction. The FTIR spectra revealed that the thiol groups and acrylate groups were successfully attached to carbon nanotube and hydroxyethyl cellulose, respectively. Moreover, the Scanning Electron Microscopy-Energy Dispersive X-Ray analyses showed that the photo-curable adsorbent contained sulfur atoms, thus indicating successful modification. The parameters affecting the recovery of the Au (III) ions were determined using the Plackett-Burman method. The optimum values of the parameters, which were pH, adsorption time, initial Au (III) concentration, and adsorbent amount were determined using the Box-Behnken method. The Langmuir adsorption isotherm was determined to be the best equation to describe the interaction of the Au (III) ions with the adsorbent (R-2: 0.995). The examination of the effectiveness of the photocurable adsorbent in the presence of different metal ions yielded prosperous results. Also, the developed method has been successfully applied for the recovery of Au(III) ions in river waters.