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    Removal of aniline from aqueous solution by PVC-CDAE ligand-exchanger
    (ELSEVIER SCIENCE BV, 2005) Gurten, AA; Ucan, S; Ozler, MA; Ayar, A
    The adsorption of aniline from aqueous solutions onto cobalt(II)-poly(vinyl chloride)-carboxylated diaminoethane (PVC-CDAE) resin has been studied using a mini-column apparatus at 25 +/- 0.1 degrees C. First of all, experimental data obtained from the breakthrough curves were tested by using the Scatchard plot analysis, to have a preliminary prediction about the types of interaction of the resin with aniline. Our aim was to determine the model which best describes the experimental data. The aspect of the Scatchard plot indicated that the aniline adsorption did not follow the Langmuir model and the presence of two types of binding sites for aniline on the resin. However. the dynamics of aniline uptake were represented by the Freundlich model reasonably well. The kinetics of aniline adsorption from aqueous solution on the cobalt(II)-PVC-CDA-E have also been tested using continuous column runs and rate-controlling step of the process was determined. In this study, homogeneous diffusion model was adapted to a column system to describe the change in the aniline concentration at the column exit begining from breakthrough point as a function of time. Kinetic studies revealed that the rate-controlling step of the aniline adsorption was predominately film diffusion controlled rather particle diffusion. (c) 2005 Elsevier B.V. All rights reserved.
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    Selective extraction of iron(III) from aqueous nitrate solution in the presence of cobalt(II), copper(II) and nickel(II) ions using BiS(Delta(2)-2-imidazolinyl)-5,5 '-dioxime
    (JAPAN SOC ANALYTICAL CHEMISTRY, 2004) Teke, M; Mercimek, B; Ozler, MA; Ayar, A
    The feasibility of using bis(Delta(2)-2-imidazolinyl)-5,5'-dioxime (H2L) for the selective extraction of iron(III) from aqueous solutions was investigated by employing an solvent-extraction technique. The extraction of iron(III) from an aqueous nitrate solution in the presence of metal ions, such as cobalt(II), copper(II) and nickel(II), was carried out using H2L in binary and multicomponent mixtures. Iron(III) extraction has been studied as a function of the pH, equilibrium time and extractant concentration. From the extracted complex species in the organic phase, iron(III) was stripped with 2 M HNO3, and later determined using atomic-absorption spectrometry. The extraction was found to significantly depend on the aqueous solution pH. The extraction of iron(III) with H2L increases with the pH value, reaching a maximum in the zone of pH 2.0, remaining constant between 2 and 3.5 and subsequently decreasing. The quantitative extraction of iron(III) with 5 x 10(-3) M H2L in toluene is observed at pH 2.0. H2L was found to react with iron(III) to form ligand complex having a composition of 1:2 (Fe:H2L).
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    Solvent extraction of Fe3+ cation by 25,26,27,28-tetraisonitrosoaceto calix[4]arene and based ligands
    (MARCEL DEKKER INC, 1999) Deligoz, H; Pekacar, AI; Ozler, MA; Ersoz, M
    25,26,27,28-Tetraisonitrosoaceto calix[4]arene [L-8] was synthesized by reacting 25,26,27,28-tetraacetyl calix[4]arene [L-7] with n-butyl nitrite. The synthesized compounds [L-7, L-8] and based ligands (p-tert-butyl phenol [L-1], p-methoxy phenol [L-2] p-methyl aldoxime [L-3], p-methoxy glyoxime [L-4], p-tert-butyl calix[4]arene [L-5], and calix[4]arene [L-6]} were utilized for solvent extraction of Fe3+ cations from the aqueous phase to the organic phase. It was observed that the p-methoxy glyoxime [L-4] and oximated derivative of calix[4]arene are more efficient carriers of Fe3+ in the extraction process at pH 2.2.