Yazar "Coskun, R" seçeneğine göre listele

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    Adsorption behavior of copper(II) ion from aqueous solution on methacrylic acid-crafted poly(ethylene terephthalate) fibers
    (John Wiley & Sons Inc, 2000) Coskun, R; Yigitoglu, M; Sacak, M
    The adsorption behavior of methacrylic acid-grafted poly(ethylene terephthalate) fibers was studied toward the copper(II) ion in aqueous solutions by a batch equilibriation technique. The influence of treatment time, temperature, pH of the solution, metal ion concentration, and graft yield were considered. One hour of adsorption time was found sufficient to reach adsorption equilibrium for the copper(II) ion. It was found that the adsorption isotherm of Cu(II)fits Langmuir-type isotherms. The adsorption process is not affected by the temperature when treated with low ion concentration, but is remarkably decreased at a high ion concentration. The heat of adsorption value was calculated as 0.71 kcal/mol. It was found that the reactive fibers are stable and regenerable by acid without losing their activity. (C) 2000 John Wiley & Sons.
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    Adsorption of copper(II), cobalt(II), and iron(III) ions from aqueous solutions on poly(ethylene terephthalate) fibers
    (John Wiley & Sons Inc, 1998) Yigitoglu, M; Ersoz, M; Coskun, R; Sanli, O; Unal, HI
    The adsorption behavior of poly(ethylene terephthalate) (PET) fibers towards copper(II), cobalt(II), and iron(III) ions in aqueous solutions was studied by a batch equilibriation technique. Influence of treatment time, temperature, pH of the solution, and metal ion concentration on the adsorption were investigated. Adsorption values for metal ion intake followed the following order: Co(II) > Cu(II) > Fe(III). One hour of adsorption time was found sufficient to reach adsorption equilibrium for all the ions. The rate of adsorption was found to decrease with the increase in the temperature. Langmuir adsorption isoterm curves were found to be significant for all the ions studied. The heat of adsorption values were calculated as -5, -2.8, and -3.6 kcal/mol for Cu(II), Co(II), and Fe(III) ions, respectively. (C) 1998 John Wiley & Sons, Inc.
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    Graft copolymerization of n-vinyl-2-pyrrolidone on dimethyl sulfoxide pretreated poly(ethylene terephthalate) films using azobisisobutyronitrile initiator
    (John Wiley & Sons Inc, 1997) Unal, HI; Coskun, R; Sanli, O; Yigitoglu, M
    Poly(ethylene terephthalate) (PET) films were grafted with n-vinyl-2-pyrrolidone (n-VP) using an azobisisobutyronitrile (AIBN) initiator. Films were pretreated in dimethyl sulfoxide (DMSO) for 1 h at 140 degrees C before the polymerization reaction was carried out. Variations of graft yield with time, temperature, initiator, and monomer concentrations were investigated. The optimum temperature and polymerization time was found to be 70 degrees C and 4 h, respectively. Increasing monomer concentration from 0.28 to 1.22M and initiator concentration from 1.77 x 10(-3) to 4.20 x 10(-3)M enhanced the percent grafting. The effects of monomer and initiator diffusion on PET films were also studied. The overall activation energy for grafting was calculated as 11.5 kcal/mol. Further changes in properties of PET films such as water-absorption capacity and intrinsic viscosity mere determined. The grafted films were characterized with FTIR and scanning electron microscopy (SEM). (C) 1997 John Wiley & Sons, Inc.