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  • Küçük Resim
    Öğe
    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.
  • Küçük Resim
    Öğe
    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.