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    Cibacron Blue F3GA-incorporated macroporous poly(2-hydroxyethyl methacrylate) affinity membranes for heavy metal removal
    (Elsevier Science Bv, 1997) Denizli, A; Salih, B; Arica, MY; Kesenci, K; Hasirci, V; Piskin, E
    Macroporous poly(2-hydroxyethyl methacrylate), poly(HEMA), membranes were prepared by UV-initiated photo-polymerization of HEMA in the presence of an initiator (azobisisobutyronitrile, AIBN). An affinity dye, i.e., Cibacron Blue F3GA was then incorporated covalently. These affinity membranes with a swelling ratio of 58%, and carrying 10.67 mmol Cibacron Blue F3GA/m(2) membrane were used in the adsorption/desorption of some selected heavy metal ions [i.e., As(III), Cd(II) and Pb(II)] from aqueous media. Very high adsorption rates were observed and adsorption equilibria were reached in about 30 min. The maximum adsorptions of heavy metal ions onto the dye-incorporated affinity membranes from their single solutions were 12.6 mmol/m(2) for As(III), 61.0 mol/m(2) for Cd(II) and 79.0 mol/m(2) for Pb(II), However, when the heavy metal ions competed (in the case of the adsorption from their mixture) the amounts of adsorption for As(III), Cd(II) and Pb(II) were quite close. Desorption of heavy metal ions was carried out by using 0.1 M HNO3 (pH 1.0). Up to 95% of the adsorbed heavy metal ions were desorbed in 60 min. Repeated adsorption/desorption cycles showed the feasibility of this novel affinity membrane for heavy metal removal.
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    Dithiocarbamate-incorporated monosize polystyrene microspheres for selective removal of mercury ions
    (Elsevier Science Bv, 2000) Denizli, A; Kesenci, K; Arica, Y; Piskin, E
    Dithiocarbamate-incorporated monosize polystyrene based microspheres (2 mu m in diameter) were used for selective removal of Hg(II) from aqueous solutions containing different amounts of Hg(II) (10-100 ppm). Adsorption rates were observed as high at the beginning of adsorption and then equilibrium was reached in about 30 min. The maximum Hg(II) adsorption capacity of the dithiocarbamate-incorporated PS microspheres was about 33.2 mg per gram of dry polymer, which was observed at pH 7.0. While non-specific Hg(II) adsorption onto the plain microspheres was 0.85 mg per gram of dry microsphere. The Hg(II) adsorption ability increased with increasing pH, in the range where the solubility of the Hg(II) was not affected by the pH. The preferential (i.e., competitive adsorption) binding of Hg(II) by the microspheres implies that this sorbent system might contain higher-affinity binding sites for Hg(ll) than Cu(II), Cd(II) and Pb(II) ions. More than 96% of the adsorbed Hg(II) was desorbed in 15 min by using 0.1 M HNO3 as an elution agent. The regeneration of the dithiocarbamate-incorporated PS microspheres was also sufficient. (C) 2000 Elsevier Science B.V. All rights reserved.
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    Novel dye-attached macroporous films for cadmium, zinc and lead sorption: Alkali Blue 6B-attached macroporous poly(2-hydroxyethyl methacrylate)
    (Elsevier Science Bv, 1998) Denizli, A; Kesenci, K; Arica, MY; Salih, B; Hasirci, V; Piskin, E
    Alkali Blue GB-attached poly(2-hydroxyethyl methacrylate) (poly(HEMA)) microporous films were investigated as chelate forming sorbents for heavy metal removal. Poly(HEMA) microporous films were prepared by UV-initiated photo-polymerization of HEMA in the presence of an initiator (azobisisobutyronitrile (AIBN)). Alkali Blue 6E was attached covalently. These films with a swelling ratio of 58%, and carrying 14.8 mmol Alkali Blue 6E m(-2) which were then used in the removal of Cd(II), Zn(II) and Pb(II) from aqueous media. Adsorption rates were very high, equilibrium was achieved in about 30 min. The maximum adsorption of heavy metal ions onto the Alkali Blue BE-attached films were 41.4 mmol m(-2) for Cd(II), 52.4 mmol m(-2) for Zn(II), and 64.5 mmol m(-2) for Pb(II). When the heavy metal ions competed during the adsorption from a mixture the adsorption values for Cd(II), Zn(II) and Pb(II) were quite close. Heavy metal ions were desorbed by using 0.1 M HNO3. A significant amount of the adsorbed heavy metal ions (up to 95%) could be desorbed in 30 min. Repeated adsorption/desorption cycles showed the feasibility of these novel dye-attached microporous films for heavy metal removal. (C) 1998 Elsevier Science B.V. All rights reserved.