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    Dye-ligand and metal chelate poly(2-hydroxyethylmethacrylate) membranes for affinity separation of proteins
    (Elsevier Science Bv, 1998) Arica, MY; Testereci, HN; Denizli, A
    Cibacron Blue F3GA was covalently immobilized onto poly(2-hydroxyethyl methacrylate) (pHEMA) membranes via the nucleophilic reaction between the chloride of its triazine ring and the hydroxyl group of pHEMA. Then, Fe3+ ions were complexed by chelation with the immobilized Cibacron Blue F3GA molecules. Different amounts of Fe3+ ions were loaded on the membranes by changing the concentration of Fe3+ ions and pH of the reaction medium. Membranes with or without Fe3+ were used in the adsorption of glucose oxidase, catalase and bovine serum albumin. The adsorption capacities of these membranes were determined by changing pH and the concentration of the proteins in the adsorption medium. The adsorption phenomena appeared to follow a typical Langmuir isotherm. The maximum capacities (q(m)) of the Fe3+ complexed membranes for glucose oxidase, catalase and bovine serum albumin (8.70.10(-3) mu mol m(-2), 2.15.10(-3) mu mol m(-3) and 2.21.10(-3) mu mol m(-2)) were greater than those of the untreated membranes (6.79.10(-3) mu mol m(-2), 1.34.10(-3) mu mol m(-2) and 1.94.10(-3) mu mol m(-2)) respectively. The nonspecific adsorption of the enzymes and the protein on the pHEMA membranes was negligible. (C) 1998 Elsevier Science B.V.
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    Electrochemical polymerization of 4-allyl-1,2-dimethoxybenzene
    (Elsevier Science Bv, 2004) Testereci, HN; Akin-Oktem, G; Oktem, Z
    Redox behaviour of 4-allyl-1,2-dimethoxybenzene (DMAB) was studied by using cyclic voltammetry and electro-chemical polymerization was conducted at the measured peak potential. Constant potential electrolysis of the monomer was carried out in acetonitrile-tetrabutylammonium-tetrafluoroborate, solvent-electrolyte couple, at room temperature. Electrochemical polymerization of the monomer yielded insoluble polymer film on the electrode surface together with the low molecular weight polymers in bulk of the solution. The effect of temperature on the rate of electro-chemical polymerization was also studied. The structural analyses of the polymers were done by H-1-NMR and FTIR spectroscopy. Molecular weight of the soluble polymer was determined by cryoscopy. (C) 2004 Elsevier B.V. All rights reserved.
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    Procion blue MX-3G-attached microporous poly(2-hydroxyethyl methacrylate) membranes for copper, arsenic, cadmium, and mercury adsorption
    (Marcel Dekker Inc, 1999) Denizli, A; Say, R; Testereci, HN; Arica, MY
    pHEMA membranes carrying 25.6 mmol Procion Blue MX-3G/m(2) were used for removal of heavy metal ions (i.e., copper, arsenic, cadmium, and mercury) from aqueous media containing different amounts of these ions (0.1-4.5 mmol/L) and at different pH values (2.0-8.0). The maximum adsorption capacities of heavy metal ions onto Procion Blue MX-3G-attached membranes under noncompetitive conditions were 5.6 mmol/m(2) for Cu(II), 19.6 mmol/m(2) for As(III), 46.2 mmol/m(2) for Cd(II), and 119.6 mmol/m(2) for Hg(II). The competitive adsorption capacities of the heavy metal ions were 6.9 mmol/m(2) for Cu(II), 21.2 mmol/m(2) for As(III), 33.9 mmol/m(2) for Cd(II), and 52.5 mmol/m(2) for Hg(II). The same affinity order was observed under noncompetitive and competitive adsorption: Hg(II) > Cd(IT) > As(III) > Cu(II). The adsorption of heavy metal ions increased with increasing pH and reached a plateau value at around pH 6.0. Adsorption of heavy metal ions from artificial wastewater was also studied. The adsorption capacities are 3.5 mmol/m(2) for Cu(I), 10.2 mmol/m(2) for As(III), 24.7 mmol/m(2) for Cd(II), and 37.3 mmol/m(2) for Hg(II). Desorption of heavy metal ions was performed using 0.1 M HNO3. Procion Blue MX-3G-attached membranes are suitable for repeated use of more than 5 cycles without noticeable loss of capacity.