Search

In this study, antimicrobial pigment cinnabarinic acid (CA) was produced from Pycnoporus cinnabarinus in laboratory-scale batch cultures. Magnetic poly(ethylene glycol dimethacrylate-N-methacryloyl-l-tryptophan methyl ester) [m-poly(EGDMA-MATrp)] beads (average diameter = 53–103 µm) were synthesized by copolymerizing of N-methacryloyl-l-tryptophan methyl ester (MATrp) with ethylene glycol dimethacrylate (EGDMA) in the presence of magnetite (Fe3O4) and used for the adsorption of CA. The m-poly(EGDMA-MATrp) beads were characterized by N2 adsorption/desorption isotherms (Brunauer Emmet Teller), X-ray photoelecron spectroscopy, scanning electron microscopy, infrared spectroscopy, thermal gravimetric analysis, electron spin resonance and swelling studies. The efficiency of m-poly(EGDMA-MATrp) beads for separation of CA from culture fluid was evaluated. The effects of pH, initial concentration, contact time and temperature on adsorption were analyzed. The maximum CA adsorption capacity of the m-poly(EGDMA-MATrp) beads was 272.9 mg g−1 at pH 7.0, 25 °C. All the isotherm data can be fitted with the Langmuir, Freundlich and Dubinin–Radushkevich isotherm models. The adsorption process obeyed pseudo-second-order kinetic model. Thermodynamic parameters ΔH = 5.056 kJ mol−1, ΔS = 52.44 J K−1 mol−1 and ΔG = −9.424 kJ mol−1 to -11.27 kJ mol−1 with the rise in temperature from 4 to 40 °C indicated that the adsorption process was endothermic and spontaneous. Copyright © 2015 John Wiley & Sons, Ltd.

In this study, Poly(ethylene glycol dimethacrylate-N-methacryloyl-L-tryptophan methyl ester) [poly(EGDMA-MATrp)] beads (average diameter = 106–300 μm) which were synthesized by copolymerizing of N-methacryloyl-L-tryptophan methyl ester (MATrp) with ethylene glycol dimethacrylate (EGDMA) were used for diethyl phthalate (DEP) adsorption. The various factors affecting the adsorption of DEP from aqueous solutions such as pH, initial concentration, contact time and temperature were analyzed. Adsorption behaviour of DEP on the poly (EGDMA-MATrp) beads was investigated by varying pH values of solution, contact time, initial concentration and temperature. An optimum adsorption capacity of 590.7 mg g−1 for DEP was obtained at 25°C. The present adsorption process obeyed pseudo-second-order kinetic model. All the isotherm data can be fitted with the Langmuir, Freundlich and Dubinin-Radushkevich isotherm models. Thermodynamic parameters ΔH = 7.745 kJ mol−1, ΔS = 81.92 J K−1 mol−1, and ΔG = -16.69 kJ mol−1 to -18.31 kJ mol−1 with the rise in temperature from 25°C to 45°C indicated the adsorption process was endothermic and spontaneous.Supplementary material

The synthesis of polylactide (PLA)-b-poly (dimethyl siloxane) (PDMS) linear block copolymers and their use in blends with pure-PLA are described. PLA-b-PDMS linear block copolymers were obtained by the transesterification reaction in chloroform solution between poly(dimethyl siloxane) bis (2-aminopropyl ether) (molecular weight 2,000 Da) with PLA in the presence of stannous octoate. Molecular weights (Mw) of the block copolymers were varied from 53,800 to 63,600 Da while that of pristine PLA was 73,600 Da. The copolymers obtained were purified by fractional precipitation and then characterized by 1 H NMR, FTIR, GPC, viscometry and DSC techniques. Blends of pure PLA with PLA-b-PDMS block copolymers displayed improved elastic properties (elongation up to 140%) compared to pure PLA (elongation ~9%). Thermal, mechanical and morphological characterization of the blends were also conducted. © 2011 Springer Science+Business Media, LLC., Fundamental Research Fund of Shandong University, Acknowledgments This work was financially supported by TUBI-TAK and Zonguldak Karaelmas University Research Fund. The Authors thank to Manolya Kukut (in Yusuf Yagci research group) and Amitav Sanyal (Bosphorus University, İstanbul) for GPC analysis of PLDMS-2), e PLA/PLDMS-2 blend (BL-4: 23 wt% of PLDMS-2). Bars shows (-) 1 µm for a, d and e, (-) 0.1 µm for b the Polymers; and to Gülden Albuz (Cilas Kauc¸uk Zonguldak, Turkey) for stres-strain measurements.

Magnetic vinylphenyl boronic acid microparticles, poly(ethylene glycol dimethacrylate(EG)-vinylphenyl boronic acid(VPBA)) [m-poly(EG-VPBA)], produced by suspension polymerization and characterized, was found to be an efficient solid polymer for Cr(VI) adsorption. The m-poly(EG-VPBA) microparticles were prepared by copolymerizing of ethylene glycol dimethylacrylate (EG) with 4-vinyl phenyl boronic acid (VPBA). The m-poly(EG-VPBA) microparticles were characterized by N-2 adsorption/desorption isotherms, electron spin resonance (ESR), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), elemental analysis, scanning electron microscope (SEM) and swelling studies. The m-poly(EG-VPBA) microparticles were used at adsorbent/Cr(VI) ion ratios. The influence of pH, Cr(VI) initial concentration, temperature of the removal process was investigated. The maximum removal of Cr(VI) was observed at pH 2. Langmuir isotherm and Dubinin-Radushkvich isotherm were found to better fit the experiment data rather than Fruendlich isotherm. The kinetics of the adsorption process of Cr(VI) on the m-poly(EG-VPBA) microparticles were investigated using the pseudo first-order, pseudo-second-order, Ritch-second-order and intraparticle diffusion models, results showed that the pseudo-second order equation model provided the best correlation with the experimental results. The thermodynamic parameters (free energy change, Delta G(0) enthalpy change, Delta H-0; and entropy change, Delta S-0) for the adsorption have been evaluated.

In this study, antimicrobial pigment cinnabarinic acid (CA) was produced from Pycnoporus cinnabarinus in laboratory-scale batch cultures. Magnetic poly(ethylene glycol dimethacrylate-N-methacryloyl-l-tryptophan methyl ester) [m-poly(EGDMA-MATrp)] beads (average diameter = 53-103 µm) were synthesized by copolymerizing of N-methacryloyl-l-tryptophan methyl ester (MATrp) with ethylene glycol dimethacrylate (EGDMA) in the presence of magnetite (Fe3O4) and used for the adsorption of CA. The m-poly(EGDMA-MATrp) beads were characterized by N2 adsorption/desorption isotherms (Brunauer Emmet Teller), X-ray photoelecron spectroscopy, scanning electron microscopy, infrared spectroscopy, thermal gravimetric analysis, electron spin resonance and swelling studies. The efficiency of m-poly(EGDMA-MATrp) beads for separation of CA from culture fluid was evaluated. The effects of pH, initial concentration, contact time and temperature on adsorption were analyzed. The maximum CA adsorption capacity of the m-poly(EGDMA-MATrp) beads was 272.9 mg g(-1) at pH 7.0, 25 °C. All the isotherm data can be fitted with the Langmuir, Freundlich and Dubinin-Radushkevich isotherm models. The adsorption process obeyed pseudo-second-order kinetic model. Thermodynamic parameters ΔH = 5.056 kJ mol(-1), ΔS = 52.44 J K(-1) mol(-1) and ΔG = -9.424 kJ mol-(1) to -11.27 kJ mol-(1) with the rise in temperature from 4 to 40 °C indicated that the adsorption process was endothermic and spontaneous.

Poly(ethylene glycol dimethacrylate- n -vinyl imidazole) [poly(EGDMA-VIM)] hydrogel (average diameter 150–200 μm) was prepared by copolymerizing ethylene glycol dimethacrylate (EGDMA) with n -vinyl imidazole (VIM). The copolymer hydrogel bead composition was characterized by elemental analysis and found to contain 5 EGDMA monomer units each VIM monomer unit. Poly(EGDMA-VIM) beads had a specific surface area of 59.8 m 2 /g. Poly(EGDMA-VIM) beads were characterized by swelling studies and SEM. Cu 2+ ions were chelated on the poly(EGDMA-VIM) beads, then these beads were used in the adsorption of α-amylase from Aspergillus Oryzae in batch system. The maximum α-amylase adsorption capacity of the poly(EGDMA-VIM)–Cu 2+ beads was observed as 38.9 mg/g at pH 4.0. The K m values for immobilized α-amylase (poly(EGDMA-VIM)–Cu 2+ ) (22.5 mM) was higher than that of free enzyme (15.8 mM). Storage stability was found to increase with immobilization. It was observed that enzyme could be repeatedly adsorbed and desorbed without significant loss in adsorption capacity or enzyme activity.

In this study, the use of the potentiometric method for the determination of the protonation constant of vinyl imidazole (VIM) and the stability constant of the Cu2+ ion complex of VIM used in the immobilized metal ion affinity chromatography (IMAC) was investigated. For this purpose, poly(ethylene glycol dimethacrylate-n-vinyl imidazole) [poly(EGDMA–VIM)] microspheres (average diameter 150–200 μm) were prepared. The microspheres were characterized by elemental analysis, N2 adsorption/desorption isotherms, elemental analysis, energy dispersive spectroscopy (EDS). Protonation constants of vinyl imidazole and the metal-ligand stability constant of vinyl imidazole with Cu2+ ions have been determined potentiometrically in 0.1M NaCl aqueous solution at 298, 318, and 338 K, respectively. The corresponding thermodynamic parameters of protonation and complexation processes (ΔG, ΔH, and ΔS) were derived and discussed. The formation kinetics of Cu2+-vinyl imidazole complex were also investigated, and the process obeyed the pseudo-second-order kinetic model. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39751.

This paper describes a method for the determination of six phthalate esters (PEs) in artificial saliva using solid phase extraction (SPE) and gas chromatography–mass spectrometry (GC–MS). A new material was developed to isolate the PEs from artificial saliva. Poly(ethylene glycol dimethacrylate-N-methacryloyl-L-tryptophan methyl ester) (poly(EGDMA-MATrp)) microspheres (average diameter = 106–300 μm) were synthesised and characterised. Several different parameters, such as pH, adsorption time and adsorbent amount, which affect SPE, were carefully optimised by central composite design (CCD). The best analytical conditions for the simultaneous determination of the analytes from a spiked artificial saliva sample were found to be a pH of 6.8, an adsorption time of 90 min, and an adsorbent amount of 1.8 g L−1, using dichloromethane as the elution solvent. These conditions were applied to study the migration of PEs found on various children's toys into saliva.

Poly(ethylene glycol dimethacrylate-N-methacryloyl-L-tryptophan methyl ester) [poly(EGDMA-MATrp)] beads (average diameter = 106-300 mu m) were synthesized by copolymerizing of N-methacryloyk-L-typtophan methyl ester (MATrp) with ethylene glycol dimethacrylate (EGDMA). The usability of newly synthesized material for the removal of dimethyl phthalate (DMP) from aqueous phase was investigated. The poly (EGDMA-MATrp) beads were characterized by N-2 adsorption/desorption isotherms (BET), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and swelling studies. Initial concentration, pH, contact time and temperature effects on the adsorption of DMP from aqueous solutions were analyzed. An optimum adsorption capacity of 237.3 mg g(-1), for DMP was obtained at 25 degrees C. The present adsorption process obeyed pseudo-second-order kinetic model. All the isotherm data can be fitted with both the Langmuir, and the Dubinin-Radushkevich isotherm models with high correlation coefficients. Thermodynamic parameters Delta N = 2.398 kJ mol(-1), Delta S = 65.76 J K-1 mol(-1), and Delta G = 17.20 kJ mol(-1) to -18.57 kJ mol(-1) with the rise in temperature from 25 degrees C to 45 degrees C indicated the adsorption process was endothermic and spontaneous. The DMP adsorption capacity did not change after 10 batch successive reactions, demonstrating the usefulness of the beads in applications.

In this study, we prepared surface plasmon resonance (SPR) sensor using the molecular imprinting technique for myoglobin detection in human serum. For this purpose, we synthesized myoglobin imprinted poly(hydroxyethyl methacrylate-N-methacryloyl-t-tryptophan methyl ester) [poly(HEMA-MATrp)] nanofilm on the surface of SPR sensor. We also synthesized non-imprinted poly(HEMA-MATrp) nanofilm without myoglobin for the control experiments. The SPR sensor was characterized with contact angle measurements, atomic force microscopy, X-ray photoelectron spectroscopy, and ellipsometry. We investigated the effectiveness of the sensor using the SPR system. We evaluated the ability of SPR sensor to sense myoglobin with myoglobin solutions (pH 7.4, phosphate buffer) in different concentration range and in the serum taken from a patient with acute myocardial infarction. We found that the Langmuir adsorption model was the most suitable for the sensor system. The detection limit was 87.6 ng/mL. In order to show the selectivity of the SPR sensor, we investigated the competitive detection of myoglobin, lysozyme, cytochrome c and bovine serum albumin. The results showed that the SPR sensor has high selectivity and sensitivity for myoglobin. (C) 2013 Published by Elsevier B.V.

Polystyrene–PEG crosslinked block copolymers were prepared from styrene copolymerization by either poly(ethylene glycol dimethymethacrylate) (PEG-DM) or macronomer initiators (MIM). Mw values of PEG of PEG-DM were 400, 600, 1000, 1500, 3000, 10,000, and 35,000, and of MIM, 400 and 1500. Swelling in H2O or CHCl3 of the sulfonated and unsulfonated block copolymers were determined under comparable conditions and found to be vary significantly. The ion-exchange capacity and selectivity coefficients of these ionexchange resins were investigated. The capacities of the obtained ion exchangers were varied between 0.4 and 2.9 meq/g. © 1996 John Wiley & Sons, Inc.

The synthesis of polylactide (PLA)-b-polyethylene glycol (PEG) linear block copolymers and their use in blends with pure-PLA is described. PLA-b-PEG linear block copolymers were obtained by the reaction between poly(ethylene glycol) bis (2-aminopropyl ether) (molecular weight 2000 Dalton) with PLA in the presence of stannous octoate via trans esterification. Molecular weight measurements of the block copolymers indicated that AB and ABA type block copolymers were obtained by controlling the feed ratio in the trans esterification reactions. The copolymers obtained were purified by the fractional precipitation and then characterized by 1H-NMR, FTIR, GPC and DSC techniques. Blends of pure PLA with PLA-b-PEG displayed improved mechanical properties compared to pure PLA. Thermal, mechanical and morphological characterization of the blends were also conducted. © 2012 Taylor and Francis Group, LLC., Fundamental Research Fund of Shandong University: 2011.10.03.01 108T423, This work was financially supported by TUBITAK (Grant #108T423) and Zonguldak Karaelmas University Research Fund (2011.10.03.01).

Designing an immobilised metal ion affinity process on large-scale demands that a thorough understanding be developed regarding the adsorption behaviour of proteins on metal-loaded gels and the characteristic adsorption parameters to be evaluated. In view of this requirement, interaction of alpha-amylase as a model protein with newly synthesised magnetic-poly(divinylbenzene-1-vinylimidazole) [m-poly(DVB-VIM)] microbeads (average diameter, 53-212 mu m) was investigated. The m-poly(DVB-VIM) microbeads were prepared by copolymerising of divinylbenzene (DVB) with 1-vinylimidazole (VIM). The m-poly(DVB-VIM) microbeads were characterised by N-2 adsorption/desorption isotherms, electron spin resonance, elemental analysis, scanning electron microscope and swelling studies. Cu2+ ions were chelated on the m-poly(DVB-VIM) beads and used in adsorption of alpha-amylase in a batch system. The maximum alpha-amylase adsorption capacity of the m-poly(DVB-VIM)-Cu2+ beads was determined as 10.84 mg/g at pH 6.0, 25 A degrees C. The adsorption data were analyzed using three isotherm models, which are the Langmuir, Freundlich and Dubinin-Radushkevich isotherm models. The pseudo-first-order, pseudo-second-order, modified Ritchie's-second-order and intraparticle diffusion models were used to test dynamic experimental data. The study of temperature effect was quantified by calculating various thermodynamic parameters such as Gibbs free energy, enthalpy and entropy changes.

The barium hexaferrite (BaFe 12 O 19 ) containing magnetic poly(ethylene glycol dimethacrylate–vinyl pyridine), (mag-poly(EGDMA–VP)) beads (average diameter = 53–212 μm) were synthesized and characterized. Their use as an adsorbent in the removal of diethyl phthalate (DEP) from an aqueous solution was investigated. The mag-poly(EGDMA–VP) beads were prepared by copolymerizing of 4-vinyl pyridine (VP) with ethylene glycol dimethacrylate (EGDMA). The mag-poly(EGDMA–VP) beads were characterized by N 2 adsorption/desorption isotherms (BET), vibrating sample magnetometer (VSM), X-ray powder diffraction (XRD), elemental analysis, scanning electron microscope (SEM) and swelling studies. At a fixed solid/solution ratio, the various factors affecting the adsorption of DEP from aqueous solutions such as pH, initial concentration, contact time and temperature were analyzed. The maximum DEP adsorption capacity of the mag-poly(EGDMA–VP) beads was determined as 98.9 mg/g at pH 3.0, 25 °C. All the isotherm data can be fitted with both the Langmuir and the Dubinin-Radushkevich isotherm models. The pseudo first-order, pseudo-second-order, Ritch-second-order and intraparticle diffusion models were used to describe the adsorption kinetics. The thermodynamic parameters obtained indicated the exothermic nature of the adsorption. The DEP adsorption capacity did not change after 10 batch successive reactions, demonstrating the usefulness of the magnetic beads in applications.

Poly(ethylene glycol dimethacrylate–1-vinyl-1,2,4-triazole) [poly(EGDMA–VTAZ)] beads with an average diameter of 100–200 μm were obtained by the copolymerization of ethylene glycol dimethacrylate (EGDMA) with 1-vinyl-1,2,4-triazole (VTAZ). The copolymer hydrogel bead composition was determined by elemental analysis and was found to contain 5 EGDMA monomer units for each VTAZ monomer unit. The poly(EGDMA–VTAZ) beads were characterized by swelling studies and scanning electron microscopy (SEM). The specific surface area of the poly(EGDMA–VTAZ) beads was found 65.8 m2/g. Cu2+ ions were chelated on the poly(EGDMA–VTAZ) beads. The Cu2+ loading was 82.6 μmol/g of support. Cu2+-chelated poly(EGDMA–VTAZ) beads with a swelling ratio of 84% were used in the immobilization of Aspergillus niger glucoamylase in a batch system. The maximum glucoamylase adsorption capacity of the poly(EGDMA–VTAZ)–Cu2+ beads was 104 mg/g at pH 6.5. The adsorption isotherm of the poly(EGDMA–VTAZ)–Cu2+ beads fitted well with the Langmuir model. Adsorption kinetics data were tested with pseudo-first- and second-order models. The kinetic studies showed that the adsorption followed a pseudo-second-order reaction model. The Michaelis constant value for the immobilized glucoamylase (1.15 mg/mL) was higher than that for free glucoamylase (1.00 mg/mL). The maximum initial rate of the reaction values were 42.9 U/mg for the free enzyme and 33.3 U/mg for the immobilized enzyme. The optimum temperature for the immobilized preparation of poly(EGDMA–VTAZ)–Cu2+–glucoamylase was 65°C; this was 5°C higher than that of the free enzyme at 60°C. The glucoamylase adsorption capacity and adsorbed enzyme activity slightly decreased after 10 batch successive reactions; this demonstrated the usefulness of the enzyme-loaded beads in biocatalytic applications. The storage stability was found to increase with immobilization. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

The ion exchange equilibria of Cr(NH3)3+, Cr(NH3)5Cl2+, cis-Cr(en)2Cl2 +, trans-Cr(en)2(SCN)2 +, Cr(H2O)6 3+ complex ions against La3+ ions were studied. The effect of the ionic charge, radius and composition of various chromium complex ions on the selectivity were discussed. The logarithms of the selectivity constants were plotted versus mole fraction of complex ions in the resin phase. Linear variations with negative slopes were observed in experiments except for the Cr(H2O)6 3+ -La3+ system.

The aim of this study was to prepare magnetic beads that could be used for the removal of heavy-metal ions from synthetic solutions. Magnetic poly(ethylene glycol dimethacrylate-1-vinyl-1,2,4-triazole) [m-poly (EGDMA-VTAZ)] beads were produced by suspension polymerization in the presence of a magnetite Fe3O4 nanopowder. The specific surface area of the m-poly(EGDMAVTAZ) beads was 74.8 m(2)/g with a diameter range of 150-200 mu m, and the swelling ratio was 84%. The average Fe3O4 content of the resulting m-poly(EGDMA-VTAZ) beads was 14.8%. The maximum binding capacities of the m-poly (EGDMA-VTAZ) beads from aquous solution were 284.3 mg/g for Hg2+, 193.8 mg/g for Pb2+, 151.5 mg/g for Cu2+, 128.1 mg/g for Cd2+, and 99.4 mg/g for Zn2+. The affinity order on a mass basis was Hg2+ > Pb2+ > Cu2+ > Cd2+> Zn2+. The binding capacities from synthetic waste water were 178.1 mg/g for Hg2+, 132.4 mg/g for Pb2+, 83.5 mg/g for Cu2+, 54.1 mg/g for Cd2+, and 32.4 mg/g for Zn2+. The magnetic beads could be regenerated (up to ca. 97%) by a treatment with 0.1 M HNO3. These features make m-poly(EGDMA-VTAZ) beads potential supports for heavy-metal removal under a magnetic field. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 2246-2253, 2009

WOS: 000250697100009 Poly(methacrylic acid) brush grafted crosslinked-chitosan (chitosan-g-poly(MAA)) beads were prepared in two sequential steps: in the first step, chitosan beads were prepared by phase-inversion technique and then were crosslinked with epichlorohydrin under alkaline condition; in the second step, the graft copolymerization of methacrylic acid onto the chitosan beads was initiated by ammonium persulfate (APS) under nitrogen atmosphere. The chitosan-g-poly(MAA) beads were first used as an ion exchange support for adsorption of lysozyme (LYZ) from aqueous solution. The influence of pH, equilibrium time, ionic strength and initial LYZ concentration on the adsorption capacity of the chitosan-g-poly(MAA) ion-exchange beads has been investigated in a batch system. Maximum LYZ adsorption onto chitosan-g-poly(MAA) beads was found to be 65.7 mg/g at pH 6.0. The experimental equilibrium data obtained LYZ adsorption onto chitosan-g-poly(MAA) ion-exchange beads fitted well to the Langmuir isotherm model. Kinetics parameters of this adsorption system were also analyzed by using the equilibrium experimental data. The result of kinetic analyzed for LYZ adsorption onto ion-exchange beads showed that the second order rate equation was favourable. Finally, the chitosan-g-poly(MAA) ion-exchange beads were used for the purification of LYZ from egg white in batch system and the purity of the eluted LYZ from ion-exchange chitosan-g-poly(MAA) beads was determined as 94% by HPLC from single step purification. (c) 2007 Elsevier B.V. All rights reserved.

Modification of chitosan by grafting of vinyl butyrate was carried out in homogeneous phase using potassium persulfate as redox initator and 1.5% acetic acid as solvent. The percent grafting and grafting efficiency were analysed and the high grafting efficiency up to 94% was observed. The effects of reaction variables such as monomer concentration, initiator concentration, temperature and reaction time were investigated. It was observed that the solubility of chitosan was markedly reduced after grafting with vinyl butyrate. The grafted product is insoluble in common organic solvents as well in dilute organic and inorganic acids. Characterization of the graft copolymers were carried out by using Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and Scanning Electron Microscopy (SEM) technics. Characteristic signal of carbonyl group was observed at 1,731 cm-1 which belongs to the poly vinyl butyrate segments in the graft copolymer. The melting transition of the chitosan main chain in the copolymer shifted to 124°C from its original value 101°C. In addition to these, we have also studied topology of the graft copolymer and the SEM micrograph showed continuous homogenous matrix which means there is no phase separation. © Springer Science+Business Media B.V. 2007., 2003/102, Acknowledgment The authors gratefully acknowledge the financial support provided by the Uludag University Scientific Research Fund through Project 2003/102.

We prepared poly(ethylene glycol dimethacrylate–1-vinyl-1,2,4-triazole) [poly(EGDMA–VTAZ)] beads (average diameter = 150–200 μm) by copolymerizing ethylene glycol dimethacrylate (EGDMA) with 1-vinyl-1,2,4-triazole (VTAZ). The copolymer composition was characterized by elemental analysis and found to contain five EGDMA monomer units for each VTAZ monomer unit. The poly(EGDMA–VTAZ) beads had a specific surface area of 65.8 m2/g. Poly(EGDMA–VTAZ) beads were characterized by Fourier transform infrared spectroscopy, elemental analysis, surface area measurements, swelling studies, and scanning electron microscopy. Poly(EGDMA–VTAZ) beads with a swelling ratio of 84% were used for the heavy-metal removal studies. The adsorption capacities of the beads for Cd(II), Hg(II), and Pb(II) were investigated in aqueous media containing different amounts of these ions (5–750 mg/L) and at different pH values (3.0–7.0). The maximum adsorption capacities of the poly(EGDMA–VTAZ) beads were 85.7 mg/g (0.76 mmol/g) for Cd(II), 134.9 mg/g (0.65 mmol/g) for Pb(II), and 186.5 mg/g (0.93 mmol/g) for Hg(II). The affinity order toward triazole groups on a molar basis was observed as follows: Hg(II) > Cd(II) > Pb(II). pH significantly affected the adsorption capacity of the VTAZ-incorporated beads. The equilibrium data were well fitted to the Redlich–Peterson isotherm. Consideration of the kinetic data suggested that chemisorption processes could have been the rate-limiting step in the adsorption process. Regeneration of the chelating-beads was easily performed with 0.1M HNO3. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4276–4283, 2006

Poly(ethylene glycol dimethacrylate-n-vinyl imidazole) [poly(EGDMA-VIM)] hydrogel (average diameter 150-200 mu m) was prepared copolymerizing ethylene glycol dimethacrylate (EGDMA) with n-vinyl imidazole (VIM). Poly(EGDMA-VIM) beads had a specific surface area of 59.8 M-2/g. Poly(EGDMA-VIM) beads were characterized by swelling studies and scanning electron microscope (SEM). Cu2+ ions were chelated on the poly(EGDMA-VIM) beads (452 mu mol Cu2+/g), then the metal-chelated beads were used in the adsorption of yeast invertase in a batch system. The maximum invertase adsorption capacity of the poly(EGDMA-VIM)-Cu2+ beads was observed as 35.2 mg/g at pH 4.5. The adsorption isotherm of the poly(EGDMA-VIM)-Cu2+ beads can be well fitted to the Langmuir model. Adsorption kinetics data were tested using pseudo-first- and -second-order models. Kinetic studies showed that the adsorption followed a pseudo- second-order reaction. The value of the Michaelis constant K-m of invertase was significantly larger upon adsorption, indicating decreased affinity by the enzyme for its substrate, whereas V-max was smaller for the adsorbed invertase. The optimum temperature for the adsorbed preparation of poly(EGDMA-VIM)-CU2+- invertase at 50 degrees C, 10 degrees C higher than that of the free enzyme at 40 degrees C. Storage stability was found to increase with adsorption. Adsorbed invertase retains an activity of 82% after 10 batch successive reactions, demonstrating the usefulness of the enzyme-loaded beads in biocatalytic applications.

Poly(ethylene glycol dimethacrylate-n-vinyl imidazole) [poly(EGDMA-VIM)] hydrogel (average diameter 150-200 mum) was prepared by copolymerizing ethylene glycol dimethacrylate (EGDMA) with n-vinyl imidazole (VIM). The copolymer hydrogel bead composition was characterized by elemental analysis and found to contain 5 EGDMA monomer units each VIM monomer unit. Poly(EGDMA-VIM) beads had a specific surface area of 59.8 m(2)/g. Poly(EGDMA-VIM) beads were characterized by swelling studies and scanning electron microscopy (SEM). These poly(EGDMA-VIM) beads with a swelling ratio of 78% were used for the heavy metal removal studies. Chelation capacity of the beads for the selected metal ions, i.e., Cd(II), Hg(II) and Pb(II) were investigated in aqueous media containing different amounts of these ions (10-750 mg/l) and at different pH values (3.0-7.0). Chelation rate was very fast. The maximum chelation capacities of the poly(EGDMA-VIM) beads were 69.4 mg/g for Cd(H), 114.8 mg/g for Pb(II) and 163.5 mg/g for Hg(II). The affinity order on molar basis was observed as follows: Hg(H) > Cd(II) > Pb(II). Chelation behavior of heavy metal ions could be modelled using both the Langmuir and Freundlich isotherms. pH significantly affected the chelation capacity of VIM incorporated beads. Chelation of heavy metal ions from synthetic wastewater was also studied. The chelation capacities are 45.6 mg/g for U(II), 74.2 mg/g for Hg(H) and 92.5 mg/g for Pb(II) at 0.5 mmol/l initial metal concentration. Regeneration of the chelating-beads was easily performed with 0.1 M HNO3. These features make poly(EGDMA-VIM) beads potential candidate adsorbent for heavy metal removal: (C) 2003 Elsevier B.V. All rights reserved.