Çiğdem Arpa

Hacettepe University, Engüri, Ankara, Turkey

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Publications (8)17.54 Total impact

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    ABSTRACT: The aim of this study was to investigate the heavy metal adsorption performance of supermacroporous poly(hydroxyethyl methacrylate) [PHEMA] cryogel. The PHEMA cryogel was produced by cryo-polymerization. The PHEMA cryogel was characterized by scanning electron microscopy (SEM). The PHEMA cryogel containing 385 μmol Reactive Green HE-4BD/g were used in the adsorption studies. Adsorption capacity of the PHEMA cryogel for the metal ions, i.e., Cu2+, Cd2+, and Pb2+ were investigated in aqueous media containing different amounts of the ions (5–600 mg/L) and at different pH values (3.2–6.9). The maximum adsorption capacities of the PHEMA cryogel were 11.6 mg/g (56 μmol/g) for Pb2+, 24.5 mg/g (385 μmol/g) for Cu2+ and 29.1 mg/g (256 μmol/g) for Cd2+. The competitive adsorption capacities were 10.9 mg/g (52 μmol/g) for Pb2+, 22.1 mg/g for Cd2+ (196 μmol/g) and 23.2 mg/g (365 μmol/g) for Cu2+. The PHEMA/Reactive Green HE-4BD cryogel exhibited the following metal ion affinity sequence on molar basis: Cu2+ > Cd2+ > Pb2+. The PHEMA/Reactive Green HE-4BD cryogel can be easily regenerated by 50 mM EDTA with higher effectiveness. These features make the PHEMA/Reactive Green HE-4BD cryogel a potential adsorbent for heavy metal removal. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
    Journal of Applied Polymer Science 06/2010; 118(4):2208 - 2215. · 1.40 Impact Factor
  • Ciğdem Arpa, Sema Bektaş
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    ABSTRACT: A simple and sensitive preconcentration analysis-atomic absorption spectrometric procedure is described for the determination of lead, cadmium and nickel. The method is based upon on-line preconcentration of metal ions on a minicolumn of Cibacron Blue F3-GA immobilized on poly(hydroxyethylmethacrylate), poly(HEMA). The enrichment factors obtained were 42 for lead, 52 for cadmium and 63 for nickel (sample volume 10 mL and sample flow rate 5 mL/min). The relative standard deviations (n = 10), in 10 mL sample solutions containing 100 microg/L Pb(2+), 10 microg/L Cd(2+) and 100 microg/L Ni(2+) were 8.9, 3.7 and 3.5%, respectively. The limits of detection (blank + 3s) (n = 10), were found to be 12.01 microg/L for Pb(2+), 1.34 microg/L for Cd(2+) and 28.73 microg/L for Ni(2+). The accuracy of the system was checked with certified and tap water samples spiked with known amounts of metal ions. No significant difference was found between the achieved results and the certified values.
    Analytical Sciences 08/2006; 22(7):1025-9. · 1.57 Impact Factor
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    ABSTRACT: Trametes versicolor and Pleurotus sajur-caju mycelia immobilized in Ca-alginate beads were used for the removal of mercuric ions from aqueous solutions. The sorption of Hg(II) ions by alginate beads and both immobilized live and heat-killed fungal mycelia of T. versicolor and P. sajur-caju was studied in the concentration range of 0.150-3.00 mmol dm(-3). The biosorption of Hg(II) increased as the initial concentration of Hg(II) ions increased in the medium. Maximum biosorption capacities for plain alginate beads were 0.144+/-0.005 mmol Hg(II)/g; for immobilized live and heat-killed fungal mycelia of T. versicolor were 0.171+/-0.007 mmol Hg(II)/g and 0.383+/-0.012 mmol Hg(II)/g respectively; whereas for live and heat-killed P. sajur-caju, the values were 0.450+/-0.014 mmol Hg(II)/g and 0.660+/-0.019 mmol Hg(II)/g respectively. Biosorption equilibrium was established in about 1 h and the equilibrium adsorption was well described by Langmuir and Freundlich adsorption isotherms. Between 15 and 45 degrees C the biosorption capacity was not affected and maximum adsorption was observed between pH 4.0 and 6.0. The alginate-fungus beads could be regenerated using 10 mmol dm(-3) HCl solution, with up to 97% recovery. The biosorbents were reused in five biosorption-desorption cycles without a significant loss in biosorption capacity. Heat-killed T. versicolor and P. sajur-caju removed 73% and 81% of the Hg(II) ions, respectively, from synthetic wastewater samples.
    Bioresource Technology 10/2003; 89(2):145-54. · 5.04 Impact Factor
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    ABSTRACT: The basidio spores of Phanerochaete chryosporium were immobilized in alginate gel beads, and the immobilized spore containing alginate beads were incubated for the growth of fungus. The biosorption of Pb2+ and Zn2+ ions on alginate beads and both immobilized live and heat inactivated fungus was studied from artificial waste waters in the concentrations range of 30–600 mg l−1. The surface charge density of the biosorbents varied with the pH of the medium and the maximum biosorption of heavy metal ions on the biosorbents was obtained between pH 5.0 and 6.0. The biosorption of Pb2+ and Zn2+ on the biosorbents increased as the initial concentration of Pb2+ and Zn2+ ions increased in the medium. Biosorption equilibrium was established about 1 h, the adsorbed heavy metal ions did not significantly change further with time. The maximum biosorption capacity (qm) of alginate beads and both immobilized live and heat inactivated fungus were 230, 282 and 355 mg for Pb2+ and 30, 37 and 48 mg for Zn2+ per gram of dry biosorbents, respectively. The experimental biosorption equilibrium data for Pb2+, and Zn2+ ions were in good agreement with those calculated by Langmuir model. The affinity order of heavy metal ions was Pb2+>Zn2+.
    Carbohydrate Polymers. 01/2003;
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    ABSTRACT: Metal chelating membranes have advantages as adsorbents in comparison to conventional microspheres or beads because they are not compressible and they considerably eliminate internal diffusion limitations. The aim of this communication was to explore in detail the performance of Procion Brown MX 5BR immobilized poly(hydroxyethylmethacrylate/chitosan) composite membranes, (also called interpenetrating network, IPN, membranes) for removal of three toxic heavy metal ions, namely, Cd(II), Pb(II) and Hg(II) from aquatic systems. The composite membranes were characterized by elemental analysis, scanning electron microscopy and Fourier Transform Infrared (FTIR) spectroscopy. The incorporated amount of the Procion Brown MX 5BR was calculated as 0.036 μmol/cm2 from the nitrogen and sulphur stoichiometry. The adsorption capacity for selected heavy metal ions from aqueous media containing different amounts of these ions (30–400 mg/L) and at different pH values (2.0–6.0) was investigated. Adsorption capacity of the membranes increased with time during the first 45 min and then levelled off toward the equilibrium adsorption. The maximum amounts of heavy metal ions adsorbed were found as 18.5, 22.7 and 68.8 mg/g for Cd(II), Pb(II) and Hg(II), respectively. Competitive adsorption of the metal ions was also studied. When the metal ions competed, the adsorbed amounts were found as 1.8 mg Cd(II)/g, 2.2 mg Pb(II)/g and 52.6 mg Hg(II)/g. Under competitive conditions, the system showed a very high selectivity for Hg(II) ions. The membrane can be regenerated by washing with a solution of nitric acid (0.01 M). The desorption ratio achieved was as high as 95%. These membranes are suitable for repeated use for more than five adsorption/desorption cycles without any considerable loss in adsorption capacity.
    Hydrometallurgy 01/2002; · 2.17 Impact Factor
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    ABSTRACT: Basidiospores of P. chryosporium were immobilized into Ca-alginate beads via entrapment, and the beads incubated for vegetation at 30 °C for 5 days. The alginate beads and both entrapped live and heat inactivated fungal mycelia of Phanerochaete chryosporium were used for the removal of Hg(II) and Cd(II) ions from aqueous solution in the concentrations range of 30–500 mg l−1. The biosorption of Hg(II) and Cd(II) ions by the biosorbents increased as the initial concentration of Hg(II) and Cd(II) ions increased in the medium. A biosorption equilibrium was established in about 1 h and the adsorbed heavy metal ions did not change further with time. The effect of pH was also investigated and the maximum biosorption of Hg(II) and Cd(II) ions on all the tested biosorbents were obtained between pH 5.0 and 6.0. Temperature over the range 15–45 °C had no significant effect on the biosorption capacity. The equilibrium was well described by Langmuir and Freundlich biosorption isotherms. The alginate-fungus beads could be regenerated using 10 mM HCl, up to 97% recovery. The biosorbents were reused in three biosorption-desorption cycles with negligible decrease in biosorption capacity.
    Process Biochemistry 01/2002; · 2.44 Impact Factor
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    ABSTRACT: Polyhydroxyethylmethacrylate (PHEMA) microbeads carrying Cibacron Blue F3GA (22.3 μmol g−1) were prepared for the removal of Pb(II), Cd(II), Cu(II) and Zn(II) ions from aqueous solutions containing different amount of these ions (10–400 mg l−1) and at different pH values (2.0–6.0). Adsorption rates were high, and adsorption equilibria were reached within 10 min. Adsorption of these metal ions onto the Cibacron Blue F3GA-immobilised microbeads from single solutions were 81.86; 75.62; 69.87; and 102.48 μmol g−1 for Pb(II), Cd(II), Cu(II) and Zn(II), respectively. When the heavy metal ions competed (in the case of the adsorption from their mixture) the amounts of adsorption were 2.00 and 5.88 mg g−1 for Cu(II) and Pb(II), respectively. Under competitive conditions the affinity of Cd(II) and Zn(II) was negligible. Therefore, it was of great importance to know the stability constants of Cibacron Blue F3GA-metal ion complexes. The formation constants of dye-metal ion complexes have been investigated applying the method of Ruzic [18]. The calculated values of stability constants were 1.88×105 l mol−1 for Pb(II)-dye; 3.10×105 l mol−1 for Cu(II)-dye; 1.85×104 l mol−1 for Zn(II)-dye and 5.15×104 l mol−1 for Cd(II)-dye complex. PHEMA microbeads carrying Cibacron Blue F3GA can be regenerated by washing with a solution of nitric acid (0.1 M). The maximum desorption ratio was as high as 99%. These PHEMA microbeads are suitable for repeated use for more than three adsorption–desorption cycles without considerable loss of adsorption capacity.
    Colloids and Surfaces A Physicochemical and Engineering Aspects 01/2001; 176(s 2–3):225–232. · 2.11 Impact Factor
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    ABSTRACT: The removal of contaminant heavy-metal ions from spiked aqueous samples containing low-to-moderate levels of contamination using Turkish Beypazari low rank coal was investigated. Carboxylic acid and phenolic hydroxyl functional groups present on the coals surface were the adsorption site to remove cations from solution via ion exchange. The equilibrium pH of the coal/solution mixture has been shown to be the principal factor controlling the extent of removal of Hg(II), Cd(II), and Pb(II) ions from aqueous solutions. The optimum pH was measured to be 4.0 for Hg and Cd, and 5.0 for Pb and it was found that the system reached equilibrium in 20 min. The maximum adsorption capacities of the metal ions from their single solutions were 0.039 mmol for Hg(II), 0.008 mmol for Cd(II) and 0.041 mmol for Pb(II) per gram of coal. The order of affinity on a mole basis was as follows: Pb(II)>Hg(II)>Cd(II). The same behavior was observed during the competitive adsorption, that is in the case of adsorption from their ternary solutions. Waste water samples were obtained from a mining industry plant located within Aegean Region, Turkey. It was observed that the use of low rank coal was considerably effective in removing Hg, Cd and Pb cations from water.
    Fuel Processing Technology 01/2000; · 2.82 Impact Factor