Browsing by Author "Şenel, Serap"
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Item Alanine containing porous beads for mercury removal from artificial solutions(Wiley, 2006-04-15) Şenel, Serap; Karabakan, Abdülkerim; Denizli, Adil; Kara, Ali; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Bölümü.; AAG-6271-2019; 7102824859N-methacryloyl-(L)-alanine (MALA) was synthesized by using methacryloyl chloride and alanine as a metal-complexing ligand or comonomer. Spherical beads with an average diameter of 150-200 mu m were obtained by suspension polymerization of MALA and 2-hydroxyethyl methacrylate (HEMA) conducted in an aqueous dispersion medium. Poly(HEMA-MALA) beads were characterized by SEM, swelling studies, surface area measurement, and elemental analysis. Poly(HEMA-MALA) beads have a specific surface area of 68.5 m(2)/g. Poly(HEMA-MALA) beads with a swelling ratio of 63%, and containing 247 mu mol MALA/g were used in the removal of H g(2+) from aqueous solutions. Adsorption equilibrium was achieved in about 60 min. The adsorption of Hg2+ ions onto PHEMA beads was negligible (0.3 mg/g). The MALA incorporation into the polymer structure significantly increased the mercury adsorption capacity (168 mg/g). Adsorption capacity of MALA containing beads increased significantly with pH. The adsorption of Hg2+ ions increased with increasing pH and reached a plateau value at around pH 5.0. Competitive heavy metal adsorption from aqueous solutions containing Cd2+, Cu2+, Pb2+, and Hg2+ was also investigated. The adsorption capacities are 44.5 mg/g for Hg2+, 6.4 mg/g for Cd2+, 2.9 mg/g for Pb2+, and 2.0 mg/g for Cu2+ ions. These results may be considered as an indication of higher specificity of the poly(HEMA-MALA) beads for the Hg2+ comparing to other ions. Consecutive adsorption and elution operations showed the feasibility of repeated use for poly(HEMA-MALA) chelating beads.Item Porous dye affinity beads for nickel adsorption from aqueous solutions: A kinetic study(Wiley, 2006-06-15) Akgöl, Sinan; Kuşvuran, Erdal; Şenel, Serap; Denizli, Adil; Kara, Ali; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Bölümü.; AAG-6271-2019; 7102824859We investigated a new adsorbent system, Reactive Red 120 attached poly(2-hydroxyethyl methacrylate ethylene dimethacrylate) [poly(HEMA-EDMA)] beads, for the removal of Ni2+ ions from aqueous solutions. Poly(HEMA-EDMA) beads were prepared by the modified suspension copolymerization of 2-hydroxyethyl methacrylate and ethylene dimethacrylate. Reactive Red 120 molecules were covalently attached to the beads. The beads (150-250 mu m), having a swelling ratio of 55% and carrying 25.5 mu mol of Reactive Red 1.20/g of polymer, were used in the removal of Ni2+ ions. The adsorption rate and capacity of the Reactive Red 120 attached poly(HEMA-EDMA) beads for Ni2+ ions was investigated in aqueous media containing different amounts of Ni2+ ions (5-35 mg/L) and having different pH values (2.0-7.0). Very high adsorption rates were observed at the beginning, and adsorption equilibria were then gradually achieved in about 60 min. The maximum adsorption of Ni2+ ions onto the Reactive Red 120 attached poly(HEMA-EDMA) beads was 2.83 mg/g at pH 6.0. The nonspecific adsorption of Ni2+ ions onto poly(HEMA-EDMA) beads was negligible (0.1 mg/g). The desorption of Ni2+ ions was studied with 0.1M HNO3. High desorption ratios (> 90%) were achieved. The intraparticle diffusion rate constants at various temperatures were calculated as k(20 degrees C) = 0.565 mg/g min(0.5), k(30 degrees C) = 0.560 mg/g min(0.5), and k(40 degrees C) = 0.385 mg/g min(0.5). Adsorption-desorption cycles showed the feasibility of repeated use of this novel adsorbent system. The equilibrium data fitted very well both Langmuir and Freundlich adsorption models. The pseudo-first-order kinetic model was used to describe the kinetic data.Item Removal of phenol and chlorophenols from water with reusable dye-affinity hollow fibers(Elsevier, 2006-11-16) Alsancak, Güleren; Şenel, Serap; Denizli, Adil; Kara, Ali; Uludağ Üniversitesi/Fen Edebiyat Fakültesi/Kimya Bölümü.; G-5151-2012; 7102824859Reactive Green HE 4BD carrying polyamide hollow fibers were investigated as dye-affinity adsorbents for removal of chlorophenols (i.e., phenol. o-chlorophenol, p-chlorophenol and 2,4,6-trichlorophenol). Adsorption rates of chlorophenols were very high. Equilibrium was achieved in about 30 min. The applicability of two kinetic models including pseudo-first order and pseudo-second order model was estimated on the basis of comparative analysis of the corresponding rate parameters, equilibrium capacity and correlation coefficients. Results suggest that chemisorption process could be the rate-limiting step in the adsorption process. The maximum adsorption values of chlorophenols onto the Reactive Green HE 4BD carrying hollow fibers were 145.9 mu mol/g for phenol, 179.2 mu mol/g for 2,4,6-trichlorophenol, 194.5 mu mol/g for p-chlorophenol and 202.8 mu mol/g for o-chlorophenol. The affinity order was as follows: o-chlorophenol > p-chlorophenol > 2,4,6-trichlorophenol > phenol. The adsorption capacity of chlorophenols decreased with increasing pH. Desorption of chlorophenols was achieved using methanol solution (30%, v/v). The Reactive Green HE 4BD-carrying hollow fibers are suitable for repeated use for more than 10 cycles without noticeable loss of adsorption capacity.