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Karakoyun N.,Yuzuncu Yil University | Kubilay S.,Yuzuncu Yil University | Aktas N.,Yuzuncu Yil University | Turhan O.,Marmore Ltd | And 4 more authors.
Desalination | Year: 2011

In this study, p(acrylamide)-chicken biochar (p(AAm)-CB), p(acrylamide)-wood biochar (p(AAm)-WB), and p(acrylamide)-tire biochar (p(AAm)-TB) hydrogel composites were prepared using acrylamide (AAm) as monomer with the corresponding biochars, with N,N'-methylenebisacrylamide (MBA) as crosslinker and ammonium persulfate (APS) as initiator. P(AAm)-CB, p(AAm)-WB, and p(AAm)-TB were used as adsorbents to remove phenol from aqueous environments. The synthesized p(AAm)-CB, p(AAm)-WB, p(AAm)-TB and p(AAm) hydrogel composites had swelling values of 1112, 1045, 847, and 623%, respectively in distilled water. The prepared hydrogel biochar material compositions were examined using an elemental analyzer. Absorption of phenol into p(AAm)-WB was studied at different pHs to determine the optimum pH for maximum removal of phenol. The ionic strength of the medium was varied between 0.01 and 1molL-1 to determine the effect of salt (NaCl) on the absorption characteristics and it was found that the absorption of phenol increased with a decrease in the amount of salt. Langmuir and Freundlich isotherms were applied to describe the absorption characteristics and the Langmuir isotherm describes the absorption phenomena in this study much better than the Freundlich isotherm. Pseudo-first-order and pseudo-second-order kinetic studies were also applied to determine absorption characteristic. © 2011 Elsevier B.V. Source


Sahiner N.,Canakkale Onsekiz Mart University | Sahiner N.,Nanomaterial and Nanotechnology Laboratory | Ozay O.,Canakkale Onsekiz Mart University | Aktas N.,Yuzuncu Yil University | And 2 more authors.
Desalination | Year: 2011

Macrogels and nanogels (5×6mm and 370nm dimensions, respectively) based on 4-vinylpyridine (p-(4VP)) were prepared using redox and microemulsion techniques. The p(4-VP)-based materials were quaternized with HCl/alkyhalides having different chain lengths to tune the charges (macro and nanogels) and size of nanogels. By developing positive charge on the p(4-VP) materials, they behaved as ion exchangers and used in removal of As(V) from aqueous environments. The prepared p(4-VP) materials were also rendered responsive to magnetic field by in situ incorporation of magnetic metal nanoparticles inside macro p(4-VP) hydrogels and by encapsulation of separately prepared magnetic ferrites by nanosized p(4-VP) particles. Nanoparticles quaternized with HCl (p(4-VP)-HCl) (1g) removed over 95% of As(V) from a stock solution (10mgL-1, 1000mL) in 15min whereas bulk hydrogels removed >82% of the As(V) from an equivalent solution in ~12h. Parameters effecting the As(V) removal, including pH, temperature and ionic strength, were also investigated. The synthesized magnetic p(4-VP) composites could be reused after elution with NaOH and regeneration with quaternization agents; these procedures were facilitated using an externally applied magnetic field. The Langmuir and Freundlich adsorption isotherms were also applied to study the removal of As(V) from aqueous environments. © 2011 Elsevier B.V. Source


Ozay O.,Canakkale Onsekiz Mart University | Aktas N.,Yuzuncu Yil University | Inger E.,Gazi University | Sahiner N.,Canakkale Onsekiz Mart University | Sahiner N.,Nanomaterial and Nanotechnology Laboratory
International Journal of Hydrogen Energy | Year: 2011

In this study, hydrogels were synthesized from 2-acrylamido-2-methyl-1- propansulfonic acid (AMPS) via a photo polymerization technique. Approximately 100 nm Ni metal nanoparticles were generated in situ inside these p(AMPS) hydrogel networks and used as a catalyst in hydrogen production by hydrolysis of sodium boron hydride in a basic medium. The effects of several parameters on the hydrolysis reaction such as the amount of catalyst, the initial concentration of NaBH 4, and the temperature were investigated. The activation energy, activation enthalpy and activation of entropy for the reaction were calculated as 42.28 kJ mol -1, 39.59 kJ mol -1 and -171.67 J mol -1 K -1, respectively. © 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved. Source


Sahiner N.,Canakkale Onsekiz Mart University | Sahiner N.,Nanomaterial and Nanotechnology Laboratory | Ozay O.,Canakkale Onsekiz Mart University | Aktas N.,Yuzuncu Yil University
Current Nanoscience | Year: 2011

Stimuli-responsive (pH, temperature and magnetic field) 4-vinylpyridine (4-VP)-based nanoparticles in copolymeric formula- tion with core-shell morphology were synthesized using N-isopropylacrylamide (NIPAM), 2-hydroxyethyl methacrylate (HEMA), acrylic acid (AAc), and methacrylic acid (MAc) as shell-forming monomers. Keeping the 4-VP ratio constant and varying the comono- mer amounts produced particles with variant shell thickness. Multi-responsive p(4-VP)-based nanoparticles were further modified by re- acting with different functional groups containing bromoalkanes by quaternization. These p(4-VP)-based particles were also utilized to include composite materials by encapsulating separately prepared magnetic ferrites. To demonstrate the potential usage of the synthesized particles and their modified forms as drug delivery devices, naproxene sodium salt as an antibacterial drug was used for in vitro release studies in PBS. ©2011 Bentham Science Publishers Ltd. Source


Ozay O.,Canakkale Onsekiz Mart University | Ekici S.,Canakkale Onsekiz Mart University | Ekici S.,Nanomaterial and Nanotechnology Laboratory | Aktas N.,Yuzuncu Yil University | And 2 more authors.
Journal of Environmental Management | Year: 2011

4-vinyl pyridine (4-VP) based hydrogels with 2-hydroxyethylmetacrylate (HEMA) and magnetic composites were prepared and tested for use in the removal of UO 2 2+ and Th 4+ ions from aqueous environments. It was found that the absorption of these metal ions from aqueous environments decreased with an increase in the amount of HEMA contained within p(4-VP-co-HEMA) hydrogels between 0.498 mmol for pure p(4-VP) and 0.027 mmol for pure p(HEMA). The characterization of the hydrogels was determined by swelling experiments, FT-IR and thermal analysis. The effects of initial metal ion concentration, hydrogel amount and the temperature of the medium on absorption of the ions were investigated. Langmuir and Freundlich isotherms were constructed for the absorption of UO 2 2+ and Th 4+. Both isotherms demonstrated that these metal ions complied with monolayer absorption kinetics. © 2011 Elsevier Ltd. Source

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