Hüseyin Deligöz

Removal of Indigo Carmine and Pb(II) Ion from Aqueous Solution by Polyaniline

In this work, we report the synthesis of polyaniline emaraldine salt (PAni-ES) by a chemical oxidative polymerization method. The obtained PAni-ES samples prepared under different conditions were used for the removal of indigo carmine anionic dye and Pb(II) ion from aqueous solutions. The results also showed that the pseudo–second-order kinetic model fitted better than the data obtained from pseudo–first-order model for the adsorption of anionic dye and Pb(II) ion onto PAni-ES. The fit of the data for indigo carmine and Pb(II) ion adsorption onto PAni-ES suggested that the Langmuir model gave closer fittings than Freundlich model.

Hydrothermal Synthesis and Characterization of PEG-Mn3O4 Nanocomposite

Here, we report on the synthesis of PEG-Mn3O4 nanocomposite (NPs) via a hydrothermal route by using Mn(acac)2, ethanol, NH3 and PEG-400. The crystalline phase was identified as Mn3O4. The crystallite size of the PEG-Mn3O4 nanocomposite was calculated as 12±5 nm from X-ray line profile fitting and the average particle size from TEM was obtained as 200 nm. This reveals polycrystalline character of Mn3O4 NPs. The interaction between PEG-400 and the Mn3O4 NPs was investigated by FTIR. Temperature independent AC conductivity of PEG-Mn3O4 nanocomposite beyond 20 kHz provides a strong evidence of ionic conduction through the structure. The conductivity and permittivity measurements strongly depend on the secondary thermal transition of nanocomposite beyond 100℃. Above that temperature, Mn3O4 particles may interact with each other yielding a percolated path that will facilitate the conduction. On the other hand, the relatively lower activation energy (Ea=0.172 eV) for relaxation process suggests that polymer segmental motions of PEG and electrons hopping between Mn 2+ and Mn 3+ may be coupled in the sample below 100℃. Room temperature magnetization curve of the sample does not reach to a saturation, which indicates the superparamagnetic character of the particles. As the temperature increases, the frequency at which (e) reaches a maximum shifted towards higher frequencies. The maximum peak was observed at 1.4 kHz for 20℃ while the maximum was detected at 23.2 kHz for 90℃.

Complementary all Solid State Electrochromic Devices Using Carboxymethyl Cellulose Based Electrolytes

The paper presents the results of the research on a new polymer-membrane and gel electrolytes for electrochromic devices. A complementary solid-state electrochromic device consisting of cathodically coloring working electrode of WO3 and anodically coloring counter electrode of NiO films is prepared to compare the effects of gel or membrane forms of carboxymethyl cellulose (CMC) polymer electrolyte on the electrochromic properties of devices. The performance evaluations of the complementary solid-state electrochromic devices indicate good reversibility, low power consumption of ±3 V in colored state, high variation of transmittance changing of 64% in gel electrolyte, and lower 7% in membrane electrolyte and good memory effect under open-circuit conditions. CMC based electrolytes can be used as an ion-conducting medium and be a good candidate for complementary electrochromic devices owing to, the improved properties as well as its cheapness.

AC conductivity of CoFe2O4 nanoparticles synthesized by polyol method

Cobalt Ferrite (CoFe2O4) nanoparticles coated with oleic acid were synthesized by polyol method. The structures of the nanoparticles were characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared with Attenuated Total Reflectance Unit (FTIR -ATR). Thermal and morphological properties of nanoparticles were determined by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmitting electron microscopy (TEM) respectively. The dielectric constant and dielectric loss of the nanoparticles were determined in the frequency range of 10 Hz-20 MHz and within the temperature range of 293 K-423 K. It was observed that AC conductivity σ(ω) α ωs. (0<;s<;1).

Synthesis, structural, magnetic and electrical properties of Co{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} (x = 0.0, 0.2) nanoparticles

Co1-xZnxFe2O4 spinel nanoparticles with Zn concentrations of x = 0.0, 0.2 were prepared by a hydrothermal route in the presence of triethylene glycol (TEG). The structural, magnetic, electrical and ...