Yazar "Karakas, Zeynep Karcioglu" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • Küçük Resim Yok
    Öğe
    The effects of heat treatment temperatures on photocatalytic activity of cobalt ferrite nanoparticles synthesised by microwave-assisted combustion method
    (Wiley, 2023) Karakas, Ibrahim Hakki; Karakas, Zeynep Karcioglu
    In this study, the effects on the photocatalytic activities of particles after heat treatment has been applied to cobalt ferrite nanoparticles produced by microwave-assisted combustion method were observed. The heat treatment applied to the samples was produced with only the microwave effect, at temperatures ranging from 300 to 1000 degrees C. Thermogravimetric analysis was performed on the precursor sample in air atmosphere. During this analysis, the gases released up to 1200 degrees C were identified with a Fourier-transform infrared (FTIR) spectrometer integrated into a thermogravimetric analysis system. Then, the cobalt ferrite nanoparticles produced with heat treatments applied at various temperatures were used as a photocatalyst to remove the dyestuff content in synthetic wastewaters prepared by using Astrazon Red GTL textile dye by photocatalytic oxidation, and their photocatalytic activities were compared. In these experiments, the operational parameters for photocatalysis processes were applied as 400 rpm for stirring speed, 50 mg/L for initial contaminant concentration, 0.5 g/L for catalyst dosage, 25 degrees C for temperature, and 4400 mu W/cm(2) for light intensity. As a result of the experiments, it was observed that the crystal structure of the cobalt ferrite nanoparticles produced with the increase of the applied heat treatment temperature improved significantly. The obtained data show a strong relationship between the structural properties of materials and their photocatalytic activities. In addition, it was determined that the dyestuff in the solution was completely degraded in the experiments, and it was determined that all processes were compatible with the pseudo-first-order kinetic model.
  • Küçük Resim Yok
    Öğe
    Photocatalytic activity of cobalt aluminate nanoparticles synthesized by microwave-assisted combustion method
    (Pergamon-Elsevier Science Ltd, 2022) Karakas, Ibrahim Hakki; Karakas, Zeynep Karcioglu; Ertugrul, Mehmet
    Cobalt aluminate is one of the most widely-used spinet aluminate types. It is known that various structural, magnetic and morphological properties of spinet ceramics can vary depending on the synthesis technique and the starting chemicals used. In this study, initially, heat treatment was applied to cobalt aluminate nanoparticles synthesized by the microwave-assisted combustion method and the effects of the applied heat treatment on the structural properties were investigated. Characterization studies showed that cobalt aluminate spinet pigments were successfully synthesized. The optimum heat treatment temperature was determined as 700 degrees C. Then, the synthesized cobalt aluminate nanoparticles were used as photocatalysts for dye removal by photocatalytic oxidation from a synthetic wastewater containing Astrazon red textile dye and their photocatalytic activity was investigated at different catalyst dosages. Moreover, the same particles were also produced by conventional combustion technique. Then, their photocatalytic activities were studied and the data were compared with the results obtained from the experiments made with the samples produced with microwave assisted combustion method under the same experimental conditions. The results show that cobalt aluminate nanoparticles synthesized by microwave assisted combustion exhibit a better photocatalytic activity. In experiments performed with samples produced via microwave-assisted combustion method, all dyestuff content in the solution containing 50 mg/L dye was completely removed under UV irradiation for approximately 60 min. It was determined that the catalyst dosage had an effect on the reaction rate and the reaction was found to be compatible with the pseudo first order kinetic model.