Chemical Engineering / Kimya Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/14

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Publisher: search.filters.publisher.Kluwer Academic PublishersWoS Q: search.filters.wosQuartile.Q3

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  • Article
    Citation - WoS: 16
    Citation - Scopus: 15
    Characterization of Silk Fibroin Based Films Loaded With Rutin-Ss Inclusion Complexes
    (Kluwer Academic Publishers, 2014) Şamlı, Merve; Bayraktar, Oğuz; Korel, Figen
    In this study, cyclodextrin inclusion complexes with rutin were prepared via co-precipitation method. Stability constant and solubility energy of beta-cyclodextrin complex were calculated as 262 M-1 and 1,737 kJ mol-1, respectively. Aqueous solubility of rutin was increased with inclusion complex of beta-cyclodextrin. The effect of temperature on both aqueous solubility of free rutin, and its inclusion complex was also studied. Characterization of cyclodextrin complexes were conducted with UV-Vis spectrophotometry, Fourier transform infrared spectroscopy, X-ray diffractometry, differential scanning calorimetry, thermal gravimetric analysis, nuclear magnetic resonance spectroscopy and scanning electron microscopy techniques. Characterization results supported formation of inclusion complexes. Dissolution profiles of rutin, physical mixture and inclusion complex of rutin were observed at 37 °C. Dissolution results proved the effect of cyclodextrin addition on solubility rate of rutin. After loading rutin and its complexes into silk fibroin based films, release tests were performed at 37 °C in neutral pH conditions for 24 h. Most of the rutin were released from silk fibroin films within the first 5 h and the rest of it was released slowly (sustained release). Electron microscope analyses showed that films had homogenous and dense morphologies. These results revealed that silk fibroin is useful for preparing bioactive films loaded with natural compounds and for modifying their release behaviour at physiological conditions.
  • Article
    Citation - WoS: 29
    Citation - Scopus: 32
    Visualization of the Equilibrium Fcc Catalyst Surface by Afm and Sem-Eds
    (Kluwer Academic Publishers, 2003) Bayraktar, Oğuz; Kugler, Edwin L.
    The deposition of metal contaminants (e.g., Ni, V, and Fe) from the hydrocarbon feed causes the deactivation of fluid catalytic cracking (FCC) catalyst used in petroleum refining. It is very important to understand the changes in the morphology and chemical composition on the catalyst surface and how these structural and chemical changes affect the catalyst performance. In this research, metal-contaminated FCC catalysts from a commercial unit have been characterized using AFM together with SEM-EDS. The AFM images showed the surface pores as well as the features that surround the pore's entrance on the catalyst surface. Catalyst surface contains debris that appear as bright spots in AFM images. SEM-EDS results have shown the presence of iron in these bright spots. Fe enrichment at the catalyst particle surface was also confirmed by XPS analyses.