Chemical Engineering / Kimya Mühendisliği

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

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Language: search.filters.language.enSubject: search.filters.subject.Scanning electron microscopy

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  • Article
    Citation - WoS: 34
    Citation - Scopus: 43
    Zinc Stearate Production by Precipitation and Fusion Processes
    (American Chemical Society, 2005) Gönen, Mehmet; Balköse, Devrim; İnal, Fikret; Ülkü, Semra
    In this study, the production of ZnSt2 using sodium stearate and zinc sulfate in a precipitation process, and stearic acid and zinc oxide in a fusion process, was investigated with regard to product purity. In the fusion process, an increase in mixing rate decreased the induction time occurring at the beginning of the reaction. While the melting point of the zinc stearate prepared by the precipitation process was found to be about 122°C by optical microscopy, it was slightly lower than 122°C for zinc stearate produced by the fusion process. Differential scanning calorimetry (DSC) indicated onset of melting at 120°C and 118°C for samples prepared by precipitation and fusion processes, respectively. Characteristic peaks of ZnSt2 were present in XRD patterns of the products obtained by both processes. From SEM micrographs, it was seen that zinc stearate obtained by both processes had lamellar structure.
  • 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.