Chemistry / Kimya

Permanent URI for this collectionhttps://hdl.handle.net/11147/4072

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Publisher: search.filters.publisher.Elsevier Ltd.Subject: search.filters.subject.Micelles

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  • Article
    Citation - WoS: 13
    Citation - Scopus: 15
    Ancillary Effects of Surfactants on Filtration of Low Molecular Weight Contaminants Through Cellulose Nitrate Membrane Filters
    (Elsevier Ltd., 2016) Olcay, Aybike Nil; Polat, Mehmet; Polat, Hürriyet
    Removal of contaminants with low molecular weight (<800 Dalton) requires the use of advanced separation techniques such as ultrafiltration (UF) or micellar enhanced ultrafiltration (MEUF). However, surface active agents invariably co-exist in waste waters along with these contaminants or they may be added intentionally as part of the separation process as in the case of MEUF. Though it is quite likely that both the filter medium and the contaminants would interact with the surfactant molecules or their micelles, there is not sufficient emphasis in the literature on the concomitant aspects of such interactions.The ancillary effects created by anionic (sodium dodecyl sulfate, SDS), cationic (hexadecyltrimethyl ammonium bromide, CTAB) and non-ionic (ethoxylated octylphenol, TX-100) surfactants on the mechanism and efficiency of the filtration process were investigated in this study. Methylene blue (MB) and cellulose nitrate membrane (CNM) filters were employed as model retentate and the separation medium. A combination of surface tension, contact angle and charge measurements demonstrated that the addition of surfactants had a remarkable effect on the filtration outcome. The effect depended on both the type and concentration of the surfactant and was manifested mainly through the creation of MB-surfactant entities which acted differently than the MB alone; but more importantly, through the interactions of the surfactant molecules/micelles and the MB-surfactant pairs with the separation membrane.
  • Other
    Erratum: Optical Transition Rates of a Meso-Substituted Thiacarbocyanine in Methanol-In Reverse Micelles (journal of Luminescence (2005) 113 (1-8)
    (Elsevier Ltd., 2005) Özçelik, Serdar; Atay, N. Zeynep
    The correct correspondence information for the first author is: Serdar Özçelik Chemistry Department, Izmir Institute of Technology, Urla-35430 Izmir, Turkey E-mail address: serdarozcelik@iyte.edu.tr Tel.: +90 232 750 7557 fax: +90 232 750 7509
  • Article
    Citation - WoS: 8
    Optical Transition Rates of a Meso-Substituted Thiacarbocyanine in Methanol-In Reverse Micelles
    (Elsevier Ltd., 2005) Özçelik, Serdar; Atay, N. Zeynep
    We report the photophysical properties of 3,3′-diethyl-5,5′-dichloro-9-phenylthiacarbocyanine (DDPT) in methanol-in-oil (m/o) reverse micellar systems which form methanol droplets stabilized with anionic surfactant aerosol-OT (AOT) in n-heptane. The fluorescence quantum yield of DDPT is enhanced by a factor of 17 in the methanol droplet in comparison with bulk methanol. The fluorescence lifetimes of DDPT in m/o reverse micelles are prolonged up to 2.2 ns with increasing molar ratio of methanol to surfactant (w0=[MeOH]/[AOT]), whereas the fluorescence lifetime of DDPT in bulk methanol is 75 ps. The non-radiative rate constants of DDPT in the droplets are decreased by a factor of 40, resulting in a remarkable enhancement in quantum yields, indicating that internal motions of DDPT in the droplets are significantly reduced due to strong electrostatic interactions between the positively charged DDPT and the negatively charged sulfonate head-groups of AOT and the spatial confinement induced by the reverse micellar structure.