Yazar "Yavuz, Omer" seçeneğine göre listele

Listeleniyor 1 - 4 / 4
  • [ X ]
    Öğe
    Bakır(II) İyonlarının Sulu Çözeltilerden Atık Portakal Kabuğu İle Uzaklaştırılması: Denge, Kinetik Ve Termodinamik Çalışmalar
    (2022) Altunkaynak, Yalçın; Canpolat, Mutlu; Yavuz, Omer
    Bu çalışmada, sulu çözeltilerden Cu2+ iyonlarını uzaklaştırmak amacıyla atık portakal kabuğu (APK) değerlendirildi. Portakal kabuğunun karakterizasyonu, yüzey morfolojisi için taramalı elektron mikroskobu-enerji dağılım spektroskopisi (SEM-EDS) ve yüzey fonksiyonel grupları için Fourier dönüşümü kızılötesi spektroskopisi (FT-IR) ile incelendi. Farklı sıcaklıklarda bulunan kinetik değerler yalancı birinci derece, yalancı ikinci derece, Elovich ve parçacık içi difüzyon modeli denklemlerine uygulanmıştır. Adsorpsiyon sürecini daha iyi anlamak için Langmuir, Freundlich, Temkin ve Dubinin-Radushkevich (D-R) adsorpsiyon izotermlerinin uygulanabilirliği değerlendirildi. Bakırın uzaklaştırılması yalancı ikinci dereceden kinetik model ile Langmuir izoterm modelini takip etti. Cu2+ için uzaklaştırma kapasitesi 298, 308 ve 318 K'de sırasıyla 7.74, 7.98 ve 8.84 mg/g olarak elde edilmiştir. Cu2+ iyonlarının Gibbs serbest enerjisi (?Go), adsorpsiyon ısısı (?Ho) ve entropisi (?So) için termodinamik veriler sırasıyla -16.76 kj/mol, 29.43 kj/mol ve 154.79 j/mol olarak bulundu.
  • [ X ]
    Öğe
    Economic fast synthesis of olive leaf extract and silver nanoparticles and biomedical applications
    (Taylor & Francis Inc, 2022) Atalar, Mehmet Nuri; Baran, Ayse; Baran, Mehmet Firat; Keskin, Cumali; Aktepe, Necmettin; Yavuz, Omer; Kandemir, Sevgi Irtegun
    In this study, silver nanoparticles (AgNPs) were synthesized economically and simply using an environmentally friendly method with the extract obtained from agricultural waste olive leaves. AgNPs synthesized according to the analysis data were determined to have maximum absorbance at 433.5 nm wavelength, spherical appearance, 7.2 nm crystal nano size and -19.9 mV zeta potential. It was determined by the microdilution method with Minimum Inhibition Concentration (MIC) that AgNPs exert a suppressive effect on the growth of pathogen gram-negative, positive bacteria and yeast at very low concentrations. The cytotoxic effects of the particles were investigated on healthy cell lines (HDF) and cancerous cell lines (U118, CaCo-2, Skov-3). AgNPs showed up to 70% suppression in cancer cell lines.
  • [ X ]
    Öğe
    Phosphorus and oxygen co-doped carbon particles based on almond shells with hydrothermal and microwave irradiation process for adsorption of lead (II) and cadmium (II)
    (Springer Heidelberg, 2023) Kahvecioglu, Kubra; Tegin, Ibrahim; Yavuz, Omer; Saka, Cafer
    In this study, the production of activated carbon based on almond shells by microwave heating with KOH activation and then the modification of activated carbon with phosphorus and oxygen as a result of hydrothermal heating with phosphoric acid were carried out to increase the Cd(II) and Pb(II) adsorption efficiency. The resulting materials were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric/differential thermal analyzer (TG-DTA), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and nitrogen adsorption. Adsorption performance, kinetics and thermodynamics of phosphorus, and oxygen-doped activated carbons were evaluated. The results showed that the adsorption of both Cd(II) and Pb(II) on phosphorus and oxygen-doped activated carbons obeyed the Langmuir isotherm and pseudo-second-order kinetics. The adsorption capacity values (Q(m)) obtained from the Langmuir isotherm for Cd(II) and Pb(II) adsorption were 185.18 mg/g and 54.64 mg/g, respectively. At the same time, the adsorption mechanism of Pb(II) and Cd(II) on the respective adsorbents was evaluated. As a result of phosphorus and oxygen atoms, Lewis base sites on carbon atoms and Lewis acid sites on phosphorus atoms are likely to form on the surface. These Lewis base sites can act as important active sites in adsorption reactions, especially of positively charged Pb(II) and Cd(II) ions.
  • [ X ]
    Öğe
    Surface modification with cold plasma application on kaolin and its effects on the adsorption of methylene blue
    (Elsevier Science Bv, 2013) Yavuz, Omer; Saka, Cafer
    In this study, cold plasma treatment was applied for the surface modification of kaolin adsorbent to improve the removal of methylene blue (MB) from aqueous solution. To achieve the aim, the conditions for adsorption, including cold plasma application time, initial dye concentration, and pH were investigated with respect to the removal efficiency of MB. The changes of the surface property before and after cold plasma treatment were discussed. The maximum adsorption capacity of MB compared with untreated raw kaolin increased from 19.60 to 51.02 mg/g (up to approximately 2, 5-fold) after modification by cold plasma. The experimental data were analyzed using pseudo first-order and second-order kinetic models. The surface properties of kaolin treated with cold plasma were investigated with scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and point of zero charge (pzc) measurements to understand the adsorption mechanism. (C) 2013 Elsevier B.V. All rights reserved.