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Öğe Classification and Separation of Solid-Liquid Systems(Elsevier Science Bv, 2008) Peker, Sumer M.; Helvaci, Serife S.Öğe Concentrated Suspensions(Elsevier Science Bv, 2008) Peker, Sumer M.; Helvaci, Serife S.Öğe Effect of the seed layer thickness on the stability of ZnO nanorod arrays(Elsevier Science Sa, 2014) Ikizler, Berrin; Peker, Sumer M.Surfaces coated with ZnO nanorods have the potential to be used as photocatalysts in flow type reactors. The prerequisite for their use is the mechanical and chemical stability of the nanorods under flow conditions. The effect of the thickness of the seed film on the stability of the ZnO nanorod arrays grown on the seed layer by hydrothermal method is investigated in this work. In addition, the viability of its use in photocatalytic flow type reactors is also assessed under flow conditions. The thickness of the seed film deposited by sol/gel method was varied in the range of 40 nm 650 nm. Verticality of the nanorods, found to be the most effective parameter in the dissolution of the rods, is related to the seed layer characteristics. Preliminary experiments showed that degradation activity of the nanorod films in photocatalytic reactors also depends on the seed layer thickness through the verticality of the rods attained. Excellent verticality and highest crystallinity could be obtained in this work with nanorods averaging 4 mu m in height, grown on 220 nm-340 nm thick seed layers. Good correlations for verticality of nanorods could be obtained with X-ray diffraction results when the seed layer is characterized by the average skewness and kurtosis of the roughness. Morphology and the structure of the seed films and the nanorod arrays are characterized by field emission scanning electron microscopy, atomic force microscopy and X-ray diffraction. The optical properties of the films are determined by photoluminescence and ultraviolet spectroscopy measurements. (C) 2014 Elsevier B.V. All rights reserved.Öğe Flow of Settling Slurries(Elsevier Science Bv, 2008) Peker, Sumer M.; Helvaci, Serife S.Öğe Mathematical Operations(Elsevier Science Bv, 2008) Peker, Sumer M.; Helvaci, Serife S.Öğe Mixing in Solid-Liquid Systems(Elsevier Science Bv, 2008) Peker, Sumer M.; Helvaci, Serife S.Öğe Modeling the Flow of Settling Suspensions(Elsevier Science Bv, 2008) Peker, Sumer M.; Helvaci, Serife S.Öğe Motion of Particles in Fluids(Elsevier Science Bv, 2008) Peker, Sumer M.; Helvaci, Serife S.Öğe Non-Newtonian Behavior of Solid-Liquid Suspensions(Elsevier Science Bv, 2008) Peker, Sumer M.; Helvaci, Serife S.Öğe The Particulate Phase: A Voyage from the Molecule to the Granule(Elsevier Science Bv, 2008) Peker, Sumer M.; Helvaci, Serife S.Öğe Population Balances(Elsevier Science Bv, 2008) Peker, Sumer M.; Helvaci, Serife S.Öğe Solid-Liquid Two Phase Flow Preface(Elsevier Science Bv, 2008) Peker, Sumer M.; Helvaci, Serife S.Öğe Synthesis of TiO2 coated ZnO nanorod arrays and their stability in photocatalytic flow reactors(Elsevier Science Sa, 2016) Ikizler, Berrin; Peker, Sumer M.Immobilized photocatalysts are preferred over suspended catalyst particles in slurry reactors due to elimination of filtration process. The requisite condition for their use is themechanical and chemical stability under flow conditions. The stability of TiO2 coated ZnO nanorods (TiO2/ZnO) immobilized at the bottom of a prototype continuous-flow reactor designed in the form of a rectangular channel is investigated under continuous flow conditions in this work. Morphology and structure of the nanorod arrays are characterized by field emission scanning electron microscopy and X-ray diffraction. Optical properties of the rods are determined by UV-Vis spectroscopy measurements. Dissolution trends of zinc ions from the TiO2/ZnO rods are determined under dark, UV radiation and photodegradation conditions, and compared with the results of uncoated ZnO. The effect of the number of TiO2 film coatings and the calcination time of the spin-coated films are investigated as parameters. Coating of the ZnO nanorods with TiO2 has greatly reduced its dissolution under UV radiation to a level less than the dissolution of uncoated ZnO rods in complete darkness. Photocatalysis under UV radiation was found to increase the dissolution rate of zinc ions. This increase was attributed to cavity or pit formation on the upper surfaces of nanorods. TiO2 coating was found to decrease the dissolution rate significantly by reducing the extent of pit formation. TiO2 was also found to increase the catalytic effectiveness of ZnO nanorod film in the photodegradation of methyl orange dye selected as a model organic pollutant. (C) 2015 Elsevier B.V. All rights reserved.