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    Decolourization of CI Reactive Orange 16 via photocatalysis involving TiO2/UV and TiO2/UV/oxidant systems
    (Desalination Publ, 2012) Kartal, Ozlem Esen; Turhan, Gulistan Deniz
    Decolourization of C.I. Reactive Orange 16 (RO16) via photocatalysis involving TiO2/UV and TiO2/UV/oxidant systems has been investigated. The experiments were carried out in a stirred cylindrical batch photoreactor under UV irradiation. The effects of pH, TiO2 concentration and addition of electron acceptors such as H2O2, Na2S2O8 and Cu+ ions were studied. The decolourization efficiency followed the order of pH 3 > pH 9 > pH 6 in TiO2/UV system. The addition of Cu+ ions to TiO2/UV/oxidant system significantly increased the decolourization efficiency. The performance of addition of 0.5 mM Cu+ ions to TiO2/UV/Na2S2O8 system was also evaluated by using synthetic dye-bath effluent. The results reveal that almost complete decolourization (99%) was achieved with RO16, while 76% decolourization was obtained with synthetic dye-bath effluent after 360 min of reaction time. Similar trend was observed with COD measurements. The rate of decolourization of RO16 was found to follow pseudo-first order kinetics and obeys L-H model. When the suspension of TiO2 containing RO16 was exposed to solar irradiation, 90% of decolourization and 64% of COD removal were obtained after 120 min of reaction time. Degradation products of RO16 were determined by LCMS.
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    DETERMINATION OF ELECTRICAL ENERGY COST OF DECOLORIZATION OF CI ACID ORANGE 7 VIA TIO2-ASSISTED PHOTOCATALYSIS UNDER UV ILLUMINATION IN THE PRESENCE OF H2O2
    (Gh Asachi Technical Univ Iasi, 2017) Kartal, Ozlem Esen; Turhan, Gulistan Deniz
    Decolorization of C.I. Acid Orange 7 (AO7) via TiO2-assisted photocatalysis under UV illumination in the presence of H2O2 has been investigated. The effect of pH on decolorization efficiency of AO7 was investigated in TiO2/UV/H2O2 process. The performance of TiO2/UV/H2O2 system was also evaluated by using synthetic dye-bath effluent of AO7. Solar driven TiO2 photocatalysis was found significantly efficient for the decolorization and degradation of AO7. The rates of decolorization and degradation of AO7 were found to follow pseudo-first order kinetics. The electrical energy consumption of decolorization of synthetic dye-bath effluent was found to be 4.1 times higher than that of AO7 solution. Similarly, the electrical energy consumption of degradation of synthetic dye-bath effluent was 2.2 times higher than that of AO7 solution under investigated conditions. Considering one order of magnitude reduction in AO7 concentration and COD value, the cost of electrical energy for decolorization and degradation of AO7 solution and synthetic dye-bath effluent of AO7 was calculated.
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    PHOTO-FENTON TREATMENT OF CI REACTIVE BLACK 5 BY USE OF RESPONSE SURFACE METHODOLOGY
    (Parlar Scientific Publications (P S P), 2010) Turhan, Gulistan Deniz; Kartal, Ozlem Esen
    Degradation of a diazo dye of C I Reactive Black 5 by photo- Fenton process has been investigated Response surface methodology was applied to evaluate the interactive effects of process variables considered as initial concentration of dye, H2O2 and Fe2+ on the process efficiency in terms of % COD removal, and to optimize the process Experimental design using central composite design allowed the development of a second-order model for RB5 degradation The experimental results satisfactorily fitted the model predictions The optimum reaction conditions to obtain maximum % COD removal were found to be 13 236 mM H2O2 0 5 mM Fe2+ and 0 1008 mM RB5 The results suggest that photo- Fenton process is a promising solution for the degradation of RB5 under both UV and sunlight
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    Photocatalytic activity of La3+-doped TiO2 synthesized via sol-gel method
    (Ice Publishing, 2013) Turhan, Gulistan Deniz; Kartal, Ozlem Esen
    La3+-doped TiO2 samples were synthesized via sol-gel method using titanium tetraisopropoxide as inorganic precursor. The X-ray diffraction, scanning electron microscopy, X-ray phototoelectron spectroscopy (XPS) and nitrogen adsorption measurements were used to characterize the samples. Doping with La3+ inhibited the transformation of anatase phase to rutile during calcination treatment and the growth of crystallite size. XPS analysis confirmed the presence of La3+ in the form of La2O3 on the surface of TiO2. The photocatalytic activity of La3+-doped TiO2 samples was investigated in terms of decolorization and degradation efficiencies of Acid Orange 7 (AO7) dye. It was found that doping with La3+ enhanced the photocatalytic activity of TiO2. The performance of doped samples was also evaluated using synthetic dye-bath effluent of AO7. Solar-driven La3+-doped TiO2 photocatalysis was found significantly efficient for the decolorization and degradation of AO7.