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- ArticleYalnız künye2024Photocatalytic application of nickel oxide/zinc oxide nanoparticles decorated kaolinite nanocomposite for the degradation of crystal violet
Keles Güner, Eda; Ertugay, Nese; Ozdemir, Agah Oktay; Doğan, Bilge; Caglar, Bulent
The photocatalysis process, which is effective, economical, and environmentally friendly can overcome rapidly increasing environmental problems, has shown rapid development in recent years. Nontoxic, low-cost natural minerals are often used in photocatalysis processes that remove organic pollution from wastewater. In this study, a selective method for the removal of crystal violet (CV) from aqueous solutions using nanocomposite of nickel oxide/zinc oxide nanoparticles (NiO/ZnO) supported on kaolinite photocatalyst was investigated. The raw kaolinite, bare NiO, bare ZnO and nanocomposite samples were characterized by the XRD, TEM, SEM-EDX, XPS and FTIR techniques. The photocatalytic performances of kaolinite-NiOZnO (K-NiO/ZnO) nanocomposite and bare samples were also investigated and comparatively evaluated by the photodegradation of CV (cationic dye) dye under visible light irradiation. The effects of various parameters such as the dosage of photocatalysis, contact time, and initial dye concentration on the rate of removal of dye were investigated and optimized. The kinetics of decolorization by samples can be well described by the pseudo-first-order model. Finally, it can be used in advanced oxidative processes for the degradation of organic pollutants.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2017The Effect of ZVI and H2O2 Concentrations on Chemical Oxygen Demand and Color Removal With Fenton-Like Process From Leachate
Ertugay, Nese; Kocakaplan, Nihal; Malkoç, Emine
Leachate are difficult to treat due to their complex structures and having high pollutants concentrations. In this study; color and chemical oxygen demand (COD) removal were studied from the leachate by Fenton-like oxidation. The effect of zero -valent iron (ZVI) and H2O2 concentrations on color and COD removal was investigated. The color removal was conducted at three different wavelengths of 436, 525 and 620 nm, respectively. The highest COD (74.4%) and color removal (71% at 436 nm, 80.3% at 525 nm and 87.9% at 620 nm) were determined at concentration of 0.05 g/L ZVI. Increasing of H2O2 concentration up to 200 mg/L also increased color and COD removal. Optimum values were 0.05 g/L and 150 mg/L for ZVI and H2O2 at a reaction time of 20 minutes and pH=2.0 and total organic carbon (TOC) removal was also determined at about 50%.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2017Ultrasound and UV stimulated heterogeneous catalytic oxidation of an azo dye: A synergistic effect
Ertugay, Nese; Acar, Filiz Nuran
This research deals with the decolourisation of direct azo dye, Direct Blue 71 (DB71), in aqueous solution by means of sonocatalytic, photocatalytic and sonophotocatalytic heterogeneous oxidation processes in the presence of a zinc oxide (ZnO) catalyst. The effect of these oxidation processes under visible light and 20 kHz ultrasound was investigated to study their influence on degradation rates by varying the initial dye concentration, pH and catalyst load and to understand the effect of synergy on the degradation process. The synergistic effect is quantified in terms of a synergy factor which has already been defined in the literature. The highest value of the factor was obtained for a low DB71 dye concentration at pH 5.5, 20 o C temperature and 400 mg L-1 optimum ZnO dosage. Pseudo first-order kinetics were followed for the removal of the azo dye according to the Langmuir-Hinshelwood model. For comparison, the Langmuir-Hinshelwood model was also used for experimental values obtained from the sonocatalytic process, the photocatalytic process and the combination of these processes. The Langmuir-Hinshelwood kinetic model demonstrated consistency in all calculations of the initial rates of degradation with the appropriate values for the reaction rate constant and DB71 dye absorption constant.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2016Decolorization of Direct Blue 71 using UV irradiation and ultrasound in the presence of TiO2 catalyst
Ertugay, Nese; Acar, Filiz Nuran
The sono, photo, and sonophotocatalytic degradations of Direct Blue 71 (DB71) in the presence heterogeneous TiO2 catalyst were studied at 20 kHz using ultrasonic (US) power of 95 W and aqueous temperature of 20°C for 20 min. The effects of various operational parameters such as the concentration of the dye, pH, and amounts of catalysts on the sonochemical degradation were also investigated. Sonochemical degradation of DB71 was strongly affected by initial substrate concentration, amounts of catalysts, and pH. Acidic pH was favored for the sonocatalytic degradation of DB71 using catalysts. The hybrid technique of sonocatalytic degradation was compared with the individual techniques of catalysis, sonolysis, and photocatalysis. The US degradation of dye was enhanced by catalyst addition. The structure and morphology of the catalyst were investigated using scanning electron microscopy and X-ray diffraction pattern.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2016Basic Violet 10 (BV10) removal from aqueous solutions using sawdust of Swietenia mahagoni (Mahogany trees): adsorbent characterization, adsorption isotherm, kinetics, and thermodynamic studies
Ertugay, Nese
In this work, the adsorption potential of sawdust of Swietenia mahagoni to remove Basic Violet 10 (BV10) from aqueous solutions was investigated by batch adsorption system. The adsorbent was characterized by Fourier transform infrared spectrophotometer, scanning electron microscope, particle size distribution, and Brunauer, Emmett, and Teller methods. The effect of various experimental parameters such as pH, initial dye concentration, adsorbent concentration, and temperature on adsorption of BV10 was investigated. The optimum pH for BV10 adsorption was found to be 4.2. Equilibrium adsorption data were analyzed by the Langmuir, Freundlich, Temkin, and Scatchard isotherm models. The results show that the best fit was achieved with the Langmuir isotherm with a maximum adsorption capacity of 222.76 mg g−1 at 50°C. Pseudo-first-order, pseudo-second-order, intraparticle diffusion, and Elovich models were used to analyze the kinetic data obtained at different BV10 concentrations. The adsorption kinetic data were well described by the pseudo-second-order model. The calculated thermodynamic parameters, namely ∆G°, ∆H°, and ∆S°, showed that adsorption of BV10 was spontaneous and endothermic under examined conditions.
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