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- ArticleYalnız künye2024Semiconductor Catalyst: Investigation for the Degradation of BB9 Azo Dye by Sonophotocatalytic Process
Ertugay, Neşe; Acar, Filiz Nuran
The degradability of an azo dye, Basic Blue 9 (BB9), by heterogeneous sonocatalytic, photocatalytic, and sonophotocatalytic oxidation process was examined using simultaneous irradiation of UV-C at 254 nm and power ultrasound at 20 kHz accompanied with a heterogeneous catalyst zinc oxide (ZnO) in the study. The effect of ZnO dose and initial dye concentration was investigated on the dye degradation in sonocatalytic, photocatalytic, and sonophotocatalytic processes at pH 5.5 (natural pH). The results obtained from the experimental studies were evaluated with the parameters of color removal, pseudo-first-order rate constant, and half-life time. It was observed that the degradation of BB9 dye by the sonophotocatalytic process was higher compared to both sonocatalytic and photocatalytic degradation. as follows: 97.46, 48.64 and 56.88 %. The combination of sono and photocatalytic showed a remarkable synergistic effect in BB9 degradation. The kinetics of sonophotocatalytic oxidations, depending on the initial BB9 dye concentration, were found to follow the Langmuir-Hinshelwood model. In addition, the effect of ZnO on the sonophotocatalytic oxidation process was higher compared to titanium dioxide and zero-valent iron as follows: 97.47, 80.77 and 80.62 %.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2022Direct Blue 71 Degradation in the Presence of ZVI and H2 O2 Advanced Fenton Process: Determination of Optimum Conditions and Kinetics
Ertugay, Neşe; Acar, Filiz Nuran
This study investigated color and COD removal of azo dye Direct Blue 71 (DB71) by a Fenton-like process in zero-valent iron (Fe0 = ZVI). The UV–vis spectra of DB71 exhibit three main absorption bands – two in the UV region and one in the visible region. UV–vis spectra showed that the azo linkages in the molecule structure of the dyes were destroyed during the decolorization. The influence of various operational parameters such as pH, ZVI dosages, hydrogen peroxide (H2 O2) concentrations and temperature are studied to determine the optimum conditions for color and COD removal. pH is highly effective parameter of decolorization and COD destruction in this work. However, H2 O2 concentration and ZVI dosages were not only effective in the removal of COD for 100 mgL-1 initial DB71 concentration. Therefore, the optimum ZVI:H2 O2 ratio is based on determining the value of COD removal. Optimum conditions were accepted to be pH of 2.5, ZVI:H2 O2 ratio 4:1 and 20ºC temperature. The result indicated that 100% of decolorization efficiency was achieved within 20 min in the range of 150-400 mg/L initial DB71 concentrations by using optimal conditions. Residual COD values were 15.38, 22.35, 22.58, 27.04, 31.86 mg/L for 150, 200, 250, 300, 400 mg/L initial DB71 concentrations at the end of reaction time, respectively. Additionally, increasing the reaction temperature from 20 to 40ºC negatively affected the decolorization and degradation rate DB71. The experimental kinetic data are fitted very well the Behnajady–Modirshahla–Ghanbery model for color removal of DB71 dye.
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.
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