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Öğe CoFe2O4 nanoparticles decorated onto graphene oxide and graphitic carbon nitride layers as a separable catalyst for ultrasound-assisted photocatalytic degradation of Bisphenol-A(Elsevier Ltd, 2022) Görmez, Erkan; Yakar, Ezgi; Gözmen, Belgin; Kayan, Berkant; Khataee, AlirezaThe advanced oxidation process (AOP) through ultrasound-assisted photocatalytic degradation has attracted much attention in removing emerging contaminants. Herein, CoFe2O4-GO and CoFe2O4-g-C3N4 nanocomposites were synthesized using the ultrasound-assisted co-precipitation method. TEM, XRD, XPS, EDS, SEM, and FT-IR techniques characterized the structural, morphological, and chemical properties of the synthesized nanocomposites. The analyses showed that CoFe2O4 structure was nano-sized and distributed more homogeneously in graphene oxide (GO) layers with oxygenated functional groups than graphitic carbon nitride (g-C3N4). While the efficiency of composite catalysts, as photocatalysts, for degradation of bisphenol-A (BPA) was low in the visible region in the presence of persulfate, their catalytic efficacy was higher with sonolytic activation. The addition of persulfate as an oxidant remarkably enhanced the target pollutant degradation and TOC removal of BPA solution. Both composite catalysts showed 100 % BPA removal with the synergistic effect of visible region photocatalytic oxidation and sonocatalytic oxidation in the presence of persulfate at pH 6.8. In ultrasound-assisted photocatalytic oxidation of BPA, the highest mineralization efficiencies were obtained at 2 h treatment time, pH 6.8, 16 mM PS, catalyst dosages of 0.1 g/L CoFe2O4-GO, and 0.4 g/L CoFe2O4-g-C3N4 as 62 % and 55 %, respectively. An effective catalyst was obtained by reducing e?/h+ recombination and charge transfer resistance by decorating the GO layers with CoFe2O4.Öğe Sonocatalytic degradation of an anthraquinone dye using TiO2-biochar nanocomposite(ELSEVIER SCIENCE BV, 2017) Khataee, Alireza; Kayan, Berkant; Gholami, Peyman; Kalderis, Dimitrios; Akay, SemaTiO2-biochar (TiO2-BC) nanocomposite was synthesized by sol-gel method. The characteristics of the prepared nanocomposite were examined using X-ray fluorescence, scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy and N-2 adsorption-desorption analysis. The performance of synthesized TiO2-BC nanocomposite as efficient sonocatalyst was studied for the degradation of Reactive Blue 69 (RB69). Sonocatalytic degradation of RB69 in the presence of TiO2-BC nanocomposite could be explained by the mechanisms of hot spots and sonoluminescence. The optimized values for main operational parameters were determined as pH of 7, TiO2-BC dosage of 1.5 g/L, RB69 initial concentration of 20 mg/L and ultrasonic power of 300 W. Furthermore, the effect of (OH)-O-center dot, h(+) and O-2(center dot-) scavengers on the RB69 degradation efficiency was studied. Gas chromatography-mass spectroscopy analysis was used to identify intermediate compounds formed during the RB69 degradation. The results of repeated applications of TiO2-BC in the sonocatalytic process verified its stability in long-term usage.Öğe Sonocatalytic degradation of fluoroquinolone compounds of levofloxacin using titanium and zirconium oxides nanostructures supported on paper sludge/wheat husk-derived biochar(Korean Society of Industrial Engineering Chemistry, 2022) Motlagh, Parisa Yekan; Soltani, Reza Darvishi Cheshmeh; Pesaran, Zoha; Akay, Sema; Kayan, Berkant; Yoon, Yeojoon; Khataee, AlirezaThe present study aimed at treating a water medium containing pharmaceutical compounds such as levofloxacin (LEV). For this purpose, ultrasound (US)-based degradation of LEV was catalyzed by TiO2 and ZrO2 nano-catalysts supported on biochar (BC). BC was obtained from a precursor composite of paper sludge and wheat husk. The application of BC-ZrO2 led to a degradation efficiency of 54.65% within 60 min. When BC-TiO2 was used, a lower degradation efficiency of 49.62% was obtained at the same reaction time. However, increasing the time to 120 min improved the sonocatalytic degradation of LEV by BC-TiO2 (72.88%) compared to that of BC-ZrO2 (66.42%). In the presence of H2O2 and S2O82?, the LEV degradation efficiency of US/BC-TiO2 increased from 72.88% to 87.98% and 94.03%, respectively, and for the US/BC-ZrO2 process, it increased from 66.42% to 76.79% and 90.14%, respectively. The addition of isopropanol caused the most suppressive effect on the sonocatalytic degradation of LEV for both US/BC-TiO2 (decreasing from 72.88% to 13.99%) and US/BC-ZrO2 (decreasing from 66.42% to 16.43%) processes. The reusability test results showed an approximately 20% reduction in the sono-reactor performance within three consecutive experimental runs with no substantial change in the functional groups of the as-prepared sonocatalyst. Intermediates of LEV decomposed by the two sonocatalytic processes were also identified.Öğe Sonocatalytic degradation of Reactive Yellow 39 using synthesized ZrO2 nanoparticles on biochar(ELSEVIER SCIENCE BV, 2017) Khataee, Alireza; Kayan, Berkant; Gholami, Peyman; Kalderis, Dimitrios; Akay, Sema; Dinpazhoh, LalehZrO2-biochar (ZrO2-BC) nanocomposite was prepared by a modified sonochemical/sol-gel method. The physicochemical properties of the prepared nanocomposite were evaluated using scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray fluorescence, Fourier transform infrared spectroscopy and Brtmauer-Emmett-Teller model. The sonocatalytic performance of ZrO2-BC was investigated in sonochemical degradation of Reactive Yellow 39 (RY39). The high observed sonocatalytic activity of the ZrO2-BC sample could be interpreted by the mechanisms of sonoluminescence and hot spots. Parameters including ZrO2-BC dosage, solution pH, initial RY39 concentration and ultrasonic power were selected as the main operational parameters and their influence on RY39 degradation efficiency was examined. A 96.8% degradation efficiency was achieved with a ZrO2-BC dosage of 1.5 g/L, pH of 6, initial RY39 concentration of 20 mg/L and ultrasonic power of 300 W. In the presence of (OH)-O-center dot radical scavengers, RY39 degradation was significantly inhibited, providing evidence for the key role of hydroxyl radicals in the process. The sonodegradation intermediates were identified using gas chromatography-mass spectroscopy and the possible decomposition route was proposed.Öğe Synthesis of pumice-TiO2 nanoflakes for sonocatalytic degradation of famotidine(Elsevier Ltd., 2018) Rad, Tannaz Sadeghi; Khataee, Alireza; Kayan, Berkant; Kalderis, Dimitrios; Akay, SemaPumice-TiO2 was synthesized through simple sol-gel method. The successful synthesis of the catalyst was verified by SEM, EDS, XRF, FT-IR and BET techniques. Then, a sonocatalytic process was performed to degrade famotidine in the presence of the synthesized catalyst and under ultrasonic irradiation. The removal efficiency of the sonocatalytic process with pumice TiO2, TiO2, pumice and sonolysis within 70 min was 71.1%, 33.9%, 31.1% and 8.9%, respectively. The main operational parameters which were examined in this study were catalyst dosage, pH, famotidine concentration and ultrasonic power which were optimized as 1.5 g/L, 5, 20 mg/L and 150 W, respectively. Moreover, the addition of radical scavengers (EDTA, Na2SO4 and 1, 4 benzoquinone) and enhancers (H2O2 and K2S2O8) which can affect the removal efficiency were investigated. Diverse degradation by-products were identified using GC-MS analysis. Eventually, the reusability tests confirmed that the synthesized pumice TiO2 catalyst had significant stability after 5 consecutive runs. (C) 2018 Elsevier Ltd. All rights reserved.Öğe Synthesis of ZrO2 nanoparticles on pumice and tuff for sonocatalytic degradation of rifampin(Elsevier Science Bv, 2018) Khataee, Alireza; Gholami, Peyman; Kayan, Berkant; Kalderis, Dimitrios; Dinpazhoh, Laleh; Akay, SemaZrO2-pumice and ZrO2-tuff nanocomposites were synthesized via a modified sol-gel method and used as efficient catalysts for sonocatalytic degradation of rifampin (RIF). The physico-chemical properties of the prepared catalysts were examined using XRF, SEM, EDX, FT-IR and BET analyses and compared to pure pumice and tuff samples. Subsequently, the efficacy of catalysts in degradation of RIF was assessed under various experimental conditions. Both ZrO2-pumice and ZrO2-tuff (1.5 g L-1) exhibited promising catalytic activity for sonocatalytic degradation of RIF at its initial concentration of 20 mg L-1, natural pH and under ultrasonic irradiation power of 300 W. In this condition, about 95% and 83% of RIF was removed through US/ZrO2-pumice and US/ZrO2-tuff processes, respectively. Furthermore, the influence of the addition of a number of scavengers, enhancers and gases on the degradation of RIF was studied. The pronounced degradation effectiveness of the catalysts under ultrasound irradiation could be assigned to their synergetic ability to produce reactive species and subsequent radical reactions. The intermediate products formed in the solution from degradation of RIF were also identified and a decomposition pathway was proposed using GC-MS, COD, TOC and IC analyses.Öğe Ultrasonic assisted photocatalytic process for degradation of ciprofloxacin using TiO2-Pd nanocomposite immobilized on pumice stone(Korean Society of Industrial Engineering Chemistry, 2021) Yekan Motlagh, Parisa; Akay, Sema; Kayan, Berkant; Khataee, AlirezaHerein, Pumice (PM)-TiO2-Pd nanocomposite as an efficient catalyst was prepared by modified sol-gel method and used for sonophotocatalytic removal of ciprofloxacin (CIP). Various analyses were used to investigate the properties of the catalysts. Based on the SEM results, the TiO2 and Pd nanoparticles on the PM surface were immobilized regularly without aggregation. Also, the crystalline structure and functional groups of PM-TiO2-Pd nanocomposite were identified successfully by XRD and FTIR analyses. The bandgap energy of 2.52, 3.17, and 3.29 eV were calculated for PM-TiO2-Pd, PM-TiO2, and PM indicating higher sonophotocatalytic activity of PM-TiO2-Pd nanocomposite. 79.44 % of CIP was removed within 120 min of treatment time using in the optimum condition ([PM-TiO2-Pd] = 0.5 g/L, [CIP]0 = 20 mg/L and pH = 6). By adding radical scavengers like EDTA, CrO3, formic acid, and enhancers like K2S2O8 and H2O2 the degradation efficiency was as follows respectively: 37.72, 31.71, 28.29, 88.78, and 72.43%. The reusability and stability of the composite after four consecutive runs was decreased only 9.44%. Also, 8 intermediate byproducts generated under sonophotocatalytic degradation of CIP by PM-TiO2-Pd nanocomposite were identified.Öğe Ultrasonic-assisted photocatalytic degradation of various organic contaminants using ZnO supported on a natural polymer of sporopollenin(Elsevier B.V., 2023) Yekan Motlagh, Parisa; Vahid, Behrouz; Akay, Sema; Kayan, Berkant; Yoon, Yeojoon; Khataee, AlirezaWater resource pollution by organic contaminants is an environmental issue of increasing concern. Here, sporopollenin/zinc oxide (SP/ZnO) was used as an environmentally friendly and durable catalyst for sonophotocatalytic treatment of three organic compounds: direct blue 25 (DB 25), levofloxacin (LEV), and dimethylphtalate (DMPh). The resulting catalyst had a 2.65 eV bandgap value and 9.81 m2/g surface area. The crystalline structure and functional groups of SP/ZnO were confirmed by X-ray diffraction (XRD) and Fourier transforms infrared spectroscopy (FTIR) analyses. After 120 min of the sonophotocatalysis, the degradation efficiencies of DB 25, LEV, and DMPh by SP/ZnO were 86.41, 75.88, and 62.54%, respectively, which were higher than that of the other investigated processes. The role of reactive oxygen species were investigated using various scavengers, enhancers, photoluminescence, and o-phenylenediamine. Owing to its stability, the catalyst exhibited good reusability after four consecutive cycles. In addition, the high integrity of the catalyst was confirmed by scanning electron microscopy (SEM), XRD, and FTIR analyses. After four consecutive examinations, the leaching of zinc in the aqueous phase was < 3 mg/L. Moreover, gas chromatography-mass spectrometry (GC–MS) analyses indicated that the contaminants were initially converted into cyclic compounds and then into aliphatic compounds, including carboxylic acids and animated products. Thus, this study synthesized an environmentally friendly and reusable SP/ZnO composite for the degradation of various organic pollutants using a sonophotocatalytic process.Öğe Ultrasound-assisted removal of Acid Red 17 using nanosized Fe3O4-loaded coffee waste hydrochar(Elsevier B.V., 2017) Khataee, Alireza; Kayan, Berkant; Kalderis, Dimitrios; Karimi, Atefeh; Akay, Sema; Konsolakis, MichalisThe Fe3O4-loaded coffee waste hydrochar (Fe3O4-CHC) was synthesized using a simple precipitation method. The as-prepared adsorbent was characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) and Fourier transform infrared spectroscopy (FT-IR). The EDX analysis indicated the presence of Fe in the structure of Fe3O4-CHC. The specific surface area of hydrochar increased from 17.2 to 34.7 m(2)/g after loading of Fe3O4 nanoparticles onto it. The prepared Fe3O4-CHC was used for removal of Acid Red 17 (AR17) through ultrasound-assisted process. The decolorization efficiency decreased from 100 to 74% with the increase in initial dye concentration and from 100 to 91 and 85% in the presence of NaCl and Na2SO4, respectively. The synthesized Fe3O4-CHC exhibited good stability in the repeated adsorption-desorption cycles. The high correlation coefficient (R-2 = 0.997) obtained from Langmuir model indicated that physical and monolayer adsorption of dye molecules occurred on the Fe3O4-CHC surface. Furthermore, the by-products generated through the degradation of AR17 was identified by gas chromatography mass spectrometry analysis.
