RE2−xEuxSn2O7 (RE:La3+ and Ho3+, x:0.10) materials were synthesized having both pholuminescence a... more RE2−xEuxSn2O7 (RE:La3+ and Ho3+, x:0.10) materials were synthesized having both pholuminescence and piezoelectric properties using with solid state reaction method at various reaction temperature and heating duration in open atmosphere. The thermal behaviors, crystal system, surface morphology, EDX analysis, Curie tempereture, photoluminescent properties, dielectric and piezoelectric properties of Eu3+ ions doped La2Sn2O7 and Ho2Sn2O7 were investigated. Both multi-functional smart materials show dielectric, piezoelectric properties and photoluminescence properties which is responsible transitions of doping Eu3+ ions.
A series of compounds with the general formula RE1.90Y0.10Zr2O7 (where RE includes Eu, Sm and Y ... more A series of compounds with the general formula RE1.90Y0.10Zr2O7 (where RE includes Eu, Sm and Y includes La, Sm, Eu) were synthesized using a solid-state reaction method. These compounds were analyzed through differential thermal analysis (DTA), thermogravimetric analysis (TG), X-ray powder diffraction (XRD), and scanning electron microscopy (SEM). Additionally, their dielectric constant, loss tangent, piezoelectric charge constant, and Curie temperature were measured using an LCR meter, d33 meter, and TG/DTA. X-ray diffraction results indicated that all samples crystallize in a cubic pyrochlore structure. Photoluminescence studies revealed that Eu3+ ions predominantly contribute to the emission, whether as activators or co-activators. Among the phosphors, Eu1.90La0.10Zr2O7 exhibited a significantly longer afterglow compared to Sm1.90Eu0.10Zr2O7 and Eu1.90Sm0.10Zr2O7. Conversely, Sm1.90Eu0.10Zr2O7 demonstrated luminescence intensity that was 20 times greater than that of Eu1.90La0.10Zr2O7 and Eu1.90Sm0.10Zr2O7. Furthermore, all samples with characteristic Eu3+ emissions also exhibited piezoelectric properties. Curie temperature (Tc) of Eu1.90La0.10Zr2O7, Sm1.90Eu0.10Zr2O7, and Eu1.90Sm0.10Zr2O7 are 770°C, 830°C, and 845°C, respectively. Therefore, Sm3+ ion improves piezoelectric properties and Curie temperature when doping into the Eu2Zr2O7 host crystal.
The effect of sintering soaking time on the dielectric, piezoelectric, and structural properties ... more The effect of sintering soaking time on the dielectric, piezoelectric, and structural properties of PMN-PT-PMS [Pb(Mg1/3Nb2/3)O3-PbTiO3-Pb(Mn1/3Sb2/3)O3] ceramics was systematically investigated. High density samples were prepared using solid-state sintering technique with different soaking times (60-150 min). Rhombohedral perovskite structure was the dominant phase for all soaking times, confirmed by XRD analysis. However, the pure perovskite structure could not be preserved at sintering times over 120 min. SEM micrographs indicated that homogeneous microstructures were obtained for all soaking times and the grain and pore sizes increased slightly with longer sintering time. Dielectric and piezoelectric test results showed that the optimum value of dielectric constant, electromechanical coupling factor, and piezoelectric strain coefficient was obtained for PMN-PT-PMS when sintered for 90 min. Ceramic samples with high density and perovskite structure prepared by proper sintering condition yielded high dielectric and piezoelectric response.
In this study, technical properties of 3 different clays from Doğanhisar/Konya region were determ... more In this study, technical properties of 3 different clays from Doğanhisar/Konya region were determined to investigate their usage potential in glazed porcelain tile production of Yurtbay Seramik Company. For this purpose, mineralogical, chemical, and thermal characterization of the clays was performed using XRD, XRF, and dilatometric analyses. Furthermore, the use of Konya clays instead of Ukrainian clay in the porcelain tile compositions was studied. Ukrainian clay was substituted gradually by Konya clays in different tile body recipes. Samples, having these new compositions, were prepared by uniaxial pressing, and exposing to a firing regime at 1190 °C for 55 min. Fired samples were then characterized based on their dry strength, fired strength, water absorption, color, and firing shrinkage properties. Experimental results proved that the use of Konya clays instead of Ukrainian clay increased the strength of fired bodies. It would be possible to use Konya clays in tile bodies up to 6 wt.% with some modifications in the body compositions and firing regime.
Journal of Dispersion Science and Technology, 2022
In this study, it was aimed to utilize red mud (RM, an industrial waste material) as a nanofiber ... more In this study, it was aimed to utilize red mud (RM, an industrial waste material) as a nanofiber adsorbent in arsenate removal from waste water. RM, obtained from Seydişehir Aluminum Plant (Konya, Turkey), was leached using nitric acid in order to recover metallic elements such as Fe, Al, and Ti. Oxides and hydroxides of these elements are known to have a high affinity toward arsenic. Metallic salt solution, obtained after leaching treatment, was used to produce nanofibers via electrospinning method to get an adsorbent material with high surface area. Compositional, phase structural, microstructural, and thermal analyses were conducted using AAS, XRF, XRD, SEM, and DT/TGA. Organic removal from nanofibers were conducted at 600 °C for 5 h, based on the DT/TGA results. After heat treatment, nanofibers with diameters ranging from 45 to 58 nm were obtained. Performance of nanofibers in As(V) (arsenate) removal from waste water was also evaluated with different amount of nanofibers (1-3 mg/L), arsenate concentration (5-100 ppm), and contact time (10-120 min). Experimental results showed that the fastest and highest removal efficiency (∼80.2%) was obtained for 3 mg/L nanofiber and 10 ppm arsenate concentration at 90 min. Kinetic studies revealed that the pseudo-second-order kinetic model was dominantly active in the adsorption process.
Abstract Effective charge separation is of importance in increasing the efficiency of photocataly... more Abstract Effective charge separation is of importance in increasing the efficiency of photocatalysts used in removing common industrial toxic dye in wastewater. The alternative spatial electric field produced by the piezoelectric effect, when combined with the semiconductor photocatalyst, can significantly accelerate the charge separation. In this study, lead magnesium niobate-lead titanate 0.65Pb(Mg1/3Nb2/3)O3-0.35PbTiO3 (PMN-PT) nanoparticles and tin dioxide (SnO2) nanofibers were synthesized using colloidal coating method and electrospinning synthesis methods, respectively. PMN-PT@SnO2 composites were prepared as a novel heterostructured photocatalyst for the degradation of dye molecules in wastewater. Degradation of an organic dye pollutant in the presence of SnO2 nanofibers or PMN-PT@SnO2 nanocomposite photocatalysts were investigated under magnetic stirring and/or ultrasonic wave vibration conditions. Morphologies and electrical properties of pure and composite samples were also investigated. It was observed that the photocatalytic efficiency of PMN-PT@SnO2 piezoelectric-based photocatalysts could be increased by about 29% in the magnetic stirring and 32% in the ultrasonic wave vibration, respectively.
In this study, Yb1.98Lu0.02Sn2O7 and Yb1.90Eu0.10Sn2O7 were produced by solid state reaction meth... more In this study, Yb1.98Lu0.02Sn2O7 and Yb1.90Eu0.10Sn2O7 were produced by solid state reaction method. The characterization of the samples was achieved by thermal analysis (TG/DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM-EDX), photoluminescence spectrophotometer (PL), LCR-meter and d33-m. Thermal behaviours, crystal structures, surface morphology, elemental analysis, photoluminescence properties, deielectric and piezoelectric properties and Curie temperature of Yb1.98Lu0.02Sn2O7 and Yb1.90Eu0.10Sn2O7 were investigated. X-ray diffraction datas indicate that the formation of cubic crystal structures were achieved for both materials. The photoluminescence and electrical measurements showed that Yb1.98Lu0.02Sn2O7 and Yb1.90Eu0.10Sn2O7 have both luminescent and piezoelectric properties
Abstract This paper describes an efficient process of recovering valuable metals from a copper an... more Abstract This paper describes an efficient process of recovering valuable metals from a copper anode slime sample using green chemicals such as choline chloride (ChCl) based deep eutectic solvents (DESs). The leaching agents include ChCl-urea, ChCl-ethylene glycol, ChCl-urea-ethylene glycol and ChCl/urea-deionized water in a 1:2, 1:2, 1:0.5:1.5, and 1:1 ratio, respectively. Prior to leaching experiments, chemical and mineralogical characterization of copper anode slime was performed. Considerable amount of precious metals was detected in the copper anode slime by chemical analysis. The main phases of copper anode slime detected by XRD and SEM/EDX analysis were namely Cu2O, SnO2, and, PbSO4. After leaching experiments, 97% of copper was recovered from the copper anode slime using ChCl-urea under an optimum condition at 95 °C of reaction temperature, 4 h reaction duration and, 1/25 g/mL solid/liquid ratio. The results showed that 91% of silver was extracted from the anode slime under the optimum condition with ChCl-urea DES composition, 95 °C reaction temperature, 48 h reaction duration, and 1/10 solid/liquid ratio. Gold was not leachable in the experiment using ChCl based DES with hydrogen bonding reagents such as urea and ethylene glycol. Moreover, the results revealed that PbSO4 was very soluble in DES prepared by ChCl and urea.
Bu calismada, pirometalurjik yontemle metalik bakir uretiminin elektrokazanim asamasinda ortaya c... more Bu calismada, pirometalurjik yontemle metalik bakir uretiminin elektrokazanim asamasinda ortaya cikan anot camurundan bakir geri kazanimi uzerine cevre ve insan sagligina duyarli dusuk otektik noktali cozucu (DES) kullanimi arastirilmistir. Taguchi optimizasyon yontemi kullanilarak lic sicakligi, lic suresi ve kati/sivi orani deneysel parametrelerin bakir geri kazanimi uzerine etkisi incelenmistir. Kolin klorur (ChCl) ve urenin 1:2 molar oranda karistirilmasiyla hazirlanan DES cozucusu ile yapilan lic islemleri sonunda optimum sartlar; 95 oC’lic sicakligi, 2 saat lic suresi ve 1/20 kati/sivi orani olarak belirlenmis ve bu sartlarda %98 bakir geri kazanimi elde edilmistir. Yapilan bu calisma ile ChCl-ure karisimiyla hazirlanan DES cozucusunun anot camurundan bakir geri kazanimi icin cevreci bir cozucu adayi olabilecegi ortaya konulmustur.
Abstract In this study, it is aimed to develop a hybrid bi-functional material which will enable ... more Abstract In this study, it is aimed to develop a hybrid bi-functional material which will enable the removal of common industrial toxic dyes in wastewater via adsorption/photocatalysis reactions. For this purpose, WO3 nanofibers and CuO particles were synthesized using electrospinning and hydrothermal synthesis methods, respectively. WO3 nanofibers were combined with different amounts of CuO particles by a simple dispersion dropping technique. Structural, morphological and optical properties of the samples were characterized by XRD, Raman, FT-IR, XPS, SEM, TEM, UV–vis, and Mott-Schottky measurements. The adsorption capacity and photocatalytic behavior of the hybrids were compared with pure WO3 nanofibers under visible light irradiations. Experimental results have shown that the hybrid samples containing only 0.75 wt.% CuO could adsorb 38.4% higher and degraded 25.7% faster the methylene blue dye compared to pure WO3 nanofibers. This improved adsorption and degradation behavior of the hybrids were discussed in detail based on the structural properties, Z-scheme heterojunction formation, and using Langmuir/Freundlich isotherm and kinetic models.
International Journal of Applied Ceramic Technology, 2020
In this study, CuO-SnO 2 p-n type heterostructures were produced and tested for the degradation o... more In this study, CuO-SnO 2 p-n type heterostructures were produced and tested for the degradation of methylene blue and 4-nitrophenol under visible light irradiation. CuO particles were produced in plate-like morphology using hydrothermal synthesis. SnO 2 nanofibers were obtained by electrospinning. Structural, morphological, optical and semiconducting property characterization of heterostructured CuO-SnO 2 and individual phases were performed. The photocatalytic activity was found to change depending on the amount of CuO particles in heterostructured samples. Among others, the sample with 0.35 wt.% CuO-SnO 2 showed the highest photocatalytic efficiency with a degradation rate constant ~2 h-1. Active specie scavenger tests revealed that the decomposition reaction occurs through direct oxidation mechanism by the holes in the valence band of SnO 2 in pure samples whereas in CuO-SnO 2 samples and radicals also form • 2 O • OH and involve in the reactions. Further, the photocatalytic degradation mechanism was revealed using relative band potentials and p-n junctions of the heterostructured photocatalyst.
Y2 Zr2 O7 -doped with Eu3+ and Sm3+ phosphors were prepared for the first time as multifunctional... more Y2 Zr2 O7 -doped with Eu3+ and Sm3+ phosphors were prepared for the first time as multifunctional smart materials using a solid-state reaction method at 1400o C. Thermal behaviour, crystal structure, surface morphology, and elemental analysis were characterized using thermogravimetric (TG) and differential thermal (DTA) analyses, X-ray diffraction (XRD) and scanning electron microscope equipped with energy-dispersive X-ray spectroscopy (SEM-EDX). Experimental results revealed that both phosphors have a pyrochlore structure with a cubic crystal system. Photoluminescence properties were also measured and red emission was observed from Y1.90 Eu0.10 Zr2 O7 and Y1.90 Sm0.10 Zr2 O7 phosphors. Dielectric constant, loss tangent, piezoelectric charge constant, and Curie temperature of all the samples were determined using an LCR-meter, d33 -meter, and TG/DTA. Eu doping in Y2 Zr2 O7 resulted in a high dielectric constant (9.61) and low loss tangent (1.67%) values, whereas high piezoelectric charge constant (0.68 pC/N) and high Curie temperature (820°C) could be obtained using Sm-doped Y2 Zr2 O7 .
International Journal of Applied Ceramic Technology, 2020
nominal compositions, oxide compounds were prepared by solid-state reaction method. X-ray diffrac... more nominal compositions, oxide compounds were prepared by solid-state reaction method. X-ray diffraction measurements show that molybdenum oxides formed cubic phase except for Nd 1.90 Er 0.10 Mo 2 O 7. Scanning electron microscopy was used to observe their microstructure and elemental analysis. The photoluminescence properties of the materials, the excitation and emission spectra and the decay curve, were investigated using photoluminescence spectrophotometer. Dielectric and piezoelectric properties of the ptoluminescent materials, the dielectric constant, dielectric loss, piezoelectric constant, and Curie temperature, were measured for electrical characterization.
Materials Science in Semiconductor Processing, 2020
CuO-TiO 2 p-n heterostructures with tailored compositions were fabricated using hydrothermally de... more CuO-TiO 2 p-n heterostructures with tailored compositions were fabricated using hydrothermally derived platelike CuO particles and electrospun TiO 2 fibers and further applied for photocatalytic degradation of typical water pollutants such as methylene blue and 4-Nitrophenol. Effect of varying amount of CuO decoration on TiO 2 fibers on microstructure, on phase constitution, and on the optical and photocatalytic properties was investigated. Photocatalytic testing results indicated that the degradation behavior was affected by the amount of CuO particles in the samples. Among all compositions studied, the samples with 1.25 and 0.5 wt% CuO exhibited the highest photocatalytic efficiency under UV (3.3 times higher compared to pure TiO 2) and visible light irradiations (3.75 times higher compared to pure TiO 2), respectively. The improved photocatalytic performance compared to pure fibers was attributed to particle-fiber architecture, increased and extended light harvesting ability, more efficient charge separation due to staggered band structure and p-n junctions of the heterostructured samples.
International Journal of Applied Ceramic Technology, 2019
In this study, TiO 2 nanofibers were fabricated via electrospinning method followed by air anneal... more In this study, TiO 2 nanofibers were fabricated via electrospinning method followed by air annealing. Then, Ti-necessity in the conventional hydrothermal synthesis of BaTiO 3 stoichiometry was supplied by using these nanofibers. The microstructural and compositional properties of BaTiO 3 nanoparticles were studied using SEM, TEM, XRD, XPS, and Raman spectroscopy. Structural analysis showed that the cubic symmetry was the dominant one in the BaTiO 3 nanoparticles whereas Raman indicated coexistence with the tetragonal polymorph. The nanoparticles displayed higher photocatalytic reactivity under UV-A light compared to visible irradiation during decomposition of methylene blue dye and reached 24.2 % and 18.8 % degradation, respectively after 1 h. Further, the dielectric properties were investigated using sintered compacts of these nanoparticles. Among the employed Accepted Article This article is protected by copyright. All rights reserved. temperatures for sintering, highest relative density (90 %) and dielectric constant (2165 at 1 MHz) was obtained after 1250 C and 5 h. The study revealed that electrospun TiO 2 nanofiber precursor can successfully be used for the production of nano-scale barium titanate particles suitable for various applications.
Tetragonal BaTiO 3 nanoparticles have been hydrothermally synthesized using the electrospun TiO 2... more Tetragonal BaTiO 3 nanoparticles have been hydrothermally synthesized using the electrospun TiO 2 nanofibers as the Ti-source. Microstructural and compositional analyses have been carried out using XRD, SEM, TEM, XPS, and Raman spectroscopy. Characterization studies confirmed that the BaTiO 3 nanoparticles had a tetragonal structure with an average particle size of 100 nm. Photocatalytic activities of the nanoparticles were investigated via the decolorization of methylene blue dye aqueous solutions under visible light and UV-A irradiations. The degradation efficiency reached to 13 and 35 % after exposing to light for 60 min with visible and UV-sources, respectively. Effect of sintering temperatures on the dielectric properties was also investigated. Among all the sintering temperatures employed, 1473 K was the optimum sintering temperature for these ceramics in terms of high relative density (95.3 %), high dielectric constant (3162 at 1 MHz), and low loss tangent (15x10-3 at 1 MHz). Experimental results showed that electrospun TiO 2 fibers can be used as a precursor template to produce nano-scale BaTiO 3 particles which are suitable for various applications such as photocatalysis and capacitors.
Motivated by the need of piezoelectric ceramics with enhanced piezoelectric properties, we invest... more Motivated by the need of piezoelectric ceramics with enhanced piezoelectric properties, we investigated the effects of Sr addition on the structural, dielectric and piezoelectric properties of PMN-PT ceramics. The synthesis of (1-x)[(Pb1−ySry)(Mg1/3Nb2/3)O3]-x(Pb1−ySryTiO3) (PsMN–PsT) (y: 0 − 0.10, x: 0.35 – 0.40) ceramics was carried out by the colloidal coating method to distribute Sr uniformly in PMN and PT respectively. When x=0.35, it was found that y=0.02 gave the optimal piezoelectric properties. Furthermore, by keeping y=0.02 and varying x, it was found that x=0.37 gave even better piezoelectric properties with the optimal piezoelectric strain coefficient d33 (630 pC/N), piezoelectric coupling factor kp (0.52), dielectric constant εr (4000), and Curie temperature Tc (210 °C), exhibiting great potential for actuator and sensor applications.
RE2−xEuxSn2O7 (RE:La3+ and Ho3+, x:0.10) materials were synthesized having both pholuminescence a... more RE2−xEuxSn2O7 (RE:La3+ and Ho3+, x:0.10) materials were synthesized having both pholuminescence and piezoelectric properties using with solid state reaction method at various reaction temperature and heating duration in open atmosphere. The thermal behaviors, crystal system, surface morphology, EDX analysis, Curie tempereture, photoluminescent properties, dielectric and piezoelectric properties of Eu3+ ions doped La2Sn2O7 and Ho2Sn2O7 were investigated. Both multi-functional smart materials show dielectric, piezoelectric properties and photoluminescence properties which is responsible transitions of doping Eu3+ ions.
A series of compounds with the general formula RE1.90Y0.10Zr2O7 (where RE includes Eu, Sm and Y ... more A series of compounds with the general formula RE1.90Y0.10Zr2O7 (where RE includes Eu, Sm and Y includes La, Sm, Eu) were synthesized using a solid-state reaction method. These compounds were analyzed through differential thermal analysis (DTA), thermogravimetric analysis (TG), X-ray powder diffraction (XRD), and scanning electron microscopy (SEM). Additionally, their dielectric constant, loss tangent, piezoelectric charge constant, and Curie temperature were measured using an LCR meter, d33 meter, and TG/DTA. X-ray diffraction results indicated that all samples crystallize in a cubic pyrochlore structure. Photoluminescence studies revealed that Eu3+ ions predominantly contribute to the emission, whether as activators or co-activators. Among the phosphors, Eu1.90La0.10Zr2O7 exhibited a significantly longer afterglow compared to Sm1.90Eu0.10Zr2O7 and Eu1.90Sm0.10Zr2O7. Conversely, Sm1.90Eu0.10Zr2O7 demonstrated luminescence intensity that was 20 times greater than that of Eu1.90La0.10Zr2O7 and Eu1.90Sm0.10Zr2O7. Furthermore, all samples with characteristic Eu3+ emissions also exhibited piezoelectric properties. Curie temperature (Tc) of Eu1.90La0.10Zr2O7, Sm1.90Eu0.10Zr2O7, and Eu1.90Sm0.10Zr2O7 are 770°C, 830°C, and 845°C, respectively. Therefore, Sm3+ ion improves piezoelectric properties and Curie temperature when doping into the Eu2Zr2O7 host crystal.
The effect of sintering soaking time on the dielectric, piezoelectric, and structural properties ... more The effect of sintering soaking time on the dielectric, piezoelectric, and structural properties of PMN-PT-PMS [Pb(Mg1/3Nb2/3)O3-PbTiO3-Pb(Mn1/3Sb2/3)O3] ceramics was systematically investigated. High density samples were prepared using solid-state sintering technique with different soaking times (60-150 min). Rhombohedral perovskite structure was the dominant phase for all soaking times, confirmed by XRD analysis. However, the pure perovskite structure could not be preserved at sintering times over 120 min. SEM micrographs indicated that homogeneous microstructures were obtained for all soaking times and the grain and pore sizes increased slightly with longer sintering time. Dielectric and piezoelectric test results showed that the optimum value of dielectric constant, electromechanical coupling factor, and piezoelectric strain coefficient was obtained for PMN-PT-PMS when sintered for 90 min. Ceramic samples with high density and perovskite structure prepared by proper sintering condition yielded high dielectric and piezoelectric response.
In this study, technical properties of 3 different clays from Doğanhisar/Konya region were determ... more In this study, technical properties of 3 different clays from Doğanhisar/Konya region were determined to investigate their usage potential in glazed porcelain tile production of Yurtbay Seramik Company. For this purpose, mineralogical, chemical, and thermal characterization of the clays was performed using XRD, XRF, and dilatometric analyses. Furthermore, the use of Konya clays instead of Ukrainian clay in the porcelain tile compositions was studied. Ukrainian clay was substituted gradually by Konya clays in different tile body recipes. Samples, having these new compositions, were prepared by uniaxial pressing, and exposing to a firing regime at 1190 °C for 55 min. Fired samples were then characterized based on their dry strength, fired strength, water absorption, color, and firing shrinkage properties. Experimental results proved that the use of Konya clays instead of Ukrainian clay increased the strength of fired bodies. It would be possible to use Konya clays in tile bodies up to 6 wt.% with some modifications in the body compositions and firing regime.
Journal of Dispersion Science and Technology, 2022
In this study, it was aimed to utilize red mud (RM, an industrial waste material) as a nanofiber ... more In this study, it was aimed to utilize red mud (RM, an industrial waste material) as a nanofiber adsorbent in arsenate removal from waste water. RM, obtained from Seydişehir Aluminum Plant (Konya, Turkey), was leached using nitric acid in order to recover metallic elements such as Fe, Al, and Ti. Oxides and hydroxides of these elements are known to have a high affinity toward arsenic. Metallic salt solution, obtained after leaching treatment, was used to produce nanofibers via electrospinning method to get an adsorbent material with high surface area. Compositional, phase structural, microstructural, and thermal analyses were conducted using AAS, XRF, XRD, SEM, and DT/TGA. Organic removal from nanofibers were conducted at 600 °C for 5 h, based on the DT/TGA results. After heat treatment, nanofibers with diameters ranging from 45 to 58 nm were obtained. Performance of nanofibers in As(V) (arsenate) removal from waste water was also evaluated with different amount of nanofibers (1-3 mg/L), arsenate concentration (5-100 ppm), and contact time (10-120 min). Experimental results showed that the fastest and highest removal efficiency (∼80.2%) was obtained for 3 mg/L nanofiber and 10 ppm arsenate concentration at 90 min. Kinetic studies revealed that the pseudo-second-order kinetic model was dominantly active in the adsorption process.
Abstract Effective charge separation is of importance in increasing the efficiency of photocataly... more Abstract Effective charge separation is of importance in increasing the efficiency of photocatalysts used in removing common industrial toxic dye in wastewater. The alternative spatial electric field produced by the piezoelectric effect, when combined with the semiconductor photocatalyst, can significantly accelerate the charge separation. In this study, lead magnesium niobate-lead titanate 0.65Pb(Mg1/3Nb2/3)O3-0.35PbTiO3 (PMN-PT) nanoparticles and tin dioxide (SnO2) nanofibers were synthesized using colloidal coating method and electrospinning synthesis methods, respectively. PMN-PT@SnO2 composites were prepared as a novel heterostructured photocatalyst for the degradation of dye molecules in wastewater. Degradation of an organic dye pollutant in the presence of SnO2 nanofibers or PMN-PT@SnO2 nanocomposite photocatalysts were investigated under magnetic stirring and/or ultrasonic wave vibration conditions. Morphologies and electrical properties of pure and composite samples were also investigated. It was observed that the photocatalytic efficiency of PMN-PT@SnO2 piezoelectric-based photocatalysts could be increased by about 29% in the magnetic stirring and 32% in the ultrasonic wave vibration, respectively.
In this study, Yb1.98Lu0.02Sn2O7 and Yb1.90Eu0.10Sn2O7 were produced by solid state reaction meth... more In this study, Yb1.98Lu0.02Sn2O7 and Yb1.90Eu0.10Sn2O7 were produced by solid state reaction method. The characterization of the samples was achieved by thermal analysis (TG/DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM-EDX), photoluminescence spectrophotometer (PL), LCR-meter and d33-m. Thermal behaviours, crystal structures, surface morphology, elemental analysis, photoluminescence properties, deielectric and piezoelectric properties and Curie temperature of Yb1.98Lu0.02Sn2O7 and Yb1.90Eu0.10Sn2O7 were investigated. X-ray diffraction datas indicate that the formation of cubic crystal structures were achieved for both materials. The photoluminescence and electrical measurements showed that Yb1.98Lu0.02Sn2O7 and Yb1.90Eu0.10Sn2O7 have both luminescent and piezoelectric properties
Abstract This paper describes an efficient process of recovering valuable metals from a copper an... more Abstract This paper describes an efficient process of recovering valuable metals from a copper anode slime sample using green chemicals such as choline chloride (ChCl) based deep eutectic solvents (DESs). The leaching agents include ChCl-urea, ChCl-ethylene glycol, ChCl-urea-ethylene glycol and ChCl/urea-deionized water in a 1:2, 1:2, 1:0.5:1.5, and 1:1 ratio, respectively. Prior to leaching experiments, chemical and mineralogical characterization of copper anode slime was performed. Considerable amount of precious metals was detected in the copper anode slime by chemical analysis. The main phases of copper anode slime detected by XRD and SEM/EDX analysis were namely Cu2O, SnO2, and, PbSO4. After leaching experiments, 97% of copper was recovered from the copper anode slime using ChCl-urea under an optimum condition at 95 °C of reaction temperature, 4 h reaction duration and, 1/25 g/mL solid/liquid ratio. The results showed that 91% of silver was extracted from the anode slime under the optimum condition with ChCl-urea DES composition, 95 °C reaction temperature, 48 h reaction duration, and 1/10 solid/liquid ratio. Gold was not leachable in the experiment using ChCl based DES with hydrogen bonding reagents such as urea and ethylene glycol. Moreover, the results revealed that PbSO4 was very soluble in DES prepared by ChCl and urea.
Bu calismada, pirometalurjik yontemle metalik bakir uretiminin elektrokazanim asamasinda ortaya c... more Bu calismada, pirometalurjik yontemle metalik bakir uretiminin elektrokazanim asamasinda ortaya cikan anot camurundan bakir geri kazanimi uzerine cevre ve insan sagligina duyarli dusuk otektik noktali cozucu (DES) kullanimi arastirilmistir. Taguchi optimizasyon yontemi kullanilarak lic sicakligi, lic suresi ve kati/sivi orani deneysel parametrelerin bakir geri kazanimi uzerine etkisi incelenmistir. Kolin klorur (ChCl) ve urenin 1:2 molar oranda karistirilmasiyla hazirlanan DES cozucusu ile yapilan lic islemleri sonunda optimum sartlar; 95 oC’lic sicakligi, 2 saat lic suresi ve 1/20 kati/sivi orani olarak belirlenmis ve bu sartlarda %98 bakir geri kazanimi elde edilmistir. Yapilan bu calisma ile ChCl-ure karisimiyla hazirlanan DES cozucusunun anot camurundan bakir geri kazanimi icin cevreci bir cozucu adayi olabilecegi ortaya konulmustur.
Abstract In this study, it is aimed to develop a hybrid bi-functional material which will enable ... more Abstract In this study, it is aimed to develop a hybrid bi-functional material which will enable the removal of common industrial toxic dyes in wastewater via adsorption/photocatalysis reactions. For this purpose, WO3 nanofibers and CuO particles were synthesized using electrospinning and hydrothermal synthesis methods, respectively. WO3 nanofibers were combined with different amounts of CuO particles by a simple dispersion dropping technique. Structural, morphological and optical properties of the samples were characterized by XRD, Raman, FT-IR, XPS, SEM, TEM, UV–vis, and Mott-Schottky measurements. The adsorption capacity and photocatalytic behavior of the hybrids were compared with pure WO3 nanofibers under visible light irradiations. Experimental results have shown that the hybrid samples containing only 0.75 wt.% CuO could adsorb 38.4% higher and degraded 25.7% faster the methylene blue dye compared to pure WO3 nanofibers. This improved adsorption and degradation behavior of the hybrids were discussed in detail based on the structural properties, Z-scheme heterojunction formation, and using Langmuir/Freundlich isotherm and kinetic models.
International Journal of Applied Ceramic Technology, 2020
In this study, CuO-SnO 2 p-n type heterostructures were produced and tested for the degradation o... more In this study, CuO-SnO 2 p-n type heterostructures were produced and tested for the degradation of methylene blue and 4-nitrophenol under visible light irradiation. CuO particles were produced in plate-like morphology using hydrothermal synthesis. SnO 2 nanofibers were obtained by electrospinning. Structural, morphological, optical and semiconducting property characterization of heterostructured CuO-SnO 2 and individual phases were performed. The photocatalytic activity was found to change depending on the amount of CuO particles in heterostructured samples. Among others, the sample with 0.35 wt.% CuO-SnO 2 showed the highest photocatalytic efficiency with a degradation rate constant ~2 h-1. Active specie scavenger tests revealed that the decomposition reaction occurs through direct oxidation mechanism by the holes in the valence band of SnO 2 in pure samples whereas in CuO-SnO 2 samples and radicals also form • 2 O • OH and involve in the reactions. Further, the photocatalytic degradation mechanism was revealed using relative band potentials and p-n junctions of the heterostructured photocatalyst.
Y2 Zr2 O7 -doped with Eu3+ and Sm3+ phosphors were prepared for the first time as multifunctional... more Y2 Zr2 O7 -doped with Eu3+ and Sm3+ phosphors were prepared for the first time as multifunctional smart materials using a solid-state reaction method at 1400o C. Thermal behaviour, crystal structure, surface morphology, and elemental analysis were characterized using thermogravimetric (TG) and differential thermal (DTA) analyses, X-ray diffraction (XRD) and scanning electron microscope equipped with energy-dispersive X-ray spectroscopy (SEM-EDX). Experimental results revealed that both phosphors have a pyrochlore structure with a cubic crystal system. Photoluminescence properties were also measured and red emission was observed from Y1.90 Eu0.10 Zr2 O7 and Y1.90 Sm0.10 Zr2 O7 phosphors. Dielectric constant, loss tangent, piezoelectric charge constant, and Curie temperature of all the samples were determined using an LCR-meter, d33 -meter, and TG/DTA. Eu doping in Y2 Zr2 O7 resulted in a high dielectric constant (9.61) and low loss tangent (1.67%) values, whereas high piezoelectric charge constant (0.68 pC/N) and high Curie temperature (820°C) could be obtained using Sm-doped Y2 Zr2 O7 .
International Journal of Applied Ceramic Technology, 2020
nominal compositions, oxide compounds were prepared by solid-state reaction method. X-ray diffrac... more nominal compositions, oxide compounds were prepared by solid-state reaction method. X-ray diffraction measurements show that molybdenum oxides formed cubic phase except for Nd 1.90 Er 0.10 Mo 2 O 7. Scanning electron microscopy was used to observe their microstructure and elemental analysis. The photoluminescence properties of the materials, the excitation and emission spectra and the decay curve, were investigated using photoluminescence spectrophotometer. Dielectric and piezoelectric properties of the ptoluminescent materials, the dielectric constant, dielectric loss, piezoelectric constant, and Curie temperature, were measured for electrical characterization.
Materials Science in Semiconductor Processing, 2020
CuO-TiO 2 p-n heterostructures with tailored compositions were fabricated using hydrothermally de... more CuO-TiO 2 p-n heterostructures with tailored compositions were fabricated using hydrothermally derived platelike CuO particles and electrospun TiO 2 fibers and further applied for photocatalytic degradation of typical water pollutants such as methylene blue and 4-Nitrophenol. Effect of varying amount of CuO decoration on TiO 2 fibers on microstructure, on phase constitution, and on the optical and photocatalytic properties was investigated. Photocatalytic testing results indicated that the degradation behavior was affected by the amount of CuO particles in the samples. Among all compositions studied, the samples with 1.25 and 0.5 wt% CuO exhibited the highest photocatalytic efficiency under UV (3.3 times higher compared to pure TiO 2) and visible light irradiations (3.75 times higher compared to pure TiO 2), respectively. The improved photocatalytic performance compared to pure fibers was attributed to particle-fiber architecture, increased and extended light harvesting ability, more efficient charge separation due to staggered band structure and p-n junctions of the heterostructured samples.
International Journal of Applied Ceramic Technology, 2019
In this study, TiO 2 nanofibers were fabricated via electrospinning method followed by air anneal... more In this study, TiO 2 nanofibers were fabricated via electrospinning method followed by air annealing. Then, Ti-necessity in the conventional hydrothermal synthesis of BaTiO 3 stoichiometry was supplied by using these nanofibers. The microstructural and compositional properties of BaTiO 3 nanoparticles were studied using SEM, TEM, XRD, XPS, and Raman spectroscopy. Structural analysis showed that the cubic symmetry was the dominant one in the BaTiO 3 nanoparticles whereas Raman indicated coexistence with the tetragonal polymorph. The nanoparticles displayed higher photocatalytic reactivity under UV-A light compared to visible irradiation during decomposition of methylene blue dye and reached 24.2 % and 18.8 % degradation, respectively after 1 h. Further, the dielectric properties were investigated using sintered compacts of these nanoparticles. Among the employed Accepted Article This article is protected by copyright. All rights reserved. temperatures for sintering, highest relative density (90 %) and dielectric constant (2165 at 1 MHz) was obtained after 1250 C and 5 h. The study revealed that electrospun TiO 2 nanofiber precursor can successfully be used for the production of nano-scale barium titanate particles suitable for various applications.
Tetragonal BaTiO 3 nanoparticles have been hydrothermally synthesized using the electrospun TiO 2... more Tetragonal BaTiO 3 nanoparticles have been hydrothermally synthesized using the electrospun TiO 2 nanofibers as the Ti-source. Microstructural and compositional analyses have been carried out using XRD, SEM, TEM, XPS, and Raman spectroscopy. Characterization studies confirmed that the BaTiO 3 nanoparticles had a tetragonal structure with an average particle size of 100 nm. Photocatalytic activities of the nanoparticles were investigated via the decolorization of methylene blue dye aqueous solutions under visible light and UV-A irradiations. The degradation efficiency reached to 13 and 35 % after exposing to light for 60 min with visible and UV-sources, respectively. Effect of sintering temperatures on the dielectric properties was also investigated. Among all the sintering temperatures employed, 1473 K was the optimum sintering temperature for these ceramics in terms of high relative density (95.3 %), high dielectric constant (3162 at 1 MHz), and low loss tangent (15x10-3 at 1 MHz). Experimental results showed that electrospun TiO 2 fibers can be used as a precursor template to produce nano-scale BaTiO 3 particles which are suitable for various applications such as photocatalysis and capacitors.
Motivated by the need of piezoelectric ceramics with enhanced piezoelectric properties, we invest... more Motivated by the need of piezoelectric ceramics with enhanced piezoelectric properties, we investigated the effects of Sr addition on the structural, dielectric and piezoelectric properties of PMN-PT ceramics. The synthesis of (1-x)[(Pb1−ySry)(Mg1/3Nb2/3)O3]-x(Pb1−ySryTiO3) (PsMN–PsT) (y: 0 − 0.10, x: 0.35 – 0.40) ceramics was carried out by the colloidal coating method to distribute Sr uniformly in PMN and PT respectively. When x=0.35, it was found that y=0.02 gave the optimal piezoelectric properties. Furthermore, by keeping y=0.02 and varying x, it was found that x=0.37 gave even better piezoelectric properties with the optimal piezoelectric strain coefficient d33 (630 pC/N), piezoelectric coupling factor kp (0.52), dielectric constant εr (4000), and Curie temperature Tc (210 °C), exhibiting great potential for actuator and sensor applications.
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Papers by Volkan Kalem