Makale Koleksiyonu

Bu koleksiyon için kalıcı URI

https://hdl.handle.net/11491/2134

Listeleniyor 1 - 20 / 133

Adsorption of Methyl Violet 2B and Direct Red 28 From Single and Binary Solution Using a Magnetic Zeolite/TiO2/Fe3O4 Nanocomposite
(SPRINGER HEIDELBERG, 2023) Fındık, Serap
In this research, a magnetic adsorbent called ZTF was synthesized by combining zeolite and TiO2. Various analytical techniques including SEM, EDS, BET, FTIR, XRD, Zeta potential, and VSM were utilized to characterize the structure of ZTF. In order to understand the pollutant removal performance of the ZTF, Methyl violet 2B (MV-2B) and Direct red 28 (DR-28) were chosen as target pollutants in adsorption experiments. The effects of the contact time, initial dye concentration, ZTF amount, temperature, ionic strength and initial pH of the solution on the adsorption of MV-2B and DR-28 were studied. The removal of MV-2B and DR-28 were found to be 94.5% and 96.8% at the original pH, with a ZTF amount of 1.5 g/L, an initial dye concentration of 20 mg/L, a contact time of 60 min, and at a temperature of 23 °C respectively. The experimental data indicated that Freundlich isotherm and pseudo second order model were suitable for the adsorption of MV-2B and DR-28. Moreover, the adsorption of DR-28 and MV-2B were found to be exothermic and spontaneous at the studied temperature range. Furthermore, the study also explored the removal of MV-2B and DR-28 in a binary system. The results showed that ZTF exhibited suitable performance for the removal of both dyes in the binary system.
Sono?assisted Adsorption of Methyl Violet 2B Using a Magnetic Kaolin/TiO2/??Fe2O3 Nano Composite
(SPRINGER INT PUBL AG, 2024) Fındık, Serap
In this study, the efficacy of sono-assisted adsorption for the removal of methyl violet 2B (MV-2B) was investigated. A magnetic adsorbent was synthesized using kaolin and TiO2, designated as KTF. Various analyses including scanning electron microscopy with energy dispersive spectroscopy (SEM–EDS), Brunauer–Emmett–Teller (BET), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), Zeta potential and vibrating sample magnetometer (VSM) were conducted to characterize the structure of KTF. The BET surface area and pore volume of KTF were determined to be 65.279 m2/g and 0.072 cm3/g, respectively. VSM analysis confirmed the superparamagnetic property of KTF. The effect of contact time, initial MV-2B concentration, KTF amount, temperature, ionic strength and initial pH of the solution on the sono-assisted adsorption of MV-2B was investigated. Sono-assisted removal of MV-2B was achieved at a rate of 85.6% under optimal conditions: original pH, KTF amount of 0.2 g/100 mL, initial MV-2B concentration of 20 mg/L, contact time of 15 min, and temperature of 22 °C. Conversely, lower removal efficiencies were observed with conventional adsorption methods employing shaking (37%) and stirring (60.5%). The kinetics of sono-assisted MV-2B removal followed a pseudo-second order model, while the Freundlich isotherm model exhibited a superior fit (R2?=?0.985) in describing the equilibrium behavior compared to Langmuir and Temkin models.
Removal of Methyl Violet 2B and Direct Black 22 from Single and Binary System Using a Magnetic Zeolite/MgO/Starch/Fe3O4 Nanocomposite
(SLOVENSKO KEMIJSKO DRUSTVO, 2024) Fındık, Serap
This study focuses on the preparation and characterization of magnetic zeolite (FSM-Zeo) using starch, magnesium oxide, and Fe3O4. Various analyses, including BET, FTIR, SEM, EDS, XRD, Zeta potential, and VSM, were conducted to assess the properties of FSM-Zeo. The adsorption capacity of FSM-Zeo was investigated for methyl violet (MV-2B) and direct black 22 (DB-22) in both single and binary dye solutions. Key parameters such as adsorbent amount, initial dye concentration, contact time, temperature, initial pH, and ionic strength were examined in the single system. Kinetic and isotherm studies revealed that DB-22 and MV-2B adsorption followed the pseudo-second-order model. Moreover, Freundlich and Langmuir models were confirmed for MV-2B and DB-22 adsorption on FSM-Zeo, respectively. In the binary system, the presence of MV-2B enhanced the adsorption of DB-22, resulting in higher removal compared to the single dye solution. A synergistic effect was observed due to the interaction between DB-22 and MV-2B, promoting the adsorption of DB-22 on FSM-Zeo.
Quantification of Phenolic Component by LC-HESI-MS/MS and Evaluation of Antioxidant Activities of Crocus Ancyrensis (Ankara cigdemi) Extracts Obtained with Different Solvents
(WILEY-V C H VERLAG GMBH, 2023) Kayır, Ömer; Doğan, Hacer; Alver, Erol; Bilici, İbrahim
In this study, Crocus ancyrensis was extracted from different parts of the plants with various solvents and their antioxidant activities and phenolic contents were investigated in detail for the first time. The highest amount of total phenolic substance in all parts of the plant was determined in the stigmaless flower. In the DPPH and FRAP methods, the highest antioxidant activity was obtained from the water extraction from the plant. Rutin is the highest detected by LC MS/MS. Stigmaless flower extract in all solvents is attributed to the component that contributes the most to antioxidant capacity. p-hydroxy benzoic acid was detected as the highest phenolic component after rutin. When the antioxidant activity results were examined, it was determined that the highest activity was in the water extract. As a result, it is evaluated that rutin and p-hydroxybenzoic acid in the plant contribute to the antioxidant capacity.
Chemical composition of essential oils from Crocus ancyrensis (Herbert) Maw Spreading In Çorum (Türkiye) Region
(Pamukkale University, 2023) Doğan, Hacer; Kayır, Ömer; Alver, Erol; Bilici, İbrahim
Abstract: Crocus ancyrensis is a yellow-flowered Crocus species and is in the same family and genus with saffron. Although various studies have been conducted on the antioxidant capacity and essential oil content characterization of saffron (Crocus sativus), there is no literature information about the C. ancyrensis plant, which is known as Crocus among the people. The members of Crocus family contain many valuable components including antioxidants, phenolic compounds and essential oils. The essential oils obtained from this family is a complex mixture of more than 30 components, which are primarily terpenes and their derivatives. These mixtures are used in paint, medicine, and food applications especially in the cosmetics sector. In the study, the essential oils of the Crocus ancyrensis plant were extracted with the clevenger system and characterized by GC-MS analyses. As a result, 23 volatile components were identified. 2-Hexenal, 1-ethylbutyl Hydroperoxide, 2-nitro-Hexane, ?-Isophorone, ?-Isophorone, 2-Caren-10-al and Eugenol are found as the main components of Crocus ancyrensis plant extract. Due to the antioxidant, antimicrobial, antifungal, anticancer and odorant properties of some of the identified components, C. ancyrensis can be used as a medicinal aromatic plant in various fields, especially in the cosmetics and perfume industry.
Mechanical and thermal properties of recycled polyethylene/surface treated hemp fiber bio-composites
(Wiley-Blackwell, 2023) Güney, Olcay; Bilici, İbrahim; Doğan, Deniz; Metin, Ayşegül Ülkü
Hemp is a good option for polyethylene additives because of its high cellulose and fibrous content. This study aims to modify natural hemp fibers with the maleic anhydride/ionic liquid method, manufacture the composites, and compare the thermal and mechanical properties of natural hemp fiber and hemp cellulose. In this study recycled polyethylene as a binder, and filling ratios between 0 and 50 (wt/wt)% are investigated as a parameter. Differential scanning calorimeter and thermomechanical analysis were performed, and it was determined that the coefficient of thermal expansion from 973 to 147 ppm/K. It was determined that the strength of composite materials obtained from cellulose fibers with maleic anhydride/liquid ionic modification improved by around 20% from 19.5 to 24.4 MPa. In addition, as a result of scanning electron microscope analyses performed on the fractured surfaces, it was determined that the pressure, temperature, and time were suitable for producing composite materials. This work shows the potential of recycled polyethylene/hemp composites as a sustainable green material with simple fabrication procedure and useful mechanical and thermal properties. © 2023 The Authors. Polymer Composites published by Wiley Periodicals LLC on behalf of Society of Plastics Engineers.
Biomechanical comparison of different suture materials with different techniques in tendon repair: An ex-vivo study
(ELSEVIER, 2023) Muslu, Ümran; Alıç, Taner; Demir, Emre; Gölpınar, Murat; Bilici, İbrahim; Demirezen, Murat Okan
Objectives Sheep Achilles tendons are used as an effective preclinical model of flexor tendon repair in plastic surgery, due to their biomechanical properties, which are similar to humans. The aim of this study was to examine the efficacy and biomechanical outcomes of suture materials and tendon repair techniques in flexor tendon repair. Material and methods 72 sheep tendons were obtained for a total of 12 different scenarios. Tendons were repaired using 4 different suture types and 3 different suture techniques. After repair, the tendons were fixed at both ends and subjected to biomechanical tests. Ultimate Failure Load (UFL) and 2-mm Gap Load (GL) per scenario were compared statistically within and between groups. Results UFL and GL of all sutures were significantly different between the modified Kessler, Bunnell and Krackow techniques (P??0.05). Conclusion When UFL and GL were considered together, our findings indicate that optimal strength scenarios were for the modified Kessler technique using Monosorb or V-loc sutures.
Adsorptive separation of CH4, H2, CO2, and N2 using fullerene pillared graphene nanocomposites: Insights from molecular simulations
(SPRINGER, 2023) Mert Balaban, Hümeyra; Deniz, Celal Utku; Baykasoğlu, Cengiz
Context The adsorptive separation performances of fullerene pillared graphene nanocomposites (FPGNs) with tunable micro and meso porous morphology are investigated for the binary mixtures of CH4, H2, CO2 and N2 by using grand canonical Monte Carlo (GCMC) simulations. Diferent fullerene types are considered in designs as pillar to investigate the efects of porosity on the gas separation performances of FPGNs, and the GCMC simulations are performed for an equimolar binary mixture of CO2/H2, CO2/CH4, CO2/N2 and CH4/H2 inspired by industrial gas mixtures. It is found that CO2/N2, CO2/H2 and CH4/H2 selectivity of FPGNs are about 72, 410 and 145 at 298 K and 1 bar, which are higher than those for several adsorbent materials reported. Methods Five diferent FPGN models which contain covalently bonded periodical fullerene and graphene units were constructed using C60, C180, C320, C540 and C720 fullerenes, followed by geometry optimization using Open Babel. All GCMC simulations of adsorption were performed in the RASPA. The adsorption isotherms of FPGNs for pure gases are comparatively examined, and their performances are discussed based on the pore structure and isosteric heat of adsorption. Then, the separation factors of FPGNs for equimolar binary mixtures of these gases are elucidated from the diference in the heat of adsorption and the adsorption selectivity
Mor lahana özütü kullanarak grafen oksitin indirgenmesi ve oksidasyon ile fotokatalitik aktivitesinin incelenmesi
(GAZI UNIV, FAC ENGINEERING ARCHITECTURE, 2023) Kütük, Nurşah; Boran, Filiz; Çetinkaya Gürer, Sevil
Grafen ve türevleri pek çok eşsiz sayılabilecek özelliğe sahip, fotokatalitik bozunum ve adsorpsiyon uygulamalarında potansiyeli olan önemli bir malzemelerdir. Grafen oksitin (GO) indirgenerek oksijen içeren fonksiyonel grupların giderilmesi son yıllarda sıkça kullanılan ilgi çekici bir yöntemdir. Bu çalışmanın amacı, kolay ve etkili bir yöntem olan, yeşil sentez yöntemi ile mor lahana sulu özütü kullanarak GO indirgenmesi ve fotokatalitik giderim uygulamalarında kullanımının incelenmesidir. Sentezleme koşullarını optimize etmek için reaksiyon sıcaklığı 25, 50 ve 100?’de ve reaksiyon süresinin etkisi ise 1, 2, 4 ve 6 h için incelendi. XRD, FTIR, UV/vis ve SEM sonuçlarına göre 100? reaksiyon sıcaklığı ve 6 h reaksiyon süresi GO’nun indirgenmesi için uygun deneysel şartlar olarak bulundu. Elde edilen indirgenmiş grafen oksit (IGO) organik ve katyonik bir boya olan metilen mavisinin (MM) sulu çözeltisinde UV lamba altında ve H2O2 varlığında fotokatalitik bozunum deneylerinde kullanıldı. Sonuçlar 120 min sonunda IGO’nun sulu çözeltiden MM’yi %85 oranında giderdiğini gösterdi. Sentezlenen IGO kullanarak MM’nin fotokatalitik bozunum tepkime kinetiğinin sözde ikinci dereceden reaksiyon kinetiğine uyduğu belirlendi.
Hydrophobic surface modification and characterization of melamine foam
(TUBİTAK, 2023) Okutan, Merve; Boran, Filiz; Ergün, Ayça; Kanca, Yusuf; Özkahraman, Bengi; Deligöz, Hüseyin
Abstract: Superhydrophobic and oleophilic modification of commercial acoustic melamine foam (MF) was made in this study. The modification was carried out with chitosan (CHI) and silica particles (SiO2 ), by using both a layer-by-layer-like approach (LbL) and dip coating technique. Subsequently, 1-octadecanethiol was used as a secondary modification agent. QCM-D, SEM, and FTIR analyses confirmed that the coating was successfully performed. After the modification, the column wall thicknesses increased than that of MF and they ranged from 25% to 48% for modified MF with an LbL-like approach (MMF) and modified MF via dip coating technique (MMFd), respectively. The sorption experiments showed that modified MFs, which had a water contact angle (WCA) above 160°, could sorb several model pollutants (vegetable oil, chloroform, ethanol, and toluene) up to 76–130 times their original weight. It had been determined that MMF protects its open-pore structure better than that of MMFd, which indicated that MF has a more uniform pore structure after modification. Furthermore, after 10 cycles of the sorption and release process, there was no significant change in sorption capacity, and they preserved their mechanical stability and flexibility
Artificial neural network approach for lead removal from aqueous solution by agricultural waste derived biochars
(YILDIZ TECHNICAL UNIV, 2023) Kaya, Nihan; Erdem, Fatma
Lead (Pb2+) which is one of the most important heavy metals found in water sources, has a toxic effect on living things in aquatic environment. Therefore, the removal of Pb2+ ions from wastewater is very important if its concentration is above the determined discharge limits. Due to its advantage such as high efficiency, the adsorption process is a widely used successful technique for heavy metals removal from an aqueous solutions. On the other hand, determining the adsorption efficiencies of different adsorbents experimentally is both costly, and timeconsuming considering that there are large number of process variables. Therefore, ANN can be used to make theoretical predictions with high efficiency in this treatment process. In this study, modeling of Pb2+ removal from an aqueous solution by using biochars that produced by pyrolyzing of hazelnut, and walnut shell was studied at different adsorption conditions; pH (2.5-5), temperature (25-45oC), initial Pb2+ concentration (15-45 mg/L), adsorbent amount (1-3 g/L), and mixing speed (200-600 rpm). The purpose of modeling studies with ANN approach was to estimate lead ions removal (%) as an output. Inputs for ANN modeling approach were selected as pH, initial Pb2+ concentration, temperature, adsorbent dosage, and mixing speed. Experimental data were categorized 50:25:25 for two adsorption systems. Levenberg-Marquardt (LM) was preferred as a training function, and tansig was used as an activation function. The number of hidden neurons in the hidden layer was found by trial, and error. Values of correlation coefficient (R2 ), and Mean Square Error (MSE) were taken to be performance criteria of the ANN modeling. R2 values were found to be 97%, and 98% for biochars derived from walnut, and hazelnut shells, respectively. Results showed that ANN is an effective tool for modeling of adsorption system for the removal of lead ions from an aqueous solution. Additionally, different training algorithms such as Bayesian Regularization (BR), and Scaled Conjugate Gradient (SCG) were used to compare the prediction capability.
NaBH4 Hidrolizi İçin Al2O3 Destekli Çok Bileşenli Nanokatalizör Sentezi ve Kinetik Değerlendirmesi
(GAZI UNIV, 2023) Çakanyıldırım, Çetin; Gökçeoğlu, Gamze
Yapılan çalışmada Al2O3 destek üzerinde ikili Co-Fe ve üçlü Co-Fe-Pt katalizörleri emdirme tekniği ile sentezlenmiştir. Üretilen katalizörler ile alkali ortamda NaBH4’ün tepkime vermesi sağlanmış ve hidrojen üretim hızı ve kinetik verileri derlenmiştir. Katalizörlerin morfolojik ve boyutsal özelliklerinin anlaşılması maksadı ile taramalı ve geçirimli electron mikroskop (SEM ve TEM) analizleri, hidrojen üretim kapasiteleri ve kinetik verilerin belirlenmesi için ise hidroliz testleri gerçekleştirilmiştir. İki ve üç bileşenli katalizörlerden Co0,95Fe0,05/Al2O3 ve Co0,85Fe0,08Pt0,07/Al2O3 kendi gruplarında en iyi performansı sergilemişlerdir. 40 mg Co0,85Fe0,08Pt0,07/Al2O3 katalizörü ile 20 ?C sıcaklıkta, 12.750 mL H2/gkat.min hidrojen üretim hızına erişilmiştir. NaBH4 ve katalizör miktarlarını farklılaştırılması ile yapılan çalışmalarda hidrojen üretim hızının katalizör miktarı ile orantılı olduğu ve NaBH4 miktarının tepkime hızına etki mertebesinin 0,22 olduğu görülmüştür. Yüksek aktivite sergileyen Co0,85Fe0,08Pt0,07/Al2O3 katalizörünün aktivasyon enerjisi 26,17 kJ/mol olarak hesaplanmıştır. Bu katalizörün tekrar kullanımlarındaki dönüşüm değerleri aktivitesine oranla daha tatmin edici düzeydedir
Synthesis optimization of ZrO2 nanostructures for photocatalytic applications
(Scientific and Technological Research Council Turkey, 2023) Boran, Filiz; Okutan, Merve
Abstract: This study aims to optimize the synthesis of semiconductor zirconia (ZrO2 ) nanoparticles for future photocatalytic applications in degradation of pollutants in wastewater under ultraviolet (UV) light. The synthesis procedure of ZrO2 nanoparticles was optimized by examining the effects of synthesis methods (ultrasound-assisted, hydrothermal method in an autoclave and conventional precipitation), reaction time (2, 6, 10, and 18 h), ambient pH (3, 7, 10, 13), and surfactant type (anionic, cationic, and non-ionic), on the particle size and crystal phase of the nanomaterial. The characterization of the synthesized samples was performed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS), high-contrast transmission electron microscopy (HR-TEM), and transmission electron microscope (TEM) analysis. Consequently, to synthesize ZrO2 nanoparticles with the smallest particle size and monoclinic/tetragonal phase, the experimental conditions were optimized as ultrasound-assisted synthesis method, pH 10, and 6 h reaction time without surfactant. Moreover, percentage yield, particle size, crystallinity, monoclinic and tetragonal volumes of ZrO2 nanostructures synthesized under optimized conditions were determined as 39.40%, approximately 9 nm, 46.77, 79%, and 21%, respectively. It has been determined that the particle sizes can be kept under control by controlling the phase composition of ZrO2 nanostructures by optimizing the synthesis parameters. Structural and morphological characterization results can be correlated to the photocatalytic application, showing the potential of this material for the photodegradation of organic dye pollutants.
ADSORPTION OF DIAZO DYE DIRECT RED-28 AND TETRA-AZO DYE DIRECT BLACK-22 USING CALCINED KAOLIN IN AQUEOUS SOLUTIONS
(CHEM SOC ETHIOPIA, 2023) Fındık, Serap
ABSTRACT. In this study, the removal of diazo and tetra-azo dyes using calcined kaolin were compared. Direct red-28 (DR-28) and Direct black-22 (DB-22) was chosen as diazo and tetra-azo dyes, respectively. The kaolin obtained from Turkiye and calcined at 200 °C was found to be the most efficient adsorbent. Natural and calcined kaolins were characterized using SEM-EDS, FTIR, TGA, and XRD. The parameters such as, calcination temperature of the kaolin, adsorbent amount, temperature, initial pH, contact time, and initial concentration were studied. It was found that the removal rate of DR-28 was higher than that of DB-22 at the studied conditions. The removal of DR-28 and DB-22 were found to be 90.1% and 46.2% under the following conditions: adsorbent amount: 1.2 g/200 mL, initial concentration: 20 mg/L, original pH, temperature: 20 °C and contact time 120 min. The adsorption of the dyes was fitted to Langmuir isotherm model. The maximum adsorption capacity of calcined kaolin at 200 °C was determined as 5.39 and 3.5 mg/g for DR-28 and DB-22, respectively. The adsorption of DR-28 and DB-22 followed a pseudo-second order model. The thermodynamic study showed that the adsorption of DB-22 onto calcined kaolin was endothermic while that of DR-28 was exothermic.
Farklı destekler ile hazırlanan sentetik Co-Mn-Pt katalizörünün NaBH4 hidroliz performansı ve kinetik değerlendirmesi
(GAZI UNIV, FAC ENGINEERING ARCHITECTURE, 2022) Çakanyıldırım, Çetin; Gürü, Metin
Bu çalışmada Co0,92-xMn0,08Ptx/TiO2 ve Co0,92-xMn0,08Ptx/Al2O3 nano katalizörleri sentezlenmiştir. Destekli katalizörlerin üretilmesinde impregnasyon tekniği kullanılmıştır. Katalizörlerin hidroliz yöntemi ile NaBH4’ü parçalararak yüksek hızda hidrojen üretme yetenekleri belirlenmiştir. Katalizörlerin özelliklerinin belirlenmesi için geçirimli ve taramalı electron mikroskopları (TEM ve SEM), X-ışını difraktometresi (XRD), yüzey alanı ölçüm ve gözenek dağılımı (Brunauer Emmett Teller) analizleri, enerji dağılım spektroskopisi (EDX) ve hidroliz testleri gerçekleştirilmiştir. Testler destek ile aktif bileşenin birbiri ile iyi bir uyum içinde ve sıkıca tutunmuş halde olduğunu göstermiştir. TiO2 destek ile aktivitenin daha yüksek olduğu ve 22? sıcaklıkta 40 mg Co0,85Mn0,08Pt0,07/TiO2 katalizör ile gerçekleştirilen hidroliz testlerinde 5 mL (0,525 M) NaBH4 çözeltisinin hidrojen üretim hızı 6.250 mL H2/min.gkat olarak bulunmuştur. Değişik NaOH, NaBH4 miktarları ve sıcaklıklarda kinetik çalışmalar yapılmıştır. Hidroliz tepkimesi için uygun NaOH miktarı 0,15 M olarak tespit edilmiştir. Tepkime hızı üzerinde katalizör miktarının etkin, NaBH4 miktarına göre ise sıfırıncı dereceden kinetiğe sahip olduğu belirlenmiştir. Co0,85Mn0,08Pt0,07 içerikli katalizörlerin TiO2 ve Al2O3 destekleri için sırasıyla 34,19 ve 40,02 kJ/mol aktivasyon enerjisine sahip olduğu tespit edilmiştir.
Decolorization of Direct Black 22 by Photo Fenton like Method Using UV Light and Zeolite Modified Zinc Ferrite: Kinetics and Thermodynamics
(SLOVENSKO KEMIJSKO DRUSTVO, 2022) Fındık, Serap
In this study, a heterogeneous catalyst was prepared to enhance photo-Fenton like oxidation of Direct Black-22 (DB-22). Zeolite modified with zinc ferrite was used as a catalyst. The prepared catalyst was characterized using FTIR, SEM, EDS and XRD. The effect of various parameters like catalyst modification with HCl, H2O2 amount, catalyst amount, CaCl2 amount, initial pH, initial concentration and temperature on the decolorization of DB-22 was studied under UV light. Kinetic and thermodynamic properties were investigated. The highest decolorization of DB-22 was found to be 93.3% under the following conditions: initial concentration: 0.070 g/L, initial temperature: 25 °C, original pH, H2O2 amount: 2.78 g/L, m-ZZF amount: 3 g/L, CaCl2 amount: 3.75 g/L, reaction time: 60 min and UV light. The activation energy was found to be –14.76 kJ/mol under the studied conditions. The decolorization reaction was an exothermic reaction, and the calculated reaction enthalpy was –17.31 kJ/mol. The activation entropy was calculated to be –0.326 kJ/mol. The standard Gibbs free energy change of the activation had a positive value, and it increased with increasing temperature.
Removal of Diazo Dye Direct Red 28 and Tetra Azo Dye Direct Black 22 Using Synthesized Magnetic Kaolin Supported Zinc Ferrite
(SLOVENSKO KEMIJSKO DRUSTVO, 2022) Fındık, Serap
The presence of dye molecules in water resources has harmful effects on environment. Therefore, it is important to remove dyes from wastewater using eco-friendly materials. In this study, adsorptive removal of diazo dye Direct Red 28 (DR-28) and tetra azo dye Direct Black 22 (DB-22) was investigated by using a new composite, kaolin supported zinc ferrite (KZF) as adsorbent. Characteristics of the composite, KZF were determined using various techniques such as FTIR, SEM, XRD, VSM, and EDS/Mapping. The adsorption of DR-28 and DB-22 on KZF was studied as a function of contact time, initial dye concentration, adsorbent amount, temperature, initial pH of the solution as well as the heat treatment of the composite. The removal of DR-28 was found to be 92.4% for the KZF concentration of 1g/200mL, initial dye concentration of 20 mg/L, contact time of 120 min at original pH and 21 °C. On the other hand the removal of DB22 was found to be 91.7% under the same conditions at 40 °C. The results showed that Langmuir isotherm is suitable for the adsorption of DR-28 and DB-22 on KZF under given conditions. It was found that adsorption of DR-28 on KZF was exothermic while that of DB-22 was endothermic. The enthalpy changes (?H0) for the adsorption of DR-28 and DB-22 dyes on KZF were found to be –24.59 kJ/mol and 61.95 kJ/mol respectively. ?S0 for the adsorption of DR-28 dye was found to be negative while ?S0 for the adsorption of DB-22 was positive. The kinetic data fitted well to the pseudo second order model for the adsorption of DR-28 and DB-22 on KZF composite. These results showed that the prepared adsorbent KZF could be used as an adsorbent for the efficient removal of anionic dyes.
Atık Polietilen Pirolizinin Dizel Motor Ve Emisyon Parametrelerine Etkisinin İncelenmesi
(2019) Bilici, İbrahim; Gürü, Metin; Keskin, Ali İhsan
Plastik malzemelerin kullanılmasının artışıyla birlikte Polietilen (PE) nin de kullanımı da bütün dünyada artmıştır. Bu yüksek miktardaki PE doğal bozulmama özelliğinden dolayı çevresel problemleri de beraberinde getirmektedir. Fakat bu PE sıvı yakıtlara dönüştürülebildiği için çevresel ve ekonomik olarak fayda sağlayabilir. Bu deneysel çalışmada PE dizel yakıt katkısına dönüştürülerek polimer bazlı yakıtların dizel motorlarda eksoz emisyonu ve performans paramatereleri incelenmiştir. PE atıklar termal piroliz yöntemiyle yakıta dönüştürülmüştür. PE atık katkılı yakıt %5, %10 ve %20 oranlarında dizel yakıt ile karıştırılarak herhangi bir modifikasyon gerçekleştrilmeden test edilmiştir. Genel olarak motor performans ve eksoz emisyon değerleri dizel yakıtlar ile benzer özellikler göstermiştir. Spesifik yakıt tüketimi (SFC) değeri PE oranının artmasıyla hafif düzeyde artış göstermiştir. Karbonmonoksit (CO) ve azot oksit (NOx) değerleri de dizel yakıt ile karşılaştırıldığında artma eğilimi göstermiştir.
Green Reduction Of Graphene Oxide By Using Kombucha Tea
(2019) Kütük, Nurşah; Boran, Filiz; Çetinkaya Gürer, Sevil
In this study, a simple and efficient method of reduction for the preparation of reduced graphene oxide (RGO) from graphene oxide (GO) using Kombucha Tea (KT) is reported. The graphene oxides (GOs) were produced from natural graphite (Gr) powders based on Hummers’ method. KT was used as natural reductants to reduction of GO. Polyphenol content of KT was determined by using Folin-Cioceltau method. KT and GO were mixed in certain ratios to reduce graphene oxide (RGO) at room temperature. RGO was characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Fourer Transform Infrared (FTIR). It was clearly observed that the functional groups containing oxygen were reduced as a result of the analyzes.
Poli(sodyum 4-stiren sülfonat) Kaplı SnO2 Nanoparçacıklarının Sentezi, Karakterizasyonu ve Gaz Algılama Özelliklerinin İncelenmesi
(2019) Boran, Filiz; Taşkıran, İmren; Çetinkaya Gürer, Sevil
Bu çalışmada, poli(etilen glikol)(PEG)-Kalay Oksit/poli(sodyum 4-stiren sülfonat) PEG-SnO2/PSS nanokompozitleri, 2 saat boyuncadimetil formamid (DMF) varlığında hidrotermal işlemle hazırlandı. Bunun için yüzey aktif madde PEG ile birlikte daha öncedensentezlenmiş olan 16,4 nm büyüklüğündeki SnO2 nanoparçacıkları kullanıldı. PEG-SnO2/PSS nanokompoziti, PSS ve PEG-SnO2 ilebirlikte DMF varlığında 0°C reaksiyon sıcaklığında 2 saat sürede sentezlendi. Hazırlanan PEG-SnO2/PSS nanokompozitinin yapısal veelementel analizi, taramalı elektron mikrokopisi (SEM), Enerji Dağılım X-Işınları Spektrometresi (EDS), X-ışını difraksiyonu (XRD)ve Fourier transform infrared (FTIR) spektroskopisi teknikleri ile yapıldı. FTIR ve XRD analizleri SnO2 nanoparçacıklarının PSSpolimer yapısına katıldığını gösterirken, SEM ve EDS analizleriSnO2nanoparçacıklarının morfolojik yapısının, PSS ile kompozitlerihazırlandığında PSS polimeri ile kapsüllenerek nanoyapıdan mikroküre yapılara dönüştüğünü gösterdi. Ayrıca, sonuçlar, PEG-SnO2yüzeyinin, güçlü ?-? etkileşimleri altında PSS ile % 39,53'lük bir kapsülleme oranı ile kaplandığını gösterdi. Bu örneklerin amonyak,etanol, aseton, formaldehit ve kloroform gibi uçucu organik bileşen (VOC) buharlarına karşı gaz duyarlılıkları, oda sıcaklığında, ikiprobe tekniği ile elektrometre kullanılarak incelendi. PEG-SnO2 nanoparçacıklarının etanol gazı için yüksek algılama performansısergilediği görüldü. Saf olarak kullanılan PSS, VOC gazlarının hepsine karşı yüksek oranda duyarlılık gösterdi. Deney sonuçlarına göre,PSS ile kapsüllenen PEG-SnO2 nanokompozitinin gaz sensörü malzemesi olarak kullanım potansiyelinin arttırılabildiği söylenebilir.

Güncel Gönderiler