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Öğe Düşük Molekül Kütleli Polistirenlerin Asetik Anhidritle Kimyasal Modifikasyonu(Selçuk Üniversitesi Fen Fakültesi, 2010) Uyanık, İbrahim; Kurbanlı, RefikaBu çalışmada, ilk olarak 350.000 molekül kütleli blok polistiren (PS) çözünme-çöktürme metodu kullanılarak fraksiyonlarına ayrılmıştır. Daha sonra 70.000, 80.000 ve 90.000 molekül kütleli PS fraksiyonlarının BF3.O(C2H5)2 katalizörlüğünde asetik anhidritle (AA) kimyasal modifikasyon reaksiyonları incelenmiştir. Ayrıca PS yapısına bağlanan fonksiyonel grup miktarının kıyaslanması için elde edilen yüksek molekül kütleli (Mn *= 290.000 ve 500.000) PS fraksiyonları da optimum şartta modifiye edilmiştir. PS yapısına bağlanmış fonksiyonel grup sayısı PS’nin molekül kütlesine bağlı olarak değişiklik göstermiştir ve daha düşük molekül kütleli PS’ye daha fazla fonksiyonel grup bağlanmıştır. PS yapısına bağlanan fonksiyonel gruplar ve miktarları spektral ve kimyasal metotlarla değerlendirilmiştir.Öğe Surfactant assisted hydrothermal synthesis of SnO nanoparticles with enhanced photocatalytic activity(ELSEVIER, 2020) Haspulat, Bircan.; Sarıbel, Muhammet.; Kamış, Handan.SnO nanoparticles have been successfully synthesized in the presence of Triton-X 100 (TX-100) surfactant via hydrothermal method for the first time, and the photocatalytic activity under UV and visible light irradiation for the degradation of Methylene Blue (MB) and Rhodamine B (RdB) organic textile dyes was investigated. The structural, morphological and chemical characterizations were investigated by using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), selected area electron diffraction (SAED), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR), UV-vis. diffuse reflectance spectroscopy (UV-vis DRS) and photoluminescence (PL) analysis. The results reveal that the addition of surfactant, TX-100, in the precursor solutions leads to reduction in crystallite size with significant changes in morphological structure of SnO nanoparticles. The synthesized SnO nanoparticles show excellent photocatalytic activity under UV or visible light irradiation. MB and RdB dyes degraded completely under UV irradiation after 90 and 150 min, respectively. Also, MB and RdB dyes degraded only 150 min later under visible light illumination with a little amount of photocatalyst (0.8 g/L). Hence, this work explores the facile route to synthesizing efficient SnO nanoparticles for degrading organic compound under both UV and visible light irradiations. (C) 2017 Production and hosting by Elsevier B.V. on behalf of King Saud University.Öğe The investigation of the use of plant-based wild mustard and boron doped oil as engine lubrication oil in diesel engines(PERGAMON-ELSEVIER SCIENCE LTD, 2019) Öğüt, H.; Oğuz, H.; Aydın, F.; Ciniviz, M.; Deveci, H.In internal combustion engines, mineral engine oils which serve as lubricants between parts are not used alone due to technical reasons and various additives are made use of for better lubrication. In these additives, liquid boron serves to reduce friction. To reduce the environmental damage caused by engine lubrication oils, it is necessary to improve the properties of biological oils so that they can be used and compete with mineral oils technically. In the study, the use of liquid boron as an engine lubrication oil additive, together with wild mustard oil methyl ester, was investigated. Two diesel engines with the same characteristics were used. In the first engine, experiments were carried out using mineral lubrication oil, then the experiments were repeated using mineral oil with additives, and the results were compared for both situations. The study was conducted mainly in the fields of element analysis of endoscopic examination and lubricating oil (Al, Fe, Cu, Pb, Cr). As a result, it was found out that the engine in which mineral lubricating oil with boron and wild mustard oil methyl ester additive was used did not pose any risks in terms of wear and engine oil life, compared to the engine without additive lubricating oil. (C) 2019 Elsevier Ltd. All rights reserved.Öğe Synthesis of Titania nanotubes/polyaniline via rotating bed-plasma enhanced chemical vapor deposition for enhanced visible light photodegradation(ELSEVIER SCIENCE BV, 2019) Subramaniam, M. N.; Goh, P. S.; Lau, W. J.; Ismail, A. F.; Gürsoy, M.; Karaman, M.This study employed rotating bed plasma enhanced chemical vapor deposition technique to coat a thin polymeric film of polyaniline (PANI) onto titania nanotubes (TNT). The effect of plasma power on the growth of thin film polymer on the photocatalyst surface was investigated. Transmission electron microscope micrographs evidenced the formation of thin polymeric layers on TNT surface. Fourier-transform infrared spectra confirmed the presence of functional groups associated with PANI. The band gap of coated photocatalyst reduced from 3.23 eV to 2.54 eV, implying the photosensitivity of TNT-PANI in visible light range, while photoluminescence spectra showed that PANI coated TNT exhibited lower recombination rates. The photocatalytic performance of the resultant TNT-PANI titania were evaluated under both UV and visible light irradiation using reactive black 5 (RB 5) as the model pollutant. Unlike TNT which could only be activated under UV light, TNT-PANI coated using a plasma power of 50 W exhibited superior photoactivity under both ultraviolet (UV) and visible light irradiation. The incorporation of PANI enhanced UV light photodegradation performance, where reaction rate improved to 0.615 ppm min(-1) and three times higher compared to uncoated TNT. The best sample TNT-PANI 50 W exhibited promising photodegradation efficiency of 56.4% within 240 min of visible light irradiation.Öğe Selective Chiral Recognition Of Alanine Enantiomers By Chiral Calix [4] Arene Coated Quartz Crystal Microbalance Sensors(SPRINGER HEIDELBERG, 2019) Temel, Farabi; Erdemir, Serkan; Tabakçı, Begüm; Akpınar, Merve; Tabakçı, MustafaWe describe the synthesis of new chiral calix[4]arene derivatives having (R)-1-phenylethylamine, (S)-1-phenylethylamine, (R)-2-phenylglycinol, and (S)-2-phenylglycinol moieties, and chiral recognition studies for enantiomers of some selected -amino acid derivatives such as alanine, phenylalanine, serine, and tryptophan using a quartz crystal microbalance (QCM). Initial experiments indicated that the highest selective chiral recognition factor was 1.42 for alanine enantiomers. The sensitivity, limit of detection, and time constant for l-alanine were calculated as 0.028 Hz/M, 60.9 M, and 36.2 s, respectively. The results indicated that real-time, sensitive, selective, and effective chiral recognition of alanine enantiomers was achieved with a QCM sensor coated with a chiral calix[4]arene derivative having (R)-2-phenylglycinol moieties.Öğe Rapid and real-time detection of arginine enantiomers by QCM sensor having a Calix[4]arene receptor bearing asymmetric centers(ELSEVIER, 2019) Temel, Farabi; Erdemir, Serkan; Ozcelik, Egemen; Tabakci, Begum; Tabakci, MustafaThis paper describes the sensing studies of a chiral calix[4]arene receptor (5) having (R)-2-phenylglycinol moiety for arginine enantiomers (D-/L-arginine) by using Quartz Crystal Microbalance (QCM) technique. The initial experiments have revealed that the chiral calix[4]arene 5 coated QCM (CCC-QCM) sensor showed good sensing for arginine enantiomers, such that it has exhibited higher sensing towards D-arginine than that of L-arginine. It has been determined that the sensitivity, limit of detection values of CCC-QCM sensor for the D-/L-arginine solutions as 0.024/0.023 Hz/mu M and 0.38/1.29 mu M, respectively. On the other hand, the racemic mixture studies were optimized using the response surface methodology with central composite design. Consequently, it has been demonstrated that the QCM sensor modification with a calix[4]arene receptor bearing asymmetric centers provided rapid, real-time, sensitive and effective sensing of arginine enantiomers.Öğe QCM sensors coated with calix[4]arenes bearing sensitive chiral moieties for chiral discrimination of 1-phenylethylamine enantiomers(SPRINGER, 2019) Ozcelik, Egemen.; Temel, Farabi.; Erdemir, Serkan.; Tabakci, Begum.; Tabakci, Mustafa.This article describes the enantiomeric discrimination properties of new chiral calix[4]arene derivatives bearing (S)-/(R)-1-phenylethylamine moieties (5a and 5b, respectively) towards the 1-phenylethylamine enantiomers on QCM surface. Initial experiments demonstrated that the 5b coated QCM sensor was the most effective sensing material for enantiomeric discrimination of (R)-/(S)-1-phenylethylamine by exhibiting much more sensing ability towards (R)-enantiomer than (S)-enantiomer. Sensitivity, detection limit and time constant of the 5b coated QCM sensor has been were calculated as 0.082 Hz/mu M, 2.7 mu M, and 319.2 s, respectively. Additionally, effects of calixarene content and different coating technique on enantiomeric discrimination, and Langmuir and Freundlich isotherms of the sensing results also were studied. As a result, it has been demonstrated that the coating of QCM sensor with a chiral calix[4]arene (5b) having (S)-1-phenylethylamine moieties provides substantially enantiomeric discrimination of 1-phenylethylamine enantiomers.Öğe Modification of biomass-derived activated carbon with magnetic alpha-Fe2O3 nanoparticles for CO2 and CH4 adsorption(SCIENTIFIC TECHNICAL RESEARCH COUNCIL TURKEY-TUBITAK, 2019) Kırbıyık, Çisem.Magnetic and nonmagnetic activated carbons (ACs) were successfully prepared by using AC obtained from spent coffee grounds (SCGs) for use in CO2 and CH4 capture. SCGs were activated by chemical activation to produce ACs and a magnetic alpha-Fe2O3 /AC composite was prepared by coprecipitation method from the ACs produced. Magnetic and nonmagnetic samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy dispersive X-ray spectrometry (EDX) techniques. The textural properties of samples were determined by nitrogen adsorption-desorption using the Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods. The results showed that the porosity of AC was not blocked by alpha-Fe2O3 particles. According to adsorption-desorption experiments, the best results were obtained with the magnetic alpha-Fe2O3/AC sample (1.68 mmol g(-1) for CO2 and 0.65 mmol g(-1) for CH4) at 0 degrees C and 120 kPa. Adsorption performances were evaluated using four isotherm models. The isosteric heats of adsorption calculated for both adsorbents were smaller than 80 kJ/mol and it revealed that CO2 and CH4 adsorption is dominated by the physical adsorption. The alpha-Fe2O3 alpha/AC multicycle CO2 adsorption tests showed that it can be successfully regenerated with high sorption capacity. The -Fe2O3/AC composite is a promising adsorbent for potential application.Öğe Modeling of trivalent chromium sorption onto commercial resins by artificial neural network(TAYLOR & FRANCIS INC, 2019) Tümer, Abdullah Erdal.; Edebali, Serpil.In this research, artificial neural network (ANN) model having three layers was developed for precise estimation of Cr(III) sorption rate varying from 17% to 99% by commercial resins as a result of obtaining 38 experimental data. ANN was trained by using the data of sorption process obtained at different pH (2-7) values with Amberjet 1200H and Diaion CR11 amount (0.01-0.1 g) dosage, initial metal concentration (4.6-31.7 ppm), contact time (5-240 min), and a temperature of 25 degrees C. A feed-forward back propagation network type with one hidden layer, different algorithm (transcg, trainlm, traingdm, traincgp, and trainrp), different transfer function (logsig, tansig, and purelin) for hidden layer and purelin transfer function for output layer were used, respectively. Each model trained for cross-validation was compared with the data that were not used. The trainlm algorithm and purelin transfer functions with five neurons were well fitted to training data and cross-validation. After the best suitable coefficient of determination and mean squared error values were found in the current network, optimal result was searched by changing the number of neurons range from 1 to 20 in the current network hidden layer.Öğe Methylation of 2-methylnaphthalene over metal-impregnated mesoporous MCM-41 for the synthesis of 2,6-triad dimethylnaphthalene isomers(SPRINGER, 2020) Niftaliyeva, Aysel.; Güleç, Fatih.; Karaduman, Ali.2,6-Dimethylnaphthalene (2,6-DMN) is one of the key intermediates for the production of polyethylene naphthalate (PEN), which demonstrates superior properties compared with the polyethylene terephthalate. However, the complex synthesis procedure of 2,6-DMN increases the production cost and decreases the commercialisation of PEN. In this study, selective synthesis of 2,6-triad DMN isomers (1,5-DMN, 1,6-DMN and 2,6-DMN) has been investigated by the methylation of 2-methylnaphthalene (2-MN) over mesoporous Cu/MCM-41 and Zr/MCM-41 zeolite catalysts. On the contrary of other DMN isomers, 2.6-triad isomers can effectively be converted to be profitable 2,6-DMN with an additional isomerisation reaction, which is a new approach to reach higher 2,6-DMN yield. The methylation reactions of 2-MN were investigated in a fixed-bed reactor at 400 degrees C and weight hourly space velocity of 1-3 h(-1). The results showed that the activity of MCM-41 on the methylation of 2-MN has been enhanced with the impregnation of Cu. The conversion increased from about 17% to 35 wt% with the impregnation of Cu. Similarly, the 2,6-triad DMN selectivity and 2,6-/2,7-DMN ratio reached the maximum level (48 wt% and 1.95, respectively) over Cu-impregnated MCM-41 zeolite catalyst.Öğe Magnetic field-assisted control of phase composition and texture in photocatalytic hematite films(WILEY-V C H VERLAG GMBH, 2019) Pyeon, Myeongwhun.; Rauch, Vanessa.; Stadler, Daniel.; Gürsoy, Mehmet.; Deo, Meenal.; Gönüllü, Yakup.; Fischer, Thomas.; Hwang, Taejin; Mathur, SanjayWe report the influence of external magnetic fields applied parallel or perpendicular to the substrate during plasma chemical vapor deposition (PECVD) of hematite (alpha-Fe2O3) nanostructures. Hematite films grown from iron precursors show pronounced changes in phase composition (pure hematite vs. coexistence of hematite and magnetite) and crystallographic textures depending upon whether PECVD is performed with or without the influence of external magnetic field. Static magnetic fields created by rod-type (RTMs) or disk-type magnets (DTMs) results in hematite films with anisotropic or equiaxed grains, respectively. Using RTMs, a superior photoelectrochemical (PEC) performance is obtained for hematite photoanodes synthesized under perpendicularly applied magnetic field (with respect to substrate), whereas parallel magnetic field results in the most efficient hematite photoanode in the case of DTM. The experimental data on microstructure and functional properties of hematite films show that application of magnetic fields has a significant effect on the crystallite size and texture with preferred growth and/or suppression of grains with specific texture in Fe2O3 films. Investigations on the water splitting properties of the hematite films in a photoelectrochemical reactor reveal that photocurrent values of hematite photoanodes are remarkably different for films deposited with (0.659 mA cm(-2)) or without (0.484 mA cm(-2)) external magnetic field.Öğe In-situ growth of NiWO4 saw-blade-like nanostructures and their application in photo-electrochemical (PEC) immunosensor system designed for the detection of neuron-specific enolase(ELSEVIER ADVANCED TECHNOLOGY, 2019) Soomro, Razium Ali; Kalwar, Nazar Hussain; Avci, Ahmet; Pehlivan, Erol; Hallam, Keith Richard; Willander, MagnusThis study describes the construction of highly-sensitive photo-electrochemical (PEC) immunosensor for the detection of neuron-specific enolase (NSE). The biosensing platform is comprised of photo-active NiWO4 nanostructures, in-situ-grown over a conductive substrate (indium tin oxide) using a low-temperature template-based co-precipitation approach. The discussed approach enables the formation of discrete, yet morphologically-analogous, nanostructures with complete coverage (pinhole-free) of the electrode surface. The in-situ-grown nanostructure possess dense population with sharp saw-blade like morphological features that can support substantial immobilisation of anti-NSE agent. The constructed platform demonstrated excellent photo-catalytic activity towards uric acid (UA) which served as the base for the Electrochemical -mechanism (EC) based PEC inhibition sensing. The detection of NSE, relied on its obstruction in analytical signal observed for the photo-oxidation of UA after binding to the electrode surface via protein-antibody interaction. The constructed PEC immunosensor exhibits signal sensitivity up to 0.12 ng mL(-1) of NSE with excellent signal reproducibility and electrode replicability. Moreover, the constructed platform was successfully used for NSE determination in human serum samples.Öğe Inhibition effects of different toothpastes on demineralisation of incipient enamel lesions(QUINTESSENCE PUBLISHING CO INC, 2019) Altan, Halenur; Göztaş, Zeynep; Kahraman, Kamil; Kuş, Mahmut; Tosun, GülPurpose: To evaluate the inhibitory effects of different toothpastes on demineralisation of incipient enamel lesions using a toothbrush simulator. Materials and Methods: Fifty enamel specimens were prepared from extracted human molars. The specimens were randomly assigned to the following groups (n = 10/group): 1. no treatment (control); 2. toothpaste containing arginine (ProRelief, Colgate;); 3. fluoride toothpaste (Pronamel, Sensodyne GlaxoSmithKlein); 4. tooth mousse containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) (Recaldent, GC); 5. toothpaste (Restore, Dr. Collins) containing bioactive glass (NovaMin, GlaxoSmithKlein). All specimens were exposed to pH cycling. The remineralising agents were applied to the samples with a toothbrush simulator for 2 min twice a day for five days. The weight percentage of mineral changes for the elements calcium (Ca), phosphorus (P), sodium (Na) and silica (Si) were measured by SEM energy-dispersive x-ray spectroscopy (SEM-EDX). SEM revealed properties of treated enamel surfaces. The data were analysed using one-way ANOVA. Results: Statistically significantly higher levels of Ca and P were found in all groups compared to the control (p < 0.05). Conclusions: The toothpastes' efficacy of inhibiting demineralisation depended on the active ingredients in the respective toothpaste. The demineralisation inhibition efficacy of the tested toothpastes depended on the active ingredients in the toothpaste.Öğe Improving the performance of inverted polymer solar cells through modification of compact TiO2 layer by different boronic acid functionalized self-assembled monolayers(ELSEVIER SCIENCE BV, 2019) Kırbıyık, Çisem.; Kara, Duygu Akın.; Kara, Koray.; Büyükçelebi, Sümeyra.; Yiğit, Mesude Zeliha.; Can, Mustafa.; Kuş, Mahmut.In this study, we demonstrate the use of a series of boronic acid functionalized self-assembled monolayers (SAMs) to improve photovoltaic device performance P3HT and PCBM based solar cells. The SAMs treated compact TiO2 (c-TiO2) layer was utilized as an electron transport layer for inverted polymer solar cells (PSCs) with a configuration of FTO/c-TiO2/SAM/P3HT:PCBM/PEDOT:PSS/Ag. The modified with 3,4,5-methoxyphenylboronic acid (3-OMe) SAM shows the best improving due to the enhancement of J(sc) and V-oc. in device, which leads to a 26% improvement (2.8%) over non-modified device (2.2%). The enhancement in the modified devices is achieved by SAM modification reducing recombination of charges and improving charge selectivity. These results prove that the surface and electrical properties of compact TiO2 (c-TiO2) layer can be easily tuned as well as the upper layer morphology can be controlled by SAM modification.Öğe Enzyme-free colorimetric sensing of glucose using L-cysteine functionalized silver nanoparticles(SPRINGER INTERNATIONAL PUBLISHING AG, 2019) Adnan, Sumaira; Kalwar, Nazar Hussain; Abbas, Malik Waseem; Soomro, Razium Ali; Saand, Mumtaz Ali; Awan, Fazli Rabbi; Avcı, Ahmet; Pehlivan, Erol; Bajwa, SadiaThe study demonstrates an efficient, simple and on-site viable approach for sensitive determination of blood glucose using colorimetric sensing approach. The devised colorimetric sensor works based on cysteine functionalized silver nanoparticles. The as-synthesized Ag NPs were elaborately characterized using advanced analytical techniques such as ultra-violet visible spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, atomic force microscopy and X-ray diffraction. The detection of glucose was carried under ambient air conditions where change in the optical characteristics of Ag NPs and subsequent interaction between glucose and functional moiety (i.e. surface bind cysteine) of Ag NPs was considered as the signal response. This interaction led to direct detection of glucose in the concentration range between 0.01 to 0.17 mu M with limit of detection up to 1 x 10(-4) mu M. It is worthwhile mentioning that success of the assay lies in application of the developed colorimetric sensor in real blood glucose measurements, which also proved its capability for field based analysis. In addition its simple design, low cost, and more reliability signifies the usefulness of colorimetric sensor and it can be extended monitor other biologically important molecules.Öğe Enhanced uptake capacities and isosteric heats of CO2 and CH4 adsorption on spent coffee ground activated carbons loaded with metal ions(SCIENTIFIC TECHNICAL RESEARCH COUNCIL TURKEY-TUBITAK, 2019) Kırbıyık, Çisem; Büyükbekar, Burak Zafer; Kuş, Mahmut; Ersöz, MustafaLow-cost activated carbon (AC) samples obtained from waste coffee grounds were used for CO2 and CH4 adsorption. ACs were prepared by chemical activation and carbonized at three different temperatures. AC carbonized at 800 degrees C showed a relatively high surface area (582.92 m(2) g(-1)) and high adsorption capacities of 2.6 mmol g(-1) and 1.1 mmol g(-1) at 25 degrees C for CO2 and CH4, respectively. Adsorbent samples were prepared by loading of Fe3+ metal ions onto ACs and their adsorption capacities were compared with those of nonloaded ACs. As expected, the loading of Fe3+ metal ions increased the adsorption capacities at all temperatures and the adsorption capacity of Fe3+-loaded AC carbonized at 800 degrees C was 3.1 mmol g(-1) for CO2 and 1.2 mmol g(-1) for CH4 at 25 degrees C. The isosteric heats of adsorption were calculated at 0-35 degrees C with the range of 20-35 kJ mol(-1) and 18-23 kJ mol(-1) for CO2 and CH4, respectively. According to our findings, bio-based ACs can be used as an effective and alternative adsorbent for capturing different gas molecules.Öğe Chitosan-coated sour cherry kernel shell beads: an adsorbent for removal of Cr(VI) from acidic solutions(SPRINGER INTERNATIONAL PUBLISHING AG, 2019) Altun, TürkanIn this study, a composite biosorbent in the form of beads was produced from chitosan and the powder of sour cherry kernel shells. Characterization of chitosan-coated sour cherry kernel shell beads was done using elemental analysis, FT-IR spectroscopy, SEM, and EDX spectrum analysis. Adsorption capacity of chitosan-coated sour cherry kernel shell beads was tested in removal of Cr(VI) under different conditions, pH 2.0-7.0, adsorbent dosage 0.01-0. 20 g, initial Cr(VI) ion concentration 10-315 mg L-1, temperature 25-55 degrees C, and contact time 0-240 min, and compared to that of uncoated sour cherry kernel shell powder. Cr(VI) adsorption was highly dependent on the solution pH, and the maximum Cr(VI) adsorption was achieved at pH 2.03 at 25 degrees C in 45 min. The adsorption data was applied to Langmuir, Freundlich, Scatchard, and Dubinin-Radushkevich (D-R) adsorption isotherm models. According to the Langmuir isotherm model, the adsorption capacity of chitosan-coated sour cherry kernel shell beads was found higher than that of uncoated sour cherry kernel shell powder, 24.492 and 13.57 mg g(-1). The study demonstrated that chitosan-coated sour cherry kernel shell beads can be used for Cr(VI) removal from acidic aqueous solutions.Öğe Biogenic silver nanoparticles for trace colorimetric sensing of enzyme disrupter fungicide vinclozolin(MDPI, 2019) Hussain, Masood.; Nafady, Ayman.; Sirajuddin.; Avcı, Ahmet.; Pehlivan, Erol.; Nisar, Jan.; Sherazi, Syed Tufail Hussain.; Balouch, Aamna.; Shah, Muhammad Raza.; Almaghrabi, Omar A.; Ul-Haq, Muhammad Anwar.We report a novel, simple, efficient, and green protocol for biogenic synthesis of silver nanoparticles (AgNPs) in aqueous solution using clove (Syzygium aromaticum) extract as a reducing and protecting agent. Ultraviolet-visible (UV-Vis) spectroscopy was employed to monitor the localized surface plasmon resonance (LSPR) band of clove extract-derived AgNPs prepared under various conditions. Fourier-transform infrared (FTIR) spectroscopy analysis provided information about the surface interaction of the clove extract with the AgNPs. Ultrahigh-resolution transmission electron microscopy (UHRTEM) results confirmed the formation of spherical, uniformly distributed clove extract-capped AgNPs with sizes in the range of 2-20 nm (average size: 14.4 +/- 2 nm). Powder X-ray diffractometry analysis (PXRD) illustrated the formation of pure crystalline AgNPs. These AgNPs were tested as a colorimetric sensor to detect trace amounts of vinclozolin (VIN) by UV-Vis spectroscopy for the first time. The AgNP-based sensor demonstrated very sensitive and selective colorimetric detection of VIN, in the range of 2-16 mu M (R-2 = 0.997). The developed sensor was green, simple, sensitive, selective, economical, and novel, and could detect trace amounts of VIN with limit of detection (LOD) = 21 nM. Importantly, the sensor was successfully employed for the determination of VIN in real water samples collected from various areas in Turkey.Öğe Doğal atık malzemeler ve biyoçarları ile biyobozunur özellikte yeni epoksi-bazlı kompozitlerin hazırlanması ve karakterizasyonu(2018) Kocaman, Süheyla; Ahmetli, Gülnare; Soğancıoğlu, MerveBu çalışmada doğal atık malzemelerden ceviz kabuğu (CK) ve pirina bisfenol-A tipi epoksi reçine (ER) kompozitlerinin hazırlanması için dolgu maddesi olarak kullanılmıştır. Ayrıca, doğal takviye malzemeleri 700 ºC’da piroliz edilerek katı ürün atığı çarla da kompozitleri oluşturulmuştur. Epoksi reçinede dolgu oranı %10-50 aralığında değiştirilerek kompozitlerin mekanik, elektriksel, iletkenlik ve termal özelliklerine dolgu maddesi oranının etkisi araştırılmıştır. Çarların morfolojisi taramalı elektron mikroskobu (SEM) ile incelenmiştir. Ayrıca, elde edilen biyobazlı kompozit malzemeler özel olarak hazırladığımız toprağa gömülerek bozunma süreleri (biyobozunurluk testi) belirlenmiştir.Öğe Baryum klorür ve sodyum metaborat reaksiyonu ile baryum metaborat sentez parametrelerinin incelenmesi(2018) Ceyhan, Ayhan Abdullah; Koçak, Fatıma Zehra; Şahin, ÖmerBu çalışmada baryum metaborat üretimi için gerekli optimum şartlar belirlenmeyeçalışılmıştır. Üretim, baryum klorür dihidrat (BaCl2.2H2O) ve sodyum metaborattetrahidrat (NaBO2.4H2O)’ın sulu ortamdaki reaksiyonu ile gerçekleştirilmiştir.Üretim için en uygun sıcaklık, NaBO2/BaCl2 oranı, karıştırma hızı, karıştırmazamanı, dinlendirme zamanı, çözücü tipi ve derişimi, etil alkol etkisi gibiparametreler incelenmiştir. Elde edilen kristallerinin karakterizasyonu, X-ışınıkırınımı (XRD), taramalı elektron mikroskobu (SEM) ve partikül boyut ölçümcihazları yardımıyla yapılmıştır. Kristallerin yapı suyu içerikleri ise TG-DTAanalizleri ile belirlenmiştir. Baryum metaborat sentezi için en yüksek verim değeri%88 olarak bulunmuştur. Sentez açısından en uygun şartlar ise; reaksiyonsıcaklığı 80 oC, 400 rpm karıştırma hızı, 60 dk karıştırma ve 60 dk dinlendirmezamanı olarak tespit edilmiştir.
