Mühendislik ve Doğa Bilimleri Fakültesi Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.13091/1624

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Citation - WoS: 18
Citation - Scopus: 24
Adsorption of Cr(vi) Onto Cross-Linked Chitosan-Almond Shell Biochars: Equilibrium, Kinetic, and Thermodynamic Studies
(SPRINGER INTERNATIONAL PUBLISHING AG, 2021) Altun, Türkan; Ecevit, Hüseyin; Kar, Yakup; Çiftçi, Birsen
In this study, to remove Cr(VI) from the solution environment by adsorption, the almond shell was pyrolyzed at 400 and 500 degrees C and turned into biochar (ASC400 and ASC500) and composite adsorbents were obtained by coating these biochars with chitosan (Ch-ASC400 and Ch-ASC500). The resulting biochars and composite adsorbents were characterized using Fourier transform infrared (FTIR) spectroscopy; Brunauer, Emmett, and Teller (BET) surface area; scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX); and the point of zero charge pH (pH(pzc)) analyses. The parameters affecting the adsorption were examined with batch adsorption experiments and the optimum parameters for the efficient adsorption of Cr(VI) in 55 mg L-1 solution were determined as follows; adsorbent dosages: 5 g L-1 for biochars, 1.5 g L-1 for composite adsorbents, contact time: 120 min, pH: 1.5. It was seen that the temperature did not affect the adsorption much. Under optimum conditions, Cr(VI) adsorption capacities of ASC400, ASC500, Ch-ASC400, and Ch-ASC500 adsorbents are 11.33, 11.58, 37.48, and 36.65 mg g(-1), respectively, and their adsorption percentages are 95.2%, 97.5%, 94.3%, and 94.0%, respectively. Adsorption data were applied to Langmuir, Freundlich, Scatchard, Dubinin-Radushkevic, and Temkin isotherms and pseudo-first-order kinetic model, pseudo-second-order kinetic model, intra-particle diffusion model, and film diffusion model. The adsorption data fitted well to the Langmuir isotherm and pseudo-second-order kinetic models. From these results, it was determined that chemical adsorption is the dominant mechanism. Also, both intra-particle diffusion and film diffusion is effective in the adsorption rate. For all adsorbents, the Langmuir isotherm proved to be the most appropriate model for adsorption. The maximum monolayer adsorption capacities calculated from this model are 24.15 mg g(-1), 27.38 mg g(-1), 54.95 mg g(-1), and 87.86 mg g(-1) for ASC400, ASC500, Ch-ASC400, and Ch-ASC500, respectively. The enthalpy change, entropy change, and free energy changes during the adsorption process were calculated and the adsorption was also examined thermodynamically. As a result, adsorption occurs spontaneously for all adsorbents.
Citation - WoS: 42
Citation - Scopus: 49
Adsorption of Malachite Green and Methyl Violet 2b by Halloysite Nanotube: Batch Adsorption Experiments and Box-Behnken Experimental Design
(Elsevier Ltd, 2022) Altun, Türkan; Ecevit, Hüseyin
Dyes constitute a significant part of the pollutants in industrial wastewater. In this study, halloysite nanotube (HNT) was used for adsorption of malachite green and methyl violet 2B dyes from the solution. Using batch adsorption experiments and response surface method, parameters affecting adsorption have been optimized. As a consequence of the batch experiments, after 60 min, the adsorption equilibrium state was achieved at 3 g L?1 HNT dosage, 125 mg L?1 dye concentration and natural solution pH. Temperature did not significantly affect the adsorption. The adsorption equilibrium data can be said to have fitted the Langmuir, Freundlich, Dubinin-Radushkevich and Temkin isotherms well for the both dyes. The Langmuir maximum monolayer malachite green and methyl violet 2B adsorption capacities (As) of HNT are 74.95 mg g?1 and 67.87 mg g?1, respectively. Adsorption processes are more consistent with the pseudo-second-order kinetic model. In addition, both intra-particle diffusion and film diffusion are effective as rate-determining steps in adsorption. Thermodynamic calculations showed that the adsorption is exothermic and spontaneous. The regeneration of HNT after adsorption was confirmed in five cycles. By using the Box-Behnken response surface method, the parameters affecting the adsorption process were modeled, the effects of these parameters on the adsorption efficiency were expressed mathematically and the optimum operating parameters were determined. © 2022
Citation - WoS: 25
Citation - Scopus: 29
Aerogels as Promising Materials for Antibacterial Applications: a Mini-Review
(ROYAL SOC CHEMISTRY, 2021) Kaya Güzel, Gülcihan; Aznar, Elena; Deveci, Hüseyin; Martinez-Manez, Ramon
The increasing cases of bacterial infections originating from resistant bacteria are a serious problem globally and many approaches have been developed for different purposes to treat bacterial infections. Aerogels are a novel class of smart porous materials composed of three-dimensional networks. Recently, aerogels with the advantages of ultra-low density, high porosity, tunable particle and pore sizes, and biocompatibility have been regarded as promising carriers for the design of delivery systems. Recently, aerogels have also been provided with antibacterial activity through loading of antibacterial agents, incorporation of metal/metal oxides and via surface functionalization and coating with various functional groups. In this mini-review, the synthesis of aerogels from both conventional and low-cost precursors is reported and examples of aerogels displaying antibacterial properties are summarized. As a result, it is clear that the encouraging antibacterial performance of aerogels promotes their use in many antibacterial applications, especially in the food industry, pharmaceutics and medicine.
Citation - Scopus: 77
Alginate-Coated Perlite Beads for the Efficient Removal of Methylene Blue, Malachite Green, and Methyl Violet From Aqueous Solutions: Kinetic, Thermodynamic, and Equilibrium Studies
(Springer, 2019) Parlayıcı, Şerife
Environmental pollution has been increasing recently due to industrialization. Many industries use dyestuffs to color their products. This work investigates the adsorption of methylene blue (MB), malachite green (MG), and methyl violet (MV) on alginate-coated perlite beads (AP). AP was prepared by a sol-gel process. The removal of MB, MG, and MV from aqueous solutions by AP as an adsorbent was tested by using a batch-type model. In order to prove the effectiveness of the study, it has been tried to obtain optimum efficiency at optimum level by working depending on mixing time (minutes), initial dye concentration (ppm), adsorbent dose (mg/L), pH, and temperature (°C). The results showed that the MB, MG, and MV adsorption process reached equilibrium within a 60-min period for AP. It has been found that the amount of adsorbed dyestuff increases with the initial dye concentration, the pH of the solution. Thermodynamic activation parameters were calculated from experimental data at different temperatures. The AP was characterized by Fourier Transform Infrared Spectroscopy (FT-IR) before and after MB, MG, and MV adsorption. The equilibrium adsorption data were described by Langmuir, Freundlich, Scatchard, Temkin and D-R isotherms. The modified Langmuir isotherm was applied to explain the experimental adsorption, and the greatest MB, MG, and MV adsorption capacity of the AP reached to 104.1, 74.6, and 149.2 mg/g, respectively. The pseudo-first and pseudo-second-order equations were used to evaluate the kinetic data, and the constants are determined. The best correlation coefficients were well described using the pseudo-second-order kinetic model. As a result, AP has claimed the possibility as an adsorbent for MB, MG, and MV removal from dilute aqueous solutions. © 2019, The Author(s).
Citation - WoS: 14
Citation - Scopus: 13
All-Dry Hydrophobic Functionalization of Paper Surfaces for Efficient Transfer of Cvd Graphene
(WILEY-V C H VERLAG GMBH, 2019) Çıtak, Emre; İstanbullu, Bilal; Şakalak, Hüseyin; Gürsoy, Mehmet; Karaman, Mustafa
In this study, the successful transfer of chemical vapor deposition (CVD)-grown graphene on an ordinary printing paper surface is demonstrated. Pristine paper is not a suitable substrate for graphene transfer because of its fragile and hydrophilic nature against the chemicals used during the transfer process. Two different fluoroalkyl polymers, namely poly(hexafluorobutyl acrylate) (PHFBA) and poly(perfluorodecyl acrylate) (PPFDA) are coated on paper surfaces by an initiated CVD (iCVD) technique to make the paper surfaces hydrophobic. Hydrophobicity is found to be an important factor in order for the graphene to be transferred onto the paper substrate. Although surfaces coated with PPFDA possess better hydrophobicity owing to their longer perfluoroalkyl group and higher roughness, the graphene transfer is found to be more successful on a PHFBA-coated surface. A thin film of PHFBA on the paper surface acts as a prime layer for effective and defect-free transfer of graphene and makes the paper surface ideal and robust during the graphene transfer process. The as-transferred graphene layer on the PHFBA-coated paper surface shows high conductivity values, even after repeated folding and flattening cycles.
Citation - WoS: 23
Citation - Scopus: 24
All-Dry Patterning Method To Fabricate Hydrophilic/Hydrophobic Surface for Fog Harvesting
(SPRINGER, 2020) Gürsoy, Mehmet
Inspired by natural creatures that live in the arid climate, fog harvesting can be an efficient approach to overcome freshwater scarcity. Fog harvesting ability of the creatures is mainly based on wettability differences of their surfaces. In this study, inspired by creatures that have hydrophilic regions surrounded by hydrophobic areas, a novel all-dry patterning method was applied to fabricate hydrophilic/hydrophobic patterned surfaces for fog harvesting. For this purpose, patterned surfaces were produced using plasma-enhanced chemical vapor deposition (PECVD) method with the help of a commercial magnet and iron powders. The idea behind the use of the magnetic field during PECVD deposition is to hold light iron particles on the substrate under the vacuum environment for masking substrate surface. For the first time, the magnetic field was used to fabricate patterned surfaces in vapor-phase polymerization. Ordinary glass slides were successfully transformed into hydrophilic/hydrophobic patterned glasses. The obtained results showed that the combination of hydrophobic and hydrophilic regions improved the fog harvesting performance.
Citation - WoS: 14
Citation - Scopus: 14
All-Dry Synthesis of Poly(2-Ethylhexyl Acrylate) Nanocoatings Using Initiated Chemical Vapor Deposition Method
(ELSEVIER SCIENCE SA, 2019) Şakalak, Hüseyin; Karaman, Mustafa
In this study, Poly(2-ethylhexyl acrylate) (PEHA) thin films were deposited on different substrates by initiated chemical vapor deposition (iCVD) technique. Being a long alkyl chain acrylate with a suitably low glass transition temperature, PEHA is an important member of acrylates family, which is used extensively in adhesives, paints, and coating applications. In iCVD, use of the tert-butyl peroxide as an initiator allowed a deposition rate of 155 nm/min at a filament temperature of 280 degrees C. Precursor flow ratios, filament and substrate temperatures were found to be important parameters that effect the deposition rates. The negative relation between substrate temperature and deposition rates implied an adsorption limited kinetics. FTIR and XPS analyses of the deposited films confirmed that the chemical functionality of the EHA monomer preserved well after iCVD. It was also revealed that the as-deposited films are smooth, uniform and optically transparent. PEHA film deposited by iCVD on glass improved the optical transmittance of glass, by acting as an anti-reflection coating due to its suitable refractive index of 1.45.
ALÜMİNYUM HİDROKSİT KRİSTALİZASYONU ÜZERİNE LİTYUM SAFSIZLIĞININ ETKİSİ
(Konya Technical University, 2020) Ceyhan, Ayhan Abdullah; Temiz, Halil
Bu çalışmada, farklı modülb değerlerine (1,35; 1,41; 1,45; 1,49; 1,8; 2,0; 2,25; 2,50) sahip sodyum alüminat çözeltilerinin nükleasyon davranışları incelenmiştir. Bu amaçla, çözeltiye verilen farklı aşırı doygunluk değeri (1,321-1,785) ve farklı derişimde (5-20 ppm) lityum (Li) varlığı için bekleme zamanı ölçümleri yapılmıştır. Deneysel çalışmalar sonucu, kritik serbest enerji değişimi, kritik nüklei yarıçapı, kritik nükleide yer alan molekül sayısı ve nükleasyon hızı hesaplanmıştır. Katkısız sodyum alüminat çözeltisi için bekleme zamanının, farklı aşırı doygunluk değerlerine bağlı olarak 100-400 dk. aralığında değiştiği belirlenmiştir. Lityum varlığında ise, en yüksek bekleme zamanı 10 ppm lityum derişimi için 20 dk. olarak tespit edilmiştir. Klasik nükleasyon teorisine göre yapılan hesaplamalar sonucu, lityum varlığında, katkısız ortama kıyasla, kritik nüklei yarıçapının düştüğü, kritik nükleideki molekül sayısının azaldığı ve nükleasyon hızının arttığı belirlenmiştir. 5 ppm lityum katkısı için, katkısız ortama kıyasla, nükleasyon hızındaki artışın yaklaşık 100 kat, 20 ppm lityum katkısı için ise yaklaşık olarak 39 kat olduğu belirlenmiştir. Lityum varlığında, farklı modülb değerlerindeki sodyum alüminat çözeltilerinin bekleme zamanlarının düşük ve yüksek modülb değerine sahip çözeltiler için 6 – 7 dk. aralığında değiştiği tespit edilmiştir. Modülb 1,49 ve 1,8 için ise maksimum 10 dk’lık bekleme süreleri elde edilmiştir.
Amonyum Floroborat Üretimi ve Üretim Parametrelerinin Belirlenmesi
(2020) Ceyhan, Ayhan Abdullah; Bağcı, Safiye; Baytar, Orhan; Şahin, Ömer
Bu çalışmada, borik asit ve amonyum hidrojen florürün reaksiyonu ile amonyum floroborat (NH4 BF4 ) üretimine ait üretim parametreleri incelenmiştir. Bu amaçla, reaktif besleme oranı, reaksiyon sıcaklığı, karıştırma hızı, karıştırıcı cinsi, ikinci çözücü etkisi parametrelerinin etkileri ayrı ayrı belirlenmiştir. Reaksiyon sonucu elde edilen kristallerin yapısal analizleri ve yüzey morfolojileri ise sırasıyla XRD, FT-IR ve SEM analizleri yapılarak aydınlatılmaya çalışılmıştır. Amonyum floroborat üretimi için en uygun reaksiyon şartları; reaktif besleme oranı, 1:2; reaksiyon sıcaklığı, 90 o C; karıştırıcı cinsi, sıcak hava şeklinde tespit edilmiştir. Limit oksijen indeksi analizleri, amonyum floroboratın mükemmel alev geciktirici olduğunu göstermiştir.
Citation - WoS: 17
Citation - Scopus: 19
Analysis of Electrospinning and Additive Effect on ? Phase Content of Electrospun Pvdf Nanofiber Mats for Piezoelectric Energy Harvester Nanogenerators
(Institute of Physics, 2022) Oflaz, Kamil; Özaytekin, İlkay
Harvesting energy with piezoelectric nanoparticles enables the development of self-powered devices. Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF) has been widely used in a variety of fields due to its superior piezoelectric properties. PVDF’s piezoelectric performance is affected by the presence of polar phase in the crystalline structure. The electrospinning process was used in this study to achieve high ? phase ratios in the PVDF crystalline structure using various additives (graphene, boron nitride, and quartz (SiO2)). The Taguchi experimental design method was used to determine the most significant parameters affecting ? phase content from seven factors, as well as the optimal levels of the significant factors. The Fourier transform infrared, x-ray diffraction, scanning electron microscopy, energy-dispersive x-ray and differential scanning calorimetry analyses were used to characterize the composite PVDF nanofiber mats produced under optimal conditions, and the output voltage was measured using an oscilloscope. The composite PVDF nanofiber mat with the highest ? phase concentration demonstrated a maximum output voltage of 8.68 V under optimal conditions, indicating that it outperformed than pure PVDF under equal electrospinning conditions. © 2022 IOP Publishing Ltd.
Citation - WoS: 18
Citation - Scopus: 19
Antibacterial Activity of Linezolid Against Gram-Negative Bacteria: Utilization of Epsilon-Poly Capped Silica Xerogel as an Activating Carrier
(MDPI, 2020) Kaya Güzel, Gülcihan; Medaglia, Serena; Candela-Noguera, Vicente; Tormo-Mas, Maria Angeles; Marcos, Maria Dolores; Aznar, Elena; Martinez-Manez, Ramon
In recent times, many approaches have been developed against drug resistant Gram-negative bacteria. However, low-cost high effective materials which could broaden the spectrum of antibiotics are still needed. In this study, enhancement of linezolid spectrum, normally active against Gram-positive bacteria, was aimed for Gram-negative bacteria growth inhibition. For this purpose, a silica xerogel prepared from a low-cost precursor is used as a drug carrier owing to the advantages of its mesoporous structure, suitable pore and particle size and ultralow density. The silica xerogel is loaded with linezolid and capped with epsilon-poly-l-lysine. The developed nano-formulation shows a marked antibacterial activity against to Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. In comparison to free linezolid and epsilon-poly-l-lysine, the material demonstrates a synergistic effect on killing for the three tested bacteria. The results show that silica xerogels can be used as a potential drug carrier and activity enhancer. This strategy could provide the improvement of antibacterial activity spectrum of antibacterial agents like linezolid and could represent a powerful alternative to overcome antibiotic resistance in a near future.
Antibacterial Properties of Nylon 6,6 Nanofibers Containing Silver Nanoparticles
(Sage Publication, 2019) Kahraman Tutar, Havva; Musaoğlu, Merve; Yüksel, Emre; Aydın, Gülsüm
The aim of this study was to develop antimicrobial nanofibers to be a candidate for potential applications. Nylon 6,6 nanofibers were fabricated via electrospinning technique, then the silver nanoparticles (AgNPs) immobilization was performed in order to gain an antimicrobial activity. In this method, generated electrospun Nylon 6,6 nanofibers were immersed into AgNO3 solution for 2 hours and removed from the solution, treated with water, and then reduced using NaBH4 for 2 hours. The formation of AgNPs was occurred through the NaBH4 reducing agent. The obtained Nylon 6,6 nanofibers containing AgNPs were washed with water and dried. Fabricated nanofibers were characterized using Scanning Electron Microscope (SEM) and Fourier-transform infrared (FT-IR) spectrophometer. Antibacterial activities of AgNPs immobilized nanofibers were evaluated using Grampositive bacteria (Staphylococcus aureus) and Gram‐negative bacteria (Escherichia coli). The inhibition zones were measured and recorded. According to the analysis, nanofibers showed better antibacterial activity against to Gram‐positive bacteria (Staphylococcus aureus) as compared to Gram‐negative bacteria (Escherichia coli).
Citation - WoS: 8
Citation - Scopus: 8
Application of the Central Composite Design and Response Surface Methodology for Investigation of Induction Time, Conjugated Diene, Conjugated Triene and Trans Fatty Acid Content of Corn Oil Enriched With Carotenoids
(SPRINGER, 2020) Topkafa, Mustafa
The central composite design technique was used to investigation of induction time, conjugated diene, conjugated triene and trans fatty acid content of corn oil enriched with lutein, beta-carotene and lycopene in this study. The levels of lutein and beta-carotene and were between 0 and 94 mg/kg, while lycopene levels was 0-49.56 mg/kg. Oil samples with and without lutein, beta-carotene and lycopene were prepared according to central composite design. The influence of these three independent variables on the four dependent variables such as time, conjugated diene and conjugated triene and trans fatty acid content was evaluated using a reduced cubic model. The each independent variable was effective on the induction time, conjugated diene, conjugated triene and trans fatty acid content of corn oil. The positive effect on the induction time was observed high concentrations of lutein and lycopene concentrations. Lutein, beta-carotene and lycopene had a significant effect on conjugated diene, conjugated triene and trans fatty acid content. The desirability function and the 3D plots suggested that optimum parameters were lutein concentration of 19 mg/kg, beta-carotene concentration of 19 mg/kg and lycopene concentration of 12.5 mg/kg as optimum parameters for maximum induction time and the minimum formation of conjugated diene, conjugated triene and trans fatty acid species.
Citation - WoS: 25
Citation - Scopus: 25
Application of Various Carboxylic Acids Modified Walnut Shell Waste as Natural Filler for Epoxy-Based Composites
(WILEY, 2021) Albaker, Ruya Isam Bakr; Kocaman, Süheyla; Martı, Mustafa Esen; Ahmetli, Gülnare
In this study, chemically modified walnut shells (WS) were used as the filling material for synthesis of bio-based epoxy composites and added to the matrix at varied mass ratios (10%-50%). The shells were initially treated with alkali and then modified with three different organic acids (citric acid [CA], oxalic acid [OA], and formic acid [FA]). The WS were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDX) and thermo gravimetric analyzer. The SEM and X-ray diffraction were employed to observe the morphology of the composites. The influences of acid type and WS percentages on the mechanical, thermal and water sorption properties were investigated. The maximum tensile strength (124.8 MPa) was obtained with CA-treated shells (CA-WS) and followed by OA-treated shells (OA-WS) (117 MPa) and FA-treated shells (FA-WS) (96.5 MPa). Acid modification had a positive effect on Young's modulus as that of epoxy resins increased by 5.45%-50.91%. The treatment did not significantly affect hardness. The optimum amount of modified shells in the composites was found to be 20 wt%. Water sorption values changed in the range of 2.78%-3.42% for composites with 20 wt% WS and observed to increase with the filler amount in the composite. However, this trend and the slight decrease in thermal properties are not critical obstacles for the use of modified WS in the manufacture of inexpensive epoxy- and bio-based eco-friendly products.
Citation - WoS: 42
Citation - Scopus: 46
Apricot Kernel Shell Waste Treated With Phosphoric Acid Used as a Green, Metal-Free Catalyst for Hydrogen Generation From Hydrolysis of Sodium Borohydride
(PERGAMON-ELSEVIER SCIENCE LTD, 2020) Fangaj, Enis; Ceyhan, Ayhan Abdullah
In this study, grinded apricot kernel shell (GAKS) biobased waste was used for the first time as a cost-effective, efficient, green and metal-free catalyst for hydrogen generation from the hydrolysis reaction of sodium borohydride (NaBH4). For the hydrogen production by NaBH4 hydrolysis reaction, GAKS was treated with various acids (HCl, HNO3, CH3COOH, H3PO4), salt (ZnCl2) and base (KOH). As a result, the phosphoric acid (H3PO4) demonstrated better catalytic activity than other chemical agents. The hydrolysis of NaBH4 with the GAKS-catalyst (GAKS(cat)) was studied depending on different parameters such as acid concentration, furnace burning temperature and time, catalyst amount, NaBH4 concentration and hydrolysis reaction temperature. The obtained GAKS(cat) was characterized by ICP-MS, elemental analysis, TGA, XRD, FT-IR, Boehm, TEM and SEM analyses and was evaluated for its catalytic activity in the hydrogen production from the hydrolysis reaction of NaBH4. According to the results, the optimal H3PO4 percentage was found as 15%. The maximum hydrogen generation rate from the hydrolysis of NaBH4 with the GAKS(cat) was calculated as 20,199 mL min(-1) g(cat)(-1) As a result, it can be said that GAKS treated with 15% H3PO4 as a catalyst for hydrogen production is an effective alternative due to its high hydrogen production rate. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Bakır Nanopartikülün Kesme Sıvısı Katışkısı Olarak Kullanılabilirliğinin İncelenmesi
(IGSCONG, 2023) Şirvan, Onur Can; Çetin, Muhammet Hüseyin; Temel, Farabi; Özçelik, Babür; Türköz, Mevlüt
Bu çalışmada kesme sıvılarının tribolojik performansının geliştirilmesi hedeflenmiştir. Bunun için kesme sıvısına jelatin kaplı bakır nanopartikülleri (CuNP) eklenerek kesme sıvısının yağlayıcılık ve soğutma performansı geliştirilmiştir. Çalışmada sfero dökme demir malzeme üzerinde sabit kesme hızı, ilerleme ve derinlik parametreleri kullanılarak frezeleme yapılmış, bor solüsyonu (%5 bor yağı + su) ile CuNP katkılı kolloidal solüsyonun performansı karşılaştırılmıştır. Ölçülen kesme kuvvetleri ve işlenen malzemenin yüzey pürüzlülük değerleri incelendiğinde, CuNP katkılı süspansiyon ortamında yapılan deneylerde kesme kuvvetlerinin bor solüsyonuna göre %2,57 daha düşük olduğu, yüzey pürüzlülük değerlerinin ise %24,49 daha fazla olduğu görülmüştür.
Behaviors of Removing Diesel Oil From Water With Ps/Ti4o7 Composite Nanofibers: Modeling Diesel Oil Sorption Capacity for Tap Water and Investigation of the Effects of Ph on Sorption at Different Temperatures for Times
(Springer Heidelberg, 2022) Dinçer, Kevser; Özaytekin, İlkay
In this study, pure polystyrene nanofiber and polystyrene composite nanofibers with different ratios of Ti4O7 were obtained. Diesel oil sorption of the obtained nanofibers was investigated in two experimental studies. The aim of the first was to experimentally determine the nanofiber with the fastest diesel oil sorption capacity. For this purpose, the diesel oil sorption capacity (q) was examined for both pure polystyrene (PS) nanofibers and PS nanofibers with 15 wt% and 25 wt% Ti4O7 nanoparticle additives in different volumetric mixing ratios (Vr) of diesel oil and tap water. The results of this study determined that the fastest diesel oil sorbent capacity was formed in 15 wt% Ti4O7 nanoparticle-doped PS nanofiber (PSNF2). The data were modeled with Rule-Based Mamdani Type Fuzzy Logic (RBMTF). The input parameters of RBMTF were density (D), Vr, time (t), initial mass of fibers (m(o)), and tap water sorption mass (m(w)), while the q was output parameter. The multiple coefficient of determination for q was calculated as R-2 = 0.9825. The purpose of the second experimental study was to examine the behavioral performance (Delta m) of nanoparticles-doped PS nanofibers (PSNF2), which has the fastest the diesel oil sorption capacity, at different pH and different temperatures, according to different timings. In this experimental study, it was determined that the behavior performance of PSNF2 was the highest at pH7, especially at 20 degrees C for the first minute.
Citation - WoS: 37
Citation - Scopus: 47
Behaviour of Waste Polypropylene Pyrolysis Char-Based Epoxy Composite Materials
(SPRINGER HEIDELBERG, 2020) Soğancıoğlu, Merve; Yel, Esra; Ahmetli, Gülnare
In this study, polypropylene (PP) plastic wastes were pyrolysed. Solid pyrolysis product (char) was used as filler material for the preparation of epoxy composite. 300, 400, 500, 600 and 700 degrees C were selected as final pyrolysis temperatures. Solid pyrolysis product (char) was analysed by elemental, FTIR, SEM, BET and TGA analysis. The epoxy composite samples were prepared with char obtained from pyrolysis. Mechanical properties of composites were analysed by hardness, tensile strength, elongation at break, electrical conductivity tests to explain the effects of pyrolysis temperature and char doses over composite properties. Thermogravimetric properties of composites were determined by TGA analyses. The water absorption behaviour of composite samples was determined by water adsorption test. Epoxy composite produced from PP char obtained under 300 degrees C showed the most ideal behaviour.
Benzene, Toluene, and Xylene (btx) Detection Using Quartz Crystal Microbalance (qcm) Sensor Deposited by Calixarene Derivative Having Methyl Ester Moieties
(EurasianBioChem, 2020) Temel, Farabi
The industrialization has brought many products and services. Although these developments are thought to provide many advantages that facilitate life such as technology, it is seen that chemical production and consumption have increased gradually. Volatile Organic Compounds (VOCs) are very important in that they can negatively affect human and environmental health, even at low concentrations among organic pollutants. Many production processes such as oil, varnish, paint, rubber and solvent production can be the source of VOCs. Among VOCs, benzene, toluene, and xylene (BTX) are very toxic chemicals that are widely used in industrial environments. For this reason, since exposure to BTX directly or indirectly causes serious health problems, they need to be monitored and kept under control. Sensors are the device which has properties of sensing to use for controlling and sensing of analytes. In sensor applications, there are several methods which are electrochemical, calorimetric, optical and acoustic systems for determination and sensing analyte via chemical interaction. Among these methods, Quartz Crystal Microbalance (QCM) technique is defined as response according to mass change on quartz crystal. QCM compose of a piezoelectric quartz crystal that has a sensitive and selective coating that serves as an adsorptive surface. Macromolecules and polymers can be widely used as a sensor for sensing of VOCs. Among macromolecules, calixarenes, well-known macrocyclic molecules that have almost unlimited derivatization potential and a unique three-dimensional structure. Calixarenes can be useful materials for sensor applications due to their sensitivity and selectivity possibilities towards many VOCs. In our previous works, we have also synthesized some calixarene compounds and they have been investigated their sensing properties for VOCs. In this study, I have prepared a calix[4]arene derivative having methyl ester moieties and coated onto QCM surface to investigate its sensing ability towards some benzene, toluene and xylene vapors.
Citation - WoS: 5
Citation - Scopus: 7
Biochar Produced From Co-Pyrolysis of Olive Pomace & Crude Oil as an Adsorbent for Cr (vi) Removal From Aqueous Solutions
(Iranian Institute of Research and Development in Chemical Industries, 2022) Almezgagi, Maha; Kaya Güzel, Gülcihan; Kar, Yakup; Deveci, Hüseyin
This study investigated aqueous solution treatment to remove Cr (VI) using a biochar-based adsorbent. Olive pomace and crude oil were used to synthesize the biochar adsorbent via co-pyrolysis for the first time. The biochar properties were examined with Fourier Transform Infra-Red (FT-IR) spectroscopy, scanning electron microscopy (SEM), and Energy Dispersive X-ray (EDX) analyses before and after adsorption. The adsorption experiments were carried out in a batch process under different experimental conditions. The optimum adsorption efficiency was experimentally found to be at pH of 1.5, contact time of 15 min, Cr (VI) initial concentration of 20 mg/L, adsorbent dose of 0.4 g, and 303 K. Langmuir and Freundlich isotherms were used to evaluating the adsorption performance of biochar, and the Langmuir isotherm model was well fitted to experimental data with a maximum adsorption capacity of 9 mg/g. Kinetic experimental data was best described using a pseudo-second-order kinetic model. The thermodynamic parameters of the adsorption process were examined in detail, and the process was exothermic and spontaneous in nature. It is concluded that biochar can be successfully used as an adsorbent for the treatment of Cr (VI) contaminated water. Additionally, the evaluation of olive pomace provided not only a decrease in waste accumulation in the olive production industry but also the synthesis of an inexpensive and environmentally friendly adsorbent. © 2022, Iranian Institute of Research and Development in Chemical Industries. All rights reserved.

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