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Öğe Biosorption of methyl orange from aqueous solution with hemp waste, investigation of isotherm, kinetic and thermodynamic studies and modeling using multigene genetic programming(SPRINGER INT PUBL AGGEWERBESTRASSE 11, CHAM CH-6330, SWITZERLAND, 16.08.2022) Kütük, Nurşah; Arslan, SibelWater resources around the world are getting polluted day by day due to the rapidly developing industry. Industrial wastes have caused serious damage to the environment in recent years. Especially, dyes are waste products that mix with waters such as lakes, rivers and seas and have toxic and carcinogenic effects. In this study, the removal of methyl orange (MO) dye, which was chosen as a model dye compound, from aqueous solution by biosorption using hemp waste was investigated. The biosorption process was optimized by the parameters of pH, initial dye concentration and amount of biosorbent. Biosorption of MO to hemp waste was investigated by isotherms, kinetics and thermodynamic studies. It was determined that the biosorption equilibrium fitted to the Langmuir isotherm (R2 =0.9739). As a result of the experimental studies, 83% biosorption value and 1428 mg/g maximum biosorption capacity were reached with 250 mg/L dye concentration and 0.5 g/L biosorbent amount at pH = 2. It was determined that the reaction kinetics were in accordance with the pseudo-second-order kinetics (R2 =0.9911). In addition to, the study aims to evaluate to what extent the modeling of the biosorption process is successful. For this purpose, we used multigene genetic programming (MGGP), which has been renewed with the latest developments in the field of model extraction. The results show that MGGP is efficient for modeling the biosorption process in real environments. The analysis of MGGP models also showed that pH is the most important parameter affecting the biosorption process.Öğe Congo Red Biosorption with Dried Mint Leaves; Isotherm and Kinetic Studies(Osman SAĞDIÇ, 2022) Kütük, NurşahThe development of the industry has resulted in a proportional increase in waste materials. Waste industrial products play a major role in the pollution of nature along with seas, lakes, and various water resources around the world. Organic dyes, which do not degrade in nature and have carcinogenic effects, are important industrial wastes. The improvement of wastewater is a research topic that has gained importance in recent years. In this study, the biosorption of Congo red dye from aqueous solution with dried mint leaves was investigated. The experiments were carried out at 20 °C and the natural pH of the dye. The process was optimized by examining the parameters of initial dye concentration, amount of biosorbent and contact time. It was determined that the biosorption equilibrium conformed to the Langmuir isotherm (R2=0.9815) and the maximum biosorption capacity (qmax) was 60.24 mg/g. In addition, the process conforms to the pseudo-second-order (R2=0.9946) kinetic model. As a result of the process, the removal of the Congo red dye from the dried mint leaves from the aqueous solution was achieved at a level of approximately 70%.Öğe Effect of Reduction Temperature and Time on The Reduction of Graphene Oxide with White Cabbage Extract(2021) Kütük, Nurşah; Gürer, Sevil ÇetinkayaGraphene is an important material that has attracted attention in recent years due to its large surface area, mechanical strength, thermal, electrical and magnetic properties. In this work, reduced graphene oxide (RGO) was obtained by reducing the graphene oxide (GO) with green synthesis. For this purpose, white cabbage aqueous extract was selected to reduce GO. The total phenolic acids, which are the reducing agent in the extract, were determined according to the Folin-Cioceltau method. It was determined that there is 0.064 grams of polyphenols in 1 mL of white cabbage extract. In order to determine the reduction experimental conditions, a reduction temperature of 25, 50 and 100 ?C and 1, 2, 4 and 6 hours of reduction time were studied. Structural characterization of synthesized RGOs was performed with XRD, FTIR and SEM techniques. The results showed that GO was reduced at a reduction reaction temperature of 100 °C and a reduction reaction time of 6 hours. The peak seen at 22.08? in the XRD data is evidence of reduction of GO.Öğe Effect of Reduction Temperature and Time on The Reduction of Graphene Oxide with White Cabbage Extract(Bitlis Eren Üniversitesi, 2021) Kütük, Nurşah; Gürer, Sevil CetınkayaGrafen, geniş yüzey alanı, mekanik dayanımı, ısıl, elektriksel ve manyetik özellikleri nedeniyle son yıllarda dikkatleri üzerine çeken önemli bir malzemedir. Bu çalışmada grafen oksitin (GO) yeşil sentezle indirgenmesi ile indirgenmiş grafen oksit (RGO) elde edilmiştir. Bu amaçla, GO'yu indirgemek için daha önce kullanılmamış beyaz lahana sulu özütü seçildi. Özütteki indirgeyici ajan olan toplam fenolik asitler Folin-Cioceltau yöntemine göre belirlendi. 1 mL beyaz lahana özütünde 0.064 gram polifenol olduğu tespit edildi. İndirgeme deney koşullarını belirlemek için 25, 50 ve 100 ⁰C indirgeme sıcaklığı ve 1, 2, 4 ve 6 saatlik indirgeme sürelerinde çalışılmıştır. Sentezlenen RGO'ların yapısal karakterizasyonu XRD, FTIR ve SEM teknikleri ile yapıldı.Öğe GREEN REDUCTION OF GRAPHENE OXIDE BY USING KOMBUCHA TEA(2019) Kütük, Nurşah; Boran, Filiz; Gürer, Sevil ÇetinkayaIn this study, a simple and efficient method of reduction for the preparation of reduced graphene oxide (RGO) from grapheneoxide (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 wasdetermined by using Folin-Cioceltau method. KT and GO were mixed in certain ratios to reduce graphene oxide (RGO) atroom temperature. RGO was characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and FourerTransform Infrared (FTIR). It was clearly observed that the functional groups containing oxygen were reduced as a result ofthe analyzes.Öğe İndirgenmiş grafen oksit-kil kompozitlerinin hazırlanması, karakterizasyonu ve ilaç salım özelliklerinin incelenmesi(Sivas Cumhuriyet Üniversitesi, 2019) Kütük, Nurşah; Gürer, Sevil ÇetinkayaBu çalışmada ilk olarak Hummers yöntemiyle grafit (Gr) tozundan grafen oksit (GO) sentezlendi. Elde edilen GO örnekleri X-Ray Difraksiyonu (XRD), Fourier Dönüşümlü İnfrared Spektroskopisi (FTIR) ve Taramalı Elektron Mikroskopisi (SEM), Ultraviyole Spektroskopisi (UV) ve Raman Spektroskopisi ile karakterize edildi. Daha sonra GO'yu indirgemek için siyah çay, beyaz ve mor lahananın sulu özütleri, indirgeyici ajan olarak kullanıldı. GO'nun indirgenmesi üzerine, özüt derişimi, tepkime sıcaklığı ve süresi gibi parametreler değiştirilerek indirgenmiş grafen oksitler (RGOs) hazırlandı. GO'nun indirgenmesi üzerine bu parametrelerin etkisi incelenerek, uygun özüt derişimi, tepkime sıcaklığı ve süresi gibi parametlere her bir özüt için ayrı ayrı belirlendi. Siyah çay özütü için en uygun deney şartları 40 mg siyah çayın 100 mL saf suda demlenerek hazırlanan özüt derişimi, 100 oC tepkime sıcaklığı ve 4 saat tepkime süresi olarak seçildi. Mor ve beyaz lahana özütü için özüt derişimi, siyah çay için seçtiğimiz derişimdeki toplam fenolik miktarı temel alınarak seçildi. Her iki özüt için de 100 oC tepkime sıcaklığı ve 6 saat tepkime süresi, en uygun deney şartları olarak seçildi. Bu şartlarda bütün özütlerle hazırlanan RGOs'in özellikleri XRD, FTIR ve SEM teknikleri ile incelendi. GO için en uygun indirgeyici ajan siyah çay özütü olarak belirlendi ve kompozitler bu özüt kullanılarak hazırlandı. Çalışmanın ikinci bölümünde, montmorilonit grubu bir kil olan sodyum bentonit (NaB) ile GO, siyah çay özütü için belirlenen deney şartlarında karıştırılarak indirgenmiş grafen oksit/ sodyum bentonit (SRGO/NaB) kompozitleri hazırlandı. Bu kompozitler hazırlanırken GO/NaB (w/w) kütle oranları 1/1, 1/2, 1/3 ve 1/4 idi. Hazırlanan bütün numunelerin XRD ve FTIR analizleri yapıldı. Analiz sonuçlarından SRGO/NaB kompozitinin en iyi GO/NaB oranının 1/1 (w/w) olduğuna karar verildi. Daha sonra bütün bu oranlarda hazırlanan SRGO/NaB kompozitlerine, hazırlanan siyah çay özütünün toplam hacmi üzerinden 1/20 oranında, Poli Etilen Glikol (PEG 400) eklenerek SRGO/NaB/PEG kompozitleri hazırlandı. PEG ile hazırlanan kompozitlerin özelliklerinin incelenmesinden sonra, ilaç salımında kullanılacak, en uygun SRGO/NaB/PEG kompozitinin GO/NaB (1/3) (w/w) oranında hazırlanan olduğuna karar verildi. Hazırlanan SRGO/NaB(1/1) ve SRGO/NaB/(1/3)/PEG kompozitleriyle GO, NaB ve PEG 400 örneklerinin antibakteriyel analizi Minimum İnhibisyon Broth yöntemine göre yapıldı. Analiz sırasında Staphylococcus aureus (ATTC 29213), Pseudomonas aeruginosa (ATCC 27853), Escherichia coli (ATCC 25922) ve Bacillus cereus (ATCC 11778) bakterileri ile Candida albicans (ATCC 10231), Candida tropicalis (DSM 11953) mayaları kullanıldı. Örneklerin antibakteriyel özellikleri minimum inhibisyonu konsantrasyonuna (MIC) göre belirlendi. SRGO/NaB(1/1) ve SRGO/NaB(1/3)/PEG kompozitlerinin Escherichia coli bakterisine karşı zayıf antimikrobiyal oldukları sonucuna varıldı. Çalışmanın üçüncü bölümünde, hazırlanan SRGO/NaB(1/1) ve SRGO/NaB(1/3)/PEG kompozitlerine, organik bir asit olan gallik asit (GA) yüklemesi, pH=7.4 (kan plazma ortamı) ve pH=4.56 (mide ortamı) değerlerinde yapılarak ilaç salım özellikleri incelendi. Sonuçlar GA'nın yüklenme veriminin hem SRGO/NaB(1/1) hem de SRGO/NaB(1/3)/PEG kompozitleri için %58.46 olduğunu ortaya çıkardı. İlaç salımının ise her iki kompozit için de yavaş seviyede olduğu belirlendi. Anahtar kelimeler: grafen oksit, grafen, indirgeme, bitkisel yöntem, siyah çay, sodyum bentonit, gallik asit, ilaç salımıÖğe İnorganik malzemeler kullanarak jeopolimer sentezi ve özelliklerinin incelenmesi(Cumhuriyet Üniversitesi, 2013) Kütük, Nurşah; Çetinkaya, SevilJeopolimerler doğal mineraller veya endüstriyel atıklardan elde edilen silikat ve alümina silikatlardan oluşan yeni malzemelerdir. Jeopolimerler atıkların yararlı ürünlere dönüştüğü potansiyel bir alternatif malzeme olarak görülür. İnorganik polimerler ve jeopolimerler, seramik ve çimento temelli malzemeler için çok iyi özelliklere sahip çeşitli alanlarda gelecek vadeden malzemeler olarak ortaya çıkmıştır. Bu çalışmanın amacı jeopolimerler hazırlayarak özelliklerini FTIR, XRD, SEM ve DTA/TGA teknikleriyle incelemektir. Karışımın ve karıştırma zamanının jeopolimerin mekaniksel özellikleri üzerine etkisi de özellikle incelenecektir. Kür sıcaklığı ve Na2SiO3/NaOH kütle oranının jeopolimerin özellikleri üzerindeki etkisi incelenecektir. Anahtar kelimeler: Jeopolimerler, Talk, Basma Dayanımı, KalsitÖğe Investigation and Optimization of Biosorbent Capacities of Some Plants Used in Daily Life(2024) Arslan, Sibel; Kütük, NurşahIn this study, sage, chamomile, and tarragon leaves, which are used as spices and consumed as beverages in daily life, were considered as different biosorbents that can be used in water purification by biosorption. At the same time, the effects of the parameters of initial dye concentration (10-200 mg/L), temperature (20-50 ⁰C) and contact time (0-120 min) on biosorption capacity were investigated. The biosorption processes were found to follow Freundlich isotherm and pseudo-second order (PSO) reaction kinetics. In the study, the process was also modeled using multi-tree evolutionary computation based automatic programming (AP) methods. The methods used initial dye concentration, temperature, and contact time as variables. According to the simulation results, these methods obtained nonlinear mathematical models of the processes with R^2 values as high as 0.99 for each biosorbent. By providing the most accurate models to accurately predict biosorption capacity, this study will make a significant contribution to the field of water treatment using experimental and AP methods.Öğe Mesoporous silica nanoparticles, methods of preparation and use of bone tissue engineering(International Society of Academicians, 2021) Kütük, NurşahBiomaterials are a large group of vitally important materials with many different inorganic and organic types. Biocomposites are produced by using materials such as polymer, metal, and ceramics. Bone tissue engineering deals with materials that can mimic the real bone structure found in the body. These materials used in the human body must be capable of many aspects such as their mechanical strength related to the area where they are used, as well as their properties such as biocompatible, biodegradable, and non-toxic. If the material is intended to treat the bone structure, it should be biodegradable, but it should be resistant to degradation if intended to be used for a long time. With the advance in technology, nanoparticles have become appealing in bone tissue engineering due to their many unique properties. In recent years, mesoporous silica nanoparticles (MSNs) have been prominent biomaterials in the medical field due to their properties such as alterable size structure, large pore volume, and surface area. This study aims to give information about the biomedical properties, synthesis methods, and importance of MSNs with unique properties in bone tissue engineering applications. This study is compiled by examining many studies in the literature.Öğe Nanoengineering and nanoscience: Current and emerging trends(De Gruyter, 2023) Kütük, Nurşah; Gürbüzer, Aslihan; Tüzün, Gamze; Tüzün, BurakThe study of science at the nanoscale has become one of the most important research topics in recent years. Almost all branches of science are interested in nano-technology. Metal and metal oxides, carbon family products, polymers, clays and composites are some of the nanomaterials used. Despite their small size, nanomaterials have different properties such as large surface area, different particle shape and size, pore volume, biocompatibility and biodispersibility. For this reason, nanotechnology has also spread to the industry. Due to their unique properties, nanomaterials are widely used in medical, water treatment, sensor and environmental applications. Although nanotechnology research has accelerated especially in recent years, there are still many unexplored materials and application areas. The aim of this study is to investigate the advantages and disadvantages of nanomaterials and nanotechnology applications by examining their usage areas in scientific and industrial fields. ©2023 Walter de Gruyter GmbH, Berlin/Boston. All rights reserved.Öğe Reduction of Graphene Oxide using purple cabbage extract and investigation of photocatalytic activity by oxidation(Gazi Universitesi, 2023) Kütük, Nurşah; Boran, Filiz; Gürer, Sevil ÇetinkayaGraphene and its derivatives are an important material with many unique properties and potential in photocatalytic degradation and adsorption applications. Removal of oxygen-containing functional groups by reduction of graphene oxide (GO) is an interesting method that has been used frequently in recent years. The aim of this study is to examine graphene oxide reduction by using green synthesis and purple cabbage aqueous extraxt, which is an easy and effective method, and its use in photocatalytic removal applications. To optimize the synthesis conditions, the reaction temperature was first studied at 25, 50, and 100?, and then the reaction time was studied for 1, 2, 4, and 6 hours. According to XRD, FTIR, UV/vis and SEM results, suitable experimental conditions for GO reduction are obtained at reaction temperature of 100? and reaction time of 6 h. The obtained reduced graphene oxide (IGO) was used in photocatalytic degradation experiments in the aqueous solution of methylene blue (MM), an organic and cationic dye, under UV lamp and in the presence of H2O2. The results showed that after 120 min, IGO removed 85% of MM from the aqueous solution. It was determined that the MM photocatalytic degradation reaction kinetics of IGO matched the pseudo second-order reaction kinetics. © 2023 Gazi Universitesi Muhendislik-Mimarlik. All rights reserved.
