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Hibrit süperkapasitörler için metal-organik kompozit temelli malzemeler
Hybrid supercapacitors, consisting of battery-like and capacitive electrodes, are considered promising energy storage devices due to their favorable power and density. The style and manufacture of battery-like and capacitive electrodes with high specific capacitances, high performance, and desired toughness are crucial to improving the overall energy storage performance of hybrid supercapacitors. Metal-organic frameworks (MOF) with functional properties, tunable chemical structures can result in preferable energy storage efficiencies of hybrid supercapacitors. Different types of MOF calcinations have been studied in supercapacitor applications In this work, a cobalt-based 2D coordination polymer was prepared under standard solvothermal conditions using Co(NO3)2.6H2O as metal precursor, 1,4-benzenedicarboxylate(BDC) and 1-vinylimidazole (1-VIM) as organic ligants and N,N-dimethylformamide (DMF) and ethanol as solvents. 2D coordination polymer [Co3(BDC)3(1-vim)2] was obtained and chracterized by thermogravimetry/differential thermal analysis (TA), powder X-ray diffraction (PXRD) and Fourier transforms infrared spectroscopy (FTIR). TA results confirmed that [Co3(BDC)3(1-vim)2] decomposes in three main stages and the finally Co3O4 formation was observed. Vibration of vinily, carboxyl and C—H were observed in FTIR results. Powder X-ray data was used to characterise crystal structures formed. Cobalt-based active materials, Co3O4 was obtained by thermal treatments at diffrenet temperratures and chracterized by powder X-ray diffraction. Polyvinylidene fluoride was used as the binder material and and conductive carbon was used to improve the conductivity in making of electrodes for supercapacitors. Electrochemical performance of [Co3(BDC)3(1-vim)2] and Co3O4 were studied by the cyclic voltammetry in a three- electrode system in KOH and Na2SO4 electrolyte. The results are compatible with the literature values.
Dental metalik malzemelerin bitki özütü katkılı biyo uyumlu polimerler ile kaplanması
The present study was designed to applicate the coating of metallic biomaterials used in dentistry with polymer materials containing plant extracts. The electrospray deposition (ESD) technique, which is a low-cost and practical method, was used to form micrometer scale coatings produced with nanoparticles produced by green synthesis, plant extracts, and Polyvinyl Alcohol (PVA). The properties of nanoparticles and polymer composite coating materials produced using Hemp seeds, St. John's Wort, Rosemar,y and Cherry Laurel Leaf extracts were investigated and compared with different concentrations and plant groups. The effects of fabrication technique and initial composition on the morphology, thermal, mechanical, and chemical behavior of nanocomposite coatings are investigated and discussed. Scanning Electron Microscope (SEM) analysis showed that green synthesized nano silvers were produced with an average size of 34 nm, with homogeneous size and distribution. It was revealed that there are different mineral elements from plant extracts in the contents of the initial nanocomposite films and post-coating surfaces produced. Dynamic mechanical analyzes showed that the samples produced with 0.3%(D) and 0.5%(E) nano silver modification were the samples with the highest thermal and mechanical strength after coating. Antibacterial tests revealed that all nano silver-added coatings reduced bacterial growth up to 100 times and the sample with the highest antibacterial effect was the 0.5% nano silver modified E sample. The scratch test applied to determine the coating mechanical properties showed that the hardest samples among the coating surfaces were 0.1%(C), 0.3%(D), and 0.5%(E). In addition, it was determined that the mechanical strength of the coatings increased at least 2 times with the modification of plant extracts to PVA compared to the pure coatings. It was determined that the chemical and mechanical stability of nanosilver-modified C, D , and E samples in water at 37°C were higher than the other samples. Toxicity tests confirmed that the green synthesized nano silvers did not show toxic effects on HaCaT live cells and A549 lung cancer cells, with the use of concentrations at 62 ug/mL and below in coatings. The present study has offered a framework for the exploration of the plant extracts and nano-silver modified polymer nanocomposite coatings coating applications in the health field. The empirical findings in this study provide a new understanding for the antibacterial and biocompatible production of metallic biomaterials using plant extracts. This study will have a wide range of uses for scientific and biomedical communities with its important findings such as low raw material and production cost, easy manufacturability, environmental and human health friendly, low toxic effect, thermal and mechanical strength.
Biyomedikal uygulamalar için kitosan/polivinilalkol/polivinilproliden hidrojellerin sentezi ve karakterizasyonu
This work focuses on the synthesis of a novel biocompatible hydrogel film for biomedical applications, incorporating chitosan, polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), and nano-hydroxyapatite (nHA) as a filler. The aim is to investigate the effect of nHA on the polymeric matrix and explore the potential of the hydrogel film in biomedical applications. The hydrogel films were prepared using a solution-casting technique. Solutions of 1.75% chitosan in 1% aqueous acetic acid at 20 C, 1% PVA, and 2% PVP in distilled water at 80°C were mixed together, followed by the addition of varying ratios of nHA. The prepared hydrogel film samples were subjected to various characterizations, including thermogravimetric analyses (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), antibacterial activity testing, Fourier transform infrared (FTIR) spectroscopy, mechanical testing, swelling analysis, and drug release profiling. The hydrogel film exhibited excellent antibacterial behavior, particularly against Gram-positive bacteria, with the incorporation of nHA enhancing the antibacterial properties. TGA results showed that the weight loss percentage during degradation stages was lower in hydrogel films containing nHA compared to those without. FTIR spectra indicated that the molecular structure of the hydrogel was minimally affected by the incorporation of nHA. The swelling behavior of the hydrogel films was influenced by the quantity of nHA incorporated. The drug release profile demonstrated rapid release and good stability. The addition of nHA to the films increases the force and elongation at break, indicating improved mechanical strength and ductility. However, it decreases Young's modulus, making the films softer or less stiff. The combination of the polymeric hydrogel film with nHA shows promising potential for biomedical applications. Further research is needed to explore its full potential in biomedical fields.
Biyolojik olarak sentezlenen gümüş nanopartiküllerine maruz kalan klebsıella pneumonıae'nın transkriptomik analizi
Silver nanoparticles play an important role in the fields of nanoscience and nanotechnology. Silver nanoparticles are promising in the development of new drugs with antibacterial and antifungal activity, especially in nanomedicine. Various physical, chemical and biological methods can be used for the synthesis of silver nanoparticles. This study was planned for the transcriptomic analysis of Klebsiella pneumoniae exposed to silver nanoparticles synthesized by an Antarctic actinobacterium Arthrobacter sp. H14-L1. The synthesized silver nanoparticles were characterized by visible and ultraviolet light spectroscopy (UV-vis), scanning electron microscopy – energy dispersive X-ray spectroscopy (SEM-EDX), and X-ray crystallography. According to the UV-vis analysis, silver nanoparticles showed maximum absorbance at 419 nm wavelength. The SEM-EDX analysis showed that the silver nanoparticles synthesized by Arthrobacter sp. H14-L1 were spherical in shape and 58-68 nm in size. The X-ray crystallography analysis confirmed that the synthesized silver nanoparticles were in crystalline form. The genome of Arthrobacter sp. H14-L1 used in the synthesis of silver nanoparticles was downloaded from the NCBI GenBank, and its biosynthetic gene clusters and phylogenetic characteristics were analyzed. It was shown that synthesized silver nanoparticles inhibit the growth of Klebsiella pneumoniae. The RNA-Seq analysis was performed to reveal the gene expression differences in K. pneumoniae cells exposed to the silver nanoparticles. Although the gene expression differences in K. pneumoniae exposed to silver nanoparticles synthesized by Arthrobacter sp. H14-L1 were not statistically significant; some differences were observed in the expressions of genes related to carbohydrate metabolism, amino acid biosynthesis and degradation, and stress response in general. The results of this study contribute to the understanding of the molecular mechanisms of the toxicity of silver nanoparticles on bacterial cells.
pH güdümlü nano ilaç taşıyıcı bir sistem olarak nanosponge eldesi, karakterizasyonu in vitro ilaç salınım ve toksisite özelliklerinin araştırılması
Thesis aimed to fabricate and investigate usability of ALD-NS as a pH responsive drug delivery agent. For this aim, functionalized β-CD with aldehyde (CHO) groups were fabricated by oxidation process using varying molar ratios of NaIO4 and characterization results confirmed formation of OX-β-CDs with functional CHO groups. OX-β-CDs was crosslinked with PMDA crosslinker to obtain water soluble, solid ALD-NS with the method developed and DOX.HCl due to the presence of NH2 group was integrated by reflux method, aiming to ensure both pH sensitive Schiff base (C=N) bond and hydrophilic part of the ALD-NS. ALD-NS+DOX was characterized, and results showed this formation, encapsulation, and morphological change with PS (372.7±8.21nm), negative ZP (-12.8±1.54), high EE (85.5%). In vitro release behavior of ALD-NS+DOX was evaluated in three buffer conditions at different pH and observed that drug release at pH 5.2 is higher than at pH 7.4 environment occurring, sustain, prolong drug release profile compared to pure DOX due to easy hydrolysis of Schiff base and crosslinker. Time and dose dependent cytotoxicity and cellular uptake of ALD-NS+DOX were determined on A549 cancer cells. Cell viabilities of drug loaded NC decreased with increasing the concentration but have found higher viabilities and displayed the intensive drug accumulation on the surface or inside of the cell compared to free DOX in the all-equivalent concentration at various time range. Drug release kinetics was best expressed by the Krosmeyyer-Peppas model based on the highest correlation coefficient (R2=0.97), revealing that diffusion coefficient "n" was found 0.622 for PBS and 0.71 for NaAcetate at pH 5.2 specifying drug release occurs due to both dissolution (hydrolysis of Schiff base) and non-Fickian diffusion. As a result, the novel kind of functionalized nanostructure has the potential to be a candidate drug carrier in a low pH environment, especially for drugs containing NH2 side group.
Biylojik sentezlenmiş gümüş nanoparticles'e maruz kalan candida albicans diferansiyel gen ekspresyon analizi
Silver nanoparticles are extensively used in nanotechnology and biomedicine for various purposes due to their intrinsic therapeutic properties. Plants, algae, fungi, and bacteria have been known to produce silver nanoparticles (AgNPs) biologically, and those nanoparticles have various effects on the cells, such as antibacterial, antioxidant, and cytotoxic. There are reports showing that actinobacteria producing many bioactive secondary metabolites could produce silver nanoparticles. In this study, an actinobacterium isolated from Antarctica, Microbacterium sp. H37-C3 was used to produce silver nanoparticles extracellularly, and the cytotoxicity of these biologically synthesized silver nanoparticles on Candida albicans was investigated by a transcriptomic approach. The physical properties of the synthesized silver nanoparticles were characterized by UV–visible spectroscopy (UV–Vis), scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). It was determined that the silver nanoparticles synthesized by Microbacterium sp. H37-C3 showed the maximum absorbance peak at 417 nm. The average particle size of the silver nanoparticles ranges from 15-30 nm, and the synthesized silver nanoparticles are in crystalline structure. Moreover, genome characteristics of strain Microbacterium sp. H37-C3 was also analyzed to reveal secondary metabolite biosynthetic gene clusters and the phylogenetic relationship of the strain by downloading the whole-genome sequence of the strain from the NCBI GenBank database. Differential gene expression analysis between silver nanoparticle-exposed Candida albicans and the control group was conducted to reveal its antimicrobial activity mechanism in gene expression level. Although no statistically significant change in the gene expression levels was observed between the samples, the expression of several genes coding for small nucleolar RNAs as well as the expression of the gene coding for cytochrome c oxidase and a gene responsible for maintenance of telomere length was affected by the AgNP treatment. The results contribute insight into the toxicity mechanisms of silver nanoparticles on eukaryotic cells at the gene expression level.
Al-sı hibrit nanokompozitlerin üretimi ve karakterizasyonu
This thesis uses the Al-Si as a base matrix composite, adding the hybrid nanoparticles of MoS 2 & BN. It aims to fabricate self-lubrication parts, and the manufacturing process utilizes the technology of powder metallurgy is a favored strategy for manufacturing metal matrix nanocomposites (MMNCs). Aluminum alloys are one of the widely applied composites in MMNCs as base alloys from analysis and manufacturing estimation. As an abrasive material, Boron Nitride (BN) has a long service life and sensible wear resistance. The Molybdenum disulfide (MoS 2 ) could be a 2-dimensional semiconductor matter; it has anti-wear properties, reinforces cohesion, and reduces abrasion. Thus, it has a greasing realization that might utilized as a solid lubricator within severe heat and compression conditions. The thermal stability of BN is far more than that of diamond and has more excellent chemical stability than iron components. Therefore, BN is suitable to use for the protection of components, anti-wear, and anti-corrosion. Several experiments have been prepared to achieve optimal conditions for the alloying procedure. The samples were characterized by different methods such as XRD, SEM, EDS, physical examination, microhardness, and tribology. This study used 2, 4, and 6 weight % addition of nanoparticles MoS 2 and h-BN to the base powder alloy of Al-Si. Before tribological characterization, novel, outstanding nanocomposites are produced by mechanical milling, 7-ton pressing, and sintering at 550 °C. It is concluded that the excellent self-lubrication, high hardness, and good surface finishing of produced parts caused the wear rate to decrease whenever the hybrid addition increased to 4 %.
SLA 3b yazıcı ile nanokompozıt üretiminin optimizasyonu
3D printing is a revolutionary technology that has transformed the manufacturing industry. It is a process of creating three-dimensional objects from a CAD model or a digital 3D model using additive manufacturing technology. The surface roughness and hardness test of the parts produced using the 3D printer is one of the most important factors that greatly affect the quality of the product. The major target of this research is to find optimal values of input parameters in 3D SLA printer to minimize the surface roughness and maximize the hardness of the object using methods of experiment design such as Box-Behnken and Taguchi Method which is done with three independent parameters with three levels. The parameters are cure time, printing speed, and the weight ratio of nanoparticle mixed with the standard resin. The purpose of mixing nano clay nanoparticles with resin to improve the mechanical property of a 3D printed object is important to used in many applications. Based on the results of Response Surface Method (RSM), the optimal input parameters to obtain minimum roughness are cure time 3 s, platform speed 50 mm/s and the nanoparticle ratio %1 and the optimal input parameters to obtain maximum hardness are cure time 5 s, platform speed 100 mm/s and the nanoparticle ratio %1. In addition, the grey relation analysis for two response surface is used to find the optimal experiment conditions. It was found that the experiment 2 has the highest value of grey relational grade. The parameters of experiment number 2 is cure time is 5 s, platform speed 100 mm/s, added nanoparticle ratio % 1.
Lazer ablasyon yöntemi kullanılarak bitki ekstraktlarından metal nanopartiküllerin üretimi
Elettaria cardamomum contains: Glycosides, Alkaloids, Saponines, Tannins, and Volatile oils,in high concentrations in several plant extracts this compound is Soluble in water.hat has been shown to have anticancer activity. However, due to its solubility and bioavailability, necessitating the use of a delivery system to achieve its therapeutic goals. In this study, Elettaria cardamomum loaded on sliver nanoparticles (Car@AgNPs) was prepared by laser ablation synthesis with hot equaes Elettaria cardamomum, silver nanoparticles as reducing and covering agents. The current biosynthesis method was simple and low cost. The formation of Elettaria cardamomum loaded onto silver nanoparticles (Car@AgNPs) was observed after preparation of silvernanoparticles and addition of Elettaria cardamomum (dissolved pale yellow) by changing the color of the prepared solution from yellow to light brown. laser ablation was used to generate Elettaria cardamomum-loaded silver nanoparticles (Car@-AgNPs) identified by UV, FTIR, XRD, TEM, to validate the synthesis of Cae@AgNPs.These tests were used to confirm the mixture of Elettaria cardamomum from silver nanoparticles. Whereas, the absorption spectra of Elettaria cardamomum on sliver nanoparticles showed a curved absorption of 412 nm. FTIR was used to evaluate the molecular and functional groups of Elettaria cardamomum, which were loaded onto silver nanoparticles. XRD and TEM Studies confirmed the presence of Elettaria cardamomum loaded on silver nanotechnology particles, and regular spherical particles were found with an average size of 4-45 nm.The antioxidant activity of Cae@AgNPs was tested against DPPH, and the results revealed thatCar@AgNPs had a strong antioxidant effect and a significant activity of high radical attraction and that this antioxidant activity was based on focus, with the greater the focus whenever efficiency occurred.The antimicrobial activity of AgNPs, Elettaria cardamomum and Car@AgNPs on resistance to Staphylococcus aureus and Escherichia coli has also been studied. The results show an increase in the inhibition of the synthesis of Elettaria cardamomum and AgNPs treated sample, and this activity was more robust in Car@AgNPs. Also, the inhibition difference was observed between Gram-negative and Gram-positive bacteria, which is due to several reasons that were discussed later.The cytotoxic effect of Car@AgNPs on the human breast cancer cell line (MCF-7) was assessed. Cell viability was suppressed in a concentration-dependent manner by Car@AgNPs in MCF-7 cells.
Bi2S3 nano-çubukları dekore edilmiş bentonit nanokompozitin yapısal karakterizasyonu ve fotokatalitik uygulamaları
Bu çalışmada, Bi2S3 nanoçubukların görünür bölge ışınları altındaki fotokatalitik performansını arttırmak için Bi2S3 nanoçubuklarının bentonit üzerine dekore edilmesiyle bentonit-Bi2S3 nanokompozitini hazırladık. Ham bentonit, Bi2S3 nanoçubuk ve bentonit-Bi2S3 nanokompozit numunelerinin yapısal, morfolojik, optik ve elektrokimyasal özellikleri XRD, TEM, SEM-EDX, XPS, UV-DRS, PL, elektrokimyasal empedans spektroskopisi, kronoamperometri, zeta potansiyeli ve BET teknikleriyle incelendi. Bentonit-Bi2S3 nanokompozit ve diğer numunelerin fotokatalitik performansları görünür bölge ışınları altında karşılaştırmalı olarak kristal viyole ve Rodamin B boyalarının fotobozunmasıyla araştırıldı. Elde edilen bentonit-Bi2S3 nanokompozitin kristal viyole ve Rodamin B için fotokatalitik bozunma verimlerinin saf Bi2S3 nanoçubuklara göre daha iyi olduğu belirlenir. Bentonit-Bi2S3 nanokompozit üzerinde boya moleküllerinin fotobozunmasına ait mekanizma önerildi.
Bütünüyle katı-hal kompozit potansiyometrik iyodür seçici elektrot ve potansiyometrik uygulamaları
Bu tez çalışmasında, iyodür iyonu tayini için potansiyometrik bir katı-hal kompozit iyon seçici elektrot (İSE) geliştirildi. Elektrotun yapısında sentezi gerçekleştirilen Cıva(II)-Salisilaldehit tiyosemikarbazon kompleksi (1:1) iyonofor madde olarak kullanıldı. Seçici kompozit tabakanın optimizasyonu için, sentezlenen madde kullanılarak grafit, çok duvarlı karbon nanotüp (MWCNT), plastikleştirici, iyonikleştirici ve ortam sağlayıcılar kullanılarak farklı kompozisyonlarda kompozit iyon seçici elektrotlar hazırlandı ve potansiyometrik performans özellikleri test edildi. En iyi potansiyometrik performans özelliklerini 10 mg civa(II)-salsilaldehit tiyosemikarbazon kompleksi, 26 mg dioktilftalat (DOP) plastikleştiricisi, 5 mg MWCNT, 4 mg metiltrioktilamonyum klorür (MTOA-Cl) ve 65 mg grafit bileşimine sahip elektrotun sergilediği belirlendi. Bu elektrotun doğrusal çalışma aralığı, 1.0×10-5-1.0×10-1 M; eğim değeri -55.2 mV/on katlık konsantrasyon değişimi; tayin sınırı, 9.0 × 10-6 M; pH çalışma aralığı, 4-8 ve cevap zamanı, ≈ 60 s olarak belirlendi. Elektrotun iyodür iyonlarına karşı oldukça tekrarlanabilir, kararlı ve seçici potansiyometrik cevap sergilediği görülmüştür. Elektrotun analitik uygulaması sentetik çözeltilerde iyodür iyonunun titrasyonunda indikatör elektrot olarak kullanımıyla ve guatr hastalığının tedavisinde kullanılan bir ilacın KI içeriğinin standart ekleme yöntemiyle belirlenmesinde kullanımı ile gerçekleştirildi.
CuCoSe2 yapıların sentezi, karakterizasyonu ve elektrokatalitik özelliklerin incelenmesi
Bu tez çalışmasında, iki basamaklı hidrotermal yöntemle CoCuSe2 sentezlenmiş ve karbon pasta elektrot yapımında kullanılmıştır. Ardından elektrot yüzeyi üzerine platin nanoparçacıklarla dekore edilmiştir. CoCuSe2 nano yapıların yapısal analizi PANanalytical Empyrean markalı cihazla X ışını difraktometresi(XRD), morfolojik özellikleri FESEM FEI Quanta 450 markalı cihazla Taramalı elektron mikroskobu (SEM), kimyasal yapısı Thermo Scientific K-Alpha markalı cihazla X ışını fotoelektron spektrometresi (XPS) ve Thermo Nicolet 6700 markalı cihazla Fourier Dönüşümlü Kızılötesi Spektroskopisi (FTIR), ile karakterize edilmiştir. Elde edilen nanokompozitin elektrokimyasal etkinliği formaldehitin yükseltgenme tepkimesi incelenerek gerçekleştirilmiştir. Bu amaçla, elektrot kompozisyonu, Pt döngü sayısı, Pt derişimi ve destek elektrolit derişimi optimize edilmiştir. Optimum koşullar altında, hazırlanan elektrot, yalın CPE, CoCuSe2/CPE, Pt/CPE ve Pt/CoCuSe2/CPE elektrotlarına göre çok daha yüksek elektrokatalitik aktivite göstermiştir. Bildiğimiz kadarıyla, bu çalışma, formaldehit oksidasyonunda CoCuSe2 ve Pt nanokompozitlerinin kullanımı ile ilgili ilk çalışmadır. Sentezlenen bu katalizör yüzeyi formaldehit oksidasyonuna yönelik katalitik aktiviteyi geliştirdiğinden, bu malzeme yakıt hücresi uygulamalarında ve formaldehitin sulu çözeltilerden giderilmesi için umut verici bir adaydır.
Ag2S/g-C3N4/TiO2 nanokompozitin sentezi, karakterizasyonu ve fotokatalitik uygulamaları
Bu çalışmada, gümüş sülfür (Ag2S), grafitik karbon nitrür (g-C3N4) ve titanyum dioksit (TiO2) nanoparçacıkları içeren Ag2S/g-C3N4/TiO2 nanokompozit hidrotermal yöntem ile hazırlandı. Hazırlanan Ag2S/g-C3N4/TiO2 nanokompozitinin yüzey morfolojisi, kristal yapısı, elementel bileşimi ve yapısal özellikleri taramalı elektron mikroskobu (SEM), enerji dağılımlı X-ışını spektroskopisi (EDX), X-ışını toz kırınımı (XRD) ve Fourier dönüşümlü kızılötesi spektroskopisi (FTIR) teknikleri kullanılarak aydınlatıldı. Sentezlenen nanokompozitin fotokatalitik aktivitesi, UVA ışını altında model kirletici olarak Kristal viyole (KV) ve Rodamin B (RhB) boyar maddeleri için başarıyla test edildi. Fotakatalitik çalışmalarda katalizör miktarının KV ve RhB boyar maddeleri ile fotobozunması üzerindeki etkisi araştırıldı. Fotokatalizör olarak Ag2S/g-C3N4/TiO2 nanokompozit varlığında, 5 mgL-1 başlangıç boya konsantrasyonu, 25 mgL-1 katalizör miktarı ve 120 dakikalık UVA ışımasından sonra KV ve RhB'de bozunma verimleri sırasıyla %72 ve % 68 olarak belirlendi. Fotokatalitik bozunma deneylerinde reaktif türlerin katkısını belirlemek ve olası bir mekanizma önerebilmek için radikal süpürücü deneyleri yapıldı. İzopropanol, L-askorbik asit ve etilendiamintetraasetik asit (EDTA) sırasıyla hidroksil radikallerini, süperoksit radikallerini ve fotojenere edilmiş boşlukları süpürmek için kullanıldı. Süpürme deneyleri, KV'nin fotobozunmasında hidroksil radikallerinin (.OH) ve boşlukların (h+) önemli etkiye sahip olduğu, RhB'nin fotobozunmasında ise süperoksit radikallerinin (∙O2-) başlıca rol oynadığını göstermiştir.
Eustigmaeus absens (Acari: stigmaidae) türünden üretilen ve gümüş nanoparçacıkları dekore edilmiş kitinin, karakterizasyonu ve antibakteriyel özellikleri
Bu çalışmada Eustigmaeus absens Doğan (Acari) akar türünden kimyasal yöntemle 3D kitin elde edildi ve elde edilen kitin üzerine gümüş nanoparçacıkları dekore edildi. Elde edilen kitinler seyreltilmiş toplam yansıma-Fourier dönüşümlü infrared spektroskopisi (ATR-FTIR), stereo mikroskop, faz-kontrast donanımlı ışık mikroskobu, taramalı elektron mikroskobu (SEM), enerji dağılımlı X-ışını spektrometresi (EDX) ve geçirimli elektron mikroskobu (TEM) analizleri ile karakterize edildi ve antibakteriyel aktiviteleri değerlendirildi. Elde edilen kitinin yapısında karbon (C), azot (N), oksijen (O) elementlerinin yer aldığı, eser miktarda kalsiyum (Ca) elementinin bulunduğu belirlendi. ATR-FTIR analizi ile α-kitin için karakteristik olan amid-I ve amid-II bantları gözlemlendi. SEM görüntüleri ile kitin yüzeyinin makro gözenekler, mikro gözenekler ve kesik nanoliflerden oluştuğu açığa çıkarıldı. TEM analizi ile gümüş nanoparçacıkların boyutlarının 6-20 nm arasında farklılık gösterdiği belirlendi. Stereo mikroskop ve faz-kontrast donanımlı ışık mikroskobundan alınan görüntüler organizmanın üç boyutlu yapısını bozmadan kitin elde edildiğini gösterdi. Ayrıca gümüş nanoparçacıklı kitinin Escherichia coli ATCC 25922 ve Staphylococcus aureus ATCC 29213bakterilerine karşı antibakteriyel aktivite sergilediği belirlendi
Ömrünü tamamlamış araç lastiklerinden elde edilen karbon siyahının karakterizasyonu ve analitik uygulamaları
Bu tez, ömrünü tamamlamış araç lastiklerinden geri dönüştürülen karbon siyahının kapsamlı bir karakterizasyonunu ve çeşitli analitik uygulamalardaki potansiyelini incelemeyi amaçlamaktadır. İlk olarak, karbon siyahının fiziksel ve kimyasal karakterizasyonu yüzey morfolojisi, partikül boyutu ve termal kararlılığı gibi özellikleri detaylı bir şekilde incelenerek belirlenmiştir. Ardından elde edilen karbon siyahının safsızlıklarından ayrılması için saflaştırma işlemi yapılmıştır. Bu amaçla, aseton ve hegzan ile yıkama işlemi gerçekleştirilmiştir. Elde edilen ürün kalan yağımsı safsızlıklarından ayrılması için sıcak sodyum hidroksit ile yıkanıp sabunlaştırılarak uzaklaştırıldı. Daha sonra ürün yıkama suyu nötralleşene kadar sıcak su ile yıkanmıştır. Ardından nitrik asit ile muamele edilmiş ve hidrazin ile indirgenerek kullanıma hazır hale getirilmiştir. Boya kirleticilerinin (metilen mavisi) atık sulardan ayrışma sürecinde adsorpsiyon yöntemi esas alınmış ve demir bazlı magnetik nanopartiküllerden en kullanışlı ve yaygın olan manyetit (Fe3O4) kullanılmıştır. Sentezlenen bu nanokompozit sulardan metilen mavisi giderimi için kullanılmış ve başarılı sonuçlar elde edilmiştir. Bu bilgiler, geri dönüşüm süreçlerini geliştirmek ve endüstriyel uygulamalarda daha etkili bir şekilde kullanımını sağlamak için değerli bir temel oluşturacaktır.