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  • Küçük Resim
    Öğe
    Magnetite nanoparticles grafted with murexide-terminated polyamidoamine dendrimers for removal of lead (II) from aqueous solution: synthesis, characterization, adsorption and antimicrobial activity studies
    (Journals & Books, 2021-03) Ekinci, Selma; İlter, Zülfiye; Ercan, Selami; Çınar, Ercan; Çakmak, Reşit
    In this study, new, efficient, eco-friendly and magnetically separable nanoadsorbents, MNPs-G1-Mu and MNPs-G2-Mu, were successfully prepared by covalently grafting murexide-terminated polyamidoamine dendrimers on 3-aminopropyl functionalized silica-coated magnetite nanoparticles, and used for rapid removal of lead (II) from aqueous medium. After each adsorption process, the supernatant was successfully acquired from reaction mixture by the magnetic separation, and then analyzed by employing ICP-OES. Chemical and physical characterizations of new nanomaterials were confirmed by XRD, FT-IR, SEM, TEM, and VSM. Maximum adsorption capacities (qm) of both prepared new nanostructured adsorbents were compared with each other and also with some other adsorbents. The kinetic data were appraised by using pseudo-first-order and pseudo-second-order kinetic models. Adsorption isotherms were found to be suitable with both Langmuir and Freundlich isotherm linear equations. The maximum adsorption capacities for MNPs-G1-Mu and MNPs-G2-Mu were calculated as 208.33 mg g−1 and 232.56 mg g−1, respectively. Antimicrobial activities of nanoparticles were also examined against various microorganisms by using microdilution method. It was determined that MNPs-G1-Mu, MNPs-G2-Mu and lead (II) adsorbed MNPs-G2-Mu showed good antimicrobial activity against S. aureus ATTC 29213 and C. Parapsilosis ATTC 22019. MNPs-G1-Mu also showed antimicrobial activity against C. albicans ATTC 10231.
  • Küçük Resim
    Öğe
    Experimental determination of the mechanical properties of adhesive joints bonded epoxy adhesive included Al2O3 nanoparticule
    (European Journal of Technic, 2016-08-01) Adin, Hamit; Saraç, İsmail; Temiz, Şemsettin
    Yapıştırma bağlantılarında, yapıştırıcı içerisine katılan nanopartiküllerin, bağlantıların mekanik özelliklerine etkisi ile ilgili araştırmalar son zamanlarda dikkat çekmektedir. Bu çalışmada; epoksi yapıştırıcı içerisine % 2 oranında Al2O3 nanopartikül katılarak ve katkısız epoksi yapıştırıcı kullanılarak tek tesirli bindirme bağlantıları oluşturulmuş ve bağlantıların mekanik özellikleri çekme yükü altında 20 mm, 25 mm ve 30 mm bindirme boylarında deneysel olarak incelenmiştir. Deneysel çalışmalarda DP460 epoksi yapıştırıcısı, Al2O3 nanopartikülleri ve yapıştırılan malzeme olarak St-37 çeliği kullanılmıştır. Deneylerden elde edilen sonuçlar incelendiğinde; % 2 Al2O3 nanopartikül katkılı yapıştırıcıların kullanılmasıyla 20 mm ve 30 mm bindirme boylu bağlantılarda genel olarak hasar yükü azalmıştır. Ancak 25 mm bindirme boyunda % 5 oranında bir artış görülmüştür. Ayrıca nanopartikül ilavesi bağlantıların uzama kapasitelerine azaltıcı yönde etki yapmıştır.
  • Küçük Resim
    Öğe
    Thermal performance enhancement of flat-plate solar collectors by means of three different nanofluids
    (Elsevier, 2018-12) Budak Ziyadanoğulları, Neşe; Yıldız, Cengiz; Yücel, Halit Lutfi
    Solar energy, which comes first among renewable energy sources, enables efficient use of energy with many applications due to its low operating cost and environmental friendliness. In this study, we experimentally investigated the effects on thermal efficiency of nanofluid and water as working fluids in flat-plate solar collector hot water solar energy systems. Nanofluids were prepared by adding Al2O3, CuO, and TiO2 nanoparticles at 0.2, 0.4, and 0.8 vol% into distilled water, and then the thermophysical properties (thermal conductivity, viscosity) of the prepared nanofluids were determined. Flow rate was adjusted to 250 l/h at given concentrations for each nanofluid in the experimental setups and data such as collector inlet and outlet temperatures, ambient and tap water temperatures; radiation, humidity, and wind speed were measured and recorded. The obtained data were used to calculate efficiencies according to ASHRAE 93-2003 standards. When compared with water, the results indicated that the use of nanofluid increased collector efficiency.