Yazar "Erden, Hanife" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • Küçük Resim
    Öğe
    NiFe2O4/polyhydroxymethyl methacrylate and Fe3O4/polyhydroxymethyl methacrylate magnetic nanogels for lipase immobilization
    (Taylor and Francis Ltd., 2023) İspirli Doğaç, Yasemin; Arabacı, Gökmen; Erden, Hanife; Öztürk, Funda
    In this study, the optimization and characterization of NiFe2O4/Polyhydroxymethyl methacrylate (NF-pHEMA) and Fe3O4/Polyhydroxymethyl methacrylate (M-pHEMA) magnetic nanogel structures were carried out and the usability of these magnetic nanogels for the immobilization of lipase enzyme was investigated. Fe3O4/pHEMA (M-pHEMA) nanogel and NiFe2O4/pHEMA (NF-pHEMA) nanogel structures were produced by the photochemical method. The characterization of these materials was performed by FTIR, SEM, AFM analysis. Then, the lipase enzyme was immobilized on magnetic nanogels by adsorption and after that cross-linking method under optimum conditions. For the characterization of lipase immobilized magnetic nanogels; optimum temperature, thermal stability, optimum pH, pH stability, reusability and kinetic parameters were investigated and nature and immobilized lipase were compared. It was observed that there was a significant improvement in the thermal and pH stability of the immobilized enzyme compared to the free enzyme. Lipase-immobilized M-pHEMA lost 50% of its activity after 15 uses and after 16 uses of lipase-immobilized NF-pHEMA. The results show that immobilization to the synthesized magnetic nanogels provides an improvement in the properties of the lipase enzyme. It is thought that the synthesized magnetic nanogels can be an alternative for different applications, especially drug delivery systems.
  • [ X ]
    Öğe
    OLEİK ASİTTEN BİYODİZEL ÜRETİMİNİN KESİKLİ REAKTÖR VE MEMBRAN REAKTÖRDE KARŞILAŞTIRILMASI
    (Bartin University, 2024) Erden, Hanife; Nigiz, Filiz Uğur; Kahraman, Seniyecan
    Son yıllarda biyodizel, fosil yakıtlara sürdürülebilir bir alternatif olarak daha fazla ilgi görmektedir. Biyodizel, petrol dizel yakıtına kıyasla daha düşük egzoz emisyonlarına ve toksisiteye sahiptir. Bu çalışmada oleik asit ve etanol arasında esterleşme reaksiyonu ile biyodizel üretimi kesikli reaktör ve membran reaktörde gerçekleştirilmiştir. Kesikli reaktörde ve membrane reaktördeki dönüşümler karşılaştırılmıştır. Membran reaktörlerin geleneksel reaktörlere göre avantajı gösterilmiştir. Katalizör olarak homojen katalizör olan sülfürik asit kullanılmıştır. Membran reaktörde kullanılmak üzere hidrofilik olan PVA membranı sentezlenmiştir. Katalizör konsantrasyonunun (ağırlıkça %2, %4, %6), etanol/oleik asit molar oranının (3, 6, 9) ve sıcaklığın (45°C, 55°C, 65°C arası) oleik asit dönüşümüne etkisi kesikli reaktörde incelenmiştir. Optimizasyon ile belirlenen noktada aynı reaksiyon membran reaktörde de gerçekleştirilmiştir. Reaksiyonlar dört saat sürdürülmüştür. Hem parametrik hem de optimizasyon sonuçlarına göre kütlece katalizör konsantrasyonunun dönüşüme etkisinin düşük olduğu, sıcaklık ve molar besleme oranının ise asit dönüşümüne etkisinin yüksek olduğu görülmüştür. Kesikli reaktörde En yüksek dönüşüm değeri % 85,5 ile 65 °C sıcaklıkta, alkol: asit molar besleme oranı 6:1 iken, %4 katalizör konsantrasyonu ile elde edilmiştir. Etanol/oleik asit molar oranı 3, sıcaklık 55 °C ve katalizör oranı ağırlıkça %4 olduğunda kesikli reaktörde %50 oranında dönüşüm elde edilirken, membran reaktörde %75 oranında elde edilmiştir. Bu sonuçlara dayanarak aynı çalışma koşullarında, membran reaktörde elde edilen asit dönüşüm sonuçları kesikli reaktörlerden %26 oranında arttığı görülmüştür
  • [ X ]
    Öğe
    Optimization and modeling of biodiesel production from oleic acid in plug flow reactor
    (Amasya University, 2024) Erden, Hanife; Nigiz, Filiz Uğur
    In recent years, biodiesel has been preferable to fossil fuels because of its renewability, biodegradability, and producibility from various wastes. In this study, the esterification reaction between oleic acid and methanol was carried out in the presence of sulfuric acid, which is a homogeneous acid catalyst, to produce biodiesel. Experiments were carried out in a plug flow reactor (PFR) and a batch reactor. The experimental conditions with the highest conversion obtained in the PFR were determined and applied to the batch reactor and results were compared. The effects of temperature (45, 55, 65 in Celsius), catalyst concentration (2%, 4%, 6% by weight), and methanol/oleic acid mole ratio (3, 6, 9) on oleic acid conversion were examined in the PFR. Retention times at different flow rates were calculated to determine the reaction time in the PFR and reactions were carried out between 2 and 6 minutes. In the reactions carried out in the PFR, the highest conversion value was obtained as 97.33% under conditions where the catalyst concentration was 6% by weight, the temperature value was 55oC and the alcohol/acid mole ratio was 6:1. These conditions were applied to the batch reactor and the conversion value was found to be 50%. When the experimental results were examined, it was seen that the effect of temperature and alcohol/acid ratio on the conversion was greater than the effect of the catalyst concentration on the conversion. The modeling of oleic acid/methanol esterification, i.e., biodiesel production, at specific boundary values was found to follow a cubic dependence in the general dependence equation via Response Surface Methodology.