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Öğe Adsorption behaviour of copper (II) ion from aqueous solution on poly(4-vinyl pyridine)(2002) Yiğitoğlu, Mustafa; Arslan, Metin; Temoçin, ZülfikarThe adsorption behaviour of poly(4 - vinyl pyridine) towards copper (II) ion in aqueous solutions was studied by a batch equilibriation technique. Influence of treatment lime, pH of the solution and metal ion concentration on the adsorption were investigated. 45 minutes of adsorption time was found sufficient to reach adsorption equilibrum for the copper (II) ion. The optimum pH was found to be 4,5. The adsorption saturation value was reached at 1,27 mmol ions per gram poly(4 - vinyl pyridine) against 3.15 mM copper (II) ions. It was observed that the adsorption isotherm of Cu (II) fits Freundlich - type isotherms.Öğe Adsorption Of Fe2+ Ions With Saccharomyces cerevisiae Immobilized Pumice Stone(2005) Lale, Mustafa; Şahin, Nazan; Temoçin, ZülfikarBu çalışmada kolon yöntemi kullanılarak Fe{2} iyonlarının Saccharomyces cerevisiae immobilize edilmiş ponza taşına adsorpsiyon şartları araştırıldı. Bu amaçla; adsorpsiyona çözelti pH sının, iyon başlangıç derişiminin ve adsorplanan iyonların geri kazanılması için uygun çözelti türü ve derişiminin etkisi araştırıldı. Maksimum adsorpsiyonun sağlandığı pH değerinin 5 olduğu belirlendi. Optimum pH değerinde, adsorbanın metal tutma kapasitesi 60 \mu g/mL başlangıç derişiminde 1,81mg/g dır. Desorpsiyona HC1, NaCl, NH4C1 ve EDTA çözeltilerinin etkisi araştırıldı. En uygun çözeltinin 0,2 M'lık EDTA çözeltisi olduğu gözlendi. 0,2 M EDTA çözeltisi ile %98 oranında desorpsiyon sağlandı.Öğe Bazı ağır metallerin mikroorganizma immobilize edilmiş ponza taşında adsorpsiyon şartlarının araştırılması(Kırıkkale Üniversitesi, 2000) Temoçin, Zülfikar; Lale, MustafaBu çalışmada Saccharomyces cerevisiae ponza taşına immobilize edildi. Saccharomyces cerevisiae immobilize edilmiş ponza taşında Cu, Zn ve Ni iyonlarının adsorpsiyon şartları araştırıldı. Bu amaçla, maksimum adsorpsiyonun sağlandığı pH değeri belirlendi. Her üç element için de maksimum adsorpsiyonun sağlandığı pH değeri 6 olarak bulundu. Optimum pH değerinde zamanın ve iyon derişiminin adsorpsiyona etkisi incelendi. Ayrıca adsorplanan metallerin geri kazanılmasına, çözelti türü ve derişiminin etkisi araştırıldı. Bu amaçla KC1, KSCN, NaCl, Na2C03 ve NH4CI çözeltileri denendi ve lM'lık KC1 (pH=2) çözeltisinin uygun olduğu görüldü. Anahtar Kelimeler : Adsorpsiyon, Saccharomyces cerevisiae, Ponza taşı, Immobilizasyon,Öğe Bazı enzimlerin modifiye edilmiş poli (etilen tereftalat) liflere immobilizasyon şartlarının araştırılması ve aktivitelerinin tayini(Kırıkkale Üniversitesi, 2008) Temoçin, Zülfikar; Yiğitoğlu, MustafaAmilaz, lipaz ve peroksidaz enzimleri Hofmann dönüşüm tepkimesi ile hazırlanan akrilamit aşılanmış poli(etilen tereftalat) lif üzerine immobilize edilmiştir. İmmobilize ve serbest enzimlerin aktivitesine pH, sıcaklık, termal kararlılık ve depolanma kararlılığı gibi değişkenlerin etkisi araştırılmıştır. Ayıca, immobilize ve serbest enzimlerin kinetik parametreleri olan Km ve Vmak değerleri de belirlenmiştir. Enzimlerin optimum pH değerleri immobilizasyon nedeniyle ? -amilaz için 5'den 6'ya, lipaz enzimi için 6'dan 7'ye, peroksidaz enzimi için, 8'den 7'ye değişim göstermiştir. İmmobilize ve serbest enzimlerin maksimum aktivite gösterdikleri sıcaklıklar ise, ? -amilaz için 50 ? C, lipaz için 40 ? C ve peroksidaz için 45 ? C olarak bulunmuştur. İmmobilize ? -amilaz enzimi 4 ? C'de 60 gün boyunca aktivitesini korurken serbest ? -amilaz enzimi 30 günün sonunda aktivitesini kaybetmiştir. İmmobilize lipaz enzimi 4 ? C'de 60 gün süresince aktivitesini %90 oranında korurken serbest lipaz enzimi aynı sürede aktivitesini %75 oranında korumuştur. İmmobilize peroksidaz enziminin serbest peroksidaz enzimine göre depolanma şartlarında kararlılığı artmıştır. İmmobilize ? -amilaz 30 tekrar kullanım sonunda aktivitesini %40 oranında, immobilize lipaz 10 tekrar kullanım sonunda aktivitesini %25 oranında, immobilize peroksidaz 20 tekrar kullanım sonunda aktivitesini %54 oranında korumuştur.Öğe Immobilization of Candida rugosa lipase on glutaraldehyde-activated polyester fiber and its application for hydrolysis of some vegetable oils(Elsevier Science Bv, 2010) Yigitoğlu, Mustafa; Temoçin, ZülfikarCandida rugosa lipase was effectively immobilized on the poly(ethylene terephthalate) grafted acrylamide (PET-g-AAm) fiber which was prepared through Hofmann reaction. The activities of the immobilized enzyme and the free enzyme were investigated in the hydrolysis reaction of olive oil in isooctane-water biphasic medium. The activities of the free and the immobilized lipases were measured at different pH values, and temperatures. The thermal stability and storage stability of them were also determined. The kinetic parameters of the free and the immobilized lipases, K-m and V-max were calculated, as well. Moreover, the application of immobilized lipase to the hydrolysis of different vegetable oils was realized. The effect of organic solvents on olive oil hydrolysis was examined and time course of the oil hydrolysis was studied. The optimum pH was shifted from 6 to 7 by immobilization of the enzyme. The maximum activity of the free and the immobilized enzymes occurred at 40 degrees C. It was found that the immobilized lipase stored at 4 degrees C retained 90% of its original activity after 60 days, whereas the free lipase stored at 4 degrees C retained 75% of its activity after the same period. In addition, the immobilized lipase exhibited as 0.06 U of the remaining activity even after 10 times reuses. Kinetics studies show that the corresponding values of K-m and V-max were 47.2 mg ml(-1) and 48.1 U mg(-1) protein for free lipase and 151.6 mg ml(-1) and 10.9 U mg(-1) protein for immobilized lipase. The immobilized and free enzymes showed similar behavior with respect to the different oil hydrolysis. The time course of the immobilized lipase on canola and olive oils hydrolysis used as substrate was much better than that of the free lipase. A high rate of oil hydrolysis was obtained when isooctane was used as solvent. (C) 2010 Elsevier B.V. All rights reserved.Öğe Immobilization of horseradish peroxidase on electrospun poly(vinyl alcohol)-polyacrylamide blend nanofiber membrane and its use in the conversion of phenol(Springer, 2018) Temoçin, Zülfikar; İnal, Murat; Gökgöz, Murat; Yigitoğlu, MustafaElectrospun nanofibers, with their porous structures, high surface-to-volume ratio, and good mechanical properties, are used as a support material for enzyme immobilization. In this study, the poly(vinyl alcohol) and polyacrylamide bicomponent (PVA-PAAm) nanofibers were fabricated via the electrospinning method. Synthesized PAAm was characterized with size exclusion chromatography (SEC). Nanofibers were characterized by fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and scanning electron microscope (SEM). DSC and TGA analyses showed that the nanofibers were more durable than PVA and PAAm polymers. SEM images demonstrated that all nanofibers possessed uniform and smooth structures (average diameter about 300 nm). FTIR results have shown that PAAm successfully participates in nanofiber structure. The produced nanofibers were used as support material for covalent immobilization of horseradish peroxidase (HRP). The optimum temperature for free HRP was 45 A degrees C, whereas it was 50 A degrees C for the immobilized enzyme. The immobilized HRP showed better storage and thermal stability than free HRP. The kinetic parameters (K (m) and V (max)) were found to be 2.42 mM and 0.027 U for the immobilized HRP and 1.86 mM and 0.079 U for the free HRP, respectively. The immobilized enzyme could be used effectively for 25 cycles with 54% retention of the activity. The immobilized HRP was also used for the conversion of phenol. Phenol removal was found to be about 29.68% at 180 min in real wastewater. The novel PVA-PAAm nanofibrous material was successfully used as a support material for covalent immobilization of HRP. Immobilized enzymes such as oxido-reductases onto the PVA-PAAm bicomponent nanofiber could be recommended in the treatment of organic pollutants in industrial effluents.Öğe Removal of Benzidine-based Azo Dye from Aqueous Solution Using Amide and Amine-functionalized Poly(ethylene terephthalate) Fibers(Korean Fiber Soc, 2010) Yigitoğlu, Mustafa; Temoçin, ZülfikarIn this study, amide and amine groups bound to poly(ethylene terephthalate) fibers are used to remove the colored toxic Congo red dye from aqueous solution. The effects of process variables like pH, contact time, graft yield, and initial dye concentration on the adsorption were investigated. The maximum adsorption of Congo red to amide and amine groups was observed at pH 3 and 5 respectively. Equilibrium was attained at approximately 60 min for the amine group. The adsorption capacity of amine group on the poly(ethylene terephthalate) fiber was 46.5 mg g(-1) at 25 degrees C, which was higher than that of the amide group on the poly(ethylene terephthalate) fiber. Desorption was done using 0.1 M NH3, and recovery was measured at 58.2 %. The used adsorbent was regenerated and recycled six times. The results showed that the amine-functionalized fiber could be considered as potential adsorbents for removal of Congo red from aqueous solution.Öğe Removal of cadmium (II) from aqueous solumns using sporopollenin(Parlar Scientific Publications (P S P), 2004) Arslan, Mehmet; Temoçin, Zülfikar; Yiğitoğlu, MustafaSorption of cadmium ion from aqueous solution by sporopollenin, a polymer obtained from Lycopodium clavatum, was investigated. The influences of adsorption time, temperature, pH of solution, and Cd(II) concentration on the adsorbed amount were investigated. 45 minutes of adsorption time was found to be sufficient to reach equilibrium. The adsorption capacity of sporopollenin was found to be 82.3 munol(.)g(-1). The heat of adsorption value was calculated as 15.3 J(.)mol(-1). Influences of HCl, H2SO4, HCl+H2SO4, and EDTA solutions on desorption were investigated.Öğe Studies on Selective Uptake Behavior of Hg(II) and Pb(II) by Functionalized Poly(Ethylene Terephthalate) Fiber with 4-Vinyl Pyridine/2-Hydroxyethylmethacrylate(Springer International Publishing Ag, 2010) Temoçin, Zülfikar; Yiğitoğlu, MustafaThe adsorption behavior of 4-vinyl pyridine and 2-hydroxyethylmethacrylate grafted poly(ethylene terephthalate) fiber toward the Hg(II) and Pb(II) ions in aqueous solutions was studied by a batch equilibration technique. The influence of the treatment time was considered as well as the pH of the solution, the initial metal ions concentration, the graft yield, and the temperature. Such parameters as the adsorption kinetics, the adsorption isotherm, and the desorption time were further studied. Maximum adsorption occurred at pH 3 and pH 6 for Hg(II) and Pb(II), respectively. The adsorption kinetics followed the mechanism of the pseudo-second-order equation for heavy metal ions. The adsorption data is a good fit with Freundlich isotherm. Desorption studies indicated that the maximum percent recovery of Hg(II) and Pb(II) was 93.4% and 76.3%, respectively with 1 M HNO3.Öğe Studies on the activity and stability of immobilized horseradish peroxidase on poly(ethylene terephthalate) grafted acrylamide fiber(Springer, 2009) Temoçin, Zülfikar; Yiğitoğlu, MustafaHaving been activated with glutaraldehyde, modified poly(ethylene terephthalate) grafted acrylamide fiber was used for the immobilization of horseradish peroxidase (HRP). Both the free HRP and the immobilized HRP were characterized by determining the activity profile as a function of pH, temperature, thermal stability, effect of organic solvent and storage stability. The optimum pH values of the enzyme activity were found as 8 and 7 for the free HRP and the immobilized HRP respectively. The temperature profile of the free HRP and the immobilized HRP revealed a similar behaviour, although the immobilized HRP exhibited higher relative activity in the range from 50 to 60 A degrees C. The immobilized HRP showed higher storage stability than the free HRP.Öğe Use of chemically modified poly(ethylene terephthalate)-g(acryl amide) fibers for a-amylase immobilization(2007) Temoçin, Zülfikar; Yiğitoğlu, MustafaAcryl amide grafted Poly(ethylene terephthalate) (AAm-g-PET) fiber was used for covalent coupling of a-amylase. The amide groups of Poly(acryl amide) were converted to the amine groups by Hofmann degradation reaction. The amine groups were activated by glutaraldehyde, before coupling of the enzyme. The free ?-amylase and immobilized ?-amylase were characterized by determining the activity profile as function of pM, temperature, thermal stability and storage stability. For the immobilized ?-amylase, operational stability was also determined. The immobilization of ?-amylase on support caused the optimal reaction pH to shift from 5 to 6. The maximum activity of the free and immobilized enzymes occurred at 50 °C. K m for the immobilized system was higher than that for the free enzyme. The activity of the free enzyme ended in 30 days, whereas the activity of the immobilized enzyme lasted for 60 days at storage conditions. ?-Amylase immobilized on matrix maintained 40% of its original activity after 30 times of repeated use.
