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Öğe Characterization of $TiO_2$ synthesized in alcohol by a sol-gel process: The effects of annealing temperature and acid catalyst(2005) Sayılkan, Funda; Asiltürk, Meltem; Sayılkan, Hikmet; Önal, Yunus; Akarsu, Murat; Arpaç, ErtuğrulThe effects of annealing temperature and hydrolysis catalyst on the crystalline form and crystallite size of $TiO_2$ prepared by a sol-gel process were investigated. Three types of $TiO_2$ were synthesized by hydrolysis of titanium(IV)-iso-propoxide with water in n-propanol without catalyst (Type-A) and with HCl as catalyst, where the $H^+/Ti^{4+}$ mol ratio was 0.54 for Type-B and 0.2 for Type-C. Hydrolysis products were thermally treated at 100, 200, 300, 400 and 500 °C for 1 h after drying at room temperature. Characterization of the particles was carried out using XRD, BET, TG/DTA and SEM analysis. The pore size distributions were computed by the DFT plus method. The results showed that the acid catalyst and catalyst/alkoxide ratio have a large effect on the formation of anatase $TiO_2$. In particular, it was found that anatase phase $TiO_2$ particles occur at 400 and 500 °C for Type-A $TiO_2$, while they do so at nearly 200 °C for Type-B and Type-C $TiO_2$. The crystallite size of Type-A, Type-B and Type-C increased from 17.96 to 19.24 nm, from 12.38 to 15.12 nm and from 10.60 to 12.20 nm, respectively, when the thermal treatment temperature was raised from 400 to 500 °C.Öğe Characterization of TiO_2 synthesized in alcohol by a sol-gel process: The effects of annealing temperature and acid catalyst(Turkish Journal of Chemistry, 2005) Sayılkan, Funda; Asiltürk, Meltem; Sayılkan, Hikmet; Önal, Yunus; Akarsu, Murat; Arpaç, ErtuğrulAbstract:The effects of annealing temperature and hydrolysis catalyst on the crystalline form and crystallite size of TiO2 prepared by a sol-gel process were investigated. Three types of TiO2 were synthesized by hydrolysis of titanium(IV)-iso-propoxide with water in n-propanol without catalyst (Type-A) and with HCl as catalyst, where the H+/Ti4+ mol ratio was 0.54 for Type-B and 0.2 for Type-C. Hydrolysis products were thermally treated at 100, 200, 300, 400 and 500 °C for 1 h after drying at room temperature. Characterization of the particles was carried out using XRD, BET, TG/DTA and SEM analysis. The pore size distributions were computed by the DFT plus method. The results showed that the acid catalyst and catalyst/alkoxide ratio have a large effect on the formation of anatase TiO2. In particular, it was found that anatase phase TiO2 particles occur at 400 and 500 °C for Type-A TiO2, while they do so at nearly 200 °C for Type-B and Type-C TiO2. The crystallite size of Type-A, Type-B and Type-C increased from 17.96 to 19.24 nm, from 12.38 to 15.12 nm and from 10.60 to 12.20 nm, respectively, when the thermal treatment temperature was raised from 400 to 500 °C.Öğe Endotrophin levels in clinically-stable chronic obstructive pulmonary disease(2021) Altun, Ozgur; Arman, Yucel; Karakutuk Yuztas, Nur; Arslan, Selay; Kutlu, Ayca Zeynep; Saner Demir, Pinar; Akarsu, Murat; Tukek, TufanAim: Chronic obstructive pulmonary disease (COPD) is characterized by chronic inflammation and permanent airflow limitations due to stenosis of the small airways. The role of the extracellular matrix (ECM) structure and its reshaping is gaining importance. Endotrophin is a division product formed during construction of type VI collagen. The aim of this study was to research the correlation between endotrophin and the stable COPD pathophysiology. Materials and Methods: The study included 90 clinically-stable COPD patients and 38 participants without COPD. The demographic data, respiratory function tests and endotrophin levels of patients were recorded and statistically evaluated. Results: Endotrophin levels were significantly high in COPD patients compared to healthy controls (p<0.001). Though there was a positive correlation between endotrophin and CRP (r=0.229, p=0.031), there was no correlation with FEV-1, FVC, mMRC dyspnea score, 6-minute walking test distance and GOLD degree. Conclusion: Endotrophin was identified to be high in clinically stable COPD cases. This elevation appears to be associated with continuing inflammation in COPD. This correlation may guide prognosis studies for COPD and ensure the opportunity to develop new treatment strategies targeting endotrophin.Öğe New adsorbents from $Ti(OPr^n )_4$ by the sol-gel process: Synthesis, characterization and application for removing some heavy metal ions from aqueous solution(2004) Sayılkan, Funda; Sayılkan, Hikmet; Erdemoğlu, Sema; Şener, Şadiye; Akarsu, MuratNew adsorbents from Ti(OPrn)4 by the sol-gel process: Synthesis, characterization and application for removing some heavy metal ions from aqueous solutionÖğe New adsorbents from Ti(OPrn )_4 by the sol-gel process: Synthesis, characterization and application for removing some heavy metal ions from aqueous solution(Turkish Journal of Chemistry, 2004) Sayılkan, Funda; Sayılkan, Hikmet; Erdemoğlu, Sema; Şener, Şadiye; Akarsu, MuratNew adsorbents from Ti(OPrn)4 by the sol-gel process: Synthesis, characterization and application for removing some heavy metal ions from aqueous solutionÖğe A novel approach to the hydrothermal synthesis of anatase titania nanoparticles and the photocatalytic degradation of rhodamine B(Turkish Journal of Chemistry, 2006) Akarsu, Murat; Asiltürk, Meltem; Sayılkan, Funda; Kiraz, Nadir; Arpaç, Ertuğrul; Sayılkan, HikmetAbstract: A novel approach was developed for the synthesis of high-dispersed anatase nano-TiO2 by a hydrothermal process without solvent at 200 °C in 1 h. It was characterized using XRD, TEM, BET and elemental analysis. Nanoparticle-TiO2 was used as a photocatalyst by considering complete degradation of Rhodamine B (RB) dye. The photocatalytic reaction parameters such as photocatalyst amount, irradiation time and dye concentration were optimized and it was found that 0.125 wt% catalyst in 30 mg/L of RB aqueous solution is adequate for full degradation of RB in 50 min with 770 W/m2 irradiation power. Photocatalytic activity of the nanoparticle- TiO2 was compared with Degussa P-25 at optimum catalysis conditions determined for the nanoparticle- TiO2. It was concluded that when compared to Degussa P-25, the nanoparticle- TiO2 can be repeatedly used with increasing photocatalytic activity. The results revealed that the photodegradation of RB proceeds by pseudo first-order reaction kinetics in which the rate constant of the degradation is 0.132 min?1.
