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Öğe Characterization and photocatalytic properties of TiO2-nanosols synthesized by hydrothermal process at low temperature(Elsevier, 2006) Sayilkan, F; Asiltürk, M; Erdemoglu, S; Akarsu, M; Sayilkan, H; Erdemoglu, M; Arpaç, ETransparent nanocrystalline pure anatase titania (nano-TiO2) was synthesized by hydrothermal process at 200 degrees C. Photocatalytic activity of the nano-TiO2 as in the form of sol was tested for degradation of Methylene Blue (MB) and Reactive Red 120 (RR-120) in aqueous solutions. Structural and physico-chemical properties of the nano-TiO2 were characterized using powder XRD, SEM, BET, FTIR and elemental analyses. Complete photodegradation of RR-120 was successfully achieved by aid of the nano-TiO2 whereas NIB was not degraded, maybe because of reversible color change in nano-TiO2 sol/MB mixture after the LTV irradiation was stopped. Potocatalytic activity of the synthesized the nano-TiO2 for degradation of RR-120 was compared with Degussa P-25 at optimum conditions determined for RR-120. It was found that the nano-TiO2 can be repeatedly used with higher photocatalytic activity than Degussa P-25. (c) 2005 Elsevier B.V All rights reserved.Öğe Characterization of the hydrothermally synthesized nano-TiO2 crystallite and the photocatalytic degradation of Rhodamine B(Elsevier, 2006) Asiltürk, M; Sayilkan, F; Erdemoglu, S; Akarsu, M; Sayilkan, H; Erdemoglu, M; Arpaç, EPure anatase-TiO2 nanoparticles with 8 nm average crystallite size was synthesized hydrothermally at 200 degrees C in 2 h. The structural and physicochemical properties of nano-TiO2 were determined by powder XRD, FT-IR, BET and SEM analyses. The behavior of anatase nano-TiO2 in catalytic degradation of Rhodamine B (RB) dye in transparent nano-TiO2 sol under UV-light was examined as a function of irradiation power of UV-Iight, irradiation time, amount of nano-TiO2 and initial RB concentration in the sol. Rhodamine B was fully degraded with the catalysis of the nano-TiO2 in a short time as low as 60 min. Photocatalytic activity of the nano-TiO2 for degradation of RB was compared with Degussa P-25 at optimum catalysis conditions determined for the nano-TiO2. It was found that, when compared to Degussa P-25, the nano-TiO2 could be repeatedly used with increasing photocatalytic activity. It was found that the photodegradation obeys the pseudo first-order reaction kinetics with the rate constant of 0.0658 min(-1), and the half period t(1/2) was 10.53 min. (c) 2005 Elsevier B.V. All rights reserved.Öğe Characterization of TiO2 synthesized in alcohol by a sol-gel process: The effects of annealing temperature and acid catalyst(Tubitak Scientific & Technological Research Council Turkey, 2005) Sayilkan, F; Asiltürk, M; Sayilkan, H; Önal, Y; Akarsu, M; Arpaç, EThe 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 degrees 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 degrees C for Type-A TiO2, while they do so at nearly 100 degrees C for Type-B and Type-C TiO2. The crystallile 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 degrees C.Öğe Heat-resistant hydrophobic-oleophobic coatings(Wiley, 2006) Uyanik, M; Arpaç, E; Schmidt, H; Akarsu, M; Sayilkan, F; Sayilkan, HThermally and chemically durable hydrophobic oleophobic coatings, containing different ceramic particles Such as SiO2, SiC, Al2O3, which can be alternative instead of Teflon, have been developed and applied on the aluminum Substrates by spin-coating method. Polyimides, which are high-thermal resistant heteroaromatic polymers, were synthesized, and fluor oligomers were added to these polymers to obtain hydrophobic-oleophobic properties. After coating, Al Surface was subjected to Taber-abrasion, adhesion, corrosion, and thermal tests. The effects of the particle size of ceramic powders, organic matrix, and heat on the coating material were investigated. Coating material was characterized by FTIR spectrophotometer. Surface properties and thermal resistance of the coating materials were investigated by SEM and TGA analyses. After thermal curing, contact angles of these coatings with H2O and n-hexadecane were measured. It was observed that coatings like ceramic particles are more resistant against scratch and abrasion than the other coatings. Also, they are harder than coatings, which do not include ceramic particles. It was seen that coatings, containing Fluorolink D10H, have high-contact angles with water and n-hexadecane. (c) 2006 Wiley Periodicals, Inc.Öğe New metal alkoxides(Kluwer Academic Publ, 1999) Sayilkan, H; Senre, S; Sener, E; Arpaç, EIn this work, (a) hydrolyses of Ti(OEt)(4) and Zr(OPrn)(4) with different amounts of water, (b) complexation of the same alkoxides with varying amounts of methacrylic acid, (c) hydrolysis of the complexation products with varying amounts of water, and subsequent polymerization, (d) adsorption capacities of the hydrolysis products (a and c) for aqueous aniline and phenol, were investigated. It was found that condensation reactions which follows the hydrolysis reactions, were alcohol condensations. The products were characterized in detail. Adsorption of aniline and phenol were compared for thermally conditioned powder of the products and some powders coated with 3-glycidyloxypropyltrimethoxysilane. It was observed that the extent of adsorption was influenced significantly by the temperature at which the adsorbents were calcinated by the coating of their surfaces. (C) 1999 Kluwer Academic Publishers.Öğe The production and application of a regenerable filter system for adsorption of some atmospheric contaminants(Elsevier Sci Ltd, 2004) Sayilkan, H; Arpaç, EIn this work, a new filter, used to prevent atmospherical pollution, has been developed. Spherical amorphous shaped silicates (such as KC-Siliperl AF 125 and Aluminium silicate 596 FA) were coated with different materials which were prepared from the hydrolysis-condensation products of organically modified silanes and metal alkoxides. The adsorption capacities of such silicates for different solvents; ethylacetate, toluene, n-hexane and cyclohexanone were investigated. It was found that KC-Siliperl AF 125 coated with IMEO (a commercial silane) adsorbed all the solvents better than Aluminium silicate 596 FA, and ethylacetate was adsorbed more than the other solvents. (C) 2003 Elsevier Ltd. All rights reserved.
