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Showing 4 results for Titania

Barzegar Alamdarit B., Ashrafi Zadeh S.n., Ashrafi Zadeh F.,
Volume 1, Issue 2 (6-2004)

In the current research, the optimum conditions for the electrolytic deposition of TiO2 coatings on titanium pieces were experimentally investigated. Flat pieces of commercially available titanium with dimensions of 50 x20 x3 mm were used as the anode and cathode electrodes. The coatings were applied on the cathode in an electrolyte solution essentially from water and methanol, containing different amounts of TiCI4, and H202. Coatings of sufficient thickness and adequate adhesion to the substrate were obtained at the optimum conditions of theELD process. The latter conditions were electrode gap distance of 3 cm, TiCl4 concentration of 0.005M, H202 concentration of 0.1 M, current density of 35 mA/cm2, methanol/water volume ratio of 9, and pH of the electrolyte in the vicinity of 1.40. Results of XRD analysis revealed the presence of anatase crystals of titanium oxide in the coated layers, where the deposited coating was treated at some temperatures in the range of 400 to 600°C for a period of at least 2 hours. Scanning electron microscopy (SEM) pictures also confirmed the formation of a uniform coating layer with cracked suiface area. At the optimum conditions of the process coatings with thicknesses of up to 10 flm were easily obtained through the application of one to three deposited layers.
Y. Safaei-Naeini, M. Aminzare, F. Golestani-Fard, F. Khorasanizadeh, E. Salahi,
Volume 9, Issue 1 (3-2012)

Ultraviolet–Visible (UV–Vis) spectroscopy was used, in the current investigation, to explore the dispersion and stability of titania nanoparticles in an aqueous media with different types of dispersants. Hydrochloric and nitric acids as well as ammonia were used to determine the stability of the suspension in the acidic region (pH=2.5) and basic area (pH=9.5), respectively. In addition, for measuring sustainability of suspension and creating steric, and electrosteric repulsive forces, ethylene glycol and ethylene glycol plus ammonia were employed, respectively. UV–V is
spectrometry was applied to realize the effect of nano titania concentrations and different types of dispersants of samples containing different amounts of nano titania and different types of dispersants on stability of TiO2-containing suspensions. In addition, the stability of dispersion could be evaluated in colloidal mixtures containing ethylene glycol plus ammonia. It was demonstrated that the mixtures containing ethylene glycol plus ammonia were stable over a period of 4 days. To support the UV–Vis results, other techniques such as atomic force microscopy (AFM) and scanning electron microscopy (SEM) were employed to study the degree of agglomeration of titania nanoparticles in terms ofmorphology and size.
V. Tajer-Kajinebaf, H. Sarpoolaky, T. Mohammadi,
Volume 10, Issue 1 (3-2013)

Abstract:Nanostructured titania was synthesized by colloidal and polymeric sol-gel routes. Stable colloidal and polymeric titania sols were prepared by adjusting the proper values of the acid/alkoxide and the water/alkoxide molar ratios. The properties of sols were determined by dynamic light scattering technique and synthesized titania was characterized by thermogravimetry and differential thermal analysis, X-ray diffraction, Fourier transform infrared spectroscopy, optical microscopy and field emission scanning electron microscopy. The results showed particle size distribution of colloidal sol 10-50 nm compared to polymeric one which was 0.5-2 nm. Phase analysis of the colloidal sample revealed anatase as the major phase up to 550 °C, while the polymeric route resulted only anatase phase up to 750 °C. On the basis of results, titania prepared by the polymeric route showed better thermal stability against phase transformation than the sample prepared by the colloidal route. Also, microstructural studies showed that titania nanopowder can be produced by both sol-gel routes
V. Tajer Kajinebaf, M. Zarrin Khame-Forosh, H. Sarpoolaky,
Volume 17, Issue 1 (3-2020)

In this research, the nanostructured titania-coated silica microsphere (NTCSM) membrane consisting of titania-silica core-shell particles on α–alumina substrate was prepared by dip-coating method. The silica microspheres were synthesized by the Stöber method, and the nanostructured titania shell was obtained from a polymeric sol. Then, the prepared core-shell particles were deposited on alumina substrates. The samples were characterized by DLS, TG-DTA, XRD, FTIR and SEM. The photo-catalytic activity of the NTCSM membranes was evaluated using photo-degradation of methyl orange solution by UV–visible spectrophotometer. Also, physical separation capability was investigated by filtration experiment based on methyl orange removal from aqueous solution using a membrane setup. The mean particle size distribution of silica microspheres was determined to be about 650 nm that by deposition of titania nano-particles increased up to about 800 nm. After 60 min UV-irradiation, the dye removal efficiency was determined to be 80% by the membrane. By coupling separation process with photo-catalytic technique, the removal efficiency was improved up to 97%. Thus, the NTCSM membranes showed simultaneous photo-degradation and separation capabilities for dye removal from water.

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