Abstract:The main objective of this work was to prepare nanosized titania (TiO 2) particles by mixed reverse microemulsion route. In this work titania was prepared by quaternary microemulsion system (water/surfactant/co-surfactant/ oil-phase). Span-80, Aerosol-OT, n-Propanol, Isooctane, and Titanium tetra isopropoxide (TTIP) were used as surfactant, co-surfactant, oil-phase and titania precursor respectively. The effect of water to surfactant ratio (w 0) on the size of titania particles was studied. The X-ray diffracti… Show more
“…A thermal treatment is necessary to improve the crystallinity of compounds. When TiO 2 powder is calcined at higher temperature, crystal structure transformations may occur, the transformation temperature depends on the nature and structure of the precursor and the preparation conditions [5].…”
Section: Resultsmentioning
confidence: 99%
“…Semiconductor nanocrystals have been widely studied for their fundamental properties [3], especially titanium dioxide (TiO 2 ). Nanosized titanium dioxide materials have been the focus of great interest because they exhibit modified physical-chemical properties in comparison with its bulk [2,4,5]. Inexpensiveness, excellent chemical stability nontoxicity, high photocatalytic property, a wide band gap and high refractive index of TiO 2 make it attractive for practical applications [6][7][8].…”
Section: Introductionmentioning
confidence: 99%
“…Inexpensiveness, excellent chemical stability nontoxicity, high photocatalytic property, a wide band gap and high refractive index of TiO 2 make it attractive for practical applications [6][7][8]. The uses and performance for a given application are strongly influenced by the crystalline structure, the morphology and the size of the particles [5]. There are three main crystalline polymorphs for TiO 2 rutile (tetragonal), anatase (tetragonal) and brookite (orthorhombic) [4,5,9], all crystallographic forms of nanocrystalline TiO 2 are of great importance from the view point of applications.…”
Section: Introductionmentioning
confidence: 99%
“…The uses and performance for a given application are strongly influenced by the crystalline structure, the morphology and the size of the particles [5]. There are three main crystalline polymorphs for TiO 2 rutile (tetragonal), anatase (tetragonal) and brookite (orthorhombic) [4,5,9], all crystallographic forms of nanocrystalline TiO 2 are of great importance from the view point of applications. Rutile has a high values of refractive index (2.7) and dielectric constant, so it is suitable for optical coating, as dielectric in thin film capacitors in microelectronic devices and as light scattering [6,8,10].Rutile is most important white pigment in paint and has other everyday uses as a whitener in toothpaste and the UV absorber in sunscreens [11].…”
Section: Introductionmentioning
confidence: 99%
“…The rutile structure is very compact and * Department of physics/ College of science for women/ University of Baghdad. thermodynamically most stable phase at all temperatures [8], whereas anatase and brookite phases are thermodynamically metastable and transform exothermally and irreversibly to the rutile phase upon annealing [4,5,13]. There are several pathways this phase transformation can take including: anatase to rutile, anatase to brookite to rutile, brookite to rutile, and brookite to anatase to rutile.…”
This work describes the effect of temperature on the phase transformation of titanium dioxide (TiO2) prepared using metal organic precursors as starting materials. X-ray diffraction (XRD) was used to investigate the structural properties of TiO2 gels calcined at different temperatures (300, 500, 700) ?C. the results showed that the samples have typical peaks of TiO2 polycrystalline brookite nanopowders after calcined at (300 ?C), which confirmed by (111), (121), (200), (012), (131), (220), (040), (231), (132) and (232) diffraction peaks. Also, XRD diffraction spectra showed the presence of crystallites of anatase with low proportion of rutile phase where calcined at (500 ?C), while rutile phase domains at (700 ?C). The crystallite size of TiO2 nanopowders was calculated by Scherer's formula and showed that the crystallite size decreased and then increased with increasing the annealing temperature.
“…A thermal treatment is necessary to improve the crystallinity of compounds. When TiO 2 powder is calcined at higher temperature, crystal structure transformations may occur, the transformation temperature depends on the nature and structure of the precursor and the preparation conditions [5].…”
Section: Resultsmentioning
confidence: 99%
“…Semiconductor nanocrystals have been widely studied for their fundamental properties [3], especially titanium dioxide (TiO 2 ). Nanosized titanium dioxide materials have been the focus of great interest because they exhibit modified physical-chemical properties in comparison with its bulk [2,4,5]. Inexpensiveness, excellent chemical stability nontoxicity, high photocatalytic property, a wide band gap and high refractive index of TiO 2 make it attractive for practical applications [6][7][8].…”
Section: Introductionmentioning
confidence: 99%
“…Inexpensiveness, excellent chemical stability nontoxicity, high photocatalytic property, a wide band gap and high refractive index of TiO 2 make it attractive for practical applications [6][7][8]. The uses and performance for a given application are strongly influenced by the crystalline structure, the morphology and the size of the particles [5]. There are three main crystalline polymorphs for TiO 2 rutile (tetragonal), anatase (tetragonal) and brookite (orthorhombic) [4,5,9], all crystallographic forms of nanocrystalline TiO 2 are of great importance from the view point of applications.…”
Section: Introductionmentioning
confidence: 99%
“…The uses and performance for a given application are strongly influenced by the crystalline structure, the morphology and the size of the particles [5]. There are three main crystalline polymorphs for TiO 2 rutile (tetragonal), anatase (tetragonal) and brookite (orthorhombic) [4,5,9], all crystallographic forms of nanocrystalline TiO 2 are of great importance from the view point of applications. Rutile has a high values of refractive index (2.7) and dielectric constant, so it is suitable for optical coating, as dielectric in thin film capacitors in microelectronic devices and as light scattering [6,8,10].Rutile is most important white pigment in paint and has other everyday uses as a whitener in toothpaste and the UV absorber in sunscreens [11].…”
Section: Introductionmentioning
confidence: 99%
“…The rutile structure is very compact and * Department of physics/ College of science for women/ University of Baghdad. thermodynamically most stable phase at all temperatures [8], whereas anatase and brookite phases are thermodynamically metastable and transform exothermally and irreversibly to the rutile phase upon annealing [4,5,13]. There are several pathways this phase transformation can take including: anatase to rutile, anatase to brookite to rutile, brookite to rutile, and brookite to anatase to rutile.…”
This work describes the effect of temperature on the phase transformation of titanium dioxide (TiO2) prepared using metal organic precursors as starting materials. X-ray diffraction (XRD) was used to investigate the structural properties of TiO2 gels calcined at different temperatures (300, 500, 700) ?C. the results showed that the samples have typical peaks of TiO2 polycrystalline brookite nanopowders after calcined at (300 ?C), which confirmed by (111), (121), (200), (012), (131), (220), (040), (231), (132) and (232) diffraction peaks. Also, XRD diffraction spectra showed the presence of crystallites of anatase with low proportion of rutile phase where calcined at (500 ?C), while rutile phase domains at (700 ?C). The crystallite size of TiO2 nanopowders was calculated by Scherer's formula and showed that the crystallite size decreased and then increased with increasing the annealing temperature.
The sustainable manufacturing of nanoparticles (NPs) has become critical to reduce life cycle energy use and the associated environmental impact. With the ever-growing production volume, titanium dioxide (TiO 2 ) NPs have been produced through various synthesis routes with differing input materials and reactions, which result in differential reactivity, crystallinity, surface areas, and size distributions. In this study, life cycle assessment is used to analyze and compare the environmental impact of TiO 2 NPs produced via seven routes covering physical, chemical, and biological syntheses. The synthesis routes are chosen to represent mainstream NP manufacturing and future trends. Mass-, surface area-, and photocatalytic reactivity-based functional units are selected to evaluate the environmental impact and reflect the corresponding changes. The results show that impact associated with the upstream production of different precursors are dominant for the chemical route. Compared to the chemical route, the physical route requires substantial quantities of supporting gas and highenergy inputs to maintain high temperature; therefore, a higher environmental burden is generated. A high environmental burden is also modeled for the biological route due to the required bacterial culture media. This present study aims to identify the most efficient synthesis route for TiO 2 NP production, lower the potential environmental impact, and improve green synthesis and sustainability.
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