Synthesis of Titanium Dioxide in Hydrogen Peroxide Solution and its Photocatalytic Character

2013 ◽  
Vol 827 ◽  
pp. 34-37 ◽  
Author(s):  
Su Kim Wan ◽  
Seok Rhee Dong
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Particle Size ◽  
Titanium Dioxide ◽  
Humic Acid ◽  
Surface Area ◽  
Crystalline Phase ◽  
Titanium Tetraisopropoxide ◽  
Surface Sites ◽  
Inorganic Acids

TiO2nanocrystals were synthesized from Titanium Tetraisopropoxide in H2O2solution, and utilized as photocatalysts for degradation of humic acid in aqueous solution. The highly pure TiO2nanocrystals were obtained by excluding the use of inorganic acids that might consequently cause contamination of active catalytic surface sites of the nanocrystals by Cl-, NO3-and SO42-. Particle size and crystallinity of the nanocrystals were increased with progressing the refluxing time 1 ~ 9 h at 120°C in an oil bath. By varying H2O2/Ti = 5.5 ~ 55, the crystalline phase of anatase/rutile ratio of the nanocrystals was controllable. The photocatalytic properties of the nanocrystals were strongly dependent upon the crystallinity and particle size. The DOC removal of humic acid was most effective for the nanocrystals prepared at H2O2/Ti= 5.5 due to the mixed crystalline phase of anatase/rutile and the increased surface area by smaller particle size. The decreases of UV254absorbance of HAs solutions were much faster than those of DOC, and not so dependent upon the variations of TiO2nanocrystals.

scholarly journals Effect of two formulations of 10% sodium ascorbate on fracture resistance of endodontically treated tooth submitted to dental bleaching with hydrogen peroxide associated titanium dioxide nanoparticles

2014 ◽  
Vol 2 (1) ◽  
pp. 13
Author(s):  
Francisco Carlos Bontorim ◽  
Milton Carlos Kuga ◽  
Sabrina Spinelli Cioffi ◽  
Marcus Vinicius Reis Só ◽  
Gisele Faria ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Titanium Dioxide ◽  
Fracture Resistance ◽  
Composite Resin ◽  
Positive Control ◽  
Sodium Ascorbate ◽  
Resistance Testing ◽  
Dental Bleaching ◽  
Endodontically Treated Tooth

PURPOSE: This study evaluated the effect of 10% sodium ascorbate (10SA), in gel (10SAg) or aqueous solution (10SAs) formulations, on fracture resistance of endodontically treated tooth submitted to dental bleaching procedures with 15% hydrogen peroxide associated with titanium dioxide (15HP-TiO2) nanoparticles and photoactivated by LED-laser. MATERIAL AND METHODS: Forty maxillary premolars were endodontically-treated and embedded in acrylic resin up to the cement-enamel junction. The specimens were divided into four groups (n=10): G1 (negative control): no bleaching, coronal access restored with composite resin; G2 (positive control): three dental bleaching  sessions using 15HP-TiO2 and LED-laser photoactivation and restored with composite resin (positive control); G3 (10SAg): similar procedures to G2, but applied  10SA, in gel formulation, for 24 hours before restoration; G4 (10SAs): similar procedures to G3, but applied  10SA, in aqueous solution formulation.  The 15HP-TiO2 was applied on buccal and lingual surfaces of the crown tooth and inside the pulp chamber and photoactivated by LED-laser. Between each bleaching session, the teeth were maintained in artificial saliva, at 37oC, for 7 days. In sequence, the teeth were submitted to fracture resistance testing using an eletromechanical machine test. The data was analyzed using Kruskal Wallis test (p = 0.05) RESULTS: There are no differences significant among the groups in relation to fracture resistance of endodontically treated teeth (p>0.05). CONCLUSIONS: The use of 10% sodium ascorbate, in gel or aqueous solution formulations, did not interfered on the fracture resistance teeth after dental bleaching using 15HP-TiO2 and LED-laser photoactivation.

THE ADSORPTION OF SODIUM MYRISTATE BY CARBON BLACK

1949 ◽  
Vol 27f (11) ◽  
pp. 426-428 ◽  
Author(s):  
Marguerite A. Reade ◽  
A. S. Weatherburn ◽  
C. H. Bayley
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Fatty Acid ◽  
Carbon Black ◽  
Surface Area ◽  
Activated Charcoal ◽  
Carbon Blacks ◽  
Preferential Adsorption

The adsorption of sodium myristate from 0.1% aqueous solution by a series of carbon blacks and an activated charcoal has been measured at 70 °C. In every case a preferential adsorption of fatty acid was observed. The extent of adsorption of both the fatty acid and alkali components of the soap increased with decreasing particle size, i.e., with increasing surface area, of the carbons. The adsorption by activated charcoal was considerably higher than that obtained with even the finest of the carbon blacks.

The influence of titanium dioxide (TiO2) nanoparticles on the structure, optical and dielectric properties of polyvinyl chloride (PVC)

2020 ◽  
Vol 34 (28) ◽  
pp. 2050310
Author(s):  
M. A. Ramazanov ◽  
A. M. Rahimli ◽  
F. V. Hajiyeva
Keyword(s):  
Particle Size ◽  
Titanium Dioxide ◽  
Dielectric Properties ◽  
Surface Area ◽  
Titanium Dioxide Nanoparticles ◽  
Inorganic Nanoparticles ◽  
Nanocomposite Films ◽  
Slight Reduction ◽  
Insulation Systems ◽  
Nanoparticle Content

The tendency to improve the properties of insulating materials by incorporating inorganic nanoparticles has become necessary in order to design new insulation systems. In this study, PVC/TiO2-based nanocomposites with different loadings (3, 5 and 10 wt.%) of TiO2 nanoparticles were prepared by the solution mixing method. The morphology of the prepared nanocomposites was studied by Atomic Force Microscope (AFM). Experimentally, it was found that as the concentration increases, the size of the surface structural elements and particle size increases. Photoluminescence (PL) analysis of samples shows improvement compared to the pristine polymer. Furthermore, PL intensity for nanocomposites increases depending on the concentration and saturation occurs at a certain amount of titanium dioxide nanoparticles. The increase in luminescence intensity till a certain nanoparticle content is due to the growth of the luminescent surface area. Further saturation is explained by the increase in particle size with no increase or a slight reduction in surface area. Dielectric properties of nanocomposites were studied. It was found that dielectric permittivity of the materials increases as the nanoparticle volume content increases and it reaches at its highest value for the nanocomposites with 3% nanoparticle content. The optical properties of the polymer and nanocomposite films were studied in the region 200 nm to 600 nm. It was found that the PVC/TiO2 nanocomposites showed enhancement in the absorbance intensities which was more significant for the nanocomposites with higher nanoparticle content compared to the pristine polymer. Furthermore, absorption spectra were used to calculate the optical bandgap of the prepared nanocomposite films and redshift observed in the calculated values of bandgap for nanocomposites. Consequently, it was proved that by incorporating TiO2 nanoparticles into the polymer matrix, the spectral region of the samples can be expanded resulting in broadened application of such systems in various fields of science and technology.

scholarly journals Structural Characterization and Adsorption Capability of Carbonaceous Matters Extracted from Carbonaceous Gold Concentrate

Minerals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 23
Author(s):  
Huiqun Niu ◽  
Hongying Yang ◽  
Linlin Tong
Keyword(s):  
Particle Size ◽  
Humic Acid ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Diameter ◽  
Mesoporous Structure ◽  
Average Pore Diameter ◽  
Average Pore ◽  
Complex Organic Compound

In this paper, the structures of element carbon and humic acid extracted from carbonaceous gold concentrate were characterized employing a variety of analytical methods. The extracted amounts of ECE (elemental carbon extract) and HAE (humic acid extract) were 14.84–38.50 and 11.55–28.05 mg g−1, respectively. SEM and porosity analysis indicated that ECE occurred mostly as irregular blocky particles with a mesoporous surface with the average pore diameter being 31.42 nm. The particle size of ECE was mainly ranged from 5.5 to 42 μm and the specific surface area was 20.35 m2 g−1. The physicochemical features and structure of ECE were close to activated carbon, and the crystallinity was slightly lower than graphite. The particle size distribution of HAE varied from 40 to 400 nm with the specific surface area of 42.84 m2 g−1, whereas the average pore diameter of HAE was 2.97 nm. FTIR and UV–VIS analyses indicated that HAE was a complex organic compound containing the enrichment of oxygen-containing structure. The results showed that the adsorption amounts of ECE and HAE under the acidic conditions were 470.46 and 357.60 mg g−1, respectively. In an alkaline environment, the amount of ECE was 449.02 mg g−1 and the value of HAE was 294.72 mg g−1. ECE mainly utilized the outer surface and mesoporous structure to adsorb gold, while the functional groups’ complexation or surface site adsorption was the leading approach for HAE to adsorb gold.

scholarly journals Characterization of Commercial Metal Oxide Nanomaterials: Crystalline Phase, Particle Size and Specific Surface Area

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1812
Author(s):  
Michael Bushell ◽  
Suzanne Beauchemin ◽  
Filip Kunc ◽  
David Gardner ◽  
Jeffrey Ovens ◽  
...  
Keyword(s):  
Particle Size ◽  
Metal Oxide ◽  
Specific Surface ◽  
Human Health ◽  
Surface Area ◽  
Specific Surface Area ◽  
Crystalline Phase ◽  
Size Distributions ◽  
Metal Oxide Nanomaterials

Physical chemical characterization of nanomaterials is critical to assessing quality control during production, evaluating the impact of material properties on human health and the environment, and developing regulatory frameworks for their use. We have investigated a set of 29 nanomaterials from four metal oxide families (aluminum, copper, titanium and zinc) with a focus on the measurands that are important for the basic characterization of dry nanomaterials and the determination of the dose metrics for nanotoxicology. These include crystalline phase and crystallite size, measured by powder X-ray diffraction, particle shape and size distributions from transmission electron microscopy, and specific surface area, measured by gas adsorption. The results are compared to the nominal data provided by the manufacturer, where available. While the crystalline phase data are generally reliable, data on minor components that may impact toxicity is often lacking. The crystal and particle size data highlight the issues in obtaining size measurements of materials with broad size distributions and significant levels of aggregation, and indicate that reliance on nominal values provided by the manufacturer is frequently inadequate for toxicological studies aimed at identifying differences between nanoforms. The data will be used for the development of models and strategies for grouping and read-across to support regulatory human health and environmental assessments of metal oxide nanomaterials.

scholarly journals Sol-Gel Synthesis of TiO2 Nanocrystalline Particles with Enhanced Surface Area through the Reverse Micelle Approach

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Mohammad Hossein Nateq ◽  
Riccardo Ceccato
Keyword(s):  
Particle Size ◽  
Surface Area ◽  
Particle Density ◽  
Sol Gel ◽  
Bet Surface Area ◽  
Molar Ratio ◽  
Titanium Tetraisopropoxide ◽  
Reflux Time ◽  
Nanocrystalline Particles ◽  
Time Extension

Titania nanocrystalline particles were synthesized by hydrolysis-condensation of titanium tetraisopropoxide in water-in-oil micellar solutions of water/cyclohexane/Triton X-100 system, and the effects of reflux time and water-to-surfactant molar ratio on the particle uniformity, crystallinity, and surface area were studied. Several characterization techniques including TEM and SEM, as well as X-ray diffraction and FT-IR spectroscopy, helium pycnometry, and nitrogen physisorption, were employed to evaluate the particle density and dimensions, crystallite size, surface area value, and the porosity features in the as-prepared condition and also after thermal treatment at 500°C. The results show that all treated samples are dense nanocrystalline anatase particles with BET surface area values over 100 m2·g−1 and primary particle size of 10–15 nm. However, for the as-prepared samples, as the reflux time increases, a better purification of particles from the synthesis environment is resulted, leading to denser and more crystalline powders with smaller particle size and higher BET surface area values culminating in 179 m2·g−1 for 24 hours of refluxing. Moreover, decreasing the water-to-surfactant molar ratio from 10 to 5 and 2 increases the particles surface area to 239 and 224 m2·g−1, respectively, at the expense of slight density and crystallinity degradation and considerable prolongation of surfactant removal step. Supportively, the comparison between photocatalytic activities of as-prepared samples also evidences the effectiveness of reflux time extension on improving the sample features and enhancing their functionality. This study can highlight how the earlier synthesis steps can influence the evolution of the structure of the final products.

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