Analysis of photocatalytic performance of nanostructured pyrogenic titanium dioxide powders in view of their polydispersity and phase transition: Critical anatase particle size as a factor for suppression of charge recombination

2013 ◽  
Vol 228 ◽  
pp. 614-621 ◽  
Author(s):  
Anna Moiseev ◽  
Marina Krichevskaya ◽  
Fei Qi ◽  
Alfred P. Weber ◽  
Joachim Deubener
Keyword(s):  
Phase Transition ◽  
Particle Size ◽  
Titanium Dioxide ◽  
Photocatalytic Performance ◽  
Charge Recombination ◽  
Anatase Particle

Hydrothermal Synthesis and Photocatalytic Properties of Nano Bi2WO6/TiO2 Powers

2012 ◽  
Vol 531-532 ◽  
pp. 473-476 ◽  
Author(s):  
Hai Feng Chen ◽  
Ting Yan
Keyword(s):  
Phase Transition ◽  
Titanium Dioxide ◽  
Hydrothermal Synthesis ◽  
Band Gap ◽  
Composite Powder ◽  
Photocatalytic Performance ◽  
Raw Materials ◽  
Illumination Time ◽  
Catalyst Amount ◽  
Alcohol Solvent

Using Bi(NO3)3•5H2O, Na2WO4•2H2O and Ti• (OC4H9)4 as the main raw materials, different alcohol solvent as medium, hexamethylene tetramine as sink set agent, tungsten bismuth and titanium dioxide composite powder were prepared by hydrothermal synthesis. It was characterized by XRD and DRS. The methyl orange imitated sewage, we study the impacts of calcinations’ temperature, catalyst amount, concentration, illumination time and pH on photocatalytic performance of Bi2WO6/TiO2 samples under visible light. The results showed that calcinations’ temperature 400 oC was the best, because the forbidden band gap decreased with temperature increased, but phase transition or decomposition exothermic of the samples would occurre at higher than 400 degree. The Bi2WO6/TiO2 prepared under acidic condition had only 2.41 eV as the smallest forbidden band gap of the samples.

Comparison of Titanium Dioxides Prepared from Different Materials and its Photocatalytic Evaluation

2013 ◽  
Vol 749 ◽  
pp. 77-81
Author(s):  
Dong Seok Rhee ◽  
Young Do Kim ◽  
Se Gu Son
Keyword(s):  
Phase Transition ◽  
Particle Size ◽  
Titanium Dioxide ◽  
Humic Acid ◽  
Room Temperature ◽  
Uv Absorbance ◽  
Higher Temperature ◽  
Titanium Dioxides

Titanium dioxides were synthesized from two different titanium salts, which contained chlorine and sulfur respectively. Titanium dioxide prepared from TiCi4 and had a particle size of ca. 20nm and its phase transition from anatase to rutile stated at 500°C. Titanium dioxide from TiOSO4 had a particle size of ca. 50nm and retained its anatase and sperit structure until 700°C by calcination. For the photocatalytic evaluation of these titanium dioxides, photocatlytic oxidation of organic model pollutant, humic acid, have been conducted. UV absorbance decrease by titanium dioxides prepared from both from TiCi4 and TiOSO4 at room temperature showed very similar results, compared to titanium dioxide prepared from TiCi4 at higher temperature.

scholarly journals Population Balance Application in TiO2 Particle Deagglomeration Process Modeling

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3523
Author(s):  
Radosław Krzosa ◽  
Łukasz Makowski ◽  
Wojciech Orciuch ◽  
Radosław Adamek
Keyword(s):  
Particle Size ◽  
Titanium Dioxide ◽  
Mechanistic Model ◽  
Population Balance ◽  
Tio2 Particle ◽  
Application Process ◽  
Titanium Dioxide Powder ◽  
Dioxide Powder ◽  
Computational Fluid Dynamics Cfd ◽  
Hydrodynamic Stresses

The deagglomeration of titanium-dioxide powder in water suspension performed in a stirring tank was investigated. Owing to the widespread applications of the deagglomeration process and titanium dioxide powder, new, more efficient devices and methods of predicting the process result are highly needed. A brief literature review of the application process, the device used, and process mechanism is presented herein. In the experiments, deagglomeration of the titanium dioxide suspension was performed. The change in particle size distribution in time was investigated for different impeller geometries and rotational speeds. The modification of impeller geometry allowed the improvement of the process of solid particle breakage. In the modelling part, numerical simulations of the chosen impeller geometries were performed using computational-fluid-dynamics (CFD) methods whereby the flow field, hydrodynamic stresses, and other useful parameters were calculated. Finally, based on the simulation results, the population-balance with a mechanistic model of suspension flow was developed. Model predictions of the change in particle size showed good agreement with the experimental data. Using the presented method in the process design allowed the prediction of the product size and the comparison of the efficiency of different impeller geometries.

Improved antimicrobial efficacy and photocatalytic performance of gold decorated titanium dioxide nanohybrid

Optik ◽  
2020 ◽  
Vol 224 ◽  
pp. 165515
Author(s):  
Suresh Sagadevan ◽  
Selvaraj Vennila ◽  
Lakshmipathy Muthukrishnan ◽  
Baranya Murugan ◽  
J. Anita Lett ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Performance ◽  
Antimicrobial Efficacy

scholarly journals Influence of Particle Size of Titanium Dioxide on the Flip-Flop Effect (2)

1996 ◽  
Vol 69 (4) ◽  
pp. 227-232
Author(s):  
Masayasu AKITSU ◽  
Haruo OKUDA ◽  
Hideo FUTAMATA ◽  
Masakazu HATTORI
Keyword(s):  
Particle Size ◽  
Titanium Dioxide ◽  
Flip Flop

Effect of Dispersant on the Measurement of Particle Size Distribution of Titanium Dioxide

2012 ◽  
Vol 512-515 ◽  
pp. 261-264
Author(s):  
Li Shen ◽  
Jin Hu ◽  
Da Ping Wu
Keyword(s):  
Particle Size ◽  
Titanium Dioxide ◽  
Zeta Potential ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Anionic Surfactant ◽  
Sodium Sulfate ◽  
Aqueous Media ◽  
Rutile Tio2 ◽  
Tio2 Particles

As anionic surfactant, a commercial salt of lauryl sodium sulfate was used. The effects of different amounts of dispersant on the measurement of particle size distribution between two titanium dioxide powders (anatase and rutile) in aqueous media were discussed. Diluted aqueous suspensions were characterized in terms of particle size distribution and zeta potential. The results demonstrate that the measurement of particle size distribution strongly depends on the amounts of dispersant. The amounts of dispersant have a significant effect on the behavior of the rutile-TiO2 particles. The particle size first decreases significantly with an increase in the amounts of dispersant and then lesser increases with a further increase in the amounts of dispersant. The tendency show significant differences between two particles.

Influence of chain length, particle size, and thermal treatment of dicarboxylic acid-functionalized titanium dioxide filler in polypropylene

2021 ◽  
Author(s):  
K. K. Gallegos-Medrano ◽  
V. Escobar-Barrios ◽  
D. A. Santamaría-Razo ◽  
E. J. Gutierrez-Castañeda ◽  
J. Vallejo Montesinos ◽  
...  
Keyword(s):  
Particle Size ◽  
Titanium Dioxide ◽  
Thermal Treatment ◽  
Dicarboxylic Acid ◽  
Chain Length

Study of the Zirconium and Silicon Homovalent Dopants Insertion on the Structure and Bandgap Energy of Titanium Dioxide Powders

2018 ◽  
Vol 930 ◽  
pp. 67-72
Author(s):  
Hiana Muniz Garcia ◽  
Eduardo Felipe de Carli ◽  
Natali Amarante da Cruz ◽  
Jusinei Meireles Stropa ◽  
Lis Regiane Vizolli Favarin ◽  
...  
Keyword(s):  
Phase Transition ◽  
Titanium Dioxide ◽  
Performance Enhancement ◽  
Thermal Analyses ◽  
Rutile Phase ◽  
Bandgap Energy ◽  
Structural Effects ◽  
Structural Refinement ◽  
Anatase Structure ◽  
Atomic Coordinates

The reconstructive transformation occurring during the anatase-to-rutile phase transition can be observed through adequate techniques such as Thermal Analyses and Z-ray diffractometry followed by structural refinement. The typical photonic properties of titanium dioxide photocatalysts depend on the anatase structure and how the modifiers can provide their performance enhancement. In the present work, we investigate the structural effects caused by the simultaneous homovalent modification on the anatase structure in order to understand the mechanisms of the anatase-to-rutile phase transition in terms of the atomic coordinates and the lattice parameters. The refined structures along the calcination temperature from 500 to 900 oC suggest the oxygen bonds are strongly affected in unmodified anatase in order to destroy and rebuilt the crystal structure and lead to the rutile phase formation above 700 oC, unless some modifier pairs stabilize them.

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