Endurance Test of TiO2-Based Photocatalytic Oxidation

1998 ◽  
Vol 3 (2) ◽  
Author(s):  
J. W. Assink ◽  
J. M. Slaager
Keyword(s):  
Waste Water ◽  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Physical Model ◽  
Photocatalytic Oxidation ◽  
Acid Dye ◽  
Endurance Test ◽  
Endurance Tests ◽  
Degussa P25

AbstractThe long term behaviour of suspended photocatalysts (Degussa P25) is studied in two endurance tests. Model waste water with an acid dye (Special Brilliant Blue FFR) or 4-chlorophenol as main contaminant have been used. Titanium dioxide is recovered from the effluent by pressure filtration and reused in the feed. A change in suspension behaviour of the titanium dioxide was observed over the period of the endurance tests (approx. 400 h). The photocatalytic activity decreased in the same period by approx. 55 % in the case of chlorophenol and approx. 25 % in the case of the dye. Intermediates from the chlorophenol degradation have been identified. The result of the tests are fitted to a physical model of the process. They are also useful for improved reactor design

scholarly journals Thermally modified titania photocatalysts for phenol removal from water

2006 ◽  
Vol 2006 ◽  
pp. 1-7 ◽  
Author(s):  
Joanna Grzechulska-Damszel ◽  
Antoni W. Morawski ◽  
Barbara Grzmil
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Thermal Treatment ◽  
Photocatalytic Oxidation ◽  
Thermal Modification ◽  
Photocatalytic Decomposition ◽  
Phenol Removal ◽  
Chemical Factory ◽  
Degussa P25 ◽  
Oxidation Of Phenol

Two kinds of titanium dioxide were used as starting materials for thermal modification: Tytanpol A11 supplied by Chemical Factory “Police” S.A. (Poland) and Degussa P25 supplied by Degussa AG (Germany). The photocatalytic activity of titania materials modified by thermal treatment was tested in the reaction of photocatalytic oxidation of phenol. It was found that the highest activity in the reaction of photocatalytic decomposition of phenol, in case of Tytanpol A11, shows the samples of material modified at temperatures of 700 and 750°C. These catalysts were more active than untreated A11, whereas materials modified at higher temperatures show lower activity. In the case of P25, all thermally treated materials were less active than the unmodified material. The photocatalyst samples were characterized by UV-Vis/DR, FTIR/DRS, and XRD methods.

scholarly journals Photocatalytic Activity Enhancement of Low-pressure Cold-Sprayed TiO2 Coatings Induced by Long-term Water Vapor Exposure

2021 ◽  
Author(s):  
Seremak Wioletta ◽  
Baszczuk Agnieszka ◽  
Jasiorski Marek ◽  
Gibas Anna ◽  
Winnicki Marcin
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Water Vapor ◽  
Sol Gel ◽  
Low Pressure ◽  
Oxygen Depletion ◽  
Amorphous Structure ◽  
Industrial Applications ◽  
Additional Parameter

AbstractThis work shows that the titanium dioxide coatings obtained by low-pressure cold gas spraying with the use of the sol–gel amorphous TiO2 powder are characterized by photocatalytic activity despite their partial amorphous content. Moreover, the research outcome suggests that the decomposition rate of organic pollutants is enhanced after long-term exposure to moisture. The condensation humidity test is not detrimental to the continuity and integrity of the coating, but the phase composition of coatings changes—with the exposure to water vapor, the portion of the amorphous phase crystallizes into brookite. The mechanism responsible for the conversion of amorphous TiO2 into brookite is attributed to the water-driven dissolution and reprecipitation of TiO6 octahedra. It has been shown that an additional parameter necessary for the stabilization of the brookite is the oxygen depletion of the amorphous structure of titanium dioxide. Considering the results presented in this paper and the advantages of a portable, low-pressure cold spray system for industrial applications, it is expected that TiO2 coatings produced from a sol–gel feedstock powder can be further developed and tested as efficient photocatalysts.

scholarly journals Stannic Oxide-Titanium Dioxide Coupled Semiconductor Photocatalyst Loaded with Polyaniline for Enhanced Photocatalytic Oxidation of 1-Octene

2007 ◽  
Vol 2007 ◽  
pp. 1-6 ◽  
Author(s):  
Hadi Nur ◽  
Izan Izwan Misnon ◽  
Lim Kheng Wei
Keyword(s):  
Electrical Conductivity ◽  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Charge Separation ◽  
Photocatalytic Oxidation ◽  
High Photocatalytic Activity ◽  
Stannic Oxide ◽  
Aqueous Hydrogen Peroxide ◽  
Semiconductor Photocatalyst ◽  
Coupled Semiconductor

Stannic oxide-titanium dioxide (SnO2–TiO2) coupled semiconductor photocatalyst loaded with polyaniline (PANI), a conducting polymer, possesses a high photocatalytic activity in oxidation of 1-octene to 1,2-epoxyoctane with aqueous hydrogen peroxide. The photocatalyst was prepared by impregnation ofSnO2and followed by attachment of PANI onto aTiO2powder to give sample PANI-SnO2–TiO2. The electrical conductivity of the system becomes high in the presence of PANI. Enhanced photocatalytic activity was observed in the case of PANI-SnO2–TiO2compared to PANI-TiO2,SnO2–TiO2, andTiO2. A higher photocatalytic activity in the oxidation of 1-octene on PANI-SnO2–TiO2thanSnO2–TiO2, PANI-TiO2, andTiO2can be considered as an evidence of enhanced charge separation of PANI-SnO2–TiO2photocatalyst as confirmed by photoluminescence spectroscopy. It suggests that photoinjected electrons are tunneled fromTiO2toSnO2and then to PANI in order to allow wider separation of excited carriers.

scholarly journals Synthesis of Titanium Containing SBA-15 and Its Application for Photocatalytic Degradation of Phenol

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Lili Yang ◽  
Zeyu Jiang ◽  
Sufeng Lai ◽  
Chongwen Jiang ◽  
Hong Zhong
Keyword(s):  
Waste Water ◽  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Physicochemical Properties ◽  
Phenol Degradation ◽  
Titanium Content ◽  
Structure Change ◽  
Cyclic Performance ◽  
One Pot ◽  
Simulated Waste

We synthesized Ti-containing SBA-15 by one-pot hydrothermal method and extensively investigated its physicochemical properties and examined its photocatalytic activity to degrade phenol. It’s shown that appropriate amount of titanium could be effectively incorporated into the framework of SBA-15 without provoking structure change and the tetrahedrally coordinated titanium species were well-ordered in Ti-incorporated SBA-15. Under UV-irradiation, the Ti-containing SBA-15 exhibits good photocatalytic activity for phenol degradation in the simulated waste water. The higher photocatalytic activity of Ti-containing SBA-15 to degrade phenol was ascribed to the more titanium content and anatase titanium dioxide. In addition, the new photocatalyst displays a good regeneration and cyclic performance after six runs.

scholarly journals Friction Behavior of Pre-Damaged Wet-Running Multi-Plate Clutches in an Endurance Test

Lubricants ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 68
Author(s):  
Thomas Schneider ◽  
Katharina Voelkel ◽  
Hermann Pflaum ◽  
Karsten Stahl
Keyword(s):  
Coefficient Of Friction ◽  
Later Life ◽  
Second Step ◽  
Experimental Investigations ◽  
Endurance Test ◽  
Friction Behavior ◽  
Speed Range ◽  
The Coefficient Of Friction ◽  
Endurance Tests

Wet-running multi-plate clutches should be prevented from failing due to the often safety-relevant functions they fulfill in the drive train. In addition to long-term damage, spontaneous damage is of particular relevance for failures. This paper focuses on the influence of spontaneous damage on frictional behavior in the later life cycle. The aim of the experimental investigations is to initially cause spontaneous damage in wet-running multi-plate clutches with sintered friction linings. For this purpose, three clutches are first pre-damaged in stage tests with different intensities, so that the first spontaneous damage (local discoloration, sinter transfer) occurs. In the second step, an endurance test is carried out with the pre-damaged clutch packs and a non-pre-damaged reference clutch. The friction behavior of the clutches during the endurance test is compared and evaluated. It shows that local discoloration and sinter transfer are no longer visible after the endurance tests. At the beginning of the endurance test, the values of coefficient of friction are higher over the entire speed range of the heavily pre-damaged clutches than with the slightly pre-damaged clutch and the non-pre-damaged reference clutch. At the end of the endurance test, it can be observed that the greater the pre-damage to the clutches is, the greater the coefficient of friction increases with decreasing sliding speed.

Photodegradation of Oily Waste Water Using Nano-TiO2

2011 ◽  
Vol 332-334 ◽  
pp. 2153-2156
Author(s):  
Zong Wei Zhang ◽  
Chuang Zhang
Keyword(s):  
Waste Water ◽  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Sol Gel ◽  
Oily Wastewater ◽  
Tio2 Powder ◽  
Nano Tio2 ◽  
Photo Degradation ◽  
Photo Oxidation ◽  
Oily Waste

Photocatalytic degradation of oily wastewater using Nano-TiO2 was studied.First Nano-TiO2 powder with photocatalytic activity were prepared by sol-gel progress.Second the photo-degradation of oily wastewater on titanium dioxide was investigated.The reaction also features the photocatalytic activity of Nano-TiO2. Finally, the mechanisms of photo-oxidation were discussed.

Sol-Gel Titania and Titania-Silica Mixed Oxides Photocatalysts

2010 ◽  
Vol 162 ◽  
pp. 221-238 ◽  
Author(s):  
Rafael van Grieken ◽  
José Aguado ◽  
María José López-Muñoz ◽  
Javier Marugán
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Surface Area ◽  
Photocatalytic Oxidation ◽  
Mixed Oxides ◽  
Sol Gel ◽  
Textural Properties ◽  
Total Surface Area ◽  
Band Gap Energy ◽  
Titania Incorporation

This paper presents a review of the work published by the authors on the synthesis, characterization and evaluation of the photocatalytic activity of TiO2/SiO2 materials. The use of titania-silica mixed oxides photocatalysts is proposed basically as a process improvement to overcome the difficulties of recovering titania from the slurries after the photocatalytic treatment of contaminated waters. To understand the mechanism governing the photocatalytic activity of these materials, several titania-silica photocatalysts have been prepared through a sol-gel method that allows controlling the main variables to obtain materials with different textural properties, degree of titania incorporation, dispersion of the photoactive phase and crystallinity of titanium dioxide. The samples have been characterized in depth, looking for correlations between the main physicochemical properties (TiO2 crystallite size, band gap energy and titania surface area) and the activity shown in the photocatalytic oxidation of cyanide, selected as model pollutant. The results suggest that the photocatalytic activity is strongly influenced by the quality of the titania crystal network, which in turn is improved by the use of a hydrothermal crystallization procedure. Additionally, the evaluation of the fraction of the total surface area corresponding to titania is mandatory for comparing the catalytic activity of different materials in processes in which titanium dioxide is the only phase catalytically active and silica behaves as an inert support.

Photocatalytic Oxidation Thiophene Using Nano-TiO2

2012 ◽  
Vol 217-219 ◽  
pp. 729-732
Author(s):  
Zong Wei Zhang ◽  
Ming Xiong Liu ◽  
Jia Gang Zhai
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Photocatalytic Oxidation ◽  
Sol Gel ◽  
Tio2 Powder ◽  
Nano Tio2 ◽  
Photo Degradation ◽  
Ultraviolet Lamp

Photocatalytic oxidation of thiophene using Nano-TiO2 at ultraviolet lamp irradiation has been studied. The result showed thiophene was photooxidized successfully. First Nano-TiO2 powder with photocatalytic activity were prepared by sol-gel progress.Second the photo-degradation of thiophene on titanium dioxide was investigated.The reaction also features the photocatalytic activity of Nano-TiO2.

scholarly journals Role of Platinum Deposited on TiO2in Photocatalytic Methanol Oxidation and Dehydrogenation Reactions

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Luma M. Ahmed ◽  
Irina Ivanova ◽  
Falah H. Hussein ◽  
Detlef W. Bahnemann
Keyword(s):  
Particle Size ◽  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Methanol Oxidation ◽  
Photocatalytic Oxidation ◽  
Photogenerated Electron ◽  
Hole Charge ◽  
Platinum Particles ◽  
Dehydrogenation Reactions ◽  
The Fourier Transform

Titania modified nanoparticles have been prepared by the photodeposition method employing platinum particles on the commercially available titanium dioxide (Hombikat UV 100). The properties of the prepared photocatalysts were investigated by means of the Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), atomic force microscopy (AFM), and UV-visible diffuse spectrophotometry (UV-Vis). XRD was employed to determine the crystallographic phase and particle size of both bare and platinised titanium dioxide. The results indicated that the particle size was decreased with the increasing of platinum loading. AFM analysis showed that one particle consists of about 9 to 11 crystals. UV-vis absorbance analysis showed that the absorption edge shifted to longer wavelength for 0.5% Pt loading compared with bare titanium dioxide. The photocatalytic activity of pure and Pt-loaded TiO2was investigated employing the photocatalytic oxidation and dehydrogenation of methanol. The results of the photocatalytic activity indicate that the platinized titanium dioxide samples are always more active than the corresponding bare TiO2for both methanol oxidation and dehydrogenation processes. The loading with various platinum amounts resulted in a significant improvement of the photocatalytic activity of TiO2. This beneficial effect was attributed to an increased separation of the photogenerated electron-hole charge carriers.

scholarly journals Photocatalytic Activity of Titanium Dioxide Nanotubes Following Long-Term Aging

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2823
Author(s):  
Stephen Abela ◽  
Clayton Farrugia ◽  
Ryan Xuereb ◽  
Frederick Lia ◽  
Edwin Zammit ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
High Surface ◽  
High Surface Area ◽  
Real Life ◽  
Organic Electrolyte ◽  
Solar Irradiation ◽  
Commercially Pure ◽  
Physical And Chemical

Anodic titanium dioxide (TiO2) nanotubes were found to be active photocatalysts. These photocatalysts possess a high surface area, even when supported, rendering them potential candidates for water treatment. In this work, photocatalytic surfaces were produced by anodizing commercially pure Ti plates using two different electrolyte compositions and correspondingly diverse process parameters. Changes in the physical and chemical stability as well as photocatalytic activity were studied over a fifty-two-week aging process. During this period, the nanotubular surfaces were exposed to flowing synthetic greywater, solar irradiation, and the natural environment. The physical and phase stability of the materials anodized using the organic electrolyte were found to be outstanding and no degradation or change in crystalline structure was observed. On the other hand, materials anodized in the aqueous electrolyte proved to suffer from light-induced phase transition from anatase to rutile. Surfaces synthesized in the organic electrolyte were more resistant to fouling and showed a better tendency to recover photocatalytic activity upon cleaning. In conclusion, the nanotubes produced in the organic electrolyte proved to be stable, rendering them potentially suitable for real-life applications.

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