Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: KEGG:D01931 (TiO2)
11,320 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this study, an innovative E-H2O2/TiO2 (E-H2O2 = electrogenerated hydrogen peroxide) photoelectrocatalytic (PEC) oxidation system was successfully developed for water and wastewater treatment. A TiO2/Ti mesh electrode was applied in this photoreactor as the anode to conduct PEC oxidation, and a reticulated vitreous carbon (RVC) electrode was used as the cathode to electrogenerate hydrogen peroxide simultaneously. The TiO2/Ti mesh electrode was prepared with a modified anodic oxidation process in a quadrielectrolyte (H2SO4-H3PO4-H2O2-HF) solution. The crystal structure, surface morphology, and film thickness of the TiO2/Ti mesh electrode were characterized by X-ray diffraction and scanning electron microscopy. The analytical results showed that a honeycomb-type anatase film with a thickness of 5 microm was formed. Photocatalytic oxidation (PC) and PEC oxidation of 2,4,6-trichlorophenol (TCP) in an aqueous solution were performed under various experimental conditions. Experimental results showed that the TiO2/Ti electrode, anodized in the H2SO4-H3PO4-H2O2-HF solution, had higher photocatalytic activity than the TiO2/Ti electrode anodized in the H2SO4 solution. It was found that the maximum applied potential would be around 2.5 V, corresponding to an optimum applied current density of 50 microA cm(-2) under UV-A illumination. The experiments confirmed that the E-H2O2 on the RVC electrode can significantly enhance the PEC oxidation of TCP in aqueous solution. The rate of TCP degradation in such an E-H2O2-assisted TiO2 PEC reaction was 5.0 times that of the TiO2 PC reaction and 2.3 times that of the TiO2 PEC reaction. The variation of pH during the E-H2O2-assisted TiO2 PEC reaction, affected by individual reactions, was also investigated. It was found that pH was well maintained during the TCP degradation in such an E-H2O2/TiO2 reaction system. This is beneficial to TCP degradation in an aqueous solution.
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PMID:Development of an E-H2O2/TiO2 photoelectrocatalytic oxidation system for water and wastewater treatment. 1604

Disinfection with photocatalysis, compared to with the conventional cleanout, is both high efficient and non contaminative, but the simple TiO2 photocatalyst is showing to be of low activity and low active stability so to be hardly practical application. In the paper, SO4(2-)/TiO2 were papered by surface modification of TiO2 with dilute H2SO4, and the photocatalytic degradation of 2-chloroethyl ethyl sulfide (2-CEES) on the samples was examined in a fixed-bed microreactor. The examination show that the acidic modification enhanced both the activity and the active stability of TiO2, and the sample ST200 prepared by calcination at 200 degrees C was better than ST400 by calcination at 400 degrees C. The effect of water vapor content and reaction temperature on the photocatalytic degradation of 2-CEES was also tested, showing that the sample ST200 had high activity and stability at 90 degrees C, and kept a constant activity when adding 30.5 mL/L water vapor into the reactive system in which 2-CEES initial concentration was low to < 61 microL x L(-1). In addition, it was found that supporting SO4(2-)/TiO2 on gamma-Al2O3, SiO2 and active carbon could improve on the activity and stability of SO4(2-)/TiO2, and on supports SiO2 is the best one.
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PMID:[Photocatalytic removing of a mustard gas analogue 2-CEES vapor over SO4(2-)/TiO2]. 1612 85

The TiO2 nanotube sample was prepared via a NaOH solution in a Teflon vessel at 150 degrees C. The as-prepared nanotubes were then treated with H2 SO4 solutions. The TiO2 nanotube has a crystalline structure with open-ended and multiwall morphologies. The TiO2 nanotubes before and after surface acid treatment were characterized by X-ray diffraction (XRD), scanning electron microscopy(SEM), transmission electron microscopy (TEM) and UV-VIS dispersive energy spectrophotometry (DRS). The photocatalytic activity of the samples was evaluated by photocatalytic degradation of acid orange II in aqueous solutions. It was found that the order of photocatalytic activity was as follows: TiO2 nanotubes treated with 1.0 mol/L H2SO4 solution (TiO2 (1.0M H2SO4) snanotubes) > TiO2 nanotubes treated with 0.2 mol/L H2SO4 solution (TiO2 (0.2M H2O4) nanotubes) > TiO2 nanotubes > TiO2 powder. This was attributed to the fact that TiO2 nanotubes treated with H2SO4 was composed of smaller particles and had higher specific surface areas. Furthermore, the smaller TiO2 particles were beneficial to the transfer and separation of photo-generated electrons and holes in the inner of and on the surface of TiO2 particles and reduced the recombination of photo-generated electrons and holes. Acid treatment was particularly effective for TiO2 nanotubes, this increase in activity was correlated with the concentration of H2 SO4 solution.
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PMID:Enhanced photocatalytic activity of nanotube-like titania by sulfuric acid treatment. 1629 8

In this work we have synthesized TiO2 nanoparticles, using either a sol-gel base catalysed process in the interior of CTAB reversed micelles (TiO2 CTAB sol), or the neutralization of a TiO2/H2SO4 solution in the interior of AOT reversed micelles. From the absorption and emission data of the TiO2 nanoparticles it is possible to conclude that in the sol-gel route there remains alkoxide groups in the structure, originating transitions lower than the energy gap of TiO2 semiconductor. These transitions disappear in the neutralization procedure, where the alkoxide groups are absent in the structure. We have assigned the observed indirect and direct optical transitions according to the anatase band structure. TiO2 Langmuir-Blodgett (LB) films were prepared either by direct deposition of titanium isopropoxide or by deposition of the TiO2 CTAB sol. These films showed photoluminescence, which was attributed to band-gap emission and to surface recombination of defect states.
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PMID:Characterization of TiO2 nanoparticles in Langmuir-Blodgett films. 1679 3

Nanocrystalline TiO2 powders were rapidly prepared by hydrolysis of Ti(OC4H9)4 under ultrasound irradiation. The influences of acids (HCl, HNO3, and H2SO4) and their corresponding salts (NaCl, KNO3, and Na2SO4) on the crystalline phase and morphology of products were investigated, respectively. Compared with NaCl and KNO3 that show no evident influence on the crystalline phase, HCl and HNO3 have a decisive influence on the crystalline phase of the products. However, both H2SO4 and Na2SO4 are favorable for the formation of anatase. By adjusting the concentration of SO2-(4) in the reaction medium, the contents of anatase and rutile phases in the TiO2 powders can be successfully controlled. The morphology of TiO2 crystallites are shown to be strongly related to the type of acid used in the reaction medium.
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PMID:Influences of acids and salts on the crystalline phase and morphology of TiO2 prepared under ultrasound irradiation. 1689 Feb 36

The pure titanium disks were divided into three groups and etched for 30 minutes with HNO3, hot H2SO4/H2O2 or hot H2SO4/HCl respectively. The treated disks were studied and analyzed with scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The disks etched with HNO3 had a smooth surface, while those etched with hot H2SO4/H2O2 or hot H2SO4/HCl had rough surfaces, and the surface etched with hot H2SO4/HCl had larger micropores. The XPS analysis demonstrated that the main elements of the surface in three groups were titanium, oxygen and carbon. The carbon concentration was the lowest on the surface etched with hot H2SO4/H2O2 and the highest on that etched with hot H2SO4/HCl. The substances were TiO2, Ti2O3, TiO and metal Ti on the surface etched with HNO3 or hot H2SO4/H2O2. Only TiO2 was detected on the surface etched with hot H2SO4/HCl.
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PMID:[Effects of three different etching methods on surface morphology and element of pure titanium]. 1700 14

Titanium oxide grown by a sol-gel route on single-walled carbon nanotubes was studied by Raman and Electrochemical Impedance techniques and compared with mixtures obtained by mechanical grinding. In spite of the superior dispersion of single-walled carbon nanotubes bundles in sol-gel composites, the lost of the small-diameter carbon nanotubes in the oxidizing sol-gel bath was inferred from their Raman spectra and the lower capacitive current of the voltammograms in 0.1 M H2SO4. We proposed proton electrosorption as the main charge storage mechanism for sol-gel composites, favoured by the hydroxylation and n-type conductivity of the oxide, while electrodes based on mixtures were dominated by double-layer charging, developing some pseudocapacitance with potential cycling due to the reversible oxidation of carbon nanotubes. Comparsion with TiO2/Carbon Blacks composites shows the effective role of single-walled carbon nanotubes as templates to control the mesoporous nature of sol-gel composite electrodes.
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PMID:Raman and electrochemical impedance studies of sol-gel titanium oxide and single walled carbon nanotubes composite films. 1745 Sep 31

Titanium and its alloys are extensively used in load-bearing metallic devices. They are bioinert material and, therefore, get encapsulated after implantation into the living body by a fibrous tissue that isolates them from the surrounding tissues. Here we report modification of titanium surface using bioactive tricalcium phosphates (TCP) and nanoscale TiO2 to enhance cell-materials interaction. We have introduced bioactivity in Ti using laser-assisted coating of TCP and by anodization to grow surface TiO2 at room temperature using a mixed aqueous solution of sodium fluoride, citric acid and sulfuric acid as electrolyte. TCP coating showed a columnar Ti grains at the substrate side of the coating and transitioned to an equiaxed grains at the outside. Coating hardness increased from 882 +/- 67 to 1029 +/- 112 Hv as the volume fraction of TCP increased in the coating. For TiO2 nanotubes, microscopic analysis showed tubes of 50 nm in diameter with wall thickness of 15 nm and typical length between 200 nm and 1 micron based on anodization times. Effects of TCP and nanoscale TiO2 coating on bone cell-material interaction were examined by culturing osteoprecursor cells (OPC1) on coated surfaces. Antibacterial activity analysis using metallic Ag via electrodeposition showed over 99% antibacterial activity against the growth of colonies of Pseudomonas aeruginosa.
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PMID:Surface modification of titanium for load-bearing applications. 1836 77

Fluorescence spectra and fluorescence quantum yield of TiO2 nanocrystals were studied. Using tetra n-butyl titanate as a starting material, a facile alcohothermal technique was used to synthesize TiO2 nanocrystals. As can be seen from the transmittance electron microscopy (TEM) image, TiO2 nanocrystals with a relatively uniform particle size distribution of < 10 nm are present in the transparent sol. The transparent sol presents a strong stable fluorescence emission with a maximum at 450 nm, which is greatly dependent on the size quantization effects, defect energy level and the surface state of TiO2 nanocrystals. The quantum yield (gamma) of TiO2 was determined by the relative comparison procedure, using freshly prepared analytical purity quinine sulfate in 0.05 mol x L(-1) H2SO4 as a relative quantum yield standard. The emission quantum yield of TiO2 nanocrystals prepared in alcoholic media was calculated to be about 0.20 at wavelengths ranging from 330 to 370 nm, which was much higher than the values reported in previous works. So, it is supposed that nano-TiO2 will be applied as a potential quantum dots fluorescence probe in biological analysis.
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PMID:[Fluorescence spectra and quantum yield of TiO2 nanocrystals synthesized by alcohothermal method]. 1842 45

We report a large-scale self-etching approach for the synthesis of monodispersed mesoporous F-TiO2 hollow microspheres. The self-etching derived from HF was elucidated by the morphology, chemical composition, and crystal size evolutions from solid to hollow microspheres with the increase in the concentration of H2SO4. The resulting TiO2 hollow microspheres exhibited ease for the concurrent membrane filtration and photocatalysis, providing high potential for engineering application in advanced water treatment, for not only increasing water production but also improving water quality.
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PMID:Self-etching reconstruction of hierarchically mesoporous F-TiO2 hollow microspherical photocatalyst for concurrent membrane water purifications. 1868 Feb 96


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