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

Chemical separations for Ga-68 from Ge-68 using adsorption chromatography on inorganic materials are described. The adsorbents used were TiO2, ZrO2, and SiO2. Distribution coefficients for Ge and Ga on these absorbents were determined as a function of reagent concentration and duration of equilibration. The distribution coefficient (w/w) for Ge on SiO2 reached 250 in 6 N HNO3, whereas Ga was no significantly adsorbed. Therefore, Ga-68 can be collected with a mall volume of 6 N HNO3 eluent. By contrast, large volumes of 1 N HNO3 were necessary to collect Ga-68 from ZrO2, since the KD of Ga under these circumstances was about 50. The Ga-68 eluted from TiO2 was chemically contaminated with titanates and would require additional chemical manipulation in order to make it injectable. All the adsorbents could lead to chromatographic systems that would allow acceptable chemical separations. However, the specific requirements for a radionuclide generator, usable in a hospital environment, make the SiO2-based system the most attractive.
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PMID:Potential column chromatography generators for ionic Ga-68. I. Inorganic substrates. 23 43

Surgical implant finishing and sterilization procedures were investigated to determine surface characteristics of unalloyed titanium (Ti). All specimens initially were cleaned with phosphoric acid and divided into five groups for comparisons of different surface treatments (C = cleaned as above, no further treatment; CP = C and passivated in nitric acid; CPS = CP and dry-heat sterilized; CPSS = CPS and resterilized; CS = C and dry-heat sterilized). Auger (AES), X-ray photoelectron (XPS), and Raman spectroscopic methods were used to examine surface compositions. The surface oxides formed by all treatments primarily were TiO2, with some Ti2O3 and possibly TiO. Significant concentrations of carbonaceous substances also were observed. The cleaning procedure alone resulted in residual phosphorus, primarily as phosphate groups along with some hydrogen phosphates. A higher percentage of physisorbed water appeared to be associated with the phosphorus. Passivation (with HNO3) alone removed phosphorus from the surface; specimens sterilized without prior passivation showed the thickest oxide and phosphorus profiles, suggesting that passivation alters the oxide characteristics either directly by altering the oxide structure or indirectly by removing moieties that alter the oxide. Raman spectroscopy showed no crystalline order in the oxide. Carbon, oxygen, phosphorus, and nitrogen presence were found to correlate with previously determined surface energy.
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PMID:Effect of surface treatment on unalloyed titanium implants: spectroscopic analyses. 959 42

In this study, methodologies for determining titanium oxide, zinc oxide and iron oxide are proposed and assayed in commercial sunscreen products. The proposed methodology for TiO2, determination in sunscreens is based on a microwave-assisted treatment for digesting the organic components in a closed teflon reactor in presence of HNO3 and HCl. Titanium is determined by inductive coupled plasma emission spectrometry (ICP-AES). The proposed methodologies for measuring ZnO and Fe2O3 are based on a sample emulsification in water with a non ionic tensioactive and IBMK, followed by Zn and Fe determination by flame atomic absorption spectrometry (FAAS). The methodologies allow a precise and accurate determination of metallic oxides in UV sunscreen creams, where the sample treatment is less time-consuming than in the classic methods. To our knowledge this is the first study focused to the determination of metallic oxides in commercial sunscreen products.
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PMID:Analytical methodologies for atomic spectrometric determination of metallic oxides in UV sunscreen creams. 1071 13

The treatment of the simulated wastewater containing formic acid and Cu(II) ions was investigated using photocatalytic technology of immobilized TiO2 film. The technology could efficiently remove COD and Cu(II) from the solution. In parallel, a rapid deactivation for COD removal was observed in a successive batch experiment. By XRD, UV-Vis diffuse reflectance spectra, SEM image and TG analysis, it was inferred that the deactivation was attributed to the shield of the deposited Cu(0) from UV light. The Cu(0)-fouled TiO2 film could be regenerated using three kinds of methods, air oxidation, electrochemical oxidation and air-assisted electrochemical oxidation. The regeneration time was mainly dependent on the used regeneration strategy while the regeneration extent was obviously associated with the tested regeneration medium. For the deactivated film with a relative activity of about 20%, the regeneration time is in order air-assisted electrochemical oxidation < electrochemical oxidation < air oxidation, and HNO3 medium has a regeneration extent of 97.2% for the air-assisted electrochemical oxidation, more desirable than HCl and H2SO4 mediums.
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PMID:Strategies for regeneration of copper(0)-deposited TiO2 photocatalytic film. 1236 45

The adsorption behavior of Cd, Co and Zn on nanometer-size TiQ2 was investigated. At pH 9.0, Cd, Co and Zn were retained on the nanometer-size TiO2, then eluted with 0.1 mol x L(-1) HNO3 and determined by ICP-AES. The adsorption capacities of nanometer TiO2 were found to be 8.1, 6.9 and 15.1 mg x g(-1) for Cd, Co and Zn respectively. The detection limits (3sigma) for Cd, Co and Zn are 5.1, 3.4 and 2.9 ng x mL(-1) respectively. The proposed method has been applied to the determination of trace Cd, Co and Zn in environmental samples with satisfactory results.
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PMID:[Nanometer-size titanium dioxide separation/preconcentration and ICP-AES for the determination of Cd, Co and Zn]. 1601 28

The adsorption behavior of nanometer TiO2 towards Gallium (Ga) Indium (In) and Thallium (Tl) was investigated with inductively coupled plasma atomic emission spectrometry (ICP-AES). The optimum conditions for adsorption were studied in detail, and the test included sorption kinetics, effect of pH on adsorption ratio, enrichment factor, and adsorption capacity. Under the optimum conditions, Ga (III), In(III) and Tl(I) ions could be adsorbed and recovered quantitatively. The static adsorption capacities of Ga(III), In(III) and Tl(I) on nanometer TiO2 were 48.6, 46.6 and 23.4 mg x g(-1) respectively. For the elution of Ga(III), In (III) and Tl(I), a mixture of 0.1 mol x L(-1) EDTA solution and 1.0 mol x L(-1) HNO3 was used, and the recovery ratio was above 92%. According to the definition of IUPAC, the detection limits (3sigma) of this method for Ga, In and Tl with an enrichment factor of 12.5 are 3.0, 6.0 and 13 ng x mL(-1), respectively; and relative standard deviations (RSD) are 1.85%, 1.96% and 3.4%, respectively (n = 6). The proposed method has been applied successfully to the analysis of geological samples with satisfactory results.
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PMID:[Study on the adsorption behavior of Ga, In and Tl on nanometer-size titanium dioxide by ICP-AES]. 1624 Oct 74

A novel and effective system was developed for the complete treatment of NOx from flue gases. The system consisted of photocatalytic or ozone oxidation of NOx, followed by scrubbing and biological denitrification. Maximum photocatalytic oxidation of NOx was achieved while using powdered TiO2 at a catalytic loading rate of 10 g/h, relative humidity of 50%, and a space time of 10 s. The used catalyst was regenerated and reused. A total of 72% of oxidized NO was recovered as HNO3/HNO2 in the regeneration process. Stoichiometrically, 10% excess ozone was able to affect 100% oxidation of NO to NO2. Presence of SO2 adversely influenced the oxidation of NO by ozone. The scrubbing of NO was effective with distilled water. Heterotrophic denitrifiers were able to denitrify the leachate with an efficiency of 90%, using sewage (COD 450 mg/L) as electron donor. The new integrated treatment system seems to be a promising alternative for complete treatment of NOx from flue gases.
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PMID:Integrated system for the treatment of oxides of nitrogen from flue gases. 1650 54

Preparation of anatase TiO2 nanorods from solutions in the absence of surfactants or templates has rarely been reported. The present work has found that hydrothermal treatment of titanate nanotube suspensions under an acidic environment resulted in the formation of single-crystalline anatase nanorods with a specific crystal-elongation direction. The nanotube suspensions were prepared by treatment of TiO2 in NaOH, followed by mixing with HNO3 to different pH values. The crystal size of the anatase nanoparticles obtained from the hydrothermal treatment increased with the pH of the suspensions, and nanorods with an aspect ratio up to 6 and a long axis along the anatase [001] were obtained at a pH slightly less than 7. A mechanism for the tube-to-rod transformation has been proposed on the basis of the crystalline structures of the tubes and rods. The local shrinkage of the tube walls to form anatase crystallites and the subsequent oriented attachment of the crystallites have been suggested to be the key steps involved in the nanorod formation.
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PMID:Hydrothermal synthesis of single-crystalline anatase TiO2 nanorods with nanotubes as the precursor. 1650 14

Nanometer titanium dioxide immobilized on silica gel (immobilized nanometer-scale TiO2 particles) was prepared by a sol-gel method and characterized by X-ray diffraction and scanning electron microscopy. The adsorptive behavior of Cr(III) and Cr(VI) on immobilized nanometer TiO2 was assessed. Cr(III) was selectively sorbed on immobilized nanometer TiO2 in the pH range of 7-9, while Cr(VI) was found to remain in solution. A sensitive and selective method has been developed for the speciation of chromium in water samples using an immobilized nanometer TiO2 microcolumn and inductively coupled plasma atomic emission spectrometry. Under optimized conditions (pH 7.0, flow rate 2.0 mL/min), Cr(III) was retained on the column, then eluted with 0.5 mol/L HNO3 and determined by ICP-AES. Total chromium was determined after the reduction of Cr(VI) to Cr(III) by ascorbic acid. The adsorption capacity of immobilized nanometer TiO2 for Cr(III) was found to be 7.04 mg/g. The detection limit for Cr(III) was 0.22 ng/mL and the RSD was 3.5% (n = 11, c = 100 ng/ mL) with an enrichment factor of 50. The proposed method has been applied to the speciation of chromium in water samples with satisfactory results.
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PMID:Speciation of chromium by selective separation and preconcentration of Cr(III) on an immobilized nanometer titanium dioxide microcolumn. 1652 98

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


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