Anatase-type Titanium Dioxide Research Articles

Preparation of Titanium Dioxide (TiO<sub>2</sub>) from Waste of Polymetallic Ore Processing <i>via</i> Sulfurization Treatment

Various experimental conditions were applied to extract titanium oxide from the waste of polymetallic ore. X-ray diffraction (XRD) analysis confirms that the waste of polymetallic ore contains including various minerals such as almandine (Fe,Mg,Ca)3Al2Si3O12, brownmillerite (FeAlO3(CaO)2), quartz (SiO2), magnetite (Fe3O4). Using H2SO4 acid with a concentration of 93% in the S/L mass ratio of 1:1.5 at 140 °C is suggested as an optimum reaction condition. Its hydrolysis subsequently leads to the formation of the titanyl sulfate (TiOSO4), and relatively pure titanium oxide is obtained through precipitation and calcination at 600 °C. The observed band gap value of 3.2 eV for the obtained TiO2 corresponds to the typical band gap value of anatase-type TiO2. We calculated the crystallite size of extracted anatase-type titanium oxide according to the Debye-Scherrer equation it was determined to be 96.35 nm. Fully reflecting X-ray fluorescence (XRF) determined that the purity of extracted TiO2 is 93.18%. This report presents a newly developed process that enables the production of relatively high-purity TiO2 (93.18%) from the waste of polymetallic ore (TiO2 5.39%) by a simple sulfurization process.

Regulating the interfacial structure in percolating graphite nanoplate/PVDF composites via TiO2 as an interlayer towards meliorative dielectric performances

Polymer nanocomposites combining large dielectric permittivity (ε′) but low loss along with high breakdown strength (Eb) have garnered significant attention in the fields of electronic devices and power systems. To concurrently accomplish these desirable performances in pristine graphite nanoplates (GNP)/poly(vinylidene fluoride, PVDF) composites, the GNP were initially encased by a layer of anatase-type titanium dioxide (TiO2) shell, and then incorporated into PVDF to investigate the effect of TiO2 interlayer on the dielectric properties of the nanocomposites, specifically in relation to the thickness of the TiO2 shell and the nanofiller concentration. The TiO2 shell acts as a barrier layer prohibiting the electronic percolating, thus significantly reducing the dielectric loss and leakage conductivity of the GNP@TiO2/PVDF. Moreover, it not only alleviates the strong dielectric mismatch between GNP and PVDF, which restrains local electric field distortion, but also introduces charge traps, raising the energy barrier height for captured charge detrapping and preventing the growth of electric trees and subsequently promoting the Eb. For example, the PVDF with 20 wt% of GNP@TiO2 exhibited good comprehensive dielectric performances: ε′ of 50.63, loss factor of 0.071 (100 Hz) and Eb of 7.89 kV/mm. Additionally, tailoring the TiO2’s thickness can simultaneously modulate the overall dielectric parameters in the GNP@TiO2/PVDF. Theoretical fitting of experimental data via Havriliak-Negami equation uncovers the underlying polarization mechanism and the interlayer’s impact on charge migration. This work provides an efficient method for developing and producing polymeric nanodielectrics that simultaneously incorporate increased Eb with high ε′ but low loss for potential use in power devices and microelectronic devices.

Enhanced dielectric properties of titanium Dioxide/Epoxy nanocomposites with different filler crystal form

In this work, two different types of titanium dioxide, anatase and rutile, were blended into a bisphenol-A epoxy resin. The dielectric properties of epoxy nanocomposites were measured to investigate whether the filler crystal form affects the behaviors of epoxy resin. All nanoparticles have a same size of ∼ 60 nm and the content of the nanocomposites is from 1 to 4 wt%. The dielectric properties of epoxy nanocomposites, including complex permittivity dependence on frequencies, volume resistivity, and breakdown strength were measured. Although the band gap of anatase-type titanium dioxide is smaller than that of rutile-type titanium dioxide, its epoxy nanocomposite has a higher volume resistivity and a higher breakdown strength at each filler content. The anatase-type titanium dioxide is more favorable than rutile-type titanium dioxide to improve the dielectric properties of epoxy resin.

Anatase and rutile titanium oxide nanoparticles induce acute kidney injury by coadministration with paraquat, cisplatin or 5-aminosalicylic acid.

Nanoparticles are used in a variety of fields; for example, titanium oxide nanoparticles are used in paints, food additives, cosmetics, and sunscreen materials. Although the use of titanium oxide nanoparticles is regulated, their safety has not been established. Furthermore, the interaction between titanium oxide nanoparticles and various chemical substances and pharmaceuticals is unknown. We co-administered rutile-type titanium oxide nanoparticles (nTR) or anatase-type titanium oxide nanoparticles (nTA) to mice together with paraquat (PQ), cisplatin (CDDP), or anti-5-aminosalicylic acid (5-ASA), and investigated the extent, if any, of liver and kidney injury. As a result, when nTA and nTR were administered alone, no increases were observed in aspartate aminotransferase (AST) and alanine aminotransferase (ALT), which are indicators of liver damage, or urea nitrogen (BUN), which is an indicator of kidney damage. Next, nTA and nTR were co-administered with PQ, CDDP or 5-ASA. Although no increase in ALT or AST was observed, BUN levels increased significantly and acute kidney injury was induced. The findings suggested that titanium oxide nanoparticles induce acute kidney injury through their interaction with chemicals and drugs.

Triboelectric Charging Behaviors of Polyester Films Doped with Titanium Dioxide Nanoparticles of Various Crystal Structures

It is empirically known that titanium dioxide nanoparticles stabilize the contact and frictional charge of the host polymers to which they are added. However, the mechanism for the stabilization process has not yet been elucidated. In this study, polyester films doped with titanium dioxide nanoparticles of different crystalline forms were triboelectrically charged and the effect of humidity on their charging characteristics was subsequently investigated to elucidate the charge stabilization mechanism. Our first finding was that the rutile-, rutile–anatase mixed crystal (P25)-, and amorphous-dominant-type titanium dioxide nanoparticles reduced the sensitivity of the films to humidity (humidity dependence), while the anatase-type titanium dioxide enhanced the humidity dependence. This difference in action was explained by associating it with the different water adsorption forms on the major crystalline surface of each titanium dioxide type. The second finding was that doping with titanium dioxide nanoparticles, particularly rutile and P25 nanoparticles, reduced fluctuations in the amount of tribocharges of the polyester film. This crystalline-form-dependent difference in action was considered to be based on the depth of the electron traps involved in each titanium dioxide type. The above two findings have allowed us to propose the first mechanism of tribocharge stabilization by titanium dioxide.

Electronic structures of hydroxylated low index surfaces of rutile and anatase-type titanium dioxide.

Different surface planes of various types of titanium dioxide (TiO2) crystals have diverse catalysis effects on the splitting of H2O and H2 and the electronic structures of the formed hydroxylated TiO2 vary significantly. A series of sixteen types of hydroxylated TiO2 surfaces containing two types of hydroxyls (OH1 and OH2) on four kinds of low index surfaces [(001), (100), (101), and (110)] of two types of crystals [anatase (A) and rutile (R)] are studied using first-principles density functional theory calculations. The catalyzed splitting of H2O and H2 on the eight low index surfaces is compared using Gibbs free energy. The geometries and electronic structures including the total and partial density of states and the charge density distribution of the sixteen hydroxylated surfaces are systematically described. The electronic structures of R-101, R-001, A-110, A-100, and A-001 surfaces are more significantly influenced by hydroxylation than other surfaces and the effects of OH2 are larger than those of OH1. In particular, the band gap values decrease and a new electronic energy state appears in R-001-OH2 and A-100-OH2. A new electronic state appears in the middle of the bands of R-101 and A-110 surfaces upon hydroxylation. The electron spin balance at the edge of the conduction band minimum of A-001-OH2 is disturbed. This research can provide theoretical guidance for experimental researchers to design surface hydroxylated TiO2 materials with tunable electronic structures and high catalytic performance.

Simple preparation of nano-anatase titanium dioxide from cold rolled titanic acid waste liquid

Anatase titanium dioxide has high photocatalytic activity and super hydrophilicity due to its special crystal structure. In this article, the anatase-type titanium dioxide has been simply prepared by cold-rolling titanic acid waste liquid for the first time, which effectively solves the problem that the valuable metal titanium in waste liquid is difficult to recover, and realizes the recycling of titanium resources. The effect of pH and EDTA on the impurity content of titanium dioxide is investigated in this study. It is found that nano-anatase-type titanium dioxide, with less impurities and uniform particle size, can be obtained at pH 2, EDTA, and iron molar ratio is 3. Meanwhile, the nitric acid pickling can effectively reduce the impurity content in the titanium dioxide, which provides a possibility for preparation of nanoscale anatase titanium dioxide from cold rolled titanic acid waste liquid.

Impact of titanium precursors on formation and electrochemical properties of Li4Ti5O12 anode materials for lithium-ion batteries

This work describes comparative study on the application of Li4Ti5O12 (LTO) as anode materials for lithium-ion batteries which were successfully prepared by sol-gel synthesis with the use of two titanium sources. One of them was anatase-type titanium dioxide (TiO2), whereas the second was tetrabutyl titanate (TBT). Both obtained LTO materials were very similar in terms of their crystallinity and purity. In turn, the sample synthetized with TBT source revealed better particle dispersibility, and its particles were slightly lower in size. These particular features resulted in higher Li+ diffusion coefficient and better kinetic of Li+ ions during charge transfer reactions for the LTO synthetized with TBT source. This reflected in specific capacitance values for both electrodes which equalled 150 mAh g−1, 120 mAh g−1, and 63 mAh g−1 for TBT-LTO and 120 mAh g−1, 80 mAh g−1, and 58 mAh g−1 for TiO2-LTO at C-rates of 1, 5, and 10 C, respectively.

Preparation and electrorheological properties of eggshell-like TiO2 hollow spheres via one step template-free solvothermal method

In this paper, we prepared eggshell-like TiO2 hollow sphere nanoparticles by one-step template-free method, and studied its electrorheological (ER) properties at different electric field strengths. The microstructure, composition, and morphology of eggshell-like TiO2 hollow sphere was characterized by SEM (scanning electron microscopy), TEM (transmission electron microscopy), XRD (X-ray powder diffractometer), FI-IR (Fourier transform infrared spectroscopy), BET (Brunner Emmett Teller) measurements. XRD and FT-IR confirm the existence of pure anatase-type titanium oxide. BET measurement verifys the hollow structure belonging to eggshell-like TiO2 hollow nanoparticles. With the help of SEM and TEM techniques, by changing the reaction time, we learned about the approximate formation process of eggshell - like TiO2 hollow nanoparticles and observed the hollow structure. After a series of characterization methods, we have a further and deeper understanding of eggshell-like TiO2 hollow ball nanoparticles. Thus, we found that the one-step templateless method we used to prepare eggshell like TiO2 hollow spherical nanoparticles is simple and easy to operate, with a short reaction cycle and non-toxic and harmless. And the electrorheological properties, including the variation of shear stress, shear viscosity, as well as electrorheological efficiency of eggshell-like TiO2 hollow sphere-based electrorheological fluid with shear rate under different electric field were studied by using high-speed rotary rheometer. At the same time, the obtained eggshell-like TiO2 hollow spherical nanoparticles have good electrorheological properties and are a kind of electrorheological materials with promising application prospects.

Preparation and Characterization of Submicron TiO2 Microspheres via Urea-formaldehyde Template

In order to obtain sub-micron TiO2 microspheres with good dispersibility and easy collection, urea-formaldehyde(UF)-TiO2 hybrid microspheres were synthesized by polymerization-induced precipitation in acidic TiO2 sol through the reaction of urea and formaldehyde. The hybrid microspheres and their calcined products were analyzed by scanning electron microscopy, laser particle size analyzer, thermogravimetric analyzer and X-ray Powder diffractometer. The results of morphological characterization showed that the UF-TiO2 hybrid microspheres were spherical and well dispersed, and their particle size ranged from 0.8∼5μm The sub-micron TiO2 microspheres with large pore volume and good dispersion were obtained by calcining and removing the organic components in the hybrid microspheres. Thermogravimetric analysis showed that the proportion of inorganic components in hybrid microspheres was about 20%. XRD analysis showed that the product of calcined hybrid microspheres was single anatase-type titanium dioxide.

Effects of hydrothermal treatment on physicochemical and anticorrosion properties of titanium nitride coating on pure titanium

Titanium nitride (TiN) coating is a promising to be used on metal implant and surface oxidation by hydrothermal treatment has been proved to effectively enhance its osteoconductivity. In this study, the physicochemical properties and corrosion resistance of the TiN coating after hydrothermal treatment in distilled water were investigated. The results showed that, Anatase-type titanium oxide (TiO2) nanoparticles formed on the TiN surface once the temperature was over 150 °C and that they formed a compact layer when the temperature increased to over 200 °C. The treatment significantly improved the wettability of TiN coating. Although surface hardness of TiN coating decreased slightly after formation of oxide layer, it could still provide enough protection for substrate. Electrochemical experiments showed that corrosion resistance of TiN was greatly improved in present of fluoride ions (F−). Immersion test for 5 weeks showed that numerous corrosion pits appeared on untreated TiN coating, whereas, the TiO2 layer on treated TiN coating remained intact and provided good protection for the underlying TiN. This work showed that hydrothermal treatment at 200–250 °C could comprehensively improve the properties of TiN coating necessary for biological applications and it also provide a possible solution to improve corrosion resistance of hard TiN coating on metal substrates.

Development of Titanium Dioxide-Supported Pd Catalysts for Ligand-Free Suzuki–Miyaura Coupling of Aryl Chlorides

The catalyst activities of various heterogeneous palladium catalysts supported by anatase-, rutile- and brookite-type titanium oxide for ligand-free Suzuki–Miyaura cross-coupling reactions of aryl chlorides were evaluated. Palladium acetate [Pd(OAc)2], supported on anatase-type titanium oxide (TiO2) via acetonitrile solution impregnation process without reduction [Pd/TiO2 (anatase-type)], demonstrated the highest catalyst activity in comparison to those of other titanium oxide (rutile- or brookite-type) supported Pd(OAc)2 without reduction and reduced Pd/TiO2 (anatase-type) [Pd(red)/TiO2 (anatase-type)]. Various aryl chloride and bromide derivatives were smoothly coupled with arylboronic acids including heteroarylboronic acids in the presence of 5–10 mol% Pd/TiO2 (anatase-type) without the addition of any ligands. Although the fresh Pd/TiO2 (anatase-type) catalyst was surprisingly comprised of ca. 1:2 mixture of palladium(II) and palladium(0) species according to X-ray photoelectron spectroscopy (XPS), in spite of no reduction process, significant further increment of palladium(0) species was observed during the Suzuki–Miyaura coupling reaction, and Pd/TiO2 (anatase-type) was converted into a catalyst, which contained palladium(0) species as the main component [ca. 1:5 mixture of palladium(II) and palladium(0) species]. Therefore, the reduction via the electron donation process to the palladium(II) species may have occurred during the reaction on anatase-type titanium oxide.

Exploring the Phase Transformation Mechanism of Titanium Dioxide by High Temperature in Situ Method

In this study, the real-time phase measurement of titanium dioxide under different temperature conditions was tested by real-time measurement of high temperature sample stage and Rietveld refinement method. The real-time phase transformation process of titanium dioxide under high temperature conditions was analyzed. The results show that the (101) crystal plane of anatase titanium dioxide is most stable when the amorphous metatitanic acid is transformed into anatase titanium dioxide during the phase transformation of titanium dioxide, and the growth of anatase has a preferred orientation along the c-axis. In the case of anatase-type titanium dioxide to rutile-type titanium dioxide, the (110) crystal plane of rutile-type titanium dioxide is the most stable, but the rutile type has no preferred orientation.

Accelerated induction of in vitro apatite formation by parallel alignment of hydrothermally oxidized titanium substrates separated by sub-millimeter gaps

ABSTRACTAlthough autoclaving is a common sterilization method for biomedical devices, the ability to induce deposition of apatite particles on hydrothermally treated titanium is still not fully realized. This is because the induction ability is too weak to be evaluated via in vitro apatite formation in Kokubo’s simulated body fluid (SBF) by the conventional immersion method, i.e. using samples with open and smooth surface. This study reports on the surface structure of hydrothermally treated titanium and the ability to induce deposition of apatite particles on the surface of parallel confined spaces separated by sub-millimeter gaps in Kokubo’s SBF. Thin-film X-ray diffraction and analyses using Fourier transform infra-red (FT-IR) spectroscopy and Raman spectroscopy revealed that a nano-crystalline anatase-type titanium oxide layer was formed on titanium substrates after hydrothermal treatment at 150°C for 2 h. When growth of the titanium oxide layer was moderately suppressed, the hydrothermally treated titanium surface exhibited a characteristic interference color, silver or gold, which does not impair the esthetic appearance of the titanium-based implant. The ability to induce deposition of apatite particles on hydrothermally treated titanium was remarkably amplified by parallel alignment of substrates separated by sub-millimeter gaps.

Permeability, Melt Flow Index, Mechanical, and Morphological Properties of Green HDPE Composites: Effect of Mineral Fillers

In this study, two types of composites, both with the same polymeric matrix, high density polyethylene (HDPE) from renewable sources, also called green HDPE, are investigated. The mineral fillers insert into HDPE are vermiculite and titanium dioxide (TIO2). The objective of this work is the evaluation of two inorganic fillers in the HDPE composites and how their presence alters the properties of this HDPE derive from sugar cane ethanol. Composites obtain by extrusion with different contents of anatase type titanium dioxide (10–30 wt%/wt) and brazilian vermiculite (5–20 wt%/wt) are evaluated as for mechanical and morphological properties, melt flow index (MFI), and permeability. The addition of fillers cause little influence on tensile strength, but increased the elasticity modulus and decreased impact strength. in relation to morphology, it is found that particles of TIO2 are well dispersed in the HDPE matrix. For composites with vermiculite, its distribution in the polymer matrix is not so good as compared with composites of TIO2, especially in proportions higher than 10 wt%. The results of MFI show that by adding vermiculite the fluidity of polyethylene does not change, but the addition of TIO2 promotes a reduction in fluidity thus suggesting that a good dispersion has been achieved. Permeability increases on the addition of the two fillers, being more pronounced at high amounts (20% vermiculite and 30% TIO2). The analyzed properties, the addition of these fillers does not interfere negatively the properties of the green HDPE and can be considered an alternative toward low cost composites.

Enhanced Bioactivity of Chemically Oxidization-Modified Titanium Alloys

Anatase-type titanium dioxide oxide layer was formed on the surface of titanium alloy by chemical oxidation. 0.9 um thick anatase was obtained by soaking in a mixed solution of a certain proportion of hydrogen peroxide and hydrochloric acid and then heat treatment. The surface morphology, phase structures and composition of oxide layers were characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). Thickness of titania coating was measured by the ball pit gauge. Inductively coupled plasma atomic emission spectroscopy (ICP-AES) was used to detect the change of Ca ion and P ion concentration in solution. The results showed that anatase layers deposited apatite within 4 days accompanying the decrease of pH when soaked in simulated human body fluid (SBF). Ion exchange between the negative ions and calcium ions in SBF is proposed as the mechanism operative to favor the deposition on apatite.

Photocatalytic Activity of Titanium Dioxide Powder Fabricated from an Anodized Titanium Sheet under Ultra-Violet and Visible Light Irradiation

A commercially pure titanium sheet with titanium carbide (TiC) precipitated in its surface layer was anodized in NH4NO3 aqueous solution and heat treated in air. The photocatalytic activity of titanium dioxide powder collected from the surface of the anodized titanium sheet was evaluated under ultra-violet and visible light irradiation. It showed relatively high photocatalytic activity in 0.1 mol/l potassium iodide solution, which was almost equal to the activity level of TiO2 powder (P-25) manufactured by Degussa Corporation. The better photocatalytic activity under ultra-violet irradiation is considered to be related to the formation of anatase type titanium dioxide. Photocatalytic activity under visible light irradiation was also observed, which was considered to be attributable to impurity doping, (carbon), in the titanium dioxide powder.

11. Bactericidal Activity of Photocatalytic TiO2 Excited by Low Intensity Pulsed Ultrasound (LIPUS): An In Vitro Study.

Photocatalysis with anatase-type titanium dioxide (TiO2) under ultraviolet has a well-recognized bactericidal effect. The purpose of the present study was to evaluate the photocatalytic bactericidal effects of TiO2 on Staphylococcus epidermidis (ATCC35984) caused by Low Intensity Pulsed Ultrasound (LIPUS) associated with bio-implant-related infections. The photocatalytic properties of the TiO2 films were confirmed by the degradation of an aqueous solution of methylene blue. The disks were seeded with cultured Staphylococcus epidermidis and irradiated by LIPUS. The bactericidal effect of the TiO2 films was evaluated by counting the surviving colonies. The viability of the bacteria on the photocatalytic TiO2 film coated titanium was suppressed significantly to 63% after 2 hours of LIPUS treatment (P < 0.05). The photocatalytic bactericidal effect of TiO2 under LIPUS is useful for sterilizing the contaminated and infected surfaces of metal bio-implants.

Titanium peroxide nanoparticles enhanced cytotoxic effects of X-ray irradiation against pancreatic cancer model through reactive oxygen species generation in vitro and in vivo.

BackgroundBiological applications of nanoparticles are rapidly increasing, which introduces new possibilities to improve the efficacy of radiotherapy. Here, we synthesized titanium peroxide nanoparticles (TiOxNPs) and investigated their efficacy as novel agents that can potently enhance the effects of radiation in the treatment of pancreatic cancer.MethodsTiOxNPs and polyacrylic acid-modified TiOxNPs (PAA-TiOxNPs) were synthesized from anatase-type titanium dioxide nanoparticles (TiO2NPs). The size and morphology of the PAA-TiOxNPs was evaluated using transmission electron microscopy and dynamic light scattering. The crystalline structures of the TiO2NPs and PAA-TiOxNPs with and without X-ray irradiation were analyzed using X-ray absorption. The ability of TiOxNPs and PAA-TiOxNPs to produce reactive oxygen species in response to X-ray irradiation was evaluated in a cell-free system and confirmed by flow cytometric analysis in vitro. DNA damage after X-ray exposure with or without PAA-TiOxNPs was assessed by immunohistochemical analysis of γ-H2AX foci formation in vitro and in vivo. Cytotoxicity was evaluated by a colony forming assay in vitro. Xenografts were prepared using human pancreatic cancer MIAPaCa-2 cells and used to evaluate the inhibition of tumor growth caused by X-ray exposure, PAA-TiOxNPs, and the combination of the two.ResultsThe core structures of the PAA-TiOxNPs were found to be of the anatase type. The TiOxNPs and PAA-TiOxNPs showed a distinct ability to produce hydroxyl radicals in response to X-ray irradiation in a dose- and concentration-dependent manner, whereas the TiO2NPs did not. At the highest concentration of TiOxNPs, the amount of hydroxyl radicals increased by >8.5-fold following treatment with 30 Gy of radiation. The absorption of PAA-TiOxNPs enhanced DNA damage and resulted in higher cytotoxicity in response to X-ray irradiation in vitro. The combination of the PAA-TiOxNPs and X-ray irradiation induced significantly stronger tumor growth inhibition compared to treatment with either PAA-TiOxNPs or X-ray alone (p < 0.05). No apparent toxicity or weight loss was observed for 43 days after irradiation.ConclusionsTiOxNPs are potential agents for enhancing the effects of radiation on pancreatic cancer and act via hydroxyl radical production; owing to this ability, they can be used for pancreatic cancer therapy in the future.Electronic supplementary materialThe online version of this article (doi:10.1186/s13014-016-0666-y) contains supplementary material, which is available to authorized users.

Anatase Type Titanium Dioxide Prepared by Oxidation of Titanium Carbide

Titanium carbide has been attractive for years an engineering ceramics due to its high hardness, high melting point, and good chemical stability. Similarly, titanium dioxide has excellent anti-microbial ceramic material by photon energy. In this study, the anatase type titanium dioxide layer prepared by oxidation of the titanium carbide powder by high temperature oxidation in air atmosphere was investigated in order to determine the possibility of its photocatalyst materials by radiant energy. TiC powder samples of different grain size were gained by ball mill. These samples were oxidized at room temperature to high temperature. The samples exhibited a steady mass gain with increasing oxidation temperature. Based on the results of the X-ray diffraction analysis, anatase type TiO2 was detected on the titanium carbide samples. It is considered, the titanium carbide showed convension anatase type titanium dioxide layer produced by oxidation.