Titanium dioxide (TiO2, rutile) nanoparticles, inorganic ultraviolet absorbers, are used extensively in sunscreen cosmetics as an inorganic ultraviolet (UV) absorber to prevent skin damage; because of their nanotoxicity, use in combination with a support, such as montmorillonite (Mnt), rather than alone, is suggested. Mnt-supported TiO2 composites (Mnt-TiO2) for sunscreens are most suitable when the particles are spherical and of relatively uniform size, which are normally accomplished by spray drying, but this is difficult to achieve because of the naturally layered structure of Mnt. The objective of the present study was, therefore, to find the ideal characteristics of spray-drying nozzles to produce the desired spherical shape and size distribution of the Mnt-TiO2 composite particles. The starting Mnt was extracted from natural bentonite by particle-size separation. An ultrasonic nozzle in the spray dryer was selected for use in the synthesis of Mnt-TiO2 composites based on the particle-size distribution (PSD) of Mnt prepared using a two-fluid nozzle and an ultrasonic nozzle at 453 K. The incorporation of TiO2 in the final Mnt-TiO2 composites was examined by X-ray powder diffraction (XRD) and elemental analysis. With increasing TiO2 concentration, the TiO2 content and average particle size of the Mnt-TiO2 composites increased. Scanning electron microscopy (SEM) images showed that all samples prepared had uniform and nearly spherical shapes. Absorbance of UV by Mnt-TiO2 (5:1) composites was greater than that by either purified Mnts or pure TiO2. The present study demonstrated a simple method, using a spray dryer with an ultrasonic nozzle, to synthesize Mnt-TiO2 composites of uniform size and shape suitable for cosmetic application.

TiO2/stevensite nanocomposite photocatalysts were synthesized by a solvothermal method using TiCl3/HCl as reactants and the stevensite clay mineral extract as support. The prepared photocatalyst samples were then characterized using various techniques such as X-ray diffraction (XRD), Infrared spectroscopy (IR) and Transmission Electron Microscopy (TEM). The Points of Zero Charge (PZC) of the various samples were evaluated by titration of the non-modified and the Ti-modified clay aqueous dispersions, with cationic surfactant solutions. The photocatalytic activity of the resulting nanocomposites samples were evaluated for the removal of Orange G (OG) from aqueous solution as a model dye pollutant. The data indicate that the formation of Na+-stevensite by the TiO2 particles leads to TiO2/stevensite nanocomposites having higher specific surface areas and mesopore volumes, and lower PZC values. Further, the photocatalytic activity was greater for the TiO2/stevensite nanocomposites having the greatest Ti amount, as compared to a pure TiO2 sample, and increased with the increase of the TiO2 content in the TiO2/stevensite nanocomposites.

Conventional glass-ionomer cements (GICs) are popular restorative materials, but their use is limited by their relatively low mechanical strength. This paper reports an attempt to improve these materials by incorporation of 10 wt% of three different types of nanoparticles, aluminum oxide, zirconium oxide, and titanium dioxide, into two commercial GICs (ChemFil® Rock and EQUIA™ Fil). The results indicate that the nanoparticles readily dispersed into the cement matrix by hand mixing and reduced the porosity of set cements by filling the empty spaces between the glass particles. Both cements showed no significant difference in compressive strength with added alumina, and ChemFil® Rock also showed no significant difference with zirconia. By contrast, ChemFil® Rock showed significantly higher compressive strength with added titania, and EQUIA™ Fil showed significantly higher compressive strength with both zirconia and titania. Fewer air voids were observed in all nanoparticle-containing cements and this, in turn, reduced the development of cracks within the matrix of the cements. These changes in microstructure provide a likely reason for the observed increases in compressive strength, and overall the addition of nanoparticles appears to be a promising strategy for improving the physical properties of GICs.

The present work investigates inorganic–organic nanocomposite polymer electrolytes (NCPEs) for lithium-ion battery applications. Nanoscale TiO2 particles were dispersed into boron comprising poly(vinyl alcohol) (PVA)-g-poly(ethylene glycol) methyl ether (PEGME) host polymer at several percentages. During preparation, nanocomposite matrices were doped with CF3SO3Li at several compositions and homogeneous soft solid materials were obtained. The interactions between host copolymer and inorganic additive and dopant were studied by Fourier transform infrared spectroscopy. The surface morphology of the NCPEs was investigated by scanning electron microscopy and their thermal properties were studied by thermogravimetric analysis and differential scanning calorimetry. The ionic conductivity of these novel NCPEs was studied by dielectric-impedance spectroscopy. High ambient temperature Li+ ion conducting (∼10−4 S/cm) NCPE matrices can be suggested for lithium battery applications.

The use of inert markers in broiler diets eliminates the need to quantitatively evaluate feed intake and excreta output to determine diet digestibility, and enables nutrient uptake at specific points along the gastrointestinal tract to be examined. Titanium dioxide (TiO2) is commonly used for this purpose and measured using a UV-spectrophotometric assay. Two experiments were conducted to observe whether an inductively coupled plasma optical emission spectrophotometer (ICP-OES) assay is able to replace the UV-spectroscopy assay for rapid analysis of TiO2 in broiler feed and ileal digesta samples. In the first experiment, TiO2 was added at 5 g/kg to 19 broiler diets. Ross 308 male broilers (n=452) fed these diets were involved in a series of digestion studies to determine ileal digesta recovery of TiO2. In the second experiment, defined amounts of TiO2 were added to ileal digesta samples from Ross 308 male broilers (n=176) and TiO2 recoveries were determined. The feed and ileal samples from both experiments were analysed by both UV-spectroscopy and ICP-OES, and relatedness of the findings from the two assays was determined. Overall relatedness of the two assays was strong for determination of TiO2 concentration in both the broiler diets and ileal digesta samples (r=0.908 and r=0.884, respectively). Overall recovery of supplemented TiO2 was 97.62% by the UV-spectroscopy assay and 98.77% by the ICP-OES assay. The ICP-OES assay in this study was as accurate as spectrophotometric determination for the quantification of TiO2 content. The ICP-OES method can also be used to analyse several elements within one assay, with a single preparation step, and thus the measurement of TiO2 may be incorporated into the analysis of other minerals. Time and resources dedicated to determining diet digestibility in broilers could be minimised by using the ICP-OES assay to replace the UV-spectroscopy assay when measuring TiO2 concentration.

The toxicity of titanium dioxide nanoparticles (TIO2 NPs) and oxidative stress effects were studied in two freshwater fish species (Carassius auratus and Danio rerio) exposed for 21 days to different concentrations (0.01, 0.1, 1, 10, 100/mgL) of TiO2 NPs and to a control (tap water). Additional fish were transferred to clean water for 14 days to assess the ability to recover from exposure to TiO2 NPs. Activities of the enzyme glutathione-S-transferase (GST) and lipid peroxidation (LPO) (malondialdheyde) were measured as indicators of oxidative stress. Histological and ultra-structural changes in livers from bothspecies of fish were evaluated by light and electron microscopy. Results show a general GST activity increase according to TiO2 NPs concentrations, which is in agreement with data from LPO. After 21 days, GST activities decreased possibly caused by suppression of GST synthesis as a result of severe stress. Histological and ultra-structural analysis of livers from exposed fish show degeneration of the hepatic tissue and alterations in hepatocytes such as glycogen depletion and an increase in lipofucsin lysosome-like granules. After a depuration period a partial recovery for biochemical markers and cells was observed. The results suggest that TiO2 promotes alterations in hepatic tissues compatible with oxidative stress.

ZnO/TiO2 heterojunction composite fibers were prepared via a physical route, i.e., first electrospinning titanium dioxide (TiO2) fibers, then pulse plating zinc (Zn) on the fibers, and at last thermal treating the fibers. The morphologies, phase structures, and photocatalytic property of the composite fibers were characterized by using field-emission gun scanning electron microscope, x-ray diffractometer, high-resolution transmission electron microscope, and ultraviolet–visible spectrophotometer. It was found that a full or partial lattice coherent heterojunction was formed between the TiO2 fibers and zinc oxide (ZnO) particles, due to thermal treatment at 400 °C, which simultaneously resulted in the phase transformations including Zn to ZnO and amorphous TiO2 to anatase TiO2. The experimental results demonstrated that the photocatalytic activity of the composite fibers was improved and exhibited a value more than two times higher than that of TiO2 fibers.

Exceptionally dense titanium dioxide (TiO2) films were prepared via dip coating from a sol containing poly(hexafluorobutyl methacrylate) as the structure-directing agent. The films were grown on glass, F-doped SnO2, and crystalline silicon (111) faces, either pure or with a thin layer of SiO2. The TiO2 films cover perfectly even rough surfaces, which was ascribed to thixotropic properties of the precursor gel. The films provide antireflection function to crystalline Si wafers for photovoltaic applications. The optical reflectance in visible to near-infrared (NIR) wave lengths region is considerably smaller for Si wafers covered by TiO2/SiO2 film compared with that of SiO2/Si. The dense TiO2 films are amorphous with small amount of anatase and monoclinic TiO2(B). These two phases withstand calcination at 900 °C in films deposited on Si. For comparison, porous TiO2 films were grown by the same dip-coating protocol, but with alternative organic additives, either polymers or ionic liquids.

Two applications of parametric Rietveld refinement employing a newly developed robust computer program are presented. The first application focuses on the parametric kinetic analysis of the reactions involving phase transitions of various polymorphic forms of copper phthalocyanine pigments. The second application concerns the parameterization of crystallite size with respect to experimental temperature. XRPD data for nanocrystalline titanium dioxide measured in dependence on temperature are used in this case study. Both the applications were realized with the help of the developed program in combination with the launch mode of topas® software.

We report the evolution of titanium dioxide nanostructures when Au nanoparticles, supported on single crystal TiO2 substrates, were heated under ∼260 Pa of flowing O2 in an environmental transmission electron microscope. Nanostructures with different morphologies were first observed around 500°C. Our measurements show that temperature, oxygen pressure, and the electron beam control the nanostructure growth. We propose a reaction-controlled growth mechanism where mobile Ti atoms generated by the electron- beam-induced reduction of TiO2 are preferentially reoxidized at the Au-TiO2 interface.

Dietary microparticles are non-biological, bacterial-sized particles. Endogenous sources are derived from intestinal Ca and phosphate secretion. Exogenous sources are mainly titanium dioxide (TiO2) and mixed silicates (Psil); they are resistant to degradation and accumulate in human Peyer's patch macrophages and there is some evidence that they exacerbate inflammation in Crohn's disease (CD). However, whether their intake differs between those with and without CD has not been studied. We aimed to identify dietary microparticle sources and intakes in subjects with and without CD. Patients with inactive CD and matched general practice-based controls (ninety-one per group) completed 7d food diaries. Intake data for dietary fibre and sucrose were compared as positive controls. All foods, pharmaceuticals and toothpastes were examined for microparticle content, and intakes of Ca and exogenous microparticles were compared between the two groups. Dietary intakes were significantly different between cases and controls for dietary fibre (12 (SD 5) v. 14 (sd 5) g/d; P=0.001) and sucrose (52 (sd 27) v. 45 (sd 18) g/d; P=0·04) but not for Ca. Estimated median TiO2 and Psil intakes (2·5 and 35mg/individual per d respectively, totalling 1012–1013 microparticles/individual per d) were broadly similar to per capita estimates and while there was wide variation in intakes between individuals there was no significant difference between subjects with CD and controls. Hence, if exposure to microparticles is associated with the inflammation of CD, then the present study rules out excess intake as the problem. Nonetheless, microparticle-containing foods have now been identified which allows a low-microparticle diet to be further assessed in CD.