SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Titanium tetrachloride

92

Food-grade titanium dioxide (TiO2) containing a nanoscale particle fraction (TiO2-NPs) is approved as a white pigment (E171 in Europe) in common foodstuffs, including confectionary. There are growing concerns that daily oral TiO2-NP intake is associated with an increased risk of chronic intestinal inflammation and carcinogenesis. In rats orally exposed for one week to E171 at human relevant levels, titanium was detected in the immune cells of Peyer’s patches (PP) as observed with the TiO2-NP model NM-105. Dendritic cell frequency increased in PP regardless of the TiO2 treatment, while regulatory T cells involved in dampening inflammatory responses decreased with E171 only, an effect still observed after 100 days of treatment. In all TiO2-treated rats, stimulation of immune cells isolated from PP showed a decrease in Thelper (Th)-1 IFN-γ secretion, while splenic Th1/Th17 inflammatory responses sharply increased. E171 or NM-105 for one week did not initiate intestinal inflammation, while a 100-day E171 treatment promoted colon microinflammation and initiated preneoplastic lesions while also fostering the growth of aberrant crypt foci in a chemically induced carcinogenesis model. These data should be considered for risk assessments of the susceptibility to Th17-driven autoimmune diseases and to colorectal cancer in humans exposed to TiO2 from dietary sources.

Concepts: Immune system, Inflammation, Monocyte, Titanium dioxide, Titanium, Rutile, Pigment, Titanium tetrachloride

26

A kind of bioinspired heterostructured bead-on-string fiber (BHBF), composed of poly-(methyl methacrylate) (PMMA) and titanium tetrachloride (TiCl4) hydrolyzed nanoparticles, was prepared via integrating a wet-assembly system, including PMMA electrospinning, fog of nanoparticles and water coalescence at multi-stages. The wet-assembly of BHBF was regulated by the difference in surface energy and Laplace pressure. Especially, BHBF is characteristic of a hydrophilic rough bead for excellent water collection ability.

Concepts: Water, Surface tension, Fiber, Titanium dioxide, Titanium, Dietary fiber, Titanium tetrachloride, Kroll process

25

Abstract The production of titanium dioxide nanoparticles (TiO2 NPs) for commercial applications has greatly increased over the last years and consequently the potential risk for human health. There is a growing awareness of the need to understand the behavior and influence these nanoparticles exert on the environment. Bioaccumulation serves as a good integrator to assess chemical exposure in aquatic systems and is dependent on factors, such as the exposure routes, diet and the aqueous medium. We analyzed the experimental bioaccumulation capability of ionic titanium and TiO2 NPs by zebrafish (Danio rerio) eleutheroembryos through bioconcentration factors (BCFs), after 48 or 72 h of exposure. The stability of both chemical forms in an aquatic medium was fully characterized for further bioaccumulation studies. Several stabilizing agents (humic acids, soluble starch, polyethylene glycol, Na4P2O7 and Na2HPO4) for anatase and rutile, the two allotrophs of TiO2 NPs, were evaluated to check the evolution of the aggregation process. Around 60% of TiO2 NPs remained disaggregated under simulated environmental conditions with the addition of 50 mg L(-1) of humic acids. However, the presence of eleutheroembryos in the exposure medium increased TiO2 NPs aggregation in the experimental tests. The BCFs values obtained in all cases were <100, which classifies ionic titanium and TiO2 NPs as non-bioaccumulative substances, under the REACH regulations.

Concepts: Oxide, Titanium dioxide, Titanium, Rutile, Danio kyathit, Anatase, Titanium tetrachloride, Ilmenite

25

We report a one-step process for the synthesis and deposition of anatase, two-dimensional (2D), disk-shaped TiO2 (DS-TiO2) using titanium isopropoxide (TTIP), ethyl cellulose (EC), and solvents. The planar structure of EC plays a pivotal role as the sacrificing template to generate the 2D disk-shaped structure with a thickness of 1.5-3.5 μm, while a disk-like structure was well developed in the tetrahydrofuran (THF)/toluene mixed solvent. The quasi-solid-state dye-sensitized solar cells (qssDSSCs), fabricated with a nanogel electrolyte and a DS-TiO2 layer on a nanocrystalline (NC)-TiO2 photoanode, showed an energy conversion efficiency of 5.0% without any TiCl4 post-treatment, which is higher than that fabricated without DS-TiO2 (4.2%). When utilizing a poly((1-(4-ethenylphenyl)methyl)-3-butyl-imidazolium iodide) (PEBII) as the solid electrolyte, a high efficiency of 6.6% was achieved due to the combination of high mobility PEBII and a bi-functional DS-TiO2 layer with a 2D structure and anatase phase. The bi-functionality of the DS-TiO2 layer allows greater light scattering back into the device and provides additional surface area for improved dye adsorption, resulting in short circuit current density (Jsc).

Concepts: Solid, Solar cell, Titanium dioxide, Energy conversion, Energy conversion efficiency, Dye-sensitized solar cell, Titanium, Titanium tetrachloride

25

Mesoporous TiO2 microspheres assembled from TiO2 nanoparticles with specific surface areas as high as 150 m(2) g(-1) were synthesized via a facile one-step solvothermal reaction of titanium isopropoxide and anhydrous acetone. Aldol condensation of acetone gradually releases structural H2O, which hydrolyzes and condenses titanium isopropoxide, forming TiO2 nanocrystals. Simultaneous growth and aggregation of TiO2 nanocrystals leads to the formation of high-surface-area TiO2 microspheres under solvothermal conditions. After a low-temperature post-synthesis calcination, carbonate could be incorporated into TiO2 as a dopant with the carbon source coming from the organic byproducts during the synthesis. Carbonate doping modifies the electronic structure of TiO2 (e.g., Fermi level, Ef), and thus influences its electrochemical properties. Solid electrolyte interface (SEI) formation, which is not common for titania, could be initiated in carbonate-doped TiO2 due to elevated Ef. After removing carbonate dopants by high-temperature calcination, the mesoporous TiO2 microspheres showed much improved performance in lithium insertion and stability at various current rates, attributed to a synergistic effect of high surface area, large pore size and good anatase crystallinity.

Concepts: Electrochemistry, Carbon, Nanotechnology, Titanium, Area, Specific surface area, Dopant, Titanium tetrachloride

9

Titanium dioxide (TiO2) is one of the most common nanoparticles found in industry ranging from food additives to energy generation. Approximately four million tons of TiO2 particles are produced worldwide each year with approximately 3000 tons being produced in nanoparticulate form, hence exposure to these particles is almost certain.

Concepts: Ultraviolet, Staphylococcus aureus, Oxide, Titanium dioxide, E number, Titanium, Rutile, Titanium tetrachloride

0

Titanium dioxide (TiO2) is a widely used additive in foods. However, in the scientific community there is an ongoing debate on health concerns about TiO2. The main goal of this study is to determine TiO2 content by using laser induced breakdown spectroscopy (LIBS). To this end, different amounts of TiO2 was added to white chickpeas and analyzed by using LIBS. Calibration curve was obtained by following Ti emissions at 390.11nm for univariate calibration, and partial least square (PLS) calibration curve was obtained by evaluating the whole spectra. The results showed that Ti calibration curve at 390.11nm provides successful determination of Ti level with 0.985 of R2 and 33.9ppm of limit of detection (LOD) value, while PLS has 0.989 of R2 and 60.9ppm of LOD. Furthermore, commercial white chickpea samples were used to validate the method, and validation R2 for simple calibration and PLS were calculated as 0.989 and 0.951, respectively.

Concepts: Oxide, Titanium dioxide, Titanium, Rutile, Pigment, Chickpea, Titanium tetrachloride, Ilmenite

0

The large-scale manufacturing and use of titanium dioxide (TiO2) particles in food and consumer products significantly increase the likelihood of human exposure and release into the environment. We present a simple and innovative approach to rapidly identify the type (anatase or rutile), as well as estimate the size and concentration, of TiO2 particles using Raman spectroscopy and surface-enhanced Raman spectroscopy (SERS). The identification and discrimination of rutile and anatase were based on their intrinsic Raman signatures. The concentration of the TiO2 particles was determined based on Raman peak intensity. Particle sizes were estimated based on the ratio between the Raman intensity of TiO2 and the SERS intensity of myricetin bound to the nanoparticles (NPs), which was proven to be independent of TiO2 nanoparticle concentrations. The ratio that was calculated from the 100 nm particles was used as a cut-off value when estimating the presence of nano-sized particles within a mixture. We also demonstrated the practical use of this approach when determining the type, concentration, and size of E171; a mixture that contains TiO2 particles of various sizes which are commonly used in many food products as food additives. The presence of TiO2 anatase NPs in E171 was confirmed using the developed approach and was validated by transmission electron micrographs. TiO2 presence among pond water was also demonstrated to be an analytical capability of this method. Our approach shows great promise for the rapid screening of nano-sized rutile and anatase TiO2 particles in complex matrices. This approach will strongly improve the measurement of TiO2 quality during production, as well as the survey capacity and risk assessment of TiO2 NPs in food, consumer goods, and environmental samples.

Concepts: Raman spectroscopy, Titanium dioxide, Titanium, Rutile, Photocatalysis, Anatase, Titanium tetrachloride, Ilmenite

0

The aim of this laboratory study was to analyze the influence of titanium dioxide (TiO2) content and antagonistic material on the wear of polyetherketoneketones (PEKKs).

Concepts: Oxide, Titanium dioxide, Titanium, Rutile, Pigment, Osseointegration, Titanium tetrachloride, Ilmenite

0

This study aimed to explore the efficiency of two adsorbents, cork granules with different granulometry and titanium dioxide nanomaterial, in the removal of chemical oxygen demand (COD), colour and toxicity from a textile effluent. The adsorption assays with cork were unsatisfactory in the removal of chemical parameters however they eliminated the acute toxicity of the raw effluent to Daphnia magna. The assay with TiO2 NM did not prove to be efficient in the removal of colour and COD even after 240 min of contact; nevertheless it also reduced the raw effluent toxicity. The best approach for complete remediation of the textile effluent has not yet been found however promising findings were achieved, which may be an asset in future adsorption assays.

Concepts: Oxygen, Nitrogen, Oxide, Titanium dioxide, Titanium, Rutile, Zirconium dioxide, Titanium tetrachloride