Anatase Form Of Titanium Dioxide Research Articles

Synthesis and stabilization of anatase form of biomimetic TiO2 nanoparticles for enhancing anti-tumor potential

Abstract The present study emphasizes the stabilization of the biologically active anatase form of titanium dioxide (TiO2) nanoparticles (NP). TiO2 NP require stringent conditions for chemical synthesis and are usually a mixture of biologically inactive bulk rutile and the active bulk anatase forms. We utilized the culture pellet of the Exiguobacterium aestuarii SBG4 MH185868 to synthesize and stabilize the anatase form of TiO2 NP. The NP showed λ max at ∼350 nm and scanning electron microscope micrographs indicated their oval and spherical shape. Steric stabilized anatase TiO2 NP exhibited substantial cytotoxicity of up to 80% reduction in cell viability at 100 µg against cervical cancer derived HeLa and SiHa cell lines, whereas the rutile form showed least cytotoxicity. Clonogenic inhibition assay of HeLa cells showed dose-dependent decline with a 75% reduction in colony formation at 100 µg TiO2 NP and cell migration assay revealed significant inhibition in recovery of the wound/scratch in presence of anatase form of TiO2 NP (10–33% at 24 h and 42–79% at 48 h). Co-incubation of HeLa cells with anatase TiO2 NP in chorioallantoic membrane of embryonated chick eggs prevented the formation of new capillaries (20 ± 5% compared with control groups), indicating appreciable anti-angiogenic activity of the NP. Further, TiO2 NP tagged with doxorubicin and paclitaxel exhibited enhanced cytotoxicity against cancer cells at very low concentrations of 9 and 120 nM itself, indicating their anti-tumor potential. In conclusion, biomimetic anatase TiO2 NP have significant anti-proliferative and anti-angiogenic activity and can have potential application in tagging with generic anti-cancer drugs for enhanced cytotoxicity against cancer cells.

In Ukrainian

The influence of the electronic subsystem of nanographene particles modified with titanium dioxide nanoparticles on the thermal destruction of the polymer matrix is analyzed. The variation in the conductivity of the modifiers made it possible to vary the effect of the metallic electronic system of graphene on thermal destruction by attenuating its effect through the transfer of energy to the electronic subsystem throughout the semiconductor film of anatase and excluding its effect on thermal destruction through a wide-band TiO2 dielectric of rutile form, which is opaque for energy transfer to the electronic subsystem. The application of such films does not affect the thermal processes in which the phonon subsystems of polymer, graphene and crystal modifiers are involved. The method of thermally programmable desorption mass spectrometry investigated the thermal destruction of hybrid composites of epoxy resin with graphene, namely the effect of surface modification of multilayer graphene particles by nanoparticles of pyrogenic titanium dioxide (anatase and rutile forms) on the thermal stability of hybrid epoxy composites in the temperature range of 40 − 800 °C. The activation energies Ed of destruction of atomic fragments of the polymer structure with the value m/z in the range of 16 ‒ 140 D were determined. It has been established that the thermal destruction of fragments of the polymer structure of epoxy resin composites with graphene modified with anatase and rutile forms of titanium dioxide is determined by the peculiarities of thermal transport at the polymer-modifier interfaces. Modification of graphene particles by the anatase form of titanium dioxide leads to increased thermal stability of polymer chains and cross-links in epoxycomposites in the entire range of m/z values of desorbed fragments. Filling the resin with graphene particles coated with the rutile form of TiO2 practically does not affect the intensity of thermal destruction of the composite matrix. The Ed values of different destruction fragments in composites with unmodified and modified graphene are in the range of 50 ‒ 130 kJ/mol. The value of Ed increases by 5 ‒ 10 kJ/mol when the resin is filled with graphene nanoparticles, while the coating of particles with titanium dioxide of the anatase and rutile phases practically does not change the value of Ed of the vast majority of fragments.

Assessing the antibacterial properties of eggshell-titanium powder

The global distribution of oral diseases caused by bacterial and the severity of their consequences constitute a pandemic condition.The present paper reports on the antibacterial properties of a modified eggshell and titanium dioxide using the mechanochemical method. EB@TiO2 was modified and characterized using X-raydiffraction (XRD) while the degradation condition was studied using Thermogravimetric analysis (TGA).The inhibitory properties of EB@TiO2at differentconcentrations (2:1; 3:1 and 4: 1) against both Grampositive (E. coli) and negative bacterial (B. Cereus)strain were studied the using disk diffusion method.The XRD result confirmed the presence of a thermodynamically stable calcite structure, which is indicative of calcium carbonate. The diffraction peak of the XRD at 2θ = 29.5o suggests the deposition of TiO2 on the surface of CaCo3. TGA curves shows the decomposition of anatase form of titanium dioxide and calcium carbonate. The study evidently shows the antibacterial activities of EB@TiO2 against Escherichia coli and B. Cereus. The salient feature of the study finding is that modifying eggshells with titanium dioxide improves the antibacterial properties, and thus offers a promising role for the development of potent d

Performance evaluation of mixed synthetic organic dye as sensitizer based dye sensitized solar cell

Abstract A combination of two synthetic organic dyes, namely eosin Y and bromophenol were utilized as a novel category of dye for dye-sensitized solar cells (DSSCs). XRD study revealed the anatase form of titanium dioxide. SEM showed roughly spherical and non-homogenous nature of particles. Energy dispersive spectroscopy (EDS) spectrum analysis showed no impurity in TiO2 and ZnO, thus revealing purity in photo electrode materials. The absorbance of dyes was observed by using UV–Vis absorbance spectroscopy. The dyes showed absorbance from visible to near infra red region. Electrochemical impedance spectroscopy (EIS) measures dye solar cell internal resistance. The performance of photovoltaic cells was studied under 100 mW/cm2 illumination. An enhancement in the power conversion was achieved by using mixed dye (2.31%) that is much higher than single dyed cell (1.62%; eosin Y). The mixed dye exhibiting good device performance and high electrocatalytic activity can provide a sufficiently low cost dye for ruthenium free DSSCs.

TiO2/Nb2O5/carbon xerogel ternary photocatalyst for efficient degradation of 4-chlorophenol under solar light irradiation

This study examines the development of ternary photocatalysts based on titanium dioxide, niobium oxide, and carbon xerogel, aimed at increasing photocatalytic efficiency under solar light irradiation. The modifications proposed are focused on diminishing charge recombination and enhancing visible light sensitivity. The new photocatalyst was prepared using discarded titanium and niobium scraps and chips, whilst black wattle tannin was used as the carbon source. The X-ray diffractometry results show that the anatase form of titanium dioxide is present in the samples, whereas the niobium oxide presents itself in the amorphous structure. The incorporation of both carbon xerogel and niobium oxide into the TiO2 is confirmed by the infrared and energy dispersive spectroscopies. The diffuse reflectance results show that the materials containing carbon xerogel present a significantly higher visible light absorption, whilst the combined effect of the modifications proposed caused the gap energy of the ternary material to drop noticeably. The photocatalytic efficiency of the ternary material was superior to the ones found for the pure oxides and binary material, probably due to its lower value of bandgap and enhanced charge separation efficiency, as confirmed by the electrochemical impedance tests.

Doping Titanium Dioxide by Fluoride Ion

Titanium dioxide has a special feature: anatase, to rutile transformation which was considered in our investigations. It is especially important to keep anatase form of titanium dioxide for photocatalytic materials, different ceramics with tribo-chemical properties, self-cleaning coatings and self-sterilizing coatings. For that only one of the titanium dioxide forms is more suitable – anatase, which is more active but not stable, because it transforms to rutile during the time or with the temperature increase loses its activity. Different methods of stabilising anatase have been considered in the paper. Several doping agents have been determined and it was chosen fluorine ion to modify titanium dioxide. Stabilization of anatase is achieved by preparing the reaction mixture by a sol-gel method with hydrofluoric acid. It has shown thermodynamic data, results of experiment, temperatures of anatase to rutile transformation of non-doped and doped titanium dioxide, its X-Ray diffraction and TGA. It is proved that titanium dioxide doped by fluorine ion keeps anatase form till the temperature is more than 1000 °C.

Development of white titanic enamel coatings with reduced burning temperature

The work contains research of the influence of modifying additives Li 2 O and ВаО on the properties of frits and optical characteristics of white titanium low-fluoric enamel coatings. Optimal concentration of research oxides (0,5 mas. % Li 2 O and 0,75 mas. % ВаО ) is determined in composition of enamel coatings. White low-fluoric titanic glass coatings are obtained with specified optical characteristics: diffuse reflectance (DR) – 78 %, yellowness (G) – 4,57 %, regular reflectance (RR) – 75 %. Softening temperature of glass enamel being lower than domestic industrial analog is established by the method of differential and thermal analysis. Prevailing crystalline phase represented foremost in anatase form of titanium dioxide is using roentgen and phase analysis. The developed enamel glass coatings with specified optical parameters are more fusible compared with industrial analogs and meet the requirements of standards for internal and external enamel coatings and can be recommended for industrial testing with low-temperature short-term mode of burning.

Photo‐induced hydrophilicity enhances initial cell behavior and early bone apposition

The anatase form of titanium dioxide (TiO(2)) exhibits photo-induced hydrophilicity when it is irradiated with ultraviolet (UV) light. In the present study, the effect of photo-induced hydrophilicity on initial cell behavior and bone formation was evaluated. Plasma source ion implantation method and post-annealing were employed for coating the anatase form of TiO(2) to the surface of the titanium disk and implant. Half of the disks and implants were illuminated with UV for 24 h beforehand, whereas the other halves were blinded and used as controls. Photo-induced hydrophilicity was confirmed by a static wettability assay. The effects of this hydrophilicity on cell behavior were evaluated by means of cell attachment, proliferation and morphology using pluripotent mesenchymal precursor C2C12 cells. Thereafter, bone formation around the hydrophilic implant inserted in the rabbit tibia was confirmed histomorphometrically. The water contact angle of the photo-induced hydrophilic disk decreased markedly from 43.5 degrees to 0.5 degree. Cell attachment and proliferation on this hydrophilic disk showed significant improvement. The cell morphology on this hydrophilic disk was extremely flattened, with an elongation of the lamellipodia, whereas a round/spherical morphology was observed on the control disk. The photo-induced hydrophilic implant enhanced the bone formation with the bone-to-metal contact of 28.2% after 2 weeks of healing (control: 17.97%). The photo-induced hydrophilic surface used in the current study improves the initial cell reactions and enhances early bone apposition to the implant.

A novel characteristic of porous titanium oxide implants

The anatase form of titanium dioxide (TiO2) is one of the most common crystalline forms of TiO2 and is normally produced by oxidation of titanium via thermal oxidation or anodizing. This crystalline form exhibits photocatalytic activity when it is irradiated with ultraviolet A (UVA) light. The aim of the current study was to analyze the crystal structure of anodic-oxidized TiUnite implants and to confirm the photocatalytic properties in vitro and in vivo. Cross-sectional observations by transmission electron microscopy were used to determine the surface crystal structure on the TiUnite implant. Subsequently, photocatalytic activity was confirmed by degradation of methylene blue, and hydrophilicity was measured based on the water contact angle. Furthermore, the in vivo effects of the photocatalytic activity of this compound were investigated. An amorphous layer that was about 10 microm thick was observed on the TiUnite implant surface. In the amorphous layer, the anatase form of the crystalline TiO2 was identified. Photocatalytic activity was clearly demonstrated by the bleaching effect of methylene blue under UVA illumination. The contact angle decreased from 44 degrees to 11 degrees after UVA illumination. Although these data suggest increased hydrophilicity for the TiUnite implant, the bone-to-metal contact at 4 weeks was not influenced. The anodic-oxidized TiUnite implant has inherent photocatalytic activity. UVA illumination increases the surface hydrophilicity of the implant. However, this increase in hydrophilicity does not improve bone apposition to the implant surface at 4 weeks.

Rapid Microwave–Hydrothermal Synthesis of Anatase Form of Titanium Dioxide

Pure anatase titanium dioxide was synthesized by a microwave (MW)‐assisted hydrolysis of diluted acidic solutions of titanium tetrachloride. MW irradiation combined with hydrothermal process has proved to be a very efficient and fast alternative to conventional hydrothermal technique, as an almost complete crystallization of anatase occurred in reaction times as short as 30 min. The addition of small amounts of sulfuric acid was necessary to obtain a pure anatase phase, as the presence of sulfate prevented the crystallization of trace amounts of brookite. Transmission electron micrographs showed nanoparticles arranged in spherical aggregates with 1% sulfuric acid, while less aggregated nanoparticles were obtained with 0.1% sulfuric acid.

Development of Carbonized TiO2-Woody Composites for Environmental Cleaning

An effort was made to develop carbonized TiO2-woody composites which can effectively remove and decompose harmful air pollutants in environments. As an example of an air pollutant, formaldehyde (HCHO) was selected for evaluating the carbonized TiO2-woody composites. The composites were composed of carbonized wood as an adsorbent and the anatase-form of titanium dioxide (TiO2) as a photo-catalyst. They showed a much higher decomposing ability toward formaldehyde, when compared with the performance of non-composite controls composed of a simple physical mixture of carbonized wood and TiO2 granules. This indicates that synergetic effects existed in the carbonized TiO2-woody composites for photo-catalytic environmental cleaning. The topochemical mechanism inducing such synergetic effects is discussed in relation to the distribution of TiO2 granules in the composites.

Polymer gel template for porous TiO2 production

AbstractPorous networks of titanium dioxide have been produced using polymer gels as templates. Titanium dioxide is well known for its semiconductor and catalysis properties, and for being a very stable material. The porous polymer gels are produced in aqueous surfactant solutions. Following cleaning and solvent exchange procedures the titanium precursor can be incorporated within the gel and hydrolysed. The organic material is removed during calcination leaving the structured titanium dioxide. Both the rutile and anatase forms of titanium dioxide can be produced. The resulting crystal structure and the surface area of the oxide are important for determining its scope of application. These properties have been studied using electron microscopy, X‐ray diffraction and gas sorption.

Dichloromethane photodegradation using titanium catalysts

The use of titanium dioxide and titanium aluminosilicates in the photocatalytic destruction of chlorinated hydrocarbons is investigated. Titanium-exchanged clays, titanium-pillared clays, and titanium dioxide in the amorphous, anatase, and rutile forms are used to photocatalytically degrade dichloromethane to hydrochloric acid and carbon dioxide. Bentonite clays pillared by titanium dioxide are observed to be more catalytically active than titanium-exchanged clays. Clays pillared by titanium aluminum polymeric cations display about the same catalytic activity as that of titanium-exchanged clays. The rutile form of titanium dioxide is the most active catalyst studied for the dichloromethane degradation reaction. The anatase form of titanium dioxide supported on carbon felt was also used as a catalyst. This material is about five times more active than titanium dioxide-pillared clays. Degradation of dichloromethane using any of these catalysts can be enhanced by oxygen enrichment of the reaction solution or by preirradiating the catalyst with light.

ChemInform Abstract: An Investigation of Phases in the Titanium‐Antimony‐Oxygen System.

Abstract The nature of solid phases formed in the titanium-antimony-oxygen system by the calcination of precipitates in air has been investigated by powder X-ray diffraction, electron microscopy, Mossbauer spectroscopy, thermal analysis, and temperature programmed reduction techniques. The amorphous solids formed by mild temperature dehydration are converted to crystalline, and frequently multiphasic, materials when calcined at temperatures exceeding ca. 500 °C. The nature of the crystalline materials depends on the relative concentrations of the titanium and antimony cations in the initial precipitates and the calcination temperature. Antimony(V) in monophasic low-antimony content solids induces the structural transformation of the anatase form of titanium dioxide to the rutile modification at a lower temperature than is normally expected. Materials containing an excess of ca. 30% antimony and heated at temperatures exceeding ca. 500 °C are usually multiphasic and contain an antimony-containing rutile related phase. Evidence has been found for the occurrence of the mixed oxide of composition Sb3Ti2O10 in some multiphasic materials. Titanium-antimony oxides calcined at high temperatures in air may be described as solid solutions of low concentrations of antimony(V) in rutile titanium(IV) oxide. The tolerance of rutile titanium dioxide for the incorporation of antimony depends on the temperature and duration of thermal treatment.

An investigation of phases in the titanium-antimony-oxygen system

The nature of solid phases formed in the titanium-antimony-oxygen system by the calcination of precipitates in air has been investigated by powder X-ray diffraction, electron microscopy, Mössbauer spectroscopy, thermal analysis, and temperature programmed reduction techniques. The amorphous solids formed by mild temperature dehydration are converted to crystalline, and frequently multiphasic, materials when calcined at temperatures exceeding ca. 500 °C. The nature of the crystalline materials depends on the relative concentrations of the titanium and antimony cations in the initial precipitates and the calcination temperature. Antimony(V) in monophasic low-antimony content solids induces the structural transformation of the anatase form of titanium dioxide to the rutile modification at a lower temperature than is normally expected. Materials containing an excess of ca. 30% antimony and heated at temperatures exceeding ca. 500 °C are usually multiphasic and contain an antimony-containing rutile related phase. Evidence has been found for the occurrence of the mixed oxide of composition Sb 3Ti 2O 10 in some multiphasic materials. Titanium-antimony oxides calcined at high temperatures in air may be described as solid solutions of low concentrations of antimony(V) in rutile titanium(IV) oxide. The tolerance of rutile titanium dioxide for the incorporation of antimony depends on the temperature and duration of thermal treatment.

Transmission of ultraviolet light by films containing titanium pigments—applications in u.v. curing

One of the problems with curing films containing a titanium pigment with ultraviolet light is the rapid attenuation of the incident light by the pigment. This limits both the pigmentation level and the thickness of film that can be effectively cured. In this study, the transmission by thin pigmented films of light of wavelength in the range 320–400 nm is measured experimentally. It is shown that the massive absorption of both the rutile and anatase forms of titanium dioxide in this region is responsible for the rapid attenuation of the light used to cure the films. The principal conclusion is that, given a constant lamp intensity and photoinitiator efficiency, the larger the wavelength of the light used to cure the film the greater will be the thickness of film that can be cured.