Spherical Titanium Research Articles

Green synthesis and characterization of titanium dioxide nanoparticles and their photocatalytic activity

In this study, we compared two low-temperature synthesis procedures for the large-scale production of titania nanoparticles (NPs). The first takes place in an aqueous medium with an acidic environment, by using a triblock polymer surfactant (Pluronic 123). The second involves a polycondensation reaction of alkoxide precursors at 70 °C in a water-in-oil (W/O) microemulsion with a volume ratio of 1:1, using cetylpyridinium bromide (CPB) as a cationic surfactant. The morphological and structural characterization of the samples was carried out through Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). The photoactivity of the nanostructured titania was evaluated by measuring the photodegradation of Methylene Blue (MB). The solvent-free synthetic approach provided spherical titania nanoparticles mainly constituted by rutile crystallites with a very good synthetic yield. However, the photodegradation rate of MB for such titania nanoparticles ranges from 30 % to 40 %, after 1h under solar irradiation. Conversely, titania nanoparticles obtained through microemulsion synthesis show a photodegradation rate of more than 90 % comparable to titania P25. This high-yield synthesis leads to the formation of TiO2 nanoparticles characterized by small crystallite aggregates (rutile and anatase).

Titania-Cored Janus Multipods as UV-Protective Pickering Emulsifiers for Sunscreens.

Pickering emulsifiers have gained significant interest as alternatives for conventional surfactants in various applications that includes pharmaceutics, food, homecare products, and cosmetics. However, their function is primarily focused on enhancing emulsion stability of which still remains to be resolved. Herein, Janus multipods are presented that simultaneously shield UV while offering high emulsion stability. These particles are prepared by growing multiple silicon dioxide (SiO2) nanopods using sol-gel method on a spherical titanium dioxide (TiO2) core with a thin SiO2 shell. The incorporation of high refractive index TiO2 in the core is shown to effectively shield UV while the SiO2 shell suppresses the photocatalytic activity. Moreover, by utilizing wax colloidosomes as templates, these multipod nanoparticles are further modified to exhibit Janus characteristics. This leads to strong adsorption of the Janus multipods at the oil/water emulsion interface where the multipod feature additionally reinforces the interfacial stabilization by interdigitation and interlocking of the Janus multipods to suppress detachment of the highly dense particles from the interface. As these Janus multipods offer effective UV protection as well as excellent emulsion stability, it is envisioned that they have great potential in advanced cosmetic formulations which require both enhanced sunscreen performance and better feeling in skincare products.

Simulation of 3D Volume Filling with Non-Spherical and Spherical Titanium Alloy Powder Particles for Additive Manufacturing

Simulation of 3D Volume Filling with Non-Spherical and Spherical Titanium Alloy Powder Particles for Additive Manufacturing

Development of a bottom-up coarse-grained model for interactions of lipids with TiO nanoparticles.

Understanding interactions of inorganic nanoparticles with biomolecules is important in many biotechnology, nanomedicine, and toxicological research, however, the size of typical nanoparticles makes their direct modeling by atomistic simulations unfeasible. Here, we present a bottom-up coarse-graining approach for modeling titanium dioxide (TiO ) nanomaterials in contact with phospholipids that uses the inverse Monte Carlo method to optimize the effective interactions from the structural data obtained in small-scale all-atom simulations of TiO surfaces with lipids in aqueous solution. The resulting coarse-grained models are able to accurately reproduce the structural details of lipid adsorption on different titania surfaces without the use of an explicit solvent, enabling significant computational resource savings and favorable scaling. Our coarse-grained simulations show that small spherical TiO nanoparticles ( nm) can only be partially wrapped by a lipid bilayer with phosphoethanolamine headgroups, however, the lipid adsorption increases with the radius of the nanoparticle. The current approach can be used to study the effect of the size and shape of TiO nanoparticles on their interactions with cell membrane lipids, which can be a determining factor in membrane wrapping as well as the recently discovered phenomenon of nanoquarantining, which involves the formation of layered nanomaterial-lipid structures.

The effect of polymer coating on nanoparticles' interaction with lipid membranes studied by coarse-grained molecular dynamics simulations.

Nanoparticles' (NPs) permeation through cell membranes, whether it happens via passive or active transport, is an essential initial step for their cellular internalization. The NPs' surface coating impacts the way they translocate through the lipid bilayer and the spontaneity of the process. Understanding the molecular details of NPs' interaction with cell membranes allows the design of nanosystems with optimal characteristics for crossing the lipid bilayer: computer simulations are a powerful tool for this purpose. In this work, we have performed coarse-grained molecular dynamics simulations and free energy calculations on spherical titanium dioxide NPs conjugated with polymer chains of different chemical compositions. We have demonstrated that the hydrophobic/hydrophilic character of the chains, more than the nature of their terminal group, plays a crucial role in determining the NPs' interaction with the lipid bilayer and the thermodynamic spontaneity of NPs' translocation from water to the membrane. We envision that this computational work will be helpful to the experimental community in terms of the rational design of NPs for efficient cell membrane permeation.

Results of X-ray studies of titanium powder obtained for additive machines from OT4 alloy metal waste in alcohol

The results of experiments aimed at conducting X-ray studies of powders obtained by electrodispersing titanium alloy OT4 metal waste in alcohol are presented. It is noted that the particles of the electroerosion powder consist of titanium and aluminum, which form phases of pure titanium α-Ti, titanium oxide TiO and intermetallic Ti3Al. The conducted studies have shown that by the method of electroerosive dispersion of metal waste of the OT4 alloy, it is possible to obtain spherical titanium powders for additive machines of the required fractional composition from secondary raw materials in small batches with minimal energy consumption and minimal damage to the environment.

Effect of Polyvinylpyrrolidone Content on Pure Titanium Injection Molding

In water-soluble binder systems, polyethylene glycol (PEG) and polymethylmethacrylate (PMMA) are often used as primary and secondary components. The PEG/PMMA binder system is clean and environmentally friendly, but the discrepancy between the crystallization temperature of PEG and the glass transition temperature of PMMA leads to the generation of pores in the feedstock. The solidification pores have an adverse impact on the final mechanical properties of the samples. Polyvinylpyrrolidone (PVP), as a crystallization inhibitor, can inhibit the formation of porosity. In this study, spherical titanium powder with a diameter of less than 45 μm was used as metal powder; the binder system consisted of PEG, PMMA and SA. Different increments of PVP (0, 10%, 20%, 30 wt.%) were added to the PEG/PMMA binder system. The uniformity of the feedstock and the open channels generated after debinding were observed using SEM. The pores’ condition before and after debinding was studied using Micro CT, and the mechanical properties of the samples were also detected. By comparing the macroscopic and microscopic morphologies of the injected samples and mechanical properties of the sintered samples, it was found that a PVP content of 20 wt.% resulted in the best properties.

Assessing the feasibility of using an irregularly shaped Ta and spherical Ti bimodal powder blend on the powder spreadability process in powder bed fusion systems

The cost of additive manufacturing can be reduced if economical non-spherical powders are used. However, current flowability tests are inadequate to determine whether these powders can flow and spread well in powder bed systems. This paper presents a novel tool called the Universal Powder Bed designed to analyse the layer-spreading process of an electron beam melting system. The spreadability and feasibility of using a novel bimodal powder comprising of irregularly shaped tantalum and spherical titanium is investigated against three measures: area fraction of build surface covered with powder, surface roughness and composition of the powder bed. The characterisation techniques revealed that increasing layer thicknesses and slower rake speeds produced more efficiently packed powder layers and decreased the effects of segregation between opposite sides of the powder bed. This study shows that despite the segregation observed with bimodal powders, acceptable levels of spreadability can be produced by refining the spreading parameters.

Rapid Preparation of Uniform High-Crystallized Mesoporous Titania Spheres without High-Temperature Treatment

Rapid Preparation of Uniform High-Crystallized Mesoporous Titania Spheres without High-Temperature Treatment

Ignition sensitivity and flame propagation of titanium powder cloud

The ignition sensitivity and flame propagation of titanium dust cloud were investigated to evaluate the risk of combustion and explosion of titanium powder. The minimum ignition temperature(MIT) was determined by Godbert-Greenwald furnace and the minimum ignition energy(MIE) was determined by Hartmann apparatus. The flame propagation behavior in the Hartmann apparatus was recorded by high-speed camera and infrared thermal imager. The results show that the spherical titanium powder with a median diameter of 12.5μm had a minimum ignition temperature of 400°C, a minimum ignition energy of less than 1mJ, and a maximum flame temperature of 1666°C. The dust concentration had a greater influence on the minimum ignition temperature than the dispersion pressure, titanium dust cloud had high ignition sensitivity and fast flame propagation speed. The experimental results can provide a reliable basis for judging the explosive risk of titanium powder.

Floating immobilized TiO2 catalyst for the solar photocatalytic treatment of micro-pollutants within the secondary effluent of wastewater treatment plants

Floating immobilized spherical titanium dioxide catalysts were used to degrade micro-pollutants by solar photocatalysis. The degradation of the micro-pollutants was performed in the secondary effluent of a wastewater treatment plant. During the experimental period, the continuous measurement of the solar ultraviolet (UV) radiation intensity was performed. The micro-pollutants were degraded to an average of 55% after 9 h of irradiation. A substance-specific degradation affinity was found, whereby degradation rates varied by a factor of up to 3.5. The substance-specific adsorption behavior was identified as a major limitation of the reaction performance. With an increasing influence of adsorption limitation, the degradation kinetics changed from the pseudo-first order to pseudo-zero order. A correlation between degradation rate and solar irradiance could only be found for substances with high degradation/adsorption affinity. For diclofenac, a 95% degradation rate could be achieved at a radiation dose of approximately 190 mWh/m². The investigated technology represents a promising possibility for a minimally invasive extension of wastewater treatment plants. Possibilities of implication were estimated and discussed within this work, whereby possibilities arise for large-scale as well as decentral treatment plants.

A method for the preparation of spherical titanium powder for additive manufacturing

In this work, a new method was designed and developed to produce spherical Ti powder for additive manufacturing (AM) process. In this method, copper was introduced to form Ti-Cu alloy with a low melting point, and spherical Ti powder was prepared by combining with several low-cost processing techniques, including solid-liquid interface dewetting spheroidization, dealloying, sintering and de‑oxygenation processes. The spherical Ti powder prepared by this method shows a low oxygen content (<0.1 wt%), and the particle size was controlled between 15 and 75 μm. Compared with the current mature technology of the preparation of spherical titanium powder, this method provideds unique advantages during the preparation of small-sized spherical Ti powder (<30 μm), which meets the requirements of high-quality AM technology. • A new method was designed and developed to produce spherical Ti powder. • Techniques and raw materials are low cost. • Spherical Ti powder with controllable size distribution and low oxygen content can be produced.

Titania spheres with nanochannel-restricted NaNO2/MgO for improving cyclic CO2 adsorption stability

ABSTRACT NaNO2/MgO/titania spheres prepared via aerosol-assisted self-assembly (AASA) were used as sorbents for CO2 adsorption at moderate temperature. The titania framework as support would allow MgO to disperse well, thereby increasing the contact between MgO and NaNO2 to enhance carbonation. In this study, the effect of Mg/Ti molar ratio and NaNO2 addition amount on CO2 adsorption was investigated. Results showed that the sorbent prepared by AASA with Mg/Ti molar ratio of 2 following the introduction of 30 wt% NaNO2 presented ∼1 μm particle size with rough sphere surface morphology and mesoporous properties, where the surface area and pore volume were 72 m2/g and 0.18 cm3/g, respectively. With NaNO2 addition, the kinetics and capacity of CO2 adsorption significant increased. In the cyclic adsorption/desorption experiment, the superior stability over the NaNO2/MgO/titania spheres was mainly ascribed to the confined space suppressed the degree of the sintering effect. These results indicated the potential application of the nanochannel-restricted sorbent for rapid, high-capacity, and stable CO2 capture at moderate temperatures.

Properties of the Spherical Titanium VT1-00 Powder Fabricated by Plasma Atomization of a Wire

Properties of the Spherical Titanium VT1-00 Powder Fabricated by Plasma Atomization of a Wire

Titanium Oxynitride Spheres with Broad Plasmon Resonance for Solar Seawater Desalination.

The facile production of hollow and solid nitridized submicrometer titania spheres has been successfully realized, with potential for mass production. The nitridation process gives submicrometer titanium oxynitride spheres, which possess a strong and broadband light absorption property. Interband-transition-induced resonance and plasmon resonance have been found to coexist in titanium oxynitride spheres through single-particle dark-field scattering measurements. Theoretical modeling has further confirmed that the excellent light absorption properties of the oxynitride spheres originate from the supported dual-mode optical resonance. A highly efficient, easy-to-build, and self-sustainable device is rationally designed for solar-driven seawater desalination, where the titanium oxynitride spheres function as photothermal transducers. The hollow spheres possess a higher water evaporation rate than the solid ones as the inner surface of the hollow spheres also provides surface sites for interaction with water molecules. Given the outstanding light absorption capability and the unique morphology of the hollow spheres, a water evaporation rate of ∼1.49 kg m-2 h-1 with a solar-to-thermal conversion efficiency of ∼89.1% has been achieved under the illumination of simulated solar light (1 sun, 1 kW m-2). This marks the record performance among reported plasmon-based solar seawater desalination systems.

The porous coating of joint implants as a factor of their stable fixation

To ensure effective biological fixation of the newly designed cementless hip joint implant, a macroporous material proposed to be used as a coating for the implant was studied. Eighty-five samples of the cylindrical implants produced via hot sintering from spherical titanium granules having different diameters were analyzed. Morphological, mechanical, and other findings revealed a rapid bone ingrowth into the sample pores and their firm biological fixation in the canine tubular bone. The selected material having optimal characteristics will be applied to the surface of the specially designed joint implant. Its pilot-designed model is manufactured to make initial clinical trials, followed by updating for applying the ball coating. The new joint implant macroporous coating with its improved geometry will enhance the fixation of the construction due to bone ingrowth, contribute to the rapid postoperative recovery of a patients full-load walking ability, and minimize the risk for aceptic loosening of the implant.

Ag nanoparticles-polypyrrole-carbon black/mesoporous TiO2 novel nanocomposite as ultrafast visible-light-driven photocatalyst

Effective design and fabrication of novel visible light-oriented photocatalysts is an existing challenging task that requires further dedicated efforts, and it has been always a main concern among the scientific community. This study deals with the design and fabrication of an extremely active and ultrafast ternary photocatalyst based on Ag nanoparticles, polypyrrole doped carbon black (PPy-C) and mesoporous TiO2 (m-TiO2). Sol-gel methodology along with sonication and photodeposition routes have been employed for the successful creation of the ternary framework. Ternary photocatalyst composed of uniform spherical titania nanoparticles (10–15 nm in size) perfectly intermingled with the polymeric linkage of PPy-C. Fruitful creation of unique trio photocatalyst between AgNPs, PPy-C and m-TiO2 was confirmed by XPS and XRD. FTIR analysis further supports the development of nanocomposite photocatalyst. TEM analysis showed uniform spherical m-TiO2 nanoparticles (10–15 nm in size) covered by PPy-C with compact nodes like appearance interlocked very well among each other. The newly developed Ag@PPy-C/m-TiO2 ternary photocatalyst exhibited band gap energy in desired visible range of spectra. The photocatalytic efficiency for all created photocatalysts has been evaluated taking Imidacloprid (insecticide derivative) and methylene blue (MB) dye as target pollutants. The novel Ag@PPy-C/m-TiO2 photocatalyst produced astonishing results with ultrafast removal of both Imidacloprid as well MB dye under visible light irradiation. The newly created ultrafast Ag@PPy-C/m-TiO2 photocatalyst has removed 96.0% of the insecticide Imidacloprid in only 25 min with almost ⁓ 2.65 times more efficient than bare m-TiO2 towards the removal of insecticide derivative. The present report offers a highly encouraging and vastly talented Ag@PPy-C/m-TiO2 ternary photocatalyst, enabling the ideal management of extremely lethal and notorious chemicals.

Efficient photocatalytic hydrogen evolution through reverse hydrogen spillover on photoactivated copper-doped mesoporous titania spheres

Transition-metal-doped mesoporous TiO2 (M-mTiO2) spheres are highly desired for photocatalysis because of their large specific surface area and extended light absorption. Herein, a universal method is developed for the preparation of M-mTiO2 spheres and their photocatalytic mechanism is unveiled. Fe-mTiO2, Co-mTiO2, Ni-mTiO2, Cu-mTiO2 spheres are successfully prepared by the developed method. Among all M-mTiO2 samples, the Cu-mTiO2 catalyst exhibits reversible photoactivation phenomenon during photocatalysis. The photocatalytic hydrogen evolution rate on photoactivated Cu-mTiO2 can reach 3.31 mmol g−1 h−1, which is much higher than those of other M-mTiO2 and is 28.3 times of that of the mTiO2. Density functional theory (DFT) calculations reveal that the photoactivation of Cu-mTiO2 is associated with the facile formation of oxygen vacancies on Cu-mTiO2. The photoactivation induces the active site change and the light absorption increase of Cu-mTiO2. The active site change has the dominant role for the enhancement of photocatalytic performance. On the photoactivated Cu-mTiO2, the hydrogen production is through a reverse hydrogen spillover process. Our findings not only provide a universal method for the preparation of M-mTiO2 but also deepen the understanding about the photoactivation and the hydrogen production mechanism.

Analysis and Assessment of the Effects of Corrosive Hydrogen Media on the Stress-Strain State of a Spherical Titanium Alloy Shell

We consider the creation of a mathematical model describing the effect of corrosive hydrogen environment on the stress state of a hollow spherical shell made of titanium alloy grade VT1-0, the load is evenly distributed throughout the shell. The solution of the problem in practice was carried out by two-step method of sequential perturbation of parameters using MatLab and Maple programs. To solve the system of solving differential equations the finite difference method was applied. The solution of the diffusion equation of the aggressive hydrogen medium has been considered and the obtained solution has been compared with the results of the classical theory which does not take into account the aggressive effect of the corrosive medium.

Increasing the Adherence of Metallic Copper to the Surface of Titanium Hydride

Studies have been carried out to increase the adhesive interaction between a titanium hydride substrate and a copper coating. An additional layer containing chemically active groups was created on the surface of the spherical titanium hydride by chemisorption modification. This paper discusses the results of scanning electron microscopy (SEM) using energy-dispersive X-ray spectroscopic mapping of coatings obtained on spherical granules of titanium hydride before and after adsorption modification. The mechanism of interaction of the surface of spherical granules of titanium hydride and titanium sulfate salt is proposed. It is shown that the creation of a chemisorbed layer of hydroxotitanyl and the subsequent electrodeposition of metallic copper contribute to the formation of a multilayer shell of a titanium–copper coating on the surface of spherical titanium hydride granules (≡Ti-O-Cu-) with a high adhesive interaction. Results have been given for an experimental study of the thermal stability of the initial spherical granules of titanium hydride and granules coated with a multilayer titanium-copper shell.