Titanium Salts Research Articles

Production of finely dispersed titanium powder by volumetric reduction of its ions with sodium dissolved in the BaCl2–CaCl2–NaCl melt

The research is intended to develop a technology for the production of finely dispersed (10 to 100 μm) powders of titanium and its alloys suitable for use in additive technologies after classification and spheroidization. A eutectic mixture was used as electrolyte, mole fractions: BaCl2 – 0.16, CaCl2 – 0.47, NaCl – 0.37, melting point of 452 °C. Electrolytes with a similar composition are used in industry for the electrolytic production of sodium with high current efficiency. No titanium salts were added to electrolyte. Sodium losses due to evaporation, corrosion, and ion recharge were replenished by a periodic increase in electrolysis current. A VT1-0 titanium plate was used as an anode. The walls of a steel crucible served as a cathode. Sodium was released on these walls and dissolved in electrolyte. Titanium ions were reduced in the bulk of electrolyte and in the anode layer. It is the first time that the results obtained were interpreted using the data on the electrode potentials of Ti3+/Ti, Ti2+/Ti, Ti3+/Ti2+ systems. It was shown that the concentration of slowly moving complex Ti3+ ions increases in the anode layer, and sodium dissolved in electrolyte reduces mainly Ti2+ ions in the electrolyte volume in the first 12 min of electrolysis. Starting from the 20th min, the concentration of Ti2+ ions in the anode layer begins to increase rapidly according to the reaction: 2Ti3+ + Ti = 3Ti2+ as titanium powder accumulates in the electrolyte volume. At the same time, the proportion of sodium consumed for the reduction of Ti3+ ions to Ti2+ decreases, which contributes to an increase in current efficiency and cathode potential stabilization for 30 minutes at –2.963 V. After the 50th min, the reactivity of the salt melt begins to decrease, the concentration of Ti3+ ions increases steadily until it levels off with the concentration of Ti2+ ions at the 85th min. This sharply increased the current consumption for ion recharge and made it necessary to stop electrolysis after switching on a current of 12 A for a short time (for 40 s). After 10 s, judging by the change in the cathode potential, sodium dissolved in electrolyte was almost completely consumed for titanium ion reduction. After 6 min, the potentials of electrodes returned to the initial anode potential value indicating that the system returned to its original state with the near-zero content of titanium salts and dissolved sodium. 95 % of powder was obtained in the electrolyte volume. Current efficiency was 84.0 % and turned out to be close to the value calculated from the average valence of titanium ions and the loss of anode weight (87.0 %). After ultrasonic dispersion, more than 80 % of powder was in the 10–100 μm range with a maximum at 36 μm. X-ray phase analysis showed that this is practically pure α-titanium (93.06 %) and oxygenated α-titanium (5.45 %). The originality of the research consists in the use of a volumetric, intensive, electrolytic method for producing finely dispersed titanium powders with no dissolved sodium and titanium chlorides in the initial and final electrolytes, in a stepwise increase in the current and potentiometric process control. The uniqueness of the research consists in the titanium powder obtained where the major part is in the melt volume in the form of intergrowths that are easily crushed by ultrasonic dispersion into individual crystals. Over 80 % of these crystals were in the range of 10–100 μm required for additive technologies with an average size of 36 μm.

Titanium-Containing Coagulants in Wastewater Treatment Processes in the Alcohol Industry

As part of the work, studies of the quality of wastewater from alcohol production were carried out; the main characteristics were determined, such as the charge of dispersed particles and the content of organic compounds and fats. A comparison is made of the effectiveness of titanium salts, traditional aluminum, and iron-containing coagulants. It has been established that titanium salts are much more effective than traditional reagents, but their high cost significantly limits the scope of their application. The possibility of increasing the efficiency of traditional coagulants by adding various titanium salts in an amount of up to 10% of the mass has been proved. It has been established that the addition of titanium compounds to aluminum or iron-containing coagulants makes it possible to increase the cleaning efficiency by an average of 10–20% while a significant reduction in the dose of reagents is possible, which will have a positive effect on the cost of the cleaning process. It was found that the addition of titanium salts to a coagulant based on aluminum sulfate allows not only an increase in the cleaning efficiency but also further intensifies the processes of sedimentation and filtration of coagulation sludge, which will significantly reduce the size of the treatment equipment and reduce capital costs.

Adsorptive behaviour of rutile phased titania nanoparticles supported on acid-modified kaolinite clay for the removal of selected heavy metal ions from mining wastewater

This study investigated the removal of metal ions pollutants in mining wastewater such as Mn (II), Fe (III), Pb (II) and Cu (II) ions by acid-activated kaolinite clay (AAC) and titanium (IV) oxide (TiO2) nanoparticles supported on the AAC (TiO2–AAC). TiO2 nanoparticles were synthesised using titanium salt precursor with leaves extract of Parkia biglobossa and impregnated on the AAC to develop TiO2-AAC as a nanoadsorbent. The AAC and TiO2–AAC nanocomposites were characterized using different analytical techniques. Actual concentrations of selected heavy metals in mining wastewater was determined prior and after treatment using the prepared adsorbents in batch adsorptive studies with atomic absorption spectrophometer. The characterisation studies confirmed that a rutile phase TiO2 was doped the on acid-activated kaolinite clay. Morphology analysis shows that the developed adsorbents were homogeneously dispersed and porous. The results of the surface area further revealed that the AAC, TiO2 and TiO2–AAC has 14.15, 10.23 and 32.98 m2/g, respectively. The percentage removal of heavy metals followed the order of TiO2–AAC > AAC due to the higher surface area and enhanced surface functionality of the former than the latter. The adsorption capacity increased from 86.13 to 91.99% (Fe (III)), 83.12 to 89.37% (Mn (II)), 68.48 to 81.95% (Cu (II)) and 29.49 to 32.39% (Pb (II)) from AAC to TiO2–AAC. The kinetic and isotherm models were best fitted by pseudo-second-order kinetics and Langmuir model. Whilst the thermodynamic investigation found that, the adsorption process was endothermic, spontaneous and chemisorption controlled. Conclusively, the TiO2–AAC nanocomposite exhibited better performance than AAC alone.

The suitability of titanium salts in coagulation removal of micropollutants and in alleviation of membrane fouling

Coagulation is a conventional method in water treatment. In recent decades, with the rapid development of membrane filtration, the use of coagulation is facing some new challenges. How to minimize the membrane fouling became a leading-edge topic in the study of coagulation. Here, the performances of three types of titanium coagulants were evaluated in terms of both the coagulation removal of toxic micropollutants and the alleviation of membrane fouling. Three oxysalts and two antibiotics were taken as representatives of inorganic and organic micropollutants. As compared with titanium tetrachloride (TiCl4) and polytitanium chloride (PTC), titanium xerogel (TXC) with a higher polymerization degree showed much better performances in direct coagulation removal of oxysalts and antibiotics and in pre-coagulation for mitigating membrane fouling in both coagulation-sedimentation-ultrafiltration (CSUF) and in-line coagulation-ultrafiltration (CUF) processes. In the CSUF system, the membrane permeate flux with TXC pre-coagulation (89.5%) was much higher than those of TiCl4 (56.1%) and PTC (57.4%). After a 5 day continuous operation, the transmembrane pressure in the CUF system with TXC coagulation was increased only to 4.9 kPa, while those of PTC and TiCl4 were 12.2 and 18.5 kPa, respectively. The results here demonstrate that TXC is a promising coagulant for pollutant removal and membrane fouling alleviation, due to the following merits: better floc properties, weaker pH-dependence, and higher resistance to coordination with organic pollutants. The observation shed new lights on the fabrication and application of coagulants in a wide variety of scenarios.

Carbon Xerogel/TiO2 composites as photocatalysts for acetaminophen degradation

This work describes the production of carbon xerogel/TiO2 nanocomposites by sol-gel polymerization of resorcinol-formaldehyde in the presence of K2TiF6 inorganic titanium salt as TiO2 precursor. The effects of different starting C/Ti molar ratios in the morphology, surface property, and photocatalytic activity on the decomposition of acetaminophen (APP) were investigated. The materials were characterized by thermogravimetric analysis, Fourier transforms infrared spectroscopy, scanning and transmission electron microscopy, X-ray diffractometry, and textural properties. The composites presented heterogeneous structure, and presence of two phases for the introduction of TiO2. A region was formed by amorphous carbon and carbon spheres, where Ti is detected only immersed in the amorphous carbon particles, in the anatase phase. CXTi-4.5 (adopted nomenclature CXTi-n, where n is the number of mmol of titanium salt inserted) composite presented the highest efficiency in the removal of the APP in the aqueous medium, as well as acceptable reusability properties after the washing step.

Effect of solution chemistry on aqueous As(III) removal by titanium salts coagulation.

Solution chemistry is of great importance to the removal of arsenic by coagulation through influencing the speciation of arsenic, the in situ precipitation of metal salts coupled with the adsorption and coprecipitation behavior of arsenic during coagulation. While the researches on the influence of solution chemistry in As(III) removal by titanium salts, a promising candidate for drinking water treatment was still deficient. Batch tests were performed to evaluate the removal of As(III) by titanium salts coagulation under solution chemistry influences. The results indicated that As(III) removal by Ti(SO4)2 and TiCl4 increased first and then decreased with the rising of solution pH from 4 to 10. TiCl4 preformed better in As(III) removal than Ti(SO4)2 at pH4-8, but the opposite trends were observed at pH9-10. XPS analysis indicated that the involvement of surface hydroxyl groups was primarily responsible for As(III) adsorption on Ti(IV) precipitates. As(III) removal was inhibited in the presence of SO42- mainly by competitive adsorption, especially at elevated SO42- concentration under acidic and alkaline conditions. F- exerted a greater suppressive effect than SO42- via indirectly hindering Ti(IV) precipitate formation, and through direct competitive adsorption with H3AsO3, the inhibitive effect increased as F- concentration increased and depended highly on solution pH. As(III) removal was promoted by co-existing Fe(II) primarily through the facilitation of Ti(IV) precipitation, especially under neutral and alkaline conditions, while it was inhibited to a different extent by the presence of high-concentration Mn(II) possibly via competitive adsorption. The presence of Ca2+ and Mg2+ enhanced the removal of As(III), but the positive effect did not increase as ionic concentration elevated.

Titanium-containing coagulants for foundry wastewater treatment

Setting up a circulation water supply system is a prerequisite for a modern competitive steel making company. The most frequent problem faced by steel makers includes the challenge of removing suspended solids from large volumes of wastewater. Residual concentration of suspended solids (1-10 mg/l) is the main criterion of treatment efficiency. The most difficult task is to remove particles smaller than 1-2 microns, which stay suspended for a long time. One of the biggest sources of wastewater includes the process of removing residual molding sand from machine parts by water jet surface cleaning. Apart from high concentrations of suspended solids, process wastewater have high concentrations of dissolved organic compounds and require prior treatment before it can go to municipal wastewater treatment plants. Titanium-containing coagulants are being used more and more commonly in water treatment processes due to their high efficiency and the lack of most of the drawbacks inherent in conventional coagulants. This paper compares the conventional coagulants (i.e. aluminum and iron compounds) and coagulants containing titanium salts. In addition, complex titanium-containing coagulants were tested in the actual process of removing residual molding sand from machine parts by water jet surface cleaning. The findings show that titanium tetrachloride outperforms the conventionally used aluminum sulphate and iron chloride, while the effective dose of titanium tetrachloride is on average 2.5 to 3.0 times smaller. The obtained experimental data characterize the effect of added titanium compounds on the water treatment efficiency when conventional reagents are used. It was found that the addition 7.5 wt% of titanium tetrachloride to the conventional aluminum sulphate increases the treatment performance of the latter by 30%. The high efficiency of titanium-containing reagents is due to specific hydrolysis effects, as well as nucleation and flocculation at the surface of hydrolysis products. The rate of sedimentation and filtration of sludges resultant from water treatment with titanium-containing coagulants significantly exceeded that reached when using conventional reagents. The use of titanium-containing reagents will enable to transfer to smaller settlers and filters, reduce the consumption of reagents and reach an enhanced treatment performance. The treated water can be reused or discharged into municipal sewage treatment plants. This research study was carried out as part of the programme supporting research projects carried out by young staff of D. Mendeleev University of Chemical Technology of Russia (Application З-2020-013)

High-efficient removal of arsenite by coagulation with titanium xerogel coagulant

Coagulation with inorganic titanium (Ti) salts is a low-cost and high-efficiency technology for arsenic removal. However, the drastic decline of solution pH, which is caused by coagulation process, usually greatly reduces the removal efficiency of arsenite (As(III)). In this study, titanium xerogel coagulant (TXC) was employed for enhanced As(III) removal, and two common Ti-based coagulants, titanium sulfate (TS) and titanium tetrachloride (TC), were used as references. TXC outperformed TS and TC over the initial pH range of 5.0–10.0, especially under acidic condition, which was attributable to the moderate pH decline during TXC coagulation. TXC with dose of 10 mg Ti/L could eliminate above 90% of As(III) at pH 7.0 and 8.0. The maximum coagulation efficiency of the three Ti salts (10 mg Ti/L) at pH 8.0 followed an order of 625 mg/g Ti (TXC) > 588 mg/g Ti (TS) > 526 mg/g Ti (TC). The enhanced mechanisms involved in TXC coagulation were the strong adsorption ability of the in-situ formed flocs and binding affinity between As(III) and hydrolysates. TXC coagulation dominated by the unique network-like hydrolysates would generate in-situ flocs with more binding sites, and thus improved coagulation efficiency. Except for phosphate and silicate ions, the common water matrices did not greatly inhibit As(III) removal efficiency. In addition, TXC performed the highest As(III) removal efficiency in actual arsenic-containing wastewater. This study provided a high-efficient coagulant for As(III) pollution control, and shed light on the application potential of TXC in removing metalloid pollutants.

Simple preparation of nitrogen-doped TiO2 and its performance in selective oxidation of benzyl alcohol and benzylamine under visible light

N-doped TiO2, denoted as T_400, was prepared simply by the facile thermal hydrolysis of TiOSO4 using NH4OH as both a precipitating agent and a nitrogen source. Compared to TiO2 without nitrogen doping, T_400 provides superior photocatalytic activity toward the selective oxidation of benzyl alcohol and benzylamine under visible light irradiation, with > 85 % conversion and > 95 % selectivity to benzaldehyde and N-benzylidenebenzylamine products, respectively. The increased photoactivity of T_400 is ascribed to enhanced visible-light absorption and efficient photogenerated charge transfer and separation as supported by UV–vis DRS, photoelectrochemical and VB-XPS results. The catalyst can tolerate the presence of substituent groups in benzyl alcohol and benzelamine molecules as > 80 % conversion and > 95 % selectivity are still achieved, which expands the scope of substrates and catalyst utilization. Band energy level of N-doped TiO2 compared to that of undoped TiO2 is determined using Mott-Schottky and UV–vis DRS measurements. Possible mechanisms for the formation of benzaldehyde and N-benzylidenebenzylamine over N-doped TiO2 are proposed. This work presents a simple synthesis of N-doped TiO2, using a low-cost and easily handled inorganic titanium salt instead of air/moisture-sensitive alkoxide precursors and reveals its potential application toward photocatalytic synthesis of organic fine chemicals under visible light.

Facile preparation of effective flame retardant silk fabric by the metal salt adsorption approach

In this study, flame retardant (FR) functional silk fabric was prepared by the facile adsorption of metal salts (ferrous, aluminum and titanium sulfate) at low concentration. This study tried to provide a good understanding on the FR ability and action of metal salts on silk fabric. The morphological structure and functional groups of silk fiber before and after treatment were studied. The thermal stability, smoke generation ability and FR ability of the treated silk were evaluated. The iron, aluminum and titanium salts endowed silk fabric with self-extinction effect at a concentration of 0.1, 0.5 and 1.0 g/L, respectively. The metal salts also showed good washing resistance on silk fabric; for example, the aluminum salt treated silk still reached self-extinction after 10 robust washings, which is attributed to the complexation capacity of silk macromolecule with metal ions. The thermal stability and char residues analyses suggested the condensed phase FR mechanism for the treated silk, and the good ability to promote char formation contributed to their FR functionality. This study suggests that certain metal salts are effective enough to serve as suitable alternative to toxic halogen-based chemicals for enhancing fire safety of silk textiles.

Simple and Scalable Synthesis of Vertically Aligned Anatase Nanowires for Enhanced Photoelectrochemical Performance

Vertically aligned 2.45 μm anatase nanowires were produced via a simple chemical bath deposition technique using a low-cost, easy to handle, water-soluble titanium salt precursor. The nanowires wer...

Titania nanotubes (TNTs) prepared through the complex compound of gallic acid with titanium; examining photocatalytic degradation of the obtained TNTs

It was for the first time that the complex compound of gallic acid with titanium (IV) salt was used as a precursor to synthesize titania nanotubes. The study was separated into four main sections; (I) synthesizing the complex of titanium with gallic acid, (II) synthesizing anatase and rutile phases through thermal decomposing of the complex, (III) investigating the possibility to synthesize titania nanotubes from the rutile and anatase phases, and (IV) photocatalytic ability of all the nanoparticles.Different methods were applied to analysis, including X-ray diffraction, 1H NMR, FT-IR spectroscopy, elemental analysis, quantum-chemical modeling, Raman spectroscopy, thermal analysis, photoluminescence, BET analysis (to investigate the specific surface activity, total pore volume), EDX, electron microscopy (SEM), acceleration voltages, electrical conductivity, BJH method (to determine average pore diameter), and UV-Vis spectroscopy.We illustrated the possibility of the synthesis of the titania nanotubes from the anatase phase, while rutile phase was not turned to a tube shape.The photocatalytic ability of the obtained nanoparticles was tested by degrading bromophenol blue, as an organic pollutant, under weak light. TiO2 in the form of nanotubes could reduce the concentration of bromophenol blue to 82%, as well as the rutile phase - to 70%, and finally anatase as nan-spheres to 36%.

Titanium salts tested in reconstructed human skin with integrated MUTZ-3-derived Langerhans cells show an irritant rather than a sensitizing potential.

BackgroundThe nature of clinically related adverse reactions to titanium is still unknown.ObjectiveTo determine whether titanium salts have irritant or sensitizing potential in a reconstructed human skin (RHS) model with integrated Langerhans cells (LCs).MethodsRHS‐LCs (ie, reconstructed epidermis) containing primary differentiated keratinocytes and CFSE+CD1a+‐LCs generated from the MUTZ‐3 cell line on a primary fibroblast‐populated collagen hydrogel (dermis) were topically exposed to titanium(IV) bis(ammonium lactato)dihydroxide (TiALH). LC migration and plasticity were determined.ResultsTiALH resulted in CFSE+CD1a+‐LC migration out of the epidermis. Neutralizing antibodies to CCL5 and CXCL12 showed that LC migration was CCL5 and not CXCL12 mediated. LCs accumulating within the dermis after TiALH exposure were CFSE+Lang+CD68+ which is characteristic of a phenotypic switch of MUTZ‐LC to a macrophage‐like cell. Furthermore, TiALH did not result in increased interleukin (IL)‐1β or CCR7 messenger RNA (mRNA) in the dermis, but did result in increased IL‐10 mRNA. In addition, monocultures of MUTZ‐LCs failed to increase LC maturation biomarkers CD83, CD86, and CXCL‐8 when exposed to noncytotoxic concentrations of four different titanium salts.ConclusionThese results classify titanium salts as irritants rather than sensitizers and indicate that titanium implant‐related complaints could be due to localized irritant‐mediated inflammation arising from leachable agents rather than a titanium metal allergy.

The investigation of magnetic property and corrosion resistance of the assisted Sol-Gel synthesis of Ti/Ni/Co nanocomposites

The synthesis of the ternary Ti/Ni/Co nanocomposites was successfully performed using the Sol-Gel process. A novel approach of using titanium nitride (TiN) powder as a titanium source, along with nickel (II) nitrate hexahydrate (Ni(NO3)2.6H2O) as a nickel source, cobalt (II) nitrate hexahydrate ((Co(NO3)2.6H2O) as a cobalt source, and PEG-6000 as a stabilizer was used to successfully prepare the ternary Ti/Ni/Co nanocomposites. These nanocomposites exhibit a crystal size of 20 to 30 nm and the cubic B2 crystal structure, which is associated with the ternary Ti/Ni/Co phase. In order to study the corrosion resistance, thin films of the Ti/Ni/Co nanocomposites were spun coated onto glass heat treated at 250 °C for 4 h. The addition of Co in the Ti/Ni systems increased the magnetic properties. The addition of cobalt also, indirectly, caused a decrease in the corrosion resistance. Moreover, this study also demonstrated the successful use of TiN powder as a titanium source (instead of the traditional Ti powder or other titanium salts) to produce Ti/Ni/Co nanocomposites.

Template-Free, Solid-State Synthesis of Hierarchically Macroporous S-Doped TiO2 Nano-Photocatalysts for Efficient Water Remediation.

Nanosized sulfur-doped titanium dioxide emerged as an attractive photocatalyst in various environmental remediation applications, yet most synthesis methods require hazardous sulfurizing agents and intricate synthesis procedures. Herein, we present a facile, sustainable, and environmentally friendly preparation process for the production of visible-light-active meso–macroporous sulfur-doped anatase TiO2 (S-TiO2) nanoparticles for the first time. This strategy encompasses solventless mixing of titanium salt and surfeit yet nontoxic abundant elemental sulfur under continuous ball milling and moderate thermoannealing. The characterizations of as-obtained S-TiO2 nanoparticles showed enhanced physicochemical properties including distinctive surface features composed of hierarchical hollow macroporous channels having nanostructured mesoporous core walls. The annealing temperature was observed to control the structure and extent of sulfur doping in TiO2. Upon insertion of a sulfur atom into the TiO2 lattice, the band gap energy of S-TiO2 was significantly lowered, facilitating the enhanced photochemical activity. Owing to the effective S doping (1.7–2.8 atom %), and the interconnected hollow meso–macroporous nanostructure, the resulting nanosized S-TiO2 exhibited unique adsorption properties and superior photocatalytic efficiency for the rapid degradation of hazardous organic dyes and phenols for water remediation. The presented strategy holds high potential to provide rapid production of a hierarchical and highly porous S-TiO2 photocatalyst on a large scale for various environmental remediation and other myriad photochemical applications.

Development of the Technology to Obtain Finely Dispersed Titanium Dioxide from the Solutions of Titanium Salts

Development of the Technology to Obtain Finely Dispersed Titanium Dioxide from the Solutions of Titanium Salts

Removal of aqueous arsenite by simultaneous ultraviolet photocatalytic oxidation–coagulation of titanium salts: effect of precipitate particles size and solution chemistry

Removal of aqueous arsenite by simultaneous ultraviolet photocatalytic oxidation–coagulation of titanium salts: effect of precipitate particles size and solution chemistry

Efficiency of titanium salts as alternative coagulants in water and wastewater treatment: short review

Efficiency of titanium salts as alternative coagulants in water and wastewater treatment: short review

Development of the Technology to Obtain Finely Dispersed Titanium Dioxide from the Solutions of Titanium Salts

Development of the Technology to Obtain Finely Dispersed Titanium Dioxide from the Solutions of Titanium Salts

A simple preparation route for polysilicate titanium salt from spent titanium solutions.

Polysilicate titanium salt (PST) is synthesized by using spent titanium solutions and polysilicic acid (PSiA) as raw materials. PSiA could improve the aggregation ability of titanium salt flocculants and also restrain the hydrolysis of Ti4+ to stabilize titanium salts. Meanwhile, replacing titanium salt with spent titanium solutions could reduce the cost of PST and solve the problem of wastewater treatment in the titanium industry, which makes valuable waste regeneration possible. Scanning electron microscopy (SEM) results show the morphology transformation (sheet, spheroid, and sphere) of PST with different Ti/Si molar ratios. The formation process of PST is analyzed by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). This study investigates the effect of Ti/Si molar ratios on PST flocculation performance in humic-kaolin water and actual domestic wastewater treatment. The in situ floc size change of PST is measured by laser particle size analyzer in humic-kaolin water treatment. Additionally, the performance of PST is comprehensively evaluated on flocculation and sedimentation ability, rapid sweep netting ability and stability. In short, the prepared PST in this study is suitable for treating wastewater with high turbidity and chemical oxygen demand (COD) in a wide range of pH values.