Titanium Chloride Research Articles

Coagulation of dissolved organic matter in surface water by novel titanium (III) chloride: Mechanistic surface chemical and spectroscopic characterisation

Problems caused by residual organics in treated water include the formation of disinfection by-products (DBP) following reaction with chlorine and being a substrate for microbial regrowth in the drinking water distribution system. Dissolved organic matter (DOM) can only be partially removed by conventional treatment process i.e. coagulation by Al- and Fe-based salts. In the present study, the performance of titanium trichloride (TiCl3) as a coagulant for surface water treatment was studied and compared with conventionally used aluminum sulfate (alum). Jar test experiments were performed at various coagulant doses and pH levels to determine the optimum conditions based on removal efficiencies of dissolved organic carbon (DOC). The zeta potential values were analysed for assessing the destabilisation mechanism of DOM flocs. The TiCl3 showed a significantly higher capacity for DOC removal at pH around 3 at which charge neutralization was found to be the dominant mechanism for the floc formation. This was further evident from the relatively larger floc sizes obtained with TiCl3 treatment. However, destabilization of Ti-flocs occurred at pH 4.5 through an adsorption-enmeshment mechanism due to a highly negative zeta potential. Additionally, fluorescence spectroscopic analyses showed that TiCl3 was more efficient than alum in removing humic compounds. A two-stage treatment process by alum and TiCl3, either as the same chemical or both showed better performance than a single dose treatment. The results indicate that TiCl3 could be an effective alternative coagulant for the treatment of waters, particularly those of low alkalinity and high DOC concentration and low pH wastewaters for removal of hydrophobic compounds and particulate matter.

The Purification of the Galvanic Industry Wastewater of Chromium(VI) Compounds Using Titanium(III) Chloride

The possibility of reduction of chromium(VI) compounds by solutions of titanium(III) chloride in hydrochloric acid has been investigated. It has been shown that the considered reagent possesses strong reductive properties over wide pH range. It has been proved that the efficiency of the reduction of chromium(VI) compounds with titanium(III) chloride in neutral medium is much higher than that when using sodium sulfite. It has been noted that in addition to the reduction properties, titanium compounds act as a highly efficient coagulant, thereby increasing the overall purification efficiency of the wastewater.

Synthesis and Photocatalytic Properties of Nitrogen Modified Titanium Dioxide

Summary Pure and nitrogen-doped titanium dioxide (N-doped TiO2) photocatalysts were prepared by non-aqueous sol-gel method by means of the reaction between titanium (IV) chloride (TiCl4) and C6H5CH2 OH (benzyl alcohol), used as precursors and urea serving as a nitrogen source. The phase formation and short-range order of the resulting particles were characterized by X-ray powder diffraction (XRD) and infrared (IR) spectroscopy. The crystallite size of as-prepared composite powders was in the range 12-35 nm. The aim of this work was to investigate the efficiency of N-doped TiO2 as a photocatalyst in degradation of model organic pollutants - dyes Reactive Black 5 (RB5) and Malachite Green (MG), under ultraviolet (UV) and visible (Vis) irradiation. 0ur results indicated that synthesized N-TiO2 nanocomposites slightly improved the photocatalytic activity under UV irradiation, compared to the pure titanium dioxide (TiO2), and had no effect under Vis light illumination.

Activation of Sulfur and Opal-Cristobalite-Tridymite Phase in Sulfur Concrete Technology

The paper investigates the influence of the metal chlorides (Al, Zn, Ti, Fe) on the properties of sulfur binder. The addition of Lewis acids stimulated the synthesis process for inorganic sulfides and sulfur concrete based on them. The resulting sulfur concrete has high performance characteristics. It was found that aluminum, titanium and iron chlorides acted as activators for sulfur ring opening, reduced the activation energy in the process and simultaneously encouraged the chemical interaction between sulfur and surface silicon of silica-containing compounds. It was revealed that the reactivity of sulfur modifiers decreased in a series of Zn>Al>Ti>Fe. Chemical modification of the silicate surface with chlorides of Zn, Al, Ti, Fe results in intended change of its chemical properties. The paper shows that modification increases a number of active reaction sites on the silicate surface. The designed technology is environmentally sound and economically feasible: it ensures the efficient use of sulfur waste from the oil and gas industry, and provides durable and corrosion resistant composite materials that have lower production cost than the known analogues. The designed materials can be used in road construction for roadbeds, paving slabs, curbstones, pavestones, gutters.

Preparation and characterization of six-coordinate titanium(IV) monothiocarbamate complexes. X-ray crystal structure of Dichlorobis(N,N-dimethylcarbamothioato-O,S)titanium(IV)

Six-coordinate titanium(IV) N,N-dialkylmonothiocarbamate complexes Ti(R2mtc)2Cl2 (R = Me, Et, i-Pr, or i-Bu) have been prepared in excellent yield by reaction of titanium(IV) chloride with stoichiometric amounts of sodium N,N-dialkylmonothiocarbamates in dichloromethane or benzene. The complexes were characterized by conductance measurements and by infrared and 1H NMR spectroscopy. The x-ray crystal structure of Ti(Me2mtc)2Cl2 was determined in order to establish the location of the sulfur atoms, which are generally cis in monothiocarbamate and monothio-β-diketonate complexes. Ti(Me2mtc)2Cl2 has a distorted octahedral structure in which the Ti(IV) atom is bonded to two cis Cl atoms and two planar, bidentate monothiocarbamate ligands. The complex exists (unexpectedly) as the C2 stereoisomer that has S atoms in trans positions.

Composition-sensitive growth kinetics and dispersive optical properties of thin HfxTi1−xO2 (0 ≤ x ≤ 1) films prepared by the ALD method

The optical quality HfxTi1−xO2 films with a wide range of the Hf/Ti ratio were prepared on Si (100) substrates by the ALD method with the use of tetrakis(ethylmethylamido)hafnium(IV) (Hf(NC2H5CH3)4, TEMAH) and titanium(IV) chloride TiCl4 as Hf and Ti precursors, respectively. The H2O vapor was applied as oxygen source. The structural properties of the as-deposited and annealed films were evaluated by the XRD analysis. The Hf/Ti ratio in the films was measured by energy dispersive spectroscopy and X-ray photoelectron spectroscopy. The dispersive optical constants were obtained by spectroscopic ellipsometry over the photon energy range of E = 1.12–4.96 eV. The specific growth kinetics is observed for 0 < x < 1. The optical constants wide-range tuning is reached in the HfxTi1−xO2 (x = 0–1) films via the chemical composition variation and annealing.

Mechanistic Study on Facet-Dependent Deposition of Metal Nanoparticles on Decahedral-Shaped Anatase Titania Photocatalyst Particles

Facet-selective gold or platinum-nanoparticle deposition on decahedral-shaped anatase titania particles (DAPs) exposing {001} and {101} facets via photodeposition (PD) from metal-complex sources was reexamined using DAPs prepared with gas-phase reaction of titanium (IV) chloride and oxygen by quantitatively evaluating the area deposition density on {001} and {101} and comparing with the results of deposition from colloidal metal particles in the dark (CDD) or under photoirradiation (CDL). The observed facet selectivity, more or less {101} preferable, depended mainly on pH of the reaction suspensions and was almost non-selective at low pH regardless of the deposition method, PD or CDL, and the metal-source materials. Based on the results, the present authors propose that facet selectivity is attributable to surface charges (zeta potential) depending on the kind of facets, {001} and {101}, and pH of the reaction mixture and that this concept can explain the observed facet selectivity and possibly the reported facet selectivity without taking into account facet-selective reaction of photoexcited electrons and positive holes on {101} and {001} facets, respectively.

Endohedral Functionalized Cage as a Tool to Create Frustrated Lewis Pairs.

A frustrated Lewis pair (FLP) system was obtained by confinement of the Lewis base partner, a Verkade's superbase, in a molecular cavity. Whereas the model superbase lacking cavity displayed no catalytic activity in Morita-Baylis-Hillman (MBH) reactions, when associated to titanium (IV) chloride, the encaged superbase turns out to be an efficient catalyst under the same conditions. The crucial role of the endohedral functionalized cage on catalytic performance was further demonstrated by the fact that model superbases with bulky substituents were much less efficient to produce active catalysts, as well as by inhibition and substrate selection experiments. 31 P NMR spectroscopy and mass spectrometry experiments evidenced that no interaction between the Lewis acidic and basic partners occurred when the superbase was capped by a cycloveratrylene (CTV) unit, thus creating a true FLP active system.

Endohedral Functionalized Cage as a Tool to Create Frustrated Lewis Pairs

AbstractA frustrated Lewis pair (FLP) system was obtained by confinement of the Lewis base partner, a Verkade's superbase, in a molecular cavity. Whereas the model superbase lacking cavity displayed no catalytic activity in Morita–Baylis–Hillman (MBH) reactions, when associated to titanium (IV) chloride, the encaged superbase turns out to be an efficient catalyst under the same conditions. The crucial role of the endohedral functionalized cage on catalytic performance was further demonstrated by the fact that model superbases with bulky substituents were much less efficient to produce active catalysts, as well as by inhibition and substrate selection experiments. 31P NMR spectroscopy and mass spectrometry experiments evidenced that no interaction between the Lewis acidic and basic partners occurred when the superbase was capped by a cycloveratrylene (CTV) unit, thus creating a true FLP active system.

Development of Sulfur and Silicon Dioxide Activation Method in the Sulfur Concrete Technology

The paper investigates the recovery problem of waste sulfur from metallurgical, oil and gas plants. The method was developed to synthesize inorganic sulfides and sulfur concretes from them using the activating agent – titanium chloride and different silica-containing raw materials. The chemical interaction between sulfur, titanium tetrachloride and silicon dioxide encourages the formation of a strong and compact structure in the material. The physical chemical and quantum chemical calculations confirmed the formation of titanium silicate sulfide and made it possible to suggest the concept of sulfur concrete synthesis. It was found how the amorphous component in the filler influenced the properties of sulfur concrete. The physical mechanical tests were performed on the specimens of sulfur concrete, based on opal crystobalite rock from the different fields. The optimum sulfur concrete formulation was determined. The specimens with the optimum composition have high coefficient of resistance to HCl, H2SO4, CaCl2, NaCl, MgSO4 solutions, high impact resistance, freeze resistance and density to meet GOST concrete standard. The resulting materials can be used for production of some construction materials: paving slabs and blocks, road building materials.

Polymerized titanium salts for municipal wastewater preliminary treatment followed by further purification via crossflow filtration for water reuse

Research concerning polymerized titanium salts for preliminary treatment of municipal wastewater remains limited. We proposed the pre-coagulation of municipal wastewater with polymerized titanium based coagulants, followed by direct crossflow ultrafiltration for water reuse by avoiding biological treatment. Compared with polymerized aluminum chloride (PAC), polymerized ferric sulfate (PFS) and polymerized titanium sulfate (PTS), the polymerized titanium chloride (PTC) achieved higher coagulation efficiency, with chemical oxygen demand (COD) and total phosphorus (TP) removal reached 80.5% and 99.1%, respectively. Besides, PTC produced larger flocs (median equivalent diameter of 1408.1 μm) with better settling ability (flocs sedimentation in 1 min), higher shear resistance (strength factor reached 95.87%) and stronger re-aggregation capability (recover factor of 225.13%). The subsequent direct crossflow ultrafiltration of primary settled municipal wastewater could achieve complete suspended solids and P removal, being accompanied by additional 10–15% of organics removal. Specifically, ultrafiltration of PTC effluent obtained larger permeate flux up to 499.5 L m−2 h−1 and the reused water having higher quality (COD removal of 90.4%). Current study demonstrated the feasibility and superiority of utilizing polymerized titanium salts (especially PTC) for preliminary treatment of municipal wastewater. The resultant high-quality effluent through direct ultrafiltration provides alternative schemes for the demanding reclaimed wastewater reuse.

In Situ-Generated Volatile Precursor for CVD Growth of a Semimetallic 2D Dichalcogenide.

Semimetallic-layered transition-metal dichalcogenides, such as TiS2, can serve as a platform material for exploring novel physics modulated by dimensionality, as well as for developing versatile applications in electronics and thermoelectrics. However, controlled synthesis of ultrathin TiS2 in a dry-chemistry way has yet to be realized because of the high oxophilicity of active Ti precursors. Here, we report the ambient pressure chemical vapor deposition (CVD) method to grow large-size, highly crystalline two-dimensional (2D) TiS2 nanosheets through in situ generating titanium chloride as the gaseous precursor. The addition of NH4Cl promoter can react with Ti powders and switch the solid-phase sulfurization reaction into a CVD process, thus enabling the controllability over the size, shape, and thickness of the TiS2 nanosheets via tuning the synthesis conditions. Interestingly, this semimetallic 2D material exhibits near-infrared surface plasmon resonance absorption and a memristor-like electrical behavior, both holding promise for further application developments. Our method hence opens a new avenue for the CVD growth of 2D metal dichalcogenides directly from metal powders and pave the way for exploring their intriguing properties and applications.

The Influence of the Precursor Type and of the Substrate on the SPD Deposited TiO2 Photocatalytic Thin Films

Abstract Photocatalytic degradation of organic pollutants from wastewater using titanium dioxide is recognized as an efficient process. To be feasible, this process needs to be solar- or visible light -activated, but, due to its wide band gap energy, titanium dioxide can only be activated by ultraviolet radiation. In this paper, thin films of titanium dioxide were deposited by Spray Pyrolysis Deposition using organo-metallic (titanium-iso-propoxide) and inorganic (titanium chloride) precursors, as a first step in optimizing the deposition process of titanium dioxide - carbon composite thin films, active in the visible spectral range. The thin films were characterized to outline the differences when using these two precursor solutions, when deposited on Fluorine doped Tin Oxide-glass, regular glass and microscopic glass, in terms of crystallinity (by using X-ray diffraction), elemental composition (using Energy Dispersive X-ray spectrometry), surface morphology (Scanning Electronic Microscopy and Atomic Force Microscopy). The photocatalytic activity of the titanium dioxide thin films was investigated based on the removal efficiencies of methylene blue from a synthetically prepared wastewater. The samples deposited using the inorganic precursor show higher roughness, and this proves to be the most important factor that influences the phocatalytic processes. After 8 hours of ultraviolet irradiation, methylene blue removal efficiencies up to 36% were observed; the highest removal efficiency was registered using the thin titanium dioxide film obtained using the titanium chloride precursor, deposited on fluorine doped tin oxide glass substrate, due to the titanium dioxide-tin dioxide semiconductor tandem formed at the interface, that limits the electron-hole recombination, thus increasing the photoctalytic performance of the substrate.

Co-catalyst-free photocatalytic hydrogen evolution on TiO2: Synthesis of optimized photocatalyst through statistical material science

An active TiO2 for co-catalyst-free photocatalytic hydrogen evolution was successfully synthesized employing a simple Evaporation-Induced Self-Assembly (EISA) method that was developed and optimized with the help of Design of Experiment (DoE) coupled with Full Factorial Design (FFD) methodology. Coupling DoE with FFD provides a statistical tool for optimizing the synthesis process while carrying out the smallest number of experiments. This tool builds a statistical framework to determine the significance of the studied factors, i.e., titanium-precursor type, surfactant type and surfactant quantity, along with their potential interactions, as well as with their optimum levels. The choice of the titanium-precursor type is found to be the predominant factor affecting the efficiency of TiO2 for hydrogen gas evolution. The interaction between precursor type and surfactant type is also statistically significant. The statistically optimized study identifies that combining F-108 amphiphilic block copolymers with titanium(III) chloride solution leads to TiO2 exhibiting the highest photocatalytic efficiency for the generation of molecular hydrogen. The thus prepared TiO2 shows relatively high photocatalytic hydrogen evolution rates (1.22 mmol h−1 g−1) compared to the commercially available TiO2 photocatalysts which are not active for hydrogen generation in the absence of a co-catalyst. Significant photocatalytic reforming of ethanol is achieved over the synthesized bare TiO2 with the formation of acetaldehyde as the main by-product in the gas phase. This unexpected photocatalytic performance is mainly attributed to the shift of flat band potential towards more negative potentials as revealed from the characterization results in addition to the high density of charge carriers exhibiting longer lifetime shown by laser transient reflectance measurements. The latter showed the presence of a high number of trapped states, which are beneficial for the photocatalytic properties.

Conformal Multilayer Photocatalytic Thin Films on Fine Particles by Atmospheric Pressure Fluidized Bed Chemical Vapor Deposition

Conformal multilayer TiO2/SiO2/TiO2 coatings were deposited on the surface of ∼27 μm spherical soda lime glass (SLG) particles using fluidized bed chemical vapor deposition at atmospheric pressure. Cost-effective precursors of titanium and silicon chlorides together with water were employed to deposit titania and silica films at 300 °C and room temperature, respectively. Focused ion beam cross-sectional transmission electron microscopy, scanning electron microscopy, energy-dispersive spectroscopy, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller surface area analysis, and X-ray diffraction were used to characterize the multilayer-coated particles. The results revealed a pinhole-free and uniform multilayer of anatase TiO2 and amorphous SiO2 with a thickness of ∼110 and 20 nm. Moreover, the photodegradation performance of the coated particles was examined by the degradation of methylene blue as the model reaction. It was found that a multilayer thin film of titania and silica can effectively prevent...

Bactericidal and photowetting effects of titanium dioxide coatings doped with iron and copper/fluorine deposited on stainless steel substrates

Titanium dioxide coatings, doped either with Fe or with a Cu/F combination, were deposited onto 316 LVM steel with radio frequency plasma enhanced chemical vapor deposition technique. As a source of titanium, titanium (IV) chloride was used, while iron pentacarbonyl and copper(II) (6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate) served as precursors for iron and copper/fluorine, respectively. The coatings were evaluated in terms of their surface topography using atomic force microscopy, phase composition using low angle X-ray diffraction and chemical composition using both Raman and Furrier transform infrared spectroscopies. Mechanical properties, such as adhesion, hardness and Young modulus, were tested. Finaly, bacteriostatic and bactericidal properties of the films as well as their water wettability under ultraviolet light illumination were assessed. The coatings had primarily amorphous structure, with the exemption being those containing 0.5 and 1.4 atomic % of iron, where anatase/rutile and rutile reflexes were recorded, respectively. Mechanical properties of the films were found to be satisfactory and their bactericidity substantial.

Synthesis and characterization of V-doped TiO2 nanoparticles through polyol method with enhanced photocatalytic activities

This work reports the synthesis of vanadium-doped titanuim dioxide nanoparticles using titanium chloride and ethylene glycol as precursor and solvent respectively. The properties of as-prepared samples were investigated by X-ray diffractometry, scaning electron microscopy, Fourier transform infrared (FTIR) spectroscopy, diffuse reflectance, and thermal analysis. X-ray diffraction patterns indicate that the TiO2 nanoparticles obtained after calcination at 500 °C under air atmosphere has the anatase phase with a tetragonal structure and the crystallite sizes were in the range 16.83–12.27 nm. The transmission electron microscopy was used to detect the morphology of synthesized nanoparticles. The functional groups present in the samples were identified by FTIR study. From the optical studies, there is a blue shift in the absorption edge for our samples that can be attributed to the presence of V in the TiO2. For V doped TiO2 nanoparticles the optical band gap varies between 3.18 and 2.60 eV with the increase of V concentration. The TGA findings allow the thermal cycle determination of samples whereas DTA findings allow the phase transition temperature identification. Finally, the evaluation of the photocatalytic activity is carried out using methyl blue as model of chemical pollutants in UV irradiation conditions and followed satisfactory the pseudo first order according to the Langmuir–Hinshelwood model.

Improved reversible dehydrogenation properties of MgH2 by the synergetic effects of graphene oxide-based porous carbon and TiCl3

In this study, we used a combination of graphene oxide-based porous carbon (GC) and titanium chloride (TiCl3) to improve the reversible dehydrogenation properties of magnesium hydride (MgH2). Examining the effects of GC and TiCl3 on the hydrogen storage properties of MgH2, the study found GC was a useful additive as confinement medium for promoting the reversible dehydrogenation of MgH2. And TiCl3 was an efficient catalytic dopant. A series of controlled experiments were carried out to optimize the sample preparation method and the addition amount of GC and TiCl3. In comparison with the neat MgH2 system, the MgH2/GC-TiCl3 composite prepared under optimized conditions exhibited enhanced dehydrogenation kinetics and lower dehydrogenation temperature. A combination of phase/microstructure/chemical state analyses has been conducted to gain insight into the promoting effects of GC and TiCl3 on the reversible dehydrogenation of MgH2. Our study found that GC was a useful scaffold material for tailoring the nanophase structure of MgH2. And TiCl3 played an efficient catalytic effect. Therefore, the remarkably improved dehydrogenation properties of MgH2 should be attributed to the synergetic effects of nanoconfinement and catalysis.

Mechanistic and constrained thermochemical modelling in chemical reactor engineering: Ti(IV) chloride oxidation revisited

In process and materials chemistry, computational modelling of complex reactive systems has been a long-time continuing process. The methodology based on numerical methods in mechanistic reaction kinetics as well as for fluid phase thermodynamics applying equations of state is well established. During the last two decades, however, thermodynamic multiphase technology based on the minimisation of Gibbs free energy has made progress in modelling both reactive flows and processing of functional materials. Recent advancements also include introduction of such new Gibbs’ian algorithms, which facilitate calculation of time-dependent changes in reactive multi-component multi-phase systems. Comparison between detailed kinetic mechanisms (DKMs) and multiphase thermochemical techniques has yet seldom been available. The present work describes a unique comparison between constrained Gibbs free energy calculation (with one constrained kinetic reaction rate) and detailed kinetic mechanism of 67 reversible reactions between 28 species, as performed for the industrially interesting Titanium(IV) chloride oxidation process. When confined to gas phase kinetics, the calculated results show fair agreement between the two different techniques. However, comparison with observations from an experimental plug flow reactor suggests that the formation of a solid Ti-oxide phase in the models becomes a necessity. The applicability of the alternative simulation techniques in chemical reactor engineering is shortly discussed.

Titanium(III, IV)-Containing Catalytic Systems for Production of Ultrahigh Molecular Weight Polyethylene Nascent Reactor Powders, Suitable for Solventless Processing-Impact of Oxidation States of Transition Metal.

Catalytic systems containing TiCl4 or TiCl3, THF, organomagnesium (n-Bu2Mg) and organoaluminum compounds capable of producing ultrahigh molecular weight polyethylene (UHMWPE) were developed. The resulting polymers were characterized by a molecular weight in the range of (1.8–7.8) × 106 Da and desirable morphology, suitable for modern methods of polymer processing—the solvent-free solid-state processing of superhigh-strength (tensile strength up to 2.1 GPa) and high-modulus (elastic modulus up to 125 GPa) oriented films and film tapes. The impacts of a THF additive, the oxidation state of the titanium atom, and the composition and nature of the nontransition organometallic compounds on the formation of catalytic systems for UHMWPE production were evaluated. The results indicate the suitability of individual titanium chloride tetrahydrofuran complex application for the formation of THF-containing catalytic systems. This approach also results in a significant increase in the system catalytic activity and mechanical properties of UHMWPE. The catalysts based on Ti(III) were inferior to systems containing Ti(IV) in productivity but were markedly superior in the mechanical properties of UHMWPE.