Analysis of lead titanate-zirconate ceramics: Determination of lead,titanium and niobium by differential cathode-ray polarography

Differential cathode-ray polarography is applied to the direct determination of lead, titanium and niobium in lead titanate-zirconate solid-solution ceramics containing small additions of niobium pentoxide. Titanium and niobium are determined in buffered EDTA solution at pH 4.0 and lead in 1 M hydrochloric acid. With the high precision comparative technique, relative standard deviations of 0.11% and 0.31% for lead and titanium respectively are obtained. Niobium is determined by the subtractive technique.     

电感耦合等离子体原子发射光谱测定铬矿中的铅、锌、镍、钛、磷

提出了电感耦合等离子体原子原子发射光谱测定铬矿中的铅、锌、镍、钛、磷含量的方法,选择各元素的分析谱线,采用正交试验的方法确定仪器的工作参数,方法的检出限0.22 ~1.50ug·L-1 ,方法的回收率在89%~112%,测定值的相对标准偏差（n=5）小于1.45%,方法用于铬矿杂元素的分析结果与现有的国标检验方法测定值一致。填补无铬矿中铅、锌、钛元素检测方法的空白。     

Electrodeposition of composite PbO2–TiO2 materials from colloidal methanesulfonate electrolytes

Journal of Solid State Electrochemistry - The influence of particles of colloidal titanium dioxide on the morphology and structure of lead dioxide electrodeposits has been investigated. The...     

Determination of lead and cadmium in titanium dioxide by differential pulse anodic stripping voltammetry

A procedure for the simultaneous determination of lead and cadmium in TiO(2) by differential pulse anodic stripping voltammetry (ASV) has been developed. The key feature of the method is the use of triethanolamine (TEA) to remove titanium interference: TiO(2) undergoes acidic digestion with HF/H(2)SO(4) at atmospheric pressure, TEA is added to the HCl solution of the residue and the solution is analysed using a standard ASV instrumentation, equipped with a hanging mercury drop electrode. The calibration curves for both lead and cadmium are linear up to 50 mugl(-1) of solution, and the detection limits are 1 mugl(-1), corresponding to 1 mugg(-1) of TiO(2). Method reliability was tested by comparing the results with those given by electrothermal atomic absorption spectroscopy. The method has been successfully applied for determination of both contaminants in powdered titanium dioxide (raw materials) and in titanium dioxide-containing cosmetics (sunscreen products).     

An acetic acid/water based sol-gel PZT process I: Modification of Zr and Ti alkoxides with acetic acid

The chemical reactions underlying the formation of a water based alkoxide sol gel solution for lead zirconate titanate thin films have been evaluated using infra-red spectroscopy and viscosity measurements. Titanium isopropoxide and zirconium propoxide are modified by acetic acid in order to use water as a solvent. Substitution reactions initially take place with the formation of titanium or zirconium alkoxide acetate and alcohol. The titanium or zirconium alkoxide acetate gradually associate through the formation of M-O-M linkages to increase the viscosity of the solution.     

Coliform bacteria immobilized on titanium dioxide nanoparticles as a biosorbent for trace lead preconcentration followed by atomic absorption spectrometric determination

Microchimica Acta - Coliform bacteria physically immobilized on titanium dioxide nanoparticles can be used as a biosorbent for solid phase extraction of lead (II) ions from aqueous solution using a...     

A novel route to perovskite lead titanate from lead and titanium glycolates via the sol–gel process

Pure perovskite lead titanate powder (PbTiO₃) is successfully produced via the sol–gel process using lead and titanium glycolates as starting precursors and has been synthesized by the oxide one spot synthesis process. The obtained lead titanate is of the tetragonal form of the perovskite phase, with high purity and nearly zero moisture content. From high‐resolution mass spectra, the XRD technique, Raman‐FTIR and TGA‐DTA analysis, the lead–titanium glycolates undergo sol–gel transition through the formation of Pb? O? Ti bonds. From the SEM micrographs, the PbTiO₃ particle shape transforms from an agglomerate sphere to a needle and fiber‐like shapes as the calcination temperature is varied above T_c. The corresponding molecular structural transformation, from the tetragonal form to the cubic form, occurs at 430 °C. The lead titanate powder calcined at 300 °C for 3 h has the highest dielectric constant and electrical conductivity values, namely 17470 and 1.83 × 10^?3, respectively. Copyright © 2006 John Wiley & Sons, Ltd.     

Department of Chemical Engineering,Tokyo Institute of Technology,Meguro, Tokyo 152, JapanReaction of organoaluminates with lead(IV) acetate. A convenien route from 1-alkenes to primary alkyl acetates via hydroaluminatio reactions

Hydroalumination of 1-alkenes with lithium aluminum hydride by catalysis of titanium tetrachloride followed by treatment with lead(IV) acetate was found to be a convenient method for the preparation of primary alkyl acetates.     

Mouse bone marrow‐derived mesenchymal stem cell response to nanostructured titanium substrates produced by high‐pressure torsion

Mesenchymal stem cells (MSCs) with the ability to differentiate into various mesoderm‐like cells are known to migrate to various organs to repair injured tissues. They can attach to the implant surface, differentiate into bone‐forming cells, and ultimately osseointegrate with the prosthesis. This study investigates bone marrow‐derived mesenchymal stem cellular response to the grain structure of titanium substrates produced by high‐pressure torsion and annealing processes. Cell attachment, proliferation, viability, and morphology are evaluated on the surface of differently processed nanostructured and coarse‐grained samples. The bacterial adhesion and calcium phosphate crystal formation and growth are also assessed on the surface of the substrates. The nanostructured titanium shows significantly higher cell adhesion, proliferation, spreading, and viability compared with the untreated and coarse‐grained titanium substrates. The adhesion of bacteria is lower and surface bioactivity is higher on the surface of the nanostructured titanium substrate. The results demonstrate the superior MSC compatibility, antibacterial efficacy, and surface bioactivity of the nanostructured titanium substrates, which could lead to early implant fixation and improved osseointegration. Copyright © 2012 John Wiley & Sons, Ltd.     

Comparative examination of titania nanocrystals synthesized by peroxo titanic acid approach from different precursors

Titanium dioxide nanocrystalline particles were synthesized by peroxo titanium acid (PTA) approach from titanium alkoxide and inorganic salt precursors, and their structural and surface properties, porosities, and photocatalytic activities were comparatively examined by XRD, TG/DTA, DRIFT, UV-vis, low temperature N(2) adsorption, and methyl orange (MO) degradation. It was found that nanoparticles with single anatase phase can be obtained from alkoxide precursor even near room temperature if synthesis conditions are appropriately controlled. PTA-derived anatase nanoparticles from titanium alkoxide precursor have smaller crystalline sizes and better porosities, and contain less amount of peroxo group and no organic impurities as compared to those from TiCl(4) precursor. The advantages in structural property, porosity, and surface properties (few deficiencies) lead to a much better photocatalytic activity for TiO(2) nanoparticles from titanium alkoxide precursor in comparison with those from TiCl(4) precursor.     

Hydrothermally etched titanium: a review on a promising mechano-bactericidal surface for implant applications

The growing demand for titanium-based implants and the subsequent rise in implant-associated infections necessitate novel developments in anti-infective technologies. Recent research has drawn inspiration from nature to solve this problem. The nanoscale topography observed on cicada and dragonfly wings serves as a blueprint for synthetic analogs which seek to kill bacteria on contact through mechanical forces. This type of interaction has been dubbed the mechano-bactericidal effect. Various techniques have been utilized to mimic and improve upon these natural bactericidal surfaces. Alkaline hydrothermal etching is a simple and cost-effective technique to fabricate nanoscale protrusions on titanium and its alloys. This review aims to consolidate the current knowledge surrounding how fabrication parameters lead to varying surface topographies on titanium substrates, and subsequently, how surface topography and bacterial characteristics affect bactericidal activity. The bactericidal mechanism of hydrothermally etched titanium is inferred from comparisons with similar mechano-bactericidal biomaterials. The hostility of hydrothermally etched titanium toward bacteria is discussed in contrast to the observed host cell compatibility. Last, suggestions are made for the standardization of terminology in this emerging field.     

On the contamination of membrane–electrode assembles of water electrolyzers with solid polymer electrolyte by the elements of titanium alloys

The aspects of contamination of membrane–electrode assemblies of water electrolyzers with solid polymer electrolyte by the elements of titanium alloys (Ti and Fe) are considered. These alloys are used as the material for current collectors/gas-diffusion electrodes, bipolar plates, and other elements of electrolysis system. It is shown that titanium is one of the main impurities that contaminate the membrane and electrocatalytic layers of membrane–electrode assembly in the case that deionized water is used as the reagent. The membrane contamination can lead to the degradation of electrolyzer characteristics and its failure.     

Determination of tin in titanium alloys

Tin-titanium alloys are becoming increasingly important; consequently a good method is needed for the determination of tin in this type of material. In this paper an accurate iodometric procedure is proposed for the determination. The sample is dissolved in sulfuric acid and the titanium oxidized with potassium permanganate. Tartaric acid is added and the tin precipitated with hydrogen, sulfide. The sulfide precipitate is dissolved in a mixture of sulfuric, perchloric and nitric acids and the solution evaporated to fumes of sulfuric acid. Water and hydrochloric acid are added, and the tin is reduced with lead and antimony trichloride and titrated with iodine. A study was made of the interfering elements that might be found in titanium alloys. The effect of antimony trichloride in reducing interference from copper was investigated. The method is recommended for titanium alloys containing 0.05 to 5.0 per cent. tin.     

电感耦合等离子体原子发射光谱(ICP-OES)法测定硫磺中的铅、铜、铁、镍、钙

提出了电感耦合等离子体原子原子发射光谱测定硫磺中的铅、铜、铁、镍、钙含量的方法,选择各元素的分析谱线,采用正交试验的方法确定仪器的工作参数,方法的检出限0.0046 ug/ml-0.012 ug/ml,方法的回收率在87.60%~111.78%,测定值的相对标准偏差(n=5)小于9.82%,填补无硫磺中铅、铜、镍、钙元素检测方法的空白。     

Determination of traces of antimony, copper, and lead in titanium dioxide by pulse polarography

Summary Traces of antimony, copper, and lead impurities in titanium dioxide have been determined simultaneously by pulse polarography. The three metals were separated from titanium(IV) by sulphide precipitation at pH 3, using cadmium as carrier and complexing titanium with fluoride. The precipitation of lead was supplementary controlled with the radio-isotope ²¹⁰Pb, showing a quantitative recovery. In hydrochlorid-hypophosphite supporting electrolyte, antimony, copper, and lead in titanium dioxide can be determined as low as 0.15, 0.03, and 0.1 ppm respectively. The method was applied in the analysis of various titanium dioxide products commercially available, showing satisfactory sensitivity and resolution for divergent copper-antimony ratios.

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Zusammenfassung Zur gleichzeitigen Bestimmung von Spuren Antimon, Kupfer und Blei in Titandioxid wird ein impulspolarographisches Verfahren beschrieben. Die drei Elemente werden durch Sulfidfällung bei pH 3 von Ti^IV abgetrennt, wobei Cadmium als Träger dient und Titan mit Fluorid maskiert wird. Die Fällung des Bleis wurde mit Hilfe des Radioisotops ²¹⁰Pb geprüft und die eingesetzten Mengen quantitativ wiedergefunden. In einem Leitelektrolyten aus HCl-NaH₂PO₂ können noch 0,15 ppm Sb, 0,03 ppm Cu und 0,1 ppm Blei in Titandioxid bestimmt werden. Das Verfahren wurde für verschiedene handelsübliche Titandioxidsorten verwendet, wobei befriedigende Ergebnisse, auch für sehr unterschiedliche Cu-Sb-Verhältnisse, erhalten wurden.

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Dedicated to Prof. Dr. M. von Stackelberg on his 70th birthday.     

A Raman Scattering Study of PbTiO3 and TiO2 Obtained by Sol-Gel

The mechanisms that give rise to the broadening and the shifts of the Raman peaks of titanium dioxide and lead titanate nanocrystals prepared by sol-gel are discussed. Phonon confinement and oxygen deficiency are competitive mechanisms in TiO2 obtained by different sol-gel preparations whereas pressure effects on the nanocrystals predominate in ferroelectric PbTiO3.     

Detitanation of MgCl2‐supported Ziegler‐Natta catalysts for the study of active sites organization

Thermal treatments under vacuum of conventional supported Ziegler‐Natta precatalysts (MgCl₂/TiCl₄/Dibutylphthalate) were conducted to gradually remove titanium to modify the active sites distribution. Only limited detitanations of precatalysts were achieved paying attention not to chemically alter the internal donor (T < 150 °C). Used in combination with the required cocatalyst and external donor in the propylene slurry polymerization, the modified precatalysts exhibited a drop of activity versus decreasing titanium content but the distributed polymer properties are almost not affected (a slight narrowing of molecular weight distribution was observed). After a titanium chloride secondary impregnation (possibly done in presence of an additional Lewis base), activity resumed but polymer properties are once again unchanged. These findings highlight the difficulty to separate the different families of active sites and lead us to propose a cluster organization of titanium active sites. Active sites are composed of titanium clusters having a size distribution at the precatalyst surface, possessing a critical operating size and operating collectively in polymerization. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5461–5470, 2008     

Effect of catalyst transition metal and ancillary ligand on syndiospecific polymerization of styrene

In the coordination polymerization of styrene, selected transition metal complexes of metals other than group 4 elements and non-metallocenes have been investigated in comparison to a known half-metallocene titanium complex with regard to the catalytic activity as well as to the thermal and molecular properties of the polymers synthesized. Whereas iron catalysts lead to syndiotactic polystyrenes, catalysts with nickel as the transition metal result only in atactic polymers with an enhanced isotactic content.In addition to the influence of the transition metal, the effect of a broad variation of the ancillary ligands of a specific half-sandwich titanocene, octahydrofluorenyl titanium trimethoxide, on polymerization activity and polymer properties has been investigated and discussed in detail.     

Surface pinking in titanium dioxide/lead stabiliser filled PVC profiles

The “pinking” phenomenon which is known to occur in white PVC profiles has been investigated in detail in terms of test evaluations and analysis methods for determining the mechanism and nature of the species responsible. An artificial weathering test method using a Microscal unit with submersion of samples in water was established where colour measurements and FTIR analysis proved the similarity of functional groups present to those in naturally pinked samples. Analysis of the artificially pinked samples using hydroperoxide concentration analysis, fluorescence spectroscopy, microscopic FTIR and scanning electron microscopy showed that artificially pinked samples presented a more extended degree of degradation than samples that remained white during the exposure in the Microscal Unit. Short chain conjugated polyenes were also identified as the most likely functional groups responsible for the development of the pink colour and interactions between the titania pigment and the lead stabilisers would seem to have an influence in the pinking development. In addition, it was found that there was an increase in production of hydroperoxy radicals at the onset of colour development. Addition of trace lead dioxide accelerated the production of pinking. Different titanium dioxide grades used in the PVC profiles showed differences in pinking in the artificial test, also an increase in the titanium dioxide concentration decreased the formation of the pinking colouration in artificial conditions The use of different analysis methods (Microwave Dielectric Spectroscopy and ESR) showed differences in carrier radical production and carrier radical trapping between the pigments used suggesting that a small difference in the coatings could play an important part in the pinking phenomenon. Finally, a mechanism was proposed involving a redox reaction between the titanium dioxide and the lead stabiliser that could facilitate the production of short polyene chains in the PVC matrix producing the pink colouration.     

Design of superhydrophobic surfaces by synthesis of carbon nanotubes over Co-Mo nanocatalysts deposited under microwave irradiation on Ti-containing mesoporous silica thin films

The superhydrophobic surface has been designed by the synthesis of carbon nanotubes (CNTs) on Ti-containing mesoporous silica thin films (Ti-MSTFs) with Co-Mo binary nanocatalysts. The active Co-Mo catalysts have been successfully deposited on Ti-MSTFs under microwave irradiation. SEM and TEM observations after CNT synthesis revealed that surfaces of Ti-MSTFs were densely covered with CNTs having a diameter of 15 nm. Raman spectra indicated that the undesired structural defects in the carbon network of the synthesized CNTs, which would lead to the formation of hydroxyl groups, were scarce. Interestingly, hydrophobic properties of samples after CNT synthesis were enhanced with increasing titanium concentration of Ti-MSTF, and the water contact angle reached up to 165° on Ti-MSTF with a titanium concentration of 10 at%. The combination of dispersed titanium oxide moieties within the silica frameworks and the microwave irradiation made a great contribution to deposit active Co-Mo catalysts responsible for the formation of well-dense CNTs.