Tellurium Content Research Articles

Determination of Tellurium in Tellurium-Containing Organic Compounds by Microwave Plasma-Atomic Emission Spectrometry

A method for determining tellurium in tellurium-containing organic compounds (TOC) by a microwave plasmaatomic emission spectrometer Agilent 4100 has been suggested. One of the sample decomposition methods - the oxygen flask combustion or the acid decomposition in a heating block-can be applied. Telluradiazole derivatives and some other TOC with 20 to 58% tellurium content have been analyzed. Elements such as nitrogen, sulfur, potassium, selenium present in the TOC do not prevent from determining tellurium. The relative error of the analysis is 1-5%. Telluradiazole derivatives and some other tellurium-containing organic compounds with 20 to 58% tellurium content have been analysed by MP-AES spectrometer Agilent 4100

A computational study on the energy bandgap engineering in performance enhancement of CdTe thin film solar cells

In this study, photovoltaic properties of CdTe thin film in the configuration of n-SnO2/n-CdS/p-CdTe/p-CdTe:Te/metal have been studied by numerical simulation software named “Analysis of Microelectronic and Photonic Structure” (AMPS-1D). A modified structure for CdTe thin film solar cell has been proposed by numerical analysis with the insertion of a back contact buffer layer (CdTe:Te). This layer can serve as a barrier that will decelerate the copper diffusion in CdTe solar cell. Four estimated energy bandgap relations versus the Tellurium (Te) concentrations and the (CdTe:Te) layer thickness have been examined thoroughly during simulation. Correlation between energy bandgap with the CdTe thin film solar cell performance has also been established.

Effect of Tellurium on Copper Electrodeposition in Copper Sulfate-Sulfuric Acid System

The influence of tellurium as an impurity during electrodeposition of copper from sulfate solution was investigated at room temperature. The effect of tellurium concentration on the current efficiency, electrochemical nucleation behavior, chemical structure and morphology at macro and micro level was studied systematically. The introduction of tellurium into the electrolyte has great influence on crystallization and nucleation growth behavior of copper on a glassy carbon substrate, making the nucleation behavior transfer from instantaneous to progressive and reducing the nucleation rate. Additionally, XRD patterns show that the introduction of tellurium can change the preferential orientation of the deposits from (220) plane to (111) plane. Tellurium (0.5–2.0 g L−1) reduced the flexibility of the electrodeposited copper.

Nanocrystal growth and morphology of PbTeSe-ZnSe composite thin films prepared by one-step synthesis method

The microstructure of polycrystalline PbTe1−xSex-ZnSe composite thin films has been studied by scanning transmission electron microscopy and electron diffraction. The films were prepared by the one-step synthesis method using simultaneous evaporation of PbTe and ZnSe. The nanocrystals of PbTe1−xSex are formed in a ZnSe matrix. Tellurium concentration can be tuned by controlling the PbTe evaporation source temperatures between 753 K and 793 K. Binary PbSe nanocrystals were formed at 753 K, while ternary PbTe1−xSex nanocrystals were formed at 793 K. The nanocrystals grow in a granular shape at the initial stage of film growth, and the morphology changes to nanowire-shape as the film grows, irrespective of the Te concentration. The ternary PbTe1−xSex nanocrystals were composed of two phases with different Te concentration; Te-rich (Se-poor) granular crystals were formed near the bottom half parts of the film and Te-poor (Se-rich) nanowires were formed at the upper half parts of the film. Columnar ZnSe crystals contain high-density {111} stacking faults due to the low stacking fault energy of ZnSe. A balance of deposition and re-evaporation on the substrate during the film growth will be responsible for the resultant nanocrystal morphology.

Phase relations and superconductivity in the Fe7(Se1−yTey)8 system: Effect of phase coexistence

The effect of the Te for Se substitution in the Fe7Se8 compound having a layered NiAs-type structure has been studied by means of X-ray diffraction, scanning electron microscopy, thermal expansion, electrical resistivity and magnetization measurements. The growth of Te tellurium content in Fe7(Se1−yTey)8 above y ∼ 0.15 is found to result in the phase segregation; besides the NiAs-type phase the superconducting tetragonal PbO-type phase appears in these samples. It has been observed that the crystal structure and composition of the hexagonal Fe7(Se,Te)8 phase (P63/mmc) transforms with increasing Te content to the CdI2-type phase (P3¯m1) and then to the monoclinic Fe3(Se,Te)4-type phase (I12/m1). The concentration intervals in which these NiAs-type phases coexist with the tetragonal phase have been determined. At y ≥ 0.4, the Fe7(Se1−yTey)8 samples show bulk superconductivity with higher superconducting transition temperatures (Tc up to 17.8 K) compared with single-phase samples of Fe(Se,Te). Such an enhancement is suggested to result from the interactions between the superconducting and non-superconducting phases coexisting in Fe7(Se1−yTey)8.

Essential and toxic elements in meat of wild birds

ABSTRACTEssential and toxic elements were determined by inductively coupled plasma–atomic emission spectrometry (ICP-AES), mass spectrometry (MS), and atomic absorption (AS) in meat of 14 migratory birds originating from central and northern Europe to provide baseline data regarding game meat consumed in central Italy. In all samples analyzed, cobalt (Co) and chromium (Cr) (total) levels were <0.326 mg/kgww. For nonessential or toxic elements, arsenic (As), barium (Ba), cadmium (Cd), stannous (Sn), thallium (Tl), tellurium (Te), titanium (Ti), cerium (Ce), lantanium (La), and uranium (U) concentrations were <0.326 mg/kgww, thorium (Th) <1.63 mg/kgww, and mercury (Hg) <0.0163 mg/kgww. When detectable, lead (Pb) concentrations always exceeded maximal admissible levels for metal (0.1 mg/kg ww) established by the European Commission for meat. These findings indicate that elevated Pb concentrations in game ingested by humans may be a cause for concern.

Low‐temperature concentration of tellurium and gold in continental red bed successions

AbstractThere is very little understanding of tellurium (Te) distribution and behaviour in sedimentary rocks. A suite of 15 samples of reduction spheroids (centimetre‐scale pale spheroids in otherwise red rock), including samples from eight localities in Triassic red beds across the British Isles, were mapped for Te using Laser Ablation–Inductively Coupled Plasma–Mass Spectrometry. Almost all showed enrichment in Te in the cores of the spheroids relative to background red bed concentrations, by up to four orders of magnitude. Some were also enriched over background in gold and/or mercury. In one case, discrete telluride minerals were recorded. The data show that Te is mobile and can be concentrated in low‐temperature sedimentary environments, controlled by redox variations. The consistency in enrichment across widely separate localities implies that the enrichment is a normal aspect of red bed diagenesis and so likely to be controlled by a ubiquitous process, such as microbial activity.

Local features of the crystal structure of superconducting iron chalcogenides Fe(TeSe)1 – δ

The local crystal structure of superconducting powders of iron chalcogenides FeTe x Se1–x (x = 0.1, 0.22, 0.49, 0.8, 0.9) prepared by dry synthesis (without mineralizer) has been studied by EXAFS spectroscopy above the K Se and K Fe absorption edges in the temperature range of 80–300 K. The dependences of Se–Fe, Fe–Te, and Fe–Fe interatomic bond lengths and degrees of their local disordering (Debye–Waller factors) on the tellurium content and temperature have been obtained. Einstein temperatures characterizing the stiffness of each bond have been determined. The correlation of the Se–Fe bond stiffness with the dependence of the critical temperature of the superconducting transition T c on the composition of the samples under study have been established, which indicates the specific role of the Se–Fe bond in the superconducting state formation in iron chalcogenides FeTe x Se1–x .

Discussion on the electrical and thermoelectrical properties of amorphous In–Sb–Te Films

Different compositions of (In0.5Sb0.5)1−xTex (0.50 ≤ x ≤ 0.65) thin films were prepared by thermal evaporated technique, onto pre-cleaned glass substrates at ~298 K. Both dark electrical resistivity (ρ) and thermoelectric power (S) were measured in the temperature range 300–420 K. The concentration of the free carriers is obtained from DC conductivity and thermoelectric power measurements. Seebeck coefficient was found to be positive over entire temperature range, indicating that (In0.5Sb0.5)1−xTex films are p-type semiconducting materials. Also, the variation of the mobility with temperature has been estimated. Increasing tellurium concentration is found to affect the DC conductivity and thermoelectric power of the studied films. The activation energies obtained from the DC conductivity and thermoelectric power increase with increasing tellurium content. The obtained results were interpreted according to the chemical bond approach.

碲对硫酸铜体系中铜电解的影响

本文系统研究了碲对硫酸铜体系中电解铜电流效率、结构组成和微观形貌的影响，同时提出一种去除碲的有效方法。研究结果表明，电解液中含有碲离子对铜的结晶取向和形核生长有明显影响。XRD测试结果表明，碲离子的存在使铜的最优生长取向从(220)晶面转变为(111)晶面。光学照片表明碲的存在可显著降低电沉积铜的韧性。扫描电镜照片表明沉积层的晶粒随碲浓度增加而逐渐减小。除碲实验表明，利用铜屑在95℃条件下反应一个小时，可将碲浓度由1 g/L降至20 mg/L，净化后的电解液电解可获得光亮阴极铜。 The influence of tellurium as an impurity during electrodeposition of copper from sulfate solution was investigated. The effect of tellurium concentration on the current efficiency, chemical structure and morphology at macro and micro level was systematically studied. XRD patterns show that the introduction of tellurium can change the preferential orientation of the deposits from (220) plane to (111) plane. And optical images exhibit that tellurium will reduce the tenacity of the elec-trodeposited copper. The eliminating experiment shows that the concentration of tellurium will reduce from 1 g/L to 20 mg/L after reacting 1 h under 95˚C, and bright copper can be obtained from the electrolyte.

Determination of Specific Activity and Tellurium (IV) Concentration in Non- Carrier Added Iodine-124 Solutions, Via UV-Vis Spectroscopy

In this work, two fast and highly sensitive analytical methods, based on UV-VIS spectroscopy, were adapted for its use on the determination of specific activity (SA) and Tellurium (IV) concentration, in 124I- solutions produced by the 124Te(p,n)124I reaction. The solutions analyzed showed high specific activity (209 - 216 Ci/mg) and Te(IV) contents below the regulatory acceptable limit (1 ppm).

Mineralogical and isotopic studies of base metal sulfides from the Jiawula Ag–Pb–Zn deposit, Inner Mongolia, NE China

The Jiawula Ag–Pb–Zn deposit is located in the northern part of the Da Hinggan Mountains metallogenic belt in the eastern section of the Central Asian Orogenic Belt. Sphalerite, galena, pyrite, chalcopyrite, and arsenopyrite are the major sulfide minerals occurring in this deposit. Here we report results from electron probe micro-analysis (EPMA), thermoelectricity, and sulfur isotope studies of the constituent silver minerals and sulfide phases of the Jiawula deposit. Petrographic observations and EPMA study reveal abundant silver mineralization in the ore, especially within sphalerite and galena. Discrete grains of silver minerals (including argentite, pyrargyrite, and canfieldite) and isomorphism in silver-bearing sulfides are identified. Silver and tellurium contents in galena are relatively high and show interrelationship. Significant substitution of S by Te in the galena lattice facilitates silver entering the galena structure, which might have been promoted by relatively low lgfS2. The thermoelectric coefficient of pyrite shows a marked gradient from N-type to P-type from pre- to post-metallogenic stages. Pyrites in Jiawula are enriched in Co and As and in the absence of Ni, displaying features typical of epithermal deposits. The isotopic data present a close relationship between the sulfur source and magmatism.

Effect of tellurium concentration on the structural and vibrational properties of phase-change Ge-Sb-Te liquids

The structural properties of several compositions of Ge-Sb-Te liquids are studied from a combination of neutron diffraction and density functional-based molecular dynamics. We investigate structural properties including structure factors, pair distribution functions, angular distributions, coordination numbers, neighbor distributions, and compare our results with experimental findings. Most noticeable is the excellent agreement found in the reproduction of the structure in real and reciprocal spaces, resulting from the incorporation of dispersion forces in the simulation. The vibrational density of states is also measured from inelastic neutron scattering for different compositions and compared to the simulated counterpart, which exhibits an excellent agreement at low frequency.

Particle size dependent isothermal crystallization kinetics in a Se–Te glassy system

Differential scanning calorimetry (DSC) was used to study the crystallization behaviour in a selenium–tellurium (Se–Te) glassy system under isothermal conditions. The particle-size-dependent isothermal crystallization kinetics were described in terms of the Johnson–Mehl–Avrami (JMA) nucleation-growth model. The complexity of the crystallization process was found to be represented by overlapping competing surface and bulk nucleation-growth mechanisms. Based on the deconvolution in terms of the JMA model, the particular crystal growth processes were identified, and the interpretation of their physical origins was performed. Presence of the A and B types of spherulitic crystallites was confirmed; the temperature range of the transition in-between these two spherulitic forms was determined to be similar as for pure selenium. Increasing tellurium content was found to cause an increase of the apparent activation energy of the overall crystallization process as well as a gradual increase of the dominance of the CNT (classical nucleation theory)-based volume-located crystal growth over the surface crystallization, which originates from mechanically induced heterogeneities.

Performance of phase-pure M1 MoVNbTeOx catalysts by hydrothermal synthesis with different post-treatments for the oxidative dehydrogenation of ethane

Phase-pure M1 catalysts with different post-treatments have been prepared from the same precursor slurry by hydrothermal synthesis and used to study the key factors influencing their performance in the oxidative dehydrogenation of ethane (ODHE) process. Different purification processes (i.e. steam treatment and hydrogen peroxide treatment) result in different tellurium (Te) contents and V5+ concentration in the catalysts. Catalytic tests reveal that there is a direct correlation between the amount of V5+ present in the catalysts and the catalytic activity. A hydrogen peroxide treatment increases the V5+concentration and decreases the Te content which can improve the catalytic activity and stability in comparison with the steam treatment. A post-treatment with oxalic acid improves the catalyst surface area (54m2/g) but causes some vanadium leaching. The phase-pure M1 catalyst calcined at 650̊C and purified by H2O2 shows the best catalyst productivity of 0.77 kgC2H4/kgcat/h at 73% ethane conversion and 85% ethylene selectivity in ODHE process. The formation of reduced Te(0) aggregates blocking the active sites is identified as a main reason for catalyst deactivation. A low Te content favors a stable catalyst with less risk of Te aggregation. However, at harsh operating conditions (i.e. high oxygen concentration and high reactor temperature) the performance of phase-pure M1 catalysts with a low Te content can also reduce obviously due to the formation of a new (V, Nb)-substituted θ-Mo5O14 and MoO2 phases.

Mechanical properties of low-cost, earth-abundant chalcogenide thermoelectric materials, PbSe and PbS, with additions of 0–4 % CdS or ZnS

PbTe-based thermoelectric (TE) materials have been extensively investigated as TE generator materials, however, the tellurium content limits the application potential due to both availability and cost. Replacing the tellurium with selenium or sulfur produces an isomorphic TE material with very good reported figure of merit, ZT, values of 1.3–1.6, but the effect of the material changes designed to increase ZT (doping, nano- and micro-precipitate additions) on mechanical properties has not been reported. In order to effectively incorporate these new materials into TE devices, it is important to understand materials’ response to thermally and mechanically imposed loads, which in turn requires knowledge of the mechanical properties. In this study, the hardness was determined by Vickers indentation and elastic modulus and Poisson’s ratio were measured using resonant ultrasound spectroscopy on PbSe- and PbS-based TE specimens as a function the addition of 0–4 at.% of CdS or ZnS. With 2.0 or 2.5 at.% Na doping, the hardness of PbSe- or PbS-based TE materials increased by about 30 % and the elastic moduli decreased by 5–10 %. In addition, PbS may be effectively sintered at 723 K when doped with 2.5 at.% Na, but requires a higher sintering temperature when undoped. This study shows that the hardness and moduli of PbSe- or PbS-based TE materials are not strong functions of the addition of CdS or ZnS precipitates.

Determination of lateral size distribution of type-II ZnTe/ZnSe stacked submonolayer quantum dots via spectral analysis of optical signature of the Aharanov-Bohm excitons

For submonolayer quantum dot (QD) based photonic devices, size and density of QDs are critical parameters, the probing of which requires indirect methods. We report the determination of lateral size distribution of type-II ZnTe/ZnSe stacked submonolayer QDs, based on spectral analysis of the optical signature of Aharanov-Bohm (AB) excitons, complemented by photoluminescence studies, secondary-ion mass spectroscopy, and numerical calculations. Numerical calculations are employed to determine the AB transition magnetic field as a function of the type-II QD radius. The study of four samples grown with different tellurium fluxes shows that the lateral size of QDs increases by just 50%, even though tellurium concentration increases 25-fold. Detailed spectral analysis of the emission of the AB exciton shows that the QD radii take on only certain values due to vertical correlation and the stacked nature of the QDs.

Bacterial recovery and recycling of tellurium from tellurium-containing compounds by Pseudoalteromonas sp. EPR3.

Tellurium-based devices, such as photovoltaic (PV) modules and thermoelectric generators, are expected to play an increasing role in renewable energy technologies. Tellurium, however, is one of the scarcest elements in the earth's crust, and current production and recycling methods are inefficient and use toxic chemicals. This study demonstrates an alternative, bacterially mediated tellurium recovery process. We show that the hydrothermal vent microbe Pseudoalteromonas sp. strain EPR3 can convert tellurium from a wide variety of compounds, industrial sources and devices into metallic tellurium and a gaseous tellurium species. These compounds include metallic tellurium (Te(0)), tellurite (TeO3(2-)), copper autoclave slime, tellurium dioxide (TeO2), tellurium-based PV material (cadmium telluride, CdTe) and tellurium-based thermoelectric material (bismuth telluride, Bi2Te3). Experimentally, this was achieved by incubating these tellurium sources with the EPR3 in both solid and liquid media. Despite the fact that many of these tellurium compounds are considered insoluble in aqueous solution, they can nonetheless be transformed by EPR3, suggesting the existence of a steady state soluble tellurium concentration during tellurium transformation. These experiments provide insights into the processes of tellurium precipitation and volatilization by bacteria, and their implications on tellurium production and recycling.

Selenium and tellurium systematics in MORBs from the southern Mid-Atlantic Ridge (47–50°S)

Selenium and tellurium concentrations along with sulfur and Highly Siderophile Element (HSE) contents as well as 187Os signatures were determined in 20 Mid-Ocean-Ridge Basalts (MORBs) from the southern Mid-Atlantic Ridge (SMAR; 47–50°S), ranging in composition from depleted N-MORBs to mantle plume-related E-MORBs. A comparison between glassy rims and crystalline pillow interiors reveal that secondary processes are only reflected in seawater-overprinted 187Os/188Os signatures and degassing-related low S contents of the crystalline pillow cores but did not affect the Se and Te abundances. In contrast, the segregation of sulfide liquids during MORB differentiation lowers the Se and Te concentrations (∼35% and 60%, respectively) and leads to higher Se/Te ratios. Recomputed primitive melt Se contents broadly overlap for both, N- and E-MORBs, while primitive E-MORB melts have systematically higher Te contents and lower Se/Te ratios compared to those of the N-MORBs (13–14ppb Te and Se/Te≈18 vs. 9–11ppb Te and Se/Te≈25). As suggested by lithophile trace element and Sr–Nd–Pb isotopic constraints, the Se–Te systematics of the E-MORB mantle source traces the involvement of a recycled component likely derived from the nearby Discovery mantle plume. Bulk mixing models suggests an addition of either 20% pyroxenitic melts, or only 10ppm of metasomatic sulfides to account for the Te-richer E-MORB compositions. A conservative correction of our MORB data for sulfide segregation combined with a near fractional melting model predicts a Te-depleted MORB mantle reservoir with a non-chondritic Se/Te of 18–25, significantly higher than the primitive mantle Se/Te estimates (6.3–9.9). The existence of these different Se–Te signatures between the E-MORB mantle source, the N-MORB mantle source and the primitive mantle support an incompatible behavior of both Se and Te during partial melting, with Te being slightly more incompatible. More importantly, this stresses the necessity of considering the full spectrum of the terrestrial silicate reservoirs to realistically constrain the budget of these volatile and highly siderophile elements in the bulk silicate Earth in order to discuss large scale planetary processes.

Soil-to-crop transfer factors of tellurium

Stable tellurium (Te) concentrations in 148 sets of agricultural soil and associated crop samples were measured in this study to obtain soil-to-crop transfer factor (TF) of Te. We used a recently developed simple method that applies digestion of samples with aqua regia and sector field inductively coupled plasma mass spectrometry to measure low Te levels in these samples. Geometric mean (GM) concentrations of Te in soil and crops were 75μgkg−1-dry (range: 15–850μgkg−1-dry) and 1.8μgkg−1-dry (range: 0.1–120μgkg−1-dry), respectively; the Te concentration range was significantly wider in crops than in soil. Using these data, we calculated TFs and obtained their range from 1.3×10−3 to 1.1×10−1. The GM of TF for upland field crops was calculated to be 2.0×10−2 and for brown rice was 3.1×10−2; all crop types had the similar GMs of their TF values. Data comparison for TF of Te was carried out with six elements, which are present in anionic forms in soil environment like Te is, i.e. P, Br, As, Se, Mo, and I. TFs of Te and I showed the highest correlation factor for upland field crops by t-test (r=0.577, p<0.001), but no correlation was found for brown rice. We considered it likely that different water management practices in upland fields and paddy fields affected the Te transfer from soil to crops.