Thermodynamic probability of formation solid solutions FexPb1-xS by hydrochemical precipitation

Analysis of the literature showed that narrow-gap lead sulfide PbS (0.4 eV at 300 K), due to its unique properties, has found wide application in such devices as photodetectors with a wide (from infrared to ultraviolet) radiation range, solar energy converters, chemical sensors, temperature sensors, flame detectors, etc. Doping of lead sulfide with various metal ions can affect the bandgap, and hence expand the scope of its application. Of particular interest is the preparation of thin film solid solutions in the PbS – FeS system, which can lead to the appearance of ferromagnetism in lead sulfide. To obtain doped films of lead sulfide and solid solutions based on it, the method of chemical deposition from aqueous media is considered promising, which, in addition to its cost-effectiveness and simplicity of the process, allows one to determine in advance the areas of formation of the semiconducting metal chalcogenides of interest. The analysis of ionic equilibria in the systems "PbAc2 – FeCl2 – Na3Cit – NH4OH – N2H4CS", "PbAc2 – FeCl2 – NaAc – NH4OH – N2H4CS "and " PbAc2 – FeCl2 – Na2С2О4 – NH4OH – N2H4CS "made it possible to reveal predominantly forms of metals in a given pH range. To assess the conditions for the deposition of the main and impurity phases by thermodynamic calculations taking into account the sizes of critical nuclei, the boundary conditions and regions of the formation of FeS, PbS, Fe(OH)2, Pb(OH)2 in the reaction systems under study were found. It is shown that the most promising for the preparation of the three-component PbFeS compound, which does not contain impurity phases of lead and iron hydroxides, is the reaction system "PbAc2 – FeCl2 – Na3Cit – NH4OH – N2H4CS". The possibility of obtaining PbS: Fe films with a uniform iron distribution of ~ 0.5 at.% and deviation from stoichiometry towards Pb deficiency (47.7 at.%) and S excess (50.7 at.%) was experimentally demonstrated.

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A wide pH-range stable crystalline framework based on the largest tin-oxysulfide cluster [Sn20O10S34]

Chemical Communications ◽

10.1039/c9cc05736f ◽

2019 ◽

Vol 55 (74) ◽

pp. 11083-11086 ◽

Cited By ~ 1

Author(s):

Shan-Lin Huang ◽

Liang He ◽

Er-Xia Chen ◽

Heng-Dong Lai ◽

Jian Zhang ◽

...

Keyword(s):

Metal Chalcogenides ◽

Wide Ph Range ◽

Ph Range

A tin-oxysulfide semiconducting framework is reported, composed of filled-T4 [Sn20O10S34], which is the largest supertetrahedral cluster based on tetravalent metal-chalcogenides.

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Large Negative Magnetoresistance Induced by Anionic Solid Solutions in Two-Dimensional Spin-Frustrated Transition Metal Chalcogenides

Physical Review Letters ◽

10.1103/physrevlett.113.157202 ◽

2014 ◽

Vol 113 (15) ◽

Cited By ~ 26

Author(s):

Yuqiao Guo ◽

Jun Dai ◽

Jiyin Zhao ◽

Changzheng Wu ◽

Dianqi Li ◽

...

Keyword(s):

Transition Metal ◽

Solid Solutions ◽

Negative Magnetoresistance ◽

Metal Chalcogenides ◽

Two Dimensional ◽

Transition Metal Chalcogenides

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Complexation, Stability and Behavior of L-Cysteine and L-Lysine with Different Iron Sources

Journal of Food Protection ◽

10.4315/0362-028x-47.1.36 ◽

1984 ◽

Vol 47 (1) ◽

pp. 36-40 ◽

Cited By ~ 10

Author(s):

S. M. FLYNN ◽

F. M. CLYDESDALE ◽

O. T. ZAJICEK

Keyword(s):

Ferric Chloride ◽

Ferrous Sulfate ◽

Mixed Valence ◽

Qualitative Evaluation ◽

Low Ph ◽

Iron Hydroxides ◽

The Stability ◽

Ph Range ◽

Effective Stability ◽

And Behavior

Effective stability constants for cysteine and lysine with five different iron sources were evaluated along with their behavior in solution. The values obtained for ferric chloride-cysteine, ferrous sulfate-cysteine, ferric chloride-lysine, ferrous sulfate-lysine, hydrogen-reduced lysine, and electrolytic-reduced lysine were 6.81 × 102 to 2.78 × 103, 1.33 × 105 to 1.36 × 105, 6.00 × 10−4 to 7.64 × 10−3, 6.37 ×10−4 to 4.82× 10−3, 9.34 × 10−2 to 1.38 × 10−1, and 4.18 × 10−4 to 7.27 × 10−4, respectively. No measurable complexation occurred with hydrogen- and electrolytic-reduced iron with cysteine nor with ferric orthophosphate and cysteine or lysine. The stability of soluble ferric cysteine over the pH range 2.0 to 7.4 indicates that this complex has the potential to be used as an iron additive in food. Approximately half of the hydrogen and electrolytic reduced iron and only 0.11% of ferric orthophosphate were soluble in acid, whereas ferric chloride and ferrous sulfate were completely soluble. Qualitative evaluation of the iron-amino acid systems over a range of pH from 2.0 to 12.0 indicated that there was a mixed valence state of free iron in most cases with low pH favoring reduction and high pH oxidation, until precipitation of iron hydroxides occurred.

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Some thermodynamic aspects of dissolution of solid solutions of hydroxylapatites of phosphorus and arsenic

Canadian Journal of Chemistry ◽

10.1139/v79-431 ◽

1979 ◽

Vol 57 (19) ◽

pp. 2662-2664 ◽

Cited By ~ 5

Author(s):

T. S. B. Narasaraju ◽

U. S. Rai

Keyword(s):

Solid Solutions ◽

Free Energies ◽

Compositional Range ◽

Calcium Phosphorus ◽

Ph Range ◽

Saturated Solutions

The solubility equilibria of synthetic samples of hydroxylapatite, its arsenic isomorph, and a series of their solid solutions, spread over the entire compositional range, were investigated at 37 °C in the pH range 5.0 to 7.6 in buffered systems through microanalytical determinations of calcium, phosphorus, and arsenic in their saturated solutions. From the ionic products of the samples so determined their stoichiometric dissolution was established and their free energies of solution evaluated.

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Photoabsorption effect in the thin films of the CdPbS solid solutions

Butlerov Communications ◽

10.37952/roi-jbc-01/20-62-6-55 ◽

2020 ◽

Vol 62 (6) ◽

pp. 55-64

Author(s):

Vyacheslav F. Markov ◽

◽

Karina V. Grashchenkova ◽

Larisa N. Maskaeva ◽

Yury G. Shashmurin ◽

...

Keyword(s):

Nitrogen Dioxide ◽

Solid Solutions ◽

Deposition Time ◽

Equilibrium Phase ◽

Reaction System ◽

Xrd Analysis ◽

Cadmium Content ◽

Crystallinity Degree ◽

First Time ◽

Crystallite Diameter

In this work, we have attempted to detect the photoadsorption effect using various photoactivation sources of semiconductor layers of CdxPb1–xS solid solutions that are sensitive to the presence of nitrogen dioxide in air. For this purpose, CdxPb1–xS films (up to 600 nm thick) were synthesized from the citrate – ammonia reaction system by the chemical bath deposition (CBD) on glass and sitall substrates. Using XRD analysis, we determined the structure and composition of CdxPb1–xS solid solutions. It was found that all films crystallize in the cubic structure B1 of lead sulfide. Taking into account the content of the substituting component in the samples and comparing it with the equilibrium phase diagrams of the PbS-CdS system, we concluded that the obtained solid solutions are strongly supersaturated in nature. The cadmium content in the PbS lattice increases in films deposited on sitall and glass from 3.9 to 5.9 and from 4.3 to 5.4 at.% with an increase in the deposition time from 60 to 120 minutes, respectively. It must be noted that their crystallinity degree increases with increasing deposition time. The size of the particles forming the layers was determined by SEM microscopy. The predominant crystallite diameter is 250-300 nm. The sensory properties of films of CdxPb1–xS solid solutions with respect to the presence of nitrogen dioxide with a concentration of 100 mg/m3 in air were studied using preliminary photoactivation by various sources with a radiation wavelength from 420 to 1000 nm. For the first time, a positive photoadsorption effect was revealed for CBD produced films of CdxPb1–xS solid solutions. The preliminary photoactivation of the films with a blue lamp (760–1000 nm) for 9-13 minutes allows the film to increase the response to NO2 more than doubled. A high relaxation rate of CdxPb1–xS -based sensor elements after contact with nitrogen dioxide was shown to be 4–10 minutes, which allows to reuse it.

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Separation of tungsten and rhenium on alumina

Journal of the Serbian Chemical Society ◽

10.2298/jsc0409683v ◽

2004 ◽

Vol 69 (8-9) ◽

pp. 683-688 ◽

Cited By ~ 5

Author(s):

Jurij Vucina ◽

Dagoljub Lukic ◽

Milovan Stoiljkovic

Keyword(s):

Nitric Acid ◽

Sodium Chloride ◽

Aqueous Phase ◽

Aqueous Media ◽

Distribution Coefficients ◽

Experimental Conditions ◽

Efficient Separation ◽

Separation Factors ◽

Ph Range

The conditions for the efficient separation of tungsten(VI) and rhenium (VII) on alumina were established. The distribution coefficients K d for tungstate and perrhenate anions, as well as the separation factors ?(? = KdWO42-/Kd ReO4-) were determined using hydrochloric or nitric acid as the aqueous media. Asolution of sodium chloride in the pH range 2?6 was also examined. Under all the tested experimental conditions, alumina is a much better adsorbent for tungsten than for rhenium. The obtained results indicated that the best separation of these two elements is achieved when 0.01? 0.1 mol dm-3HCl or 1.0mol dm-3 HNO3 are used as the aqueous media. If NaCl is used as the aqueous phase, the best separation is achieved with 0.20 mol dm-3 NaCl pH 4?6. Under these experimental conditions, the breakthrough and saturation capacities of alumina for tungsten at pH4 are 17 and 26 mg W/g Al2O3 respectively. With increasing pH, these values decrease. Thus, at pH 6 they are only 4 and 13 mg W/g Al2O3, respectively.

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Tuning the Properties of High Molecular Weight Chitosans to Develop Full Water Solubility Within a Wide pH Range

10.26434/chemrxiv.11854293.v1 ◽

2020 ◽

Author(s):

Anderson Fiamingo ◽

Sergio Paulo Campana Filho ◽

Osvaldo Novais Oliveira Junior

Keyword(s):

Molecular Weight ◽

Biomedical Applications ◽

Random Distribution ◽

Water Solubility ◽

Aqueous Media ◽

Degree Of Polymerization ◽

Molecular Weights ◽

H Nmr ◽

Wide Ph Range ◽

Ph Range

The preparation of chitosans soluble in physiological conditions has been sought for years, but so far solubility in non-acidic aqueous media has only been achieved at the expense of lowering chitosan molecular weight. In this work, we applied the multistep ultrasound-assisted deacetylation process (USAD process) to β-chitin and obtained extensively deacetylated chitosans with high molecular weights (Mw ≥ 1,000,000 g mol-1). The homogeneous N-acetylation of a chitosan sample resulting from three consecutive USAD procedures allowed us to produce chitosans with a high weight average degree of polymerization (DPw ≈ 6,000) and tunable degrees of acetylation (DA from 5 to 80%). N-acetylation was carried out under mild conditions to minimize depolymerization, while preserving a predominantly random distribution of 2-amino-2-deoxy-D-glucopyanose (GlcN) and 2-acetamido-2-deoxy-D-glucopyanose (GlcNAc) units. This close to random distribution, inferred with deconvolution of nuclear magnetic resonance (1H NMR) spectra, is considered as responsible for the solubility within a wide pH range. Two of the highly N-acetylated chitosans (DA ≈ 60 % and ≈ 70 %) exhibited full water solubility even at neutral pH, which can expand the biomedical applications of chitosans.

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Effects of Doping of Lead Sulfide with Silver on the Lattice and Optical Properties of Pb1 –xAgxS Solid Solutions

Semiconductors ◽

10.1134/s1063782619160243 ◽

2019 ◽

Vol 53 (12) ◽

pp. 1665-1671 ◽

Cited By ~ 1

Author(s):

S. I. Sadovnikov

Keyword(s):

Optical Properties ◽

Solid Solutions ◽

Lead Sulfide

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Preparation of Potassium Ferrate and Ferrate(VI) Oxidation of Phenanthrene

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.518-523.784 ◽

2012 ◽

Vol 518-523 ◽

pp. 784-789 ◽

Cited By ~ 1

Author(s):

Xue Mei Tan ◽

Fang Ying Ji ◽

Xiao Dong Wang ◽

Gui Zhi Zhang

Keyword(s):

Reaction System ◽

Target Object ◽

Xenon Lamp ◽

Potassium Ferrate ◽

Calcium Hypochlorite ◽

Degradation Ratio ◽

Polycyclic Aromatic ◽

Ph Range ◽

Degradation Effect ◽

Main Material

Potassium ferrate has good application prospect in water treatment owing to its strong oxidation in the entire pH range and its decomposition Fe3+ with the characteristics of non-toxic and good coagulation effect of flocculation, etc. In this paper, the main material is calcium hypochlorite, which is used to optimize the preparation of potassium ferrate by traditional hypochlorite oxidation methods without applying chlorine in addition. XRD and IR were used to characterize the final product-potassium ferrate; while the concentration of potassium ferrate solution is determined using direct spectrophotometric method for quantitative analysis during the reaction system. The results show that the reaction temperature 25 °C, re-crystallization temperature -5 °C and reaction time 40 minutes will make yield up to 80% and the purity of the product to 97%. As the representitive substance of polycyclic aromatic hydrocarbon (PAHs), Phenanthrene can be used as target object in the analysis of K2FeO4’ oxidation property when pH is 9.5 and illuminated by xenon lamp. The result shows that as reaction concentration is 10mg/L, phenanthrene’s degradation effect becomes very obvious while accumilative degradation ratio reaches up to 65.5% after 60 mins of system reaction.

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