Measurements of Enthalpy Change of Reaction of Formation, Molar Heat Capacity and Constant-Volume Combustion Energy of Solid Complex Yb（Et2dtc）3（phen）

A ternary solid complex Yb(Et2dtc)3(phen) was obtained from the reaction of hydrous ytterbium chloride with sodium diethyldithiocarbamate (NaEt2dtc), and 1, 10-phenanthroline (o-phen·H2O) in absolute ethanol.The bonding characteristics of the complex were characterized by IR.The result shows Yb3 bands with two sulfur atoms in the Na(Et2dtc)3 and two nitrogen atoms in the o-phen.The enthalpy change of liquid-phase reaction of formation of the complex ΔrHθm (l), was determined as being (-24.838±0.114) kJ·mol-1 at 298.15 K, by an RD-496 Ⅲ type heat conduction microcalormeter.The enthalpy change of the solid-phase reaction of formation of the complex ΔrHθm (s), was calculated as being (108.015±0.479) kJ·mol-1 on the basis of an appropriate thermochemistry cycle.The thermodynamics of liquid-phase reaction of formation of the complex was investigated by changing the temperature during the liquid-phase reaction.Fundamental parameters, the activation enthalpy, ΔHθ≠, the activation entropy, ΔSθ≠, the activation free energy, ΔGθ≠, the apparent reaction rate constant k, the apparent activation energy E, the pre-exponential constant A, and the reaction order n, were obtained by a combination of the reaction thermodynamic and kinetic equations with the data from the thermokinetic experiments.At the same time, the molar heat capacity of the complex cm, p, was determined to be (86.34±1.74) J·mol-1·K-1 by the same microcalormeter.The constant-volume combustion energy of the complex, ΔcU, was determined to be (-17954.08±8.11) kJ·mol-1 by an RBC-Ⅱ type rotating-bomb calorimeter at 298.15 K.Its standard enthalpy of combustion, ΔcHθm, and standard enthalpy of formation, ΔfHθm, were calculated to be (-17973.29±8.11) kJ·mol-1 and (-770.36±9.02) kJ·mol-1, respectively.     

Thermochemical Study on Ternary Solid Complex of La(Gly)2 (Ala)3 Cl3 ·2H2O (s)

The complex of lanthanum chloride with Glycine and Alanine, La(Gly)₂(Ala)₃Cl₃ · 2H₂O, was synthesized and characterized by IR, elementary analysis, thermogravimetric analysis, and chemical analysis. The dissolution enthalpies of LaCl₃ · 7H₂O(s), 2Gly(s) + 3Ala(s) and La(Gly)₂(Ala)₃Cl₃ · 2H₂O(s) were determined in 2 mol · L⁻¹ HCl by a solution-reaction isoperibol calorimeter. By designing a thermochemical cycle in terms of Hess' Law and through calculation, the reaction enthalpy of lanthanum chloride seven-hydrate with Glycine and Alanine was obtained: Δ_rH^θ_m(298.15 K) = (29.652 ± 0.504) kJ · mol⁻¹, and the standard enthalpy of formation of La(Gly)₂(Ala)₃Cl₃ · 2H₂O(s) Δ_fH^θ_m[La(Gly)₂ (Ala)₃Cl₃ · 2H₂O, s, 298.15 K] = −4467.6 ± 8.3 kJ · mol⁻¹.     

Study on Sulfation of CeO2/γ-Al2O3 Sorbent in Simulated Flue Gas

It is well known that sulfur dioxide(SO2) , morethan50%of which arise fromcombustion of fossil fu-els ,are precursors of acidrain andtheir emission pos-es a global threat tothe atmosphere .Environmental a-gencies have ,therefore ,regulated emissions of SO…     

Thermochemical Properties of the Complexes RE(HSal)3·2H2O(RE = La, Ce, Pr, Nd, Sm)

Five solid rare earth salicylate complexes were synthesized by low hydrated lathanide chloride and salicylic acid. The complexes in this experiment were identified as the general formula RE(HSal)₃·2H₂O(RE = La, Ce, Pr, Nd, Sm) by elemental analysis and EDTA volumetric analysis. IR spectra of the complexes show that carboxyl of salicylic acid coordinates to RE³⁺ ions. Electrochemical behaviors of the complexes on the glass-carbon electrode were researched with cyclic voltammetry (CV). It is indicated that the electrochemical process of the complexes is a one-electron redox process and the electrochemical reversibility of complexes is less than that of the lanthanide chlorides. The constant-volume combustion energies of complexes, Δ_cU, were determined with a precise rotating-bomb calorimeter at 298.15 K. Their standard molar enthalpies of combustion, Δ_cH_m^θ, and standard molar enthalpies of formation, Δ_fH_m^θ, were calculated.     

Stability of 3CaO · Al2O3 · 6H2O in KOH + K2CO3 + H2O system for chromate production

In the novel clean chromate production process, the alkali liquor recycled to decompose the chromite ore mainly consists of KOH and K₂CO₃ which accumulates aluminium impurity and affects the quality of the product greatly. Aluminium impurity can be removed by adding CaO to precipitate as 3CaO · Al₂O₃ · 6H₂O (C₃AH₆). A study of the effects of various parameters, such as KOH concentration, K₂CO₃ concentration and temperature on the behaviour of C₃AH₆ show that C₃AH₆ is decomposed to 3CaO · Al₂O₃ · CaCO₃ · 11H₂O and CaCO₃ below 150 g L^− 1 KOH, and decomposed to Ca(OH)₂ above 150 g L^− 1 KOH. With K₂CO₃ concentration increasing, C₃AH₆ decomposes significantly, which results in more CaCO₃ or 3CaO · Al₂O₃ · CaCO₃ · 11H₂O produced. Temperature has a large positive effect on the decomposition of C₃AH₆ at 45 g L^− 1 KOH but has no significant effect at 150 g L^− 1 KOH. The optimal condition for removing aluminium impurity in the KOH + K₂CO₃ + H₂O system is 150 g L^− 1 KOH, 50 g L^− 1 K₂CO₃ and 80 °C.     

Adsorption of rhenium(VII) on 4-amino-1,2,4-triazole resin

The adsorption properties of 4-amino-1,2,4-triazole resin (4-ATR) for Re(VII) were investigated by static and dynamic adsorption–desorption measurements with ultraviolet–visible spectroscopy. The influence of conditions such as temperature, initial solution pH and contact time on the adsorption curve was studied. It was found that the 4-amino-1,2,4-triazole resin was suitable for adsorption of Re(VII). The saturated adsorption capacity was 354 mg·g^− 1resin at pH 2.6 in HAc–NaAc medium at 298 K. The adsorption rate constant was k₂₉₈ = 8.2 × 10^− 5 s^− 1. The adsorption behavior of 4-ATR for Re(VII) obeyed the Freundlich empirical equation; whilst changes in adsorption with temperature gave an enthalpy change ΔH  = − 11.8 kJ·mol^− 1. The molar ratio of the functional group of 4-ATR to Re(VII) was about 2:1. Re(VII) adsorbed on 4-ATR was eluted by 1.0 ~ 5.0 mol·L^− 1 HCl with 100% quantitative elution in 4.0 mol·L^− 1 HCl solution. The resin can be regenerated and reused without apparent decrease in adsorption capacity.     

Nitric Oxide Alleviates Oxidative Stress Caused by Lanthanum in Rice Leaves

The effect of NO on lanthanum-induced antioxidant activities in rice was evaluated. The results showed that the uptake and translocation of La from root to shoot were obviously inhibited by 10μmol·L^-1 sodium nitropmsside （SNP）, a donor of NO, in the seedlings grown in Mura B nutrient solution with 100μmol·L^-1 La. Although the content of ascorbate acid （AsA） were scarcely affected by La or NO in our experiment, La decreased significantly the activity of SOD and content of GSH, while promoted H202 content in leaves. Furthermore, NO blocked these La effects. Taken together, the results suggested that NO relieved La toxicity in rice. A possible role for NO effects on antioxidant activity was discussed.     

Possible Involvement of NADPH Oxidase in Lanthanide Cation-Induced Superoxide Anion Generation in BY-2 Tobacco Cell Suspension Culture

A rapid and concentration-dependent generation of superoxide anion (·O-2), measured with a superoxide-specific Cypridina luciferin-derived chemiluminescent reagent, was observed when two lanthanide salts (LaCl3 and GdCl3) were added to tobacco (Nicotiana tabacum) cell suspension culture.Addition of superoxide dismutase (480 U·ml-1) and Tiron (5 μmol·L-1) to cell culture suspension decreases the level of lanthanide cation-induced ·O-2 generation, suggesting that ·O-2 generation is extra-cellular.Pretreatment of the cell culture suspension with diphenyleneiodonium (10 and 50 μmol·L-1), quinacrine (1 and 5 mmol·L-1) and imidazol (10 mmol·L-1), inhibitors of NADPH oxidase, notably inhibits the generation of superoxide induced by lanthanide cation, implying the possible involvement of activation of NADPH oxidase.In addition, addition of SHAM (1 and 5 mmol·L-1), azide (0.2 and 1 mmol·L-1), inhibitor of peroxidase, has no influence on ·O-2 generation.     

Effect of Gallium Addition on Magnetic Properties of Nd2Fe14B-Based/ α-Fe Nanocomposite Magnets

The influence of Ga addition on the crystallization behavior and the magnetic properties of nanocomposite Nd2Fe14B-based/α-Fe magnets was investigated. It was found that the addition of 0.2% did not change the crystallization temperature of amorphous alloy, but the magnetic properties were improved significantly because of the strong exchange coupling interaction between the hard and soft magnetic phases. The optimum magnetic properties with iHc = 600. 3 kA· m^-1, B r = 0.75 T, and （BH）max = 88.03 kJ· m^-3 were obtained in bonded Nd9.5（FeCoZr）83.8 Ga0.3 B6.5 magnet with 15 m·s^- 1 wheel speed and 670 ℃ annealing treatment. The apparent improvement of magnetic properties originates from the grain refinement calculated using the Scherrer formula from corresponding XRD patterns and the excellent rectangularity of the demagnetization curve.     

Synthesis, characterization and fluorescence of N,N'-BIS (6-metyl-2-pyridine-carboxylamide-N-oxide)-1,2-ethane and corresponding rare earth (Ⅲ) complexes

A new ligand, N,N-BIS (6-metyl-2-pyridinecarboxylamide-N-oxide)-1,2-ethane (L) and six lanthanide(III) complexes (RE=La, Sm, Eu, Tb, Gd, Yb) were synthesized and characterized in detail. The results indicated that the composition of the binary complexes was determined as [REL(H₂O)(NO₃)₂]NO₃·nH₂O (n=0–2), and the Eu³⁺ complex had bright red fluorescence in solid state. Three complexes of Eu³⁺, Tb³⁺, and Gd³⁺ with 6-methylpicolinic acid N-oxide (L') were also synthesized. The relative intensity of sensitized luminescence for Eu³⁺ increased in the following order: L>L'. The phosphorescence spectra of the Gd³⁺ complexes at 77 K were measured. The energies of excited triplet state for the ligands were 20704 cm⁻¹ (L) and 20408 cm⁻¹ (L'). The facts that the ligands sensitized Eu³⁺ strongly and the order of the emission intensity for Eu³⁺ complexes were explained by ΔE(T-⁵D). This meant that the triplet energy level of the ligand was the main factor to influence RE³⁺ luminescence.     

Characterization and alkaline decomposition–cyanidation kinetics of industrial ammonium jarosite in NaOH media

A complete characterization was carried out on a jarositic residue from the zinc industry. This residue consists of ammonium jarosite, with some contents of H₃O⁺, Ag⁺, Pb²⁺, Na⁺ and K⁺ in the alkaline “sites” and, Cu²⁺ and Zn²⁺ as a partial substitution of iron. The formula is: [Ag_0.001Na_0.07K_0.02Pb_0.007(NH₄)_0.59(H₃O)_0.31]Fe₃(SO₄)₂(OH)₆. Some contents of franklinite (ZnO^·Fe₂O₃), gunninguite (ZnSO₄·H₂O) and quartz were also detected. The jarosite is interconnected rhombohedral crystals of 1–2 μm, with a size distribution of particles of 2–100 μm, which could be described by the Rosin–Rammler model.The alkaline decomposition curves exhibit an induction period followed by a progressive conversion period; the experimental data are consistent with the spherical particle with shrinking core model for chemical control. The alkaline decomposition of the ammonium jarosite can be shown by the following stoichiometric formula:NH₄Fe₃(SO₄)₂(OH)_6(s)+3OH_(aq)⁻→(NH)_4(aq)⁺+3Fe(OH)_3(s)+2SO_4(aq)²⁻.The decomposition (NaOH) presents an order of reaction of 1.1 with respect to the [OH⁻] and an activation energy of 77 kJ mol⁻¹. In NaOH/CN⁻ media, the process is of 0.8 order with respect to the OH⁻ and 0.15 with respect to the CN⁻. The activation energy was 46 kJ mol⁻¹. Products obtained are amorphous. Franklinite was not affected during the decomposition process. The presence of this phase is indicative that the franklinite acted like a nucleus during the ammonium jarosite precipitation.     

Synthesis, Characterization, and Reactivity of Amine Bis（phenolato） Cyclopentadienyl Lanthanide Complexes

（C5H5）3Ln（THF）reacted with amine bis（phenol） LH2 [ L = Me2NCH2CH2N {CH2-（2-O-C6H2-But^1-3-Me- 5）}2 ] in a 1：1 molar ratio in THF to generate the amine bis（phenolato） cyclopentadienyl lanthanide complexes LLn（C5H5） （THF）·（THF）,（Ln = La （1）, n =0; Ln = Sm（2）, n = 1） in high yields. Complexes 1 and 2 were fully characterized by elemental analysis, NMR （for 1） and IR spectra, and X-ray structural determination. The crystal data of complex 1 are monoclinic, P21/c space goup, a= 1.1595（1） nm, b = 1.8588（2） nm, c = 1.6647（1） nm, β = 98.490（2）°, V =3.5486（5） nm^3, Z =4, Dc = 1.338 mg· m^3,μ = 1240 mm^-1, F（000）= 1488, R =0.0249, wR = 0.0568. The crystal data of complex 2 are monoclinic, P21/c sp ace goup, a = 0.9692 （1） nm, b = 1.4583 （2） nm, c = 2.8192 （3） nm, = 96.805 （2）°, V = 3.9584 （7） nm^3, Z=4, Dc =1.340 mg · ma, μ = 1.524 mm^-1, F（000）= 1668, R =0.0346, wR =0.0756. The attempts failed to synthesize the amine bis（phenolate） lanthanide alkoxides by the reactions of complexes 1 and 2 with alcohols. The preliminary results revealed that complex 1 can initiate ε-caprolactone polymerization.     

Investigation on pumping oxygen characteristics of （Bi2O3）0.73（Y2O3）0.27 solid electrolyte

（Bi2O3）0.73（Y2O3）0.27 fine powders prepared by wet chemical precipitation method were cold isostatically pressed to form solid electrolyte tubes, and sintered at 900 ℃ for 10 h in the air. Their pumping oxygen characteristics in non-dehydrated Ar gas were investigated, where a ZrO2 （Y2O3 stabilized） oxygen sensor was used to measure the oxygen partial pressure Po2. The results showed that the Po2 value reached magnitudes of 1×10^-2-1×10^-10 Pa at the applied pumping oxygen voltage of 0.5 V, 1×10^-37-1×10^-27 Pa at 1.0 V and 1×10^-53-1×10^47 Pa at 2.0 V within the temperature range from 550 to 650 ℃. Moreover, no cracks were found in the tested solid electrolyte tubes. Thus, the Bi2O3-Y2O3 system might be used in solid electrolyte oxygen pump for purifying gases.     

Synthesis of ZrO2-HfO2-Y2O3-Sc2O3 Nano-Particles by Sol-Gel Technique in Aqueous Solution of Alcohol

Zirconium dioxide is a significant material withgood physicochemical characteristics . It is used inmanyfields such as energysources ,material and envi-ronment . Cubic phase zirconium dioxide doped withyttria (YSZ) is alreadyin wide use in solid oxygenfu-…     

Desilication of sodium aluminate solution by Friedel's salt (FS: 3CaO·A12O3·CaCl2·10H2O)

Controlling silica level in Bayer liquor is critical in order to prevent scaling or alumina quality issues. The conventional method of removing silicates from aluminate solutions requires the introduction of calcium oxide or calcium hydroxide. In this work, Friedel's salt (FS: 3CaO·A1₂O₃·CaCl₂·10H₂O) is proved for the first time to remove up to 95% silica from sodium aluminate solution. FS is a mineral anion exchanger belonging to the layered double hydroxides (LDHs) which was prepared by adding calcium chloride to sodium aluminate over the temperature range of 50–90 °C. It was characterized by XRD, SEM, Particle Size Analyzer and TG-DSC. FS prepared at 50 °C has a relatively high desilication capacity, better than calcium oxide.Experimental parameters affecting the desilication process, such as temperature, sodium aluminate liquor composition, initial silica concentration (4–10 g/L) and FS dosage were investigated in detail and a comparison of desilication between FS and CaO was carried out. The desilication products (DSP) were mainly calcium aluminium silicates, identified by XRD to be Chabazite and Wadalite and the final chloride concentration in the sodium aluminate solution after anion exchange with FS was  0.015 g/L. The rate of desilication by FS was first order with a rate constant 2.582 × 10⁶ min^− 1. The apparent activation energy was estimated to be 57.7 kJ mol^− 1 over the temperature range of 80–110 °C.     

Synthesis, crystal structure and fluorescence of a new europium complex with 2-bromobenzoate and 2,2′-bipyridine

A new complex of {[Eu2(2-BrBA)6(2,2'-bpy)2]2.CH3CH2OH·H2O} (2-BrBA=2-bromobenzoate; 2,2'-bpy=2,2'-bipyridine) was prepared by solvent method and characterized with X-ray single-crystal diffraction, IR spectroscopy, UV spectrscopy, and fluorescence spectroscopy. The complex crystallized in triclinic crystal system, PT space group, with a=1.17196(4) nm, b=-2.36142(9) nm, c=2.59151(9) nm, a=113.266(2)°, β=101.100(2)°, and γ=94.400(2)°. Two independent dinuclear molecules were contained in the asymmetric unit. The two molecules were similar to each other. Each Eu(Ⅲ) ion was nine-coordinated with seven oxygen atoms from five 2-BrBA ligands and two ni-trogen atoms from 2,2'-bpy molecule. The carboxylate groups acted as bidentate-chelating, bidentate-bridging and chelating-bridging coor-dination modes. The complex adopted a distorted monocapped square-antiprism coordination geometry. Five peaks at 579, 591, 613, 652,and 697 nm appeared in the fluorescence spectrum, corresponding to 5D0→7F0, 5D0→7F1, 5D0→7F2, 5D0→7F3, and 5D0→7F4 transition emis-sions of the Eu(Ⅲ) ion, respectively.     

Phase control of magnetron sputtering deposited Gd2O3 thin films as high-κ gate dielectrics

Gd2O3 thin films as high-κ gate dielectrics were deposited directly on Si（001） substrates by magnetron sputtering at a pressure of 1.3 Pa and different temperatures. X-ray diffraction results revealed that all the films grown from 450 to 570 ℃ were crystalline, and the Gd2O3 thin films consisted of a mixture of cubic and monoclinic phases. The growth temperature was a critical parameter for the phase constituents and their relative amount. Low temperature was favorable for the formation of cubic phase while higher temperature gave rise to more monoclinic phase. All the Gd2O3 thin films grown from different temperatures exhibited acceptable electrical properties, such as low leakage current density （JL） of 10-5 A/cm^2 at zero bias with capacitance equivalent SiO2 thickness in the range of 6-13 nm. Through the comparison between films grown at 450 and 570 ℃, the existence of monoclinic phase caused an increase in JL by nearly one order of magnitude and a reduction of effective dielectric constant from 17 to 9.     

Study on Ferroelectric and Dielectric Properties of La-Doped CaBi4Ti4O15-Based Ceramics

Research on bismuthlayer structuredferroelectricceramics as piezoelectric material with high Curie tem-perature ,strong anisotropic characters ,lowdielectricdissipationfactor and lowaging rate has attracted in-creasing interest[1,2].It can be used to manu…     

Electrochemical Behavior of Dissolved Fe2O3 in Molten CaCl2-KF

The electrochemical behavior of dissolved Fe2O2 in 82.5CaCl2-17.5KF （mole percent, %） was studied using cy clic voltammetry, chronoamperometry, and galvanostatic electrolysis at 827 ℃, and the deposits were characterized by XRD and SEM. Pure iron was deposited on a rotating cylinder （210 r/min） with a cell voltage less than -- 1.0 V. Deposition rate was controlled by diffusion on a molybdenum electrode. The diffusion coefficient of iron species Fe（ Ⅲ ） in the melt at 827 ℃ was found to be 9.7×10^-5 cm^2/s.     

Speciation of the Fe(II)–Fe(III)–H2SO4–H2O system at 25 and 50 °C

This work presents theoretical and experimental results on the speciation of the Fe(II)–Fe(III)–H₂SO₄–H₂O system in concentrated solutions (up to 2.2 m H₂SO₄ and 1.3 m Fe). The aim was to study the chemical equilibria of iron at 25 and 50 °C in synthetic aqueous sulphuric acid solutions that contain dissolved ferric and ferrous ion species. Raman spectroscopy, volumetric titration and conductivity measurements have been carried out in order to study the presence of specific ions and to characterize the ionic equilibrium. A thermochemical equilibrium model incorporating an extended Debye–Hückel relationship was used to calculate the activities of ionic species in solution. Model calculations were compared with experimental results. Model simulations indicate that anions, cations and neutral complexes coexisted in the studied system, where the dominant species were HSO₄⁻, H⁺, Fe²⁺ and FeH(SO₄)₂⁰. This indicated that these solutions showed a high buffer capacity due to the existence of bisulphate ions (HSO₄⁻), which presented the highest concentration. A decrease in the concentration of H⁺ and Fe³⁺ took place with increasing temperature due to the formation of complex species. Standard equilibrium constants for the formation of FeH(SO₄)₂⁰ were obtained in this work: log K_f⁰ = 8.1 ± 0.3 at 25 °C and 10.0 ± 0.3 at 50 °C.