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71.
Joseph A. Rard Kirk J. Staggs S. Dan Day Susan A. Carroll 《Journal of solution chemistry》2006,35(8):1187-1215
Boiling temperature measurements have been made at ambient pressure for saturated ternary solutions of NaCl + KNO3 + H2O, NaNO3 + KNO3 + H2O, and NaCl + Ca(NO3)2 + H2O over the full composition range, along with those of the single salt systems. Boiling temperatures were also measured for the four component NaCl + NaNO3 + KNO3 + H2O and five component NaCl + NaNO3 + KNO3 + Ca(NO3)2 + H2O mixtures, where the solute mole fraction of Ca(NO3)2, x{Ca(NO3)2}, was varied between 0 and 0.25. The maximum boiling temperature found for the NaCl + KNO3 + H2O system is ≈134.9 ∘C; for the NaNO3 + KNO3 + H2O system is ≈165.1 ∘C at x(NaNO3) ≈ 0.46 and x(KNO3) ≈ 0.54; and for the NaCl + Ca(NO3)2 + H2O system is 164.7 ± 0.6 ∘C at x{NaCl} ≈ 0.25 and x{Ca(NO3)2} ≈ 0.75. The NaCl + NaNO3 + KNO3 + Ca(NO3)2 + H2O system forms molten salts below their maximum boiling temperatures and the temperatures corresponding to the cessation of boiling (dry-out temperatures) of these liquid mixtures were determined. These dry-out temperatures range from ≈300 ∘C when x{Ca(NO3)2} = 0 to ≥ 400 ∘C when x{Ca(NO3)2} = 0.20 and 0.25. Mutual deliquescence/efflorescence relative humidity (MDRH/MERH) measurements were also made for the NaNO3 + KNO3 and NaCl + NaNO3 + KNO3 salt mixture from 120 to 180 ∘C at ambient pressure. The NaNO3 + KNO3 salt mixture has a MDRH of 26.4% at 120 ∘C and 20.0% at 150 ∘C. This salt mixture also absorbs water at 180 ∘C, which is higher than expected from the boiling temperature experiments. The NaCl + NaNO3 + KNO3 salt mixture was found to have a MDRH of 25.9% at 120 ∘C and 10.5% at 180 ∘C. The investigated mixture compositions correspond to some of the major mineral assemblages that are predicted to control brine composition due to the deliquescence of salts formed in dust deposited on waste canisters in the proposed nuclear repository at Yucca Mountain, Nevada. 相似文献
72.
Cigdem Yagci 《European Polymer Journal》2005,41(1):177-184
Redox initiated free-radical polymerization of methyl methacrylate (MMA) with allyl alcohol 1,2-butoxylate-block-ethoxylate (AABE) was carried out using cerium(IV) ammonium nitrate/nitric acid (HNO3) redox system to yield AABE-b-PMMA copolymers. The effects of MMA, AABE, Ce(IV) and HNO3 concentrations on the polymerization rate and polymer yield were investigated. The effect of temperature on the rate of polymerization and polymer yield was also investigated in the temperature range of 25-70 °C. Copolymers were characterized using GPC, FT-IR, 1H NMR and viscometry methods. 相似文献
73.
J. A. Navio M. Macias A. Justo C. Real 《Journal of Thermal Analysis and Calorimetry》1992,38(4):673-682
The thermal decomposition of sodium nitrite or nitrate pre-adsorbed upon TiO2 surfaces has been investigated by employing several techniques as infrared spectroscopy (IR) and temperature programmed desorption in conjunction with mass spectrometry analysis (TPD-MS) to study the features observed during these thermal decompositions. Differential thermal analysis (DTA) in combination with X-ray diffraction analysis (XRD) were used to investigate the possibility of a solid state chemical reaction between the solid products originated from the thermal decomposition of the pre-adsorbed species and the TiO2. On the basis of our results, various characteristic features of these thermal decomposition reactions will be discussed.This work was supported by JUNTA DE ANDALUCIA (financial support for research groups/1990). 相似文献
74.
Tenu R. Gentil S. Baudu S. Counioux J. J. 《Journal of Thermal Analysis and Calorimetry》1999,58(1):89-101
The binary system H2O—UO2(NO3)2 was studied by solubility measurements and constant heat flow thermal analysis. Temperature and composition of the eutectic transformation between ice and uranyl nitrate hexahydrate were accurately defined. A new hydrate with 24 molecules of water decomposes at –21°C according to the peritectoid reaction<UO2(NO3)2·24H2O> <UO2(NO3)2·6H2O> + 18<H2O>The quasi-ideal model was applied to the solid—liquid equilibria, using the following reaction hypothesis:((UO
2
2+
)) + 2((NO
3
–
))+ h((H2O)) ((UO2OH+aq)) + ((H3O+aq + 2((NO
3
–
aq))A complete calculation of the binary system was carried out with a global ionic hydration number h equal to 9 in the aqueous solutions. It allowed to the melting enthalpies of uranyl nitrate hydrates.
This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
75.
Hesham Ibrahim Saleh 《中国化学会会志》2002,49(3):341-348
The reactions between strontium and iron nitrates have been studied in an open atmosphere system using three different molar ratios, 1:1 (I), 1:2 (II) and 2:1 (III) at different temperatures as pointed out from the DTA data. The reaction mechanism was discussed based on the chemical composition characterized by means of thermal analysis, X‐ray diffraction patterns, infrared spectra and magnetic susceptibility. It was found that the reaction products depend on both temperature of reaction and the ratio between reactants. The reaction products were found to be composed of a variety of iron compounds that possess different valences: SrFeO2.86, SrFeO2.97, SrFe2O4, SrFe12O19, Sr2Fe2O5 and Sr7Fe10O22 in addition to some accessory reaction products namely α‐Fe2O3 and FeO(OH). 相似文献
76.
The effect of ammonium nitrate concentration in the citric acid biosynthesis by Aspergillus niger NC-12 in single-stage continuous cultures with biomass retention was investigated. Experiments were carried out in a BIOMER
laboratory fermenter with 5 dm3 working volume. At the initial stage of each cultivation, the substrate in the bioreactor contained 1.5 g NH4NO3 dm−3. After 120 h onwards, the bioreactor was fed continuously at a constant dilution rate of 0.009 h−1. NH4NO3 concentration in the feed was varied from one culture to another, ranging between 0.5 g dm−3 and 2.5 g dm−3. Promising results were obtained when NH4NO3 concentration of 1.5 g dm−3 was used. The observed concentration of citric acid (c
P) and yield of citric acid with respect to the introduced sucrose (Y
P/S) were 117.88 g dm−3 and 78.59 %, respectively. The efficiency coefficient of citric acid biosynthesis (K
ef) was very high, amounting to 83.38.
Presented at the 33rd International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 22–26 May
2006. 相似文献
77.
78.
In this paper, the effect of bismuth doping on the structural, morphological, optical and electrical properties of Cu2ZnSnS4 (CZTS) films has been investigated. The undoped and bismuth doped CZTS films (0, 0.5, 1, 1.5 and 2 mol%) were deposited on glass substrates by solution based method. The XRD result shows a significant improvement in the crystallinity of the films with increase in bismuth concentration. The Raman spectra of the films show the dominant peak at 334 cm–1 corresponding to A1 vibrational mode of CZTS kesterite phase. The FESEM micrographs of the films show an enhancement in the grain size and densification with the addition of bismuth ion concentration. The optical bandgap of the films was found to vary (1.59–1.40 eV) with the doping of bismuth ions. The I –V characteristics indicate twofold increment in the photoconductivity for the bismuth doped CZTS films under 100 mW/cm2 illumination suggesting their potential application in photovoltaic devices. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
79.
Jisna Jos 《固体与材料科学评论》2017,42(6):470-498
Ammonium nitrate (AN) has received attraction globally not only as a nitrogenous fertilizer but also as an oxidizer in gas generators and propellants. Nowadays, great attention is being focused on the development of composite solid propellants with green oxidizers in realizing eco–friendly combustion products. The ammonium perchlorate (AP), which is the work horse oxidizer in composite propellant, needs replacement due to its environmental and human health issues. In this context, AN is regarded as an alternative to AP because of its easy availability and environmentally friendly chlorine free combustion products. However, AN has its own inherent drawbacks such as hygroscopicity, room temperature phase transition, and low burning rate. Recently, several studies have been focused on its phase stabilization and burning rate modification so as to develop solid propellants with improved properties. The knowledge of thermal characteristics of AN is a crucial factor for its applications in propellants and gas generators. This article details the different aspects of polymorphism, phase stabilization, thermal decomposition, hygroscopicity, specific impulse, and burn rate modification of AN and also addresses ways to overcome the inherent weakness of AN as a propellant oxidizer in formulating an effective propellant composition. 相似文献
80.
F. Briski S. Cerjan-stefanovic L. Sipos 《International journal of environmental analytical chemistry》2013,93(1-4):137-148
Abstract The removal of ammonia from mineral medium containing known concentrations of ammonia (up to 300 mg/L) and from ground water by biological oxidation was studied. Nitrifying bacteria were isolated from ground water containing ammonia. Ammonium ion was determined by a standard titration technique while nitrite and nitrate ions were determined by ion chromatography (IC Supersep anion column) using 1.5 mM phtalic acid solution containing 5 % acetonitril as eluent. Depending on its concentration in water biooxidation of ammonia lasted from 48 hours till three weeks. 相似文献