Strontium Chlorides Research Articles

Screening of salt hydrates and cellulose nanocrystal composites for thermochemical energy storage using life cycle assessment

Salt hydrate systems via thermochemical reactions can provide thermal storage for renewable-sourced alternatives to traditional heating systems like natural gas. In this study, we use life cycle analysis (LCA) along with the material prices to screen salts based on environmental impact and cost. Additionally, we performed LCA of producing a composite material of salt and cellulose nanocrystals (CNC) at a weight ratio of four to one. CNC is a stabilizing agent for salt. We assessed the salt-CNC composites based on a laboratory scale and scaled-up processing to identify low environmental impact formulations and to identify high environmental impact processes in the composite production. In general, lanthanum chloride, lithium hydroxide, and lithium chloride should be avoided due to high environmental impact or cost. For pure salts, our results showed magnesium sulfate, zinc sulfate, and calcium chloride are typically preferred with a close second tier of magnesium and strontium chlorides and strontium bromide. For the composite material, magnesium sulfate was preferred followed by zinc sulfate, sodium sulfide, and strontium chloride. CNC has a significant environmental impact, contributing over 50% of the environmental impact for these composites. Therefore, CNC production with lower environmental impacts needs to be pursued. In composite production, the environmental impact of mixing and sonication can be reduced by scaling production. However, drying remains a high-impact process. These results can help guide salt selection for other salt-based thermochemical materials and further development of the salt-CNC composite.

Phase Equilibria of Quaternary Systems Containing the Chlorides of Ammonium, Strontium(Magnesium), and Aluminum at 298.2 K

Phase Equilibria of Quaternary Systems Containing the Chlorides of Ammonium, Strontium(Magnesium), and Aluminum at 298.2 K

Novel composite materials of modified roasted date pits using ferrocyanides for the recovery of lithium ions from seawater reverse osmosis brine

In this paper, novel composite materials from modified roasted date pits using ferrocyanides were developed and investigated for the recovery of lithium ions (Li+) from seawater reverse osmosis (RO) brine. Two composite materials were prepared from roasted date pits (RDP) as supporting material, namely potassium copper hexacyanoferrate-date pits composite (RDP-FC-Cu), and potassium nickel hexacyanoferrate-date pits composite (RDP-FC-Ni). The physiochemical characterization of the RO brine revealed that it contained a variety of metals and salts such as strontium, zinc, lithium, and sodium chlorides. RDP-FC-Cu and RDP-FC-Ni exhibited enhanced chemical and physical characteristics than RDP. The optimum pH, which attained the highest adsorption removal (%) for all adsorbents, was at pH 6. In addition, the highest adsorption capacities for the adsorbents were observed at the initial lithium concentration of 100 mg/L. The BET surface area analysis confirmed the increase in the total surface area of the prepared composites from 2.518 m2/g for RDP to 4.758 m2/g for RDP-FC-Cu and 5.262 m2/g for RDP-FC-Ni. A strong sharp infrared peak appeared for the RDP-FC-Cu and RDP-FC-Ni at 2078 cm−1. This peak corresponds to the C≡N bond, which indicates the presence of potassium hexacyanoferrate, K4[Fe(CN)6]. The adsorption removal of lithium at a variety of pH ranges was the highest for RDP-FC-Cu followed by RDP-FC-Ni and RDP. The continuous increase in the adsorption capacity for lithium with increasing initial lithium concentrations was also observed. This could be mainly attributed to enhance and increased lithium mass transfer onto the available adsorption active sites on the adsorbents’ surface. The differences in the adsorption in terms of percent adsorption removal were clear and significant between the three adsorbents (P value < 0.05). All adsorbents in the study showed a high lithium desorption percentage as high as 99%. Both composites achieved full recoveries of lithium from the RO brine sample despite the presence of various other competing ions.

Application of Phosphate Precipitation for Removing Strontium and Barium from Alkali Chloride Based Melts

The reaction of solutions of barium and strontium chlorides in LiCl–KCl, NaCl–KCl, and NaCl–KCl–CsCl based melts with sodium orthophosphate was studied at 450 and 750oC. The initial phosphate-to-alkaline earth molar ratio varied from 0.5 to 14 and the excess of phosphate required for the complete conversion of AECl2 (AE = Sr, Ba) to phosphates as well as phase composition of the phosphates produced were determined. Normal orthophosphates alongside with lithium phosphate were formed in lithium chloride containing melts, whilst double alkali–alkaline earth phosphates and chloro-phosphates were obtained in NaCl–KCl and NaCl–KCl–CsCl based melts. Size of the particles comprising solid precipitates was determined; the values varied from 0.1 to tens microns. Increasing the initial PO4 3– : AE2+ molar ratio did not have a pronounced effect on the particle size.

Effect of Non-aqueous Media on Nano-crystalline SrFe12O19 Particles Produced by Co-precipitation with Metal Chlorides and Evaluation of Their Magnetic and Photocatalytic Properties

The strontium ferrite nano-crystals were prepared via co-precipitation method in different synthesis media including a mixture of ethanol and water (with a volume ratio equal to 3:1) and water. In this way, the iron and strontium chlorides with various molar ratios were utilized as sources for Fe3+ and Sr2+ ions, respectively. Phase analyses, structural properties and morphology of the SrFe12O19 powders were characterized by various techniques including X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometer and Fourier transform infrared spectra. Thermal decomposition behaviors of the as-synthesized precursors were monitored by DTA/TGA (differential thermal analysis/thermo-gravimetric analysis). The effects of molar ratio, calcination temperature and co-precipitation media of the strontium ferrite powder were investigated. The results of DTA indicated that the strontium hexaferrite prepared by co-precipitation in ethanol/water media was formed at a lower temperature. The maximum saturation magnetization of the strontium ferrite powder with the value of 58 emu/g was achieved at a temperature of 950 °C by a Fe3+/Sr2+ molar ratio of 12. Wide coercivity in the range of 1512–5764 Oe was observed by tuning calcination temperatures. Furthermore, the photocatalytic properties of the resultant optimum SrFe12O19 particles were assessed. The destruction of methylene blue dye was about 46% in the presence of the strontium ferrite under UV light irradiation for 120 min.

Enhancement of sorption capacity to Sr and Cs of a cement composite by addition of brick powder

Concrete is a suitable material for secondary casings in multi-barrier systems used in radioactive waste repositories, because it is durable and radiation- and thermal resistant and it has good mechanical properties. The casings should also limit possible leaching of radionuclides in case of failure of inner barriers. An efficient way to tackle this problem is the addition of a sorption material in the concrete mixture. Here mechanical and thermal properties of concrete containing different amounts of brick powder are studied in relation to the concrete mixture porosity. It is found out that, as expected, the bulk density and compressive and bending strengths decreased with an increasing amount of the brick powder. In addition, the sorption of cesium and strontium chlorides into the mixtures was analyzed under laboratory conditions, and their sorption isotherms and distribution coefficients were calculated. The results indicate that brick has higher sorption capacity for Sr than for Cs. Relatively low distribution coefficients indicate, however, that the studied brick is not a very suitable additive material for sorption of Sr and Cs elements.

Mitigation of radionuclide deposition in contaminated water: effects of pH on coprecipitation of Cs(I) and Sr(II) with Fe(III) in aqueous solutions

In the present study, the amounts of caesium and strontium were quantified in the precipitates formed in solutions of sodium hydroxide and iron(III), caesium, and strontium chlorides in the pH range of 7–13. At pH 8 or lower, less caesium and strontium were found in the precipitates. It was verified that for water radioactively contaminated after a severe accident at a nuclear power plant, both iodine volatilization and metal coprecipitation with iron(III) hydroxide can be minimized at ambient temperature by maintaining the water pH near 7.

Synthesis of irregular graphene oxide tubes using green chemistry and their potential use as reinforcement materials for biomedical applications.

Micrometer length tubes of graphene oxide (GO) with irregular form were synthesised following facile and green metal complexation reactions. These materials were obtained by crosslinking of GO with calcium, zinc or strontium chlorides at three different temperatures (24, 34 and 55°C) using distilled water as solvent for the compounds and following a remarkably simple and low-cost synthetic method, which employs no hazardous substances and is conducted without consumption of thermal or sonic energy. These irregular continuous GO networks showed a very particular interconnected structure by Field Emission Scanning Electron Microscopy with Energy-Disperse X-Ray Spectroscopy for elemental analysis and High-resolution Transmission Electron Microscopy with Scanning Transmission Electron Microscope Dark Field Imaging, and were analysed by Raman Spectroscopy. To demonstrate the potential use of these 3D GO networks as reinforcement materials for biomedical applications, two composites of calcium alginate with irregular tubes of GO and with single GO nanosheets were prepared with the same amount of GO and divalent atoms and analysed. Thus, the dynamic-mechanical modulus of the composites synthesised with the 3D crosslinked GO networks showed a very significant mechanical improvement due to marked microstructural changes confirmed by confocal microscopy, differential scanning calorimetry and Fourier transform infrared spectroscopy.

Nontransition metal–crown ether complexes as hydroperoxide decomposition catalysts

The decomposition of tert-butyl hydroperoxide in a chlorobenzene medium in the presence of complexes of dibenzo-18-crown-6 with calcium, strontium, and barium chlorides has been studied. It has been found and kinetically proven that the decomposition of tert-butyl hydroperoxide is preceded by the formation of an intermediate hydroperoxide–catalyst complex. Kinetic and thermodynamic parameters of the complex formation have been determined.

Effects of Crosslink Agents on Sodium Alginate and Lignosulphonic Acid Blends

Blends of sodium alginate (SA) and lignosulphonic acid (LS) has been prepared in the ratio of 80/20. The prepared blends were crosslinked using chlorides of calcium, barium, strontium and aluminum. The crosslinking of blends was done for different time intervals and then these blends were subjected for swelling studies in aqueous medium of pH 7.4. The observations indicate that the crosslinking is diffusion controlled and is affected by the size of metal ion and the type of alginate used. The improved swelling time for crosslinked blends in aqueous medium supports the fact that the stability under physiological conditions of the blends is improved due to crosslinking with the metal ions. Calcium chloride and barium chloride forms strong crosslink with the blend. Calcium ion crosslinked blends can be considered suitable for biomedical drug applications. The investigations on crosslinked blends using FTIR, SEM, XRD and EDAX are in close agreement with swelling results.

Thermochemical characteristics of SrCeO3 doped by Eu2O3

For the first time, dissolution enthalpies of strontium cerate doped by europium and a mixture of strontium, cerium, and europium chlorides have been measured by solution calorimetry. Using experimental data, the standard formation enthalpy of SrCe0.9Eu0.1O2.95 has been calculated as follows: ΔfH° (298.15 K) = −1692.1 ± 3.9 kJ mol−1. The stabilization energy of this complex oxide has been calculated and established that its value is negative (ΔstE = −36.7 ± 4.2 kJ mol−1).

Evaluation and determination of chloride in crude oil based on the counterions Na, Ca, Mg, Sr and Fe, quantified via ICP-OES in the crude oil aqueous extract

Abstract Of the salts present in crude oil, sodium, calcium, magnesium, strontium and iron chlorides are the most abundant and are considered the main cause of corrosion in crude oil refineries. Therefore, the objective of this study was to quantify the main chloride counterions (Na, Ca, Mg, Sr and Fe) using inductively coupled plasma-optical emission spectrometry (ICP-OES) after hot solvent extraction (modified ASTM D 6470-99). The procedure developed in this work allowed samples with different °API values (17.4–30.2) originating from the post-salt to be studied. Under the operational conditions of ICP-OES, robust plasma (Mg II/Mg I > 10 for the axial and radial configurations) was obtained based on evaluation of the ratio of the Mg II/Mg I intensities. Furthermore, yttrium was used as an internal standard, resulting in as little interference with the analytical signal as possible. This procedure achieved detection limits on the order of 0.99 mg L−1, 0.025 mg L−1, 0.33 μg L−1, 0.06 ng L−1 and 0.26 μg L−1 for Na, Ca, Mg, Sr and Fe, respectively. The accuracy of the procedure was confirmed through addition/recovery tests (91–120%) and through comparison with the results obtained with flame atomic absorption spectrometry (FAAS). The modified standard test method of ASTM D 6470-99 extraction was compared with microwave-assisted acid digestion and was found to achieve extractions higher than 92.44% for Na and 81.06% for Sr from two of the analysed extracts. Finally, the chloride concentrations obtained via potentiometric titration and ICP-OES (through the analysis of chloride with its counterions) in the aqueous extract indicated a high correlation between Na, Ca, Mg, Sr and Fe and chloride (105.10%, 99.33% and 102.12% for the evaluated samples).

Synthesis, Crystal Structures, and Hydrogen-Storage Properties of Eu(AlH4)2 and Sr(AlH4)2 and of Their Decomposition Intermediates, EuAlH5 and SrAlH5

Complex Eu(AlH(4))(2) and Sr(AlH(4))(2) hydrides have been prepared by a mechanochemical metathesis reaction from NaAlH(4) and europium or strontium chlorides. The crystal structures were solved from powder X-ray diffraction data in combination with solid-state (27)Al NMR spectroscopy. The thermolysis pathway was analyzed in detail, allowing identification of new intermediate EuAlH(5)/SrAlH(5) compounds. Rehydrogenation experiments indicate that the second decomposition step is reversible.

Strontium–copper selenite–chlorides: Synthesis and structural investigation

Two new complex selenite–chlorides of strontium and copper Sr 2Cu(SeO 3) 2Cl 2 (I) and SrCu 2(SeO 3) 2Cl 2 (II) were obtained and characterized by X-ray diffraction technique, DTA and IR spectroscopy. Both compounds crystallize in the monoclinic system I: Sp. gr. P2 1/ n, a=5.22996(3) Å, b=6.50528(4) Å, c=12.34518(7) Å, β=91.3643(2)°, Z=2; II: Sp. gr. P2 1, a=7.1630(14) Å, b=7.2070(14) Å, c=8.0430(16) Å, β=95.92(3)°, Z=2. Comparison of the crystal structure of (I) with the structures of Sr 2 M(SeO 3) 2Cl 2 ( M=Co, Ni) was performed. The substitution of strontium atom in the structure of (I) by Cu 2+ ion with a 3 d 9 Jahn–Teller distorted surrounding leads to the lowering of the structure symmetry and to the appearance of the noncentrosymmetric structure of (II). The noncentrosymmetric character of the structure of (II) was confirmed by SHG signal (1.2 units relative to an α-quartz powder sample).

Carbonate Reaction of Alkaline-Earth Element by Carbonate Agent Injection Method

The carbonate reaction of some alkaline-earth chlorides was investigated by a carbonate agent injection method in LiCl-KCl eutectic salts containing both SrCl2 and BaCl2 and LiCl molten salts containing SrCl2. The effects of the injected molar ratio of a carbonate agent (Li2CO3 or K2CO3) and the temperature (450–750°C) on the conversion efficiencies of the strontium and barium chloride to their carbonates were determined. The forms of strontium and barium carbonate resulting from the carbonate reaction with carbonate agents were identified by XRD and SEM-EDS analyses. In these experiments, the carbonate agent injection method can carbonate strontium and barium chlorides effectively at over 99% under LiCl-KCl eutectic and LiCl molten salt conditions. For LiCl-KCl eutectic molten salts, carbonation efficiency was more favorable in the case of K2CO3 injection than in the case of Li2CO injection, where strontium and barium were carbonated in the form of Ba0.5Sr0.5CO3. For LiCl molten salts, strontium was carbonated in the form of SrCO3 by Li2CO3 injection.

Carbonate Reaction of Alkaline-Earth Element by Carbonate Agent Injection Method

The carbonate reaction of some alkaline-earth chlorides was investigated by a carbonate agent injection method in LiCl-KCl eutectic salts containing both SrCl2 and BaCl2 and LiCl molten salts containing SrCl2. The effects of the injected molar ratio of a carbonate agent (Li2CO3 or K2CO3) and the temperature (450–750°C) on the conversion efficiencies of the strontium and barium chloride to their carbonates were determined. The forms of strontium and barium carbonate resulting from the carbonate reaction with carbonate agents were identified by XRD and SEM-EDS analyses. In these experiments, the carbonate agent injection method can carbonate strontium and barium chlorides effectively at over 99% under LiCl-KCl eutectic and LiCl molten salt conditions. For LiCl-KCl eutectic molten salts, carbonation efficiency was more favorable in the case of K2CO3 injection than in the case of Li2CO injection, where strontium and barium were carbonated in the form of Ba0.5Sr0.5CO3. For LiCl molten salts, strontium was carbonated in the form of SrCO3 by Li2CO3 injection.

Studies on the effect of chlorides of magnesium, calcium, strontium and barium on the temperature of the sound velocity maximum of water

The effect of chlorides of magnesium, calcium, strontium and barium on the temperature of the sound velocity maximum (TSVM) of water, T w, has been studied by determining the ultrasonic velocity using a single crystal variable path interferometer working at 3 MHz. The accuracy in ultrasonic velocity measurement is ± 0.05 m s − 1 . The ultrasonic velocity measurements were carried out at ≃ 2 °C intervals over a range of 5 °C to either side of TSVM of the solutions. The accuracy in fixing TSVM is ± 0.2 °C. The shifts in TSVM of water due to the addition of MgCl 2 and CaCl 2, (Δ T obs), are found to be positive at low concentrations becoming maxima around the weight fraction w ≃ 2.3 × 10 − 2 for MgCl 2 and w ≃ 3.8 × 10 − 2 for CaCl 2 and becoming negative around w ≃ 5.6 × 10 − 2 for MgCl 2 and w ≃ 3.8 × 10 − 2 for CaCl 2. (Δ T obs) for MgCl 2 > CaCl 2 > SrCl 2 > BaCl 2 indicating that the strength of the structural interactions in modifying the hydrogen-bonded structure of water is in the order Mg 2+ > Ca 2+ > Sr 2+ > Ba 2+. The results are explained in the light of the structural properties of the anions and cations in the solutions in modifying the three dimensional hydrogen-bonded structure of water.

Identification of molecules in graphite furnace by laser ionization time-of-flight mass spectrometry: sulfur and chlorine containing compounds

An electrothermal vaporizer (ETV) coupled to a time-of-flight mass spectrometer (TOF-MS) with laser ionization (LI) was applied to the identification of molecules from sulfur and chlorine matrices in the furnace. An interface was developed to entrain furnace vapors from the matrices under study, i.e., sulfur, sulfuric acid, magnesium sulfate, chlorides of sodium, potassium, caesium, magnesium, calcium and strontium, into the TOF-MS. These were then ionized on the TOF axis with 219, 240 and 266 nm laser radiations. The S+ and SO+ ions were mainly detected from sulfuric acid and magnesium sulfate in the furnace when ionized with a 219 nm beam. SO2+ was observed with 266 nm. Mainly S+ and S2+ were detected when sulfur was ionized with 219 and 266 nm. The spectra obtained at 219 nm were identical to those attained at 240 nm for the chloride matrices. The MCl+, M2Cl+, M+, and M2+ (where M is the metal) were observed for Na, K and Cs. Various compositions of oxides (MxOy)+, M2OCl+ and chlorides MCl+ and MCl2+ were identified for Ca and Sr. Mg only produced the Mg+ isotopes.

Occlusion and ion exchange in the molten (lithium chloride+potassium chloride+alkaline-earth chloride) salt+zeolite 4A system with alkaline-earth chlorides of calcium and strontium and in the molten (lithium chloride+potassium chloride+actinide chloride) salt+zeolite 4A system with the actinide chloride of uranium

The interaction between molten salts of the type LiCl-KCl-MeCl n (Me=Ca, Sr, U; \(x_{MeCl_n } \)= to 0.45; and x KCl/x LiCl=0.69) and zeolite 4A have been studied at 823 K. The main interactions between these salts and zeolite are molten salt occlusion to form salt-loaded zeolite and ion exchange between the molten salt and salt-loaded zeolite. An irreversible chemical reaction has been observed in the LiCl-KCl-UCl3+zeolite system. The extent of occlusion is a function of the concentration of MeCl n in the zeolite and is equal to 10±1 Cl− per zeolite unit cell, (AlSiO4)12, at infinite MeCl n dilution. The ion-exchange mole-fraction equilibrium constants (separation factors) with respect to Li are decreasing functions of the concentration of SrCl2 and UCl3, but an increasing function of the concentration of CaCl2 in the zeolite. At infinite MeCl n dilution, they are equal to 0.9, 11.9, and 13 for CaCl2, SrCl2, and UCl3, respectively. The standard ion-exchange chemical potentials are equal to −50.0, −84, and −101.1 kJ·mol−1 for Ca2+, Sr2+, and U3+, respectively.

Limiting Electroconductivity and Structure of Molten Chlorides of Alkaline-Earth Metals

It is established experimentally that the electroconductivity of individual molten chlorides of calcium, strontium, and barium increases with the electric field strength and reaches limiting values, which are dependent on the salt nature and the temperature. The limiting electroconductivity of molten calcium and strontium chlorides satisfactorily obeys the Nernst–Einstein relationship. The relaxation kinetics of excess conductivity induced by high-voltage pulsed discharges is studied. The relaxation time is equal to about 104 s.