NaCl Na2SO4 Research Articles

Bi2SiO5 nanosheets prepared by molten salt method

Bi2SiO5 nanosheets were successfully synthesized by the molten salt method in NaCl–Na2SO4 flux using Bi2O3 and SiO2 as raw materials. XRD analysis and SEM observation show that the incorporation of salt medium can greatly lower the formation temperature of Bi2SiO5 phase, and promote their crystallization. The results also demonstrate that the mass ratio of salts to reactants, the reaction time, and the calcination temperature have significant effects on the phase formation and morphology of the Bi2SiO5 powders. The UV–vis spectra result shows that the absorption of the Bi2SiO5 powders located at 380 nm, and the corresponding band gap energy (Eg) calculated is 3.26 eV.

Synthesis of Bi2SiO5 powder by molten salt method

Pure Bi2SiO5 powders were synthesized by molten salt method in NaCl–Na2SO4 flux using Bi2O3 and SiO2 as raw materials. The results showed that the pure metastable state compound Bi2SiO5 was obtained in NaCl–Na2SO4 flux at 625°C for 1h, which was lower than that (generally 750°C) of conventional solid state reaction. X-ray diffraction revealed that in the case of NaCl–Na2SO4 molten salt, with increasing synthesis temperature (600°C to 625°C), stable state Bi12SiO20 transformed into metastable state Bi2SiO5 and with synthesis temperature increasing from 625°C to 700°C, metastable state Bi2SiO5 transformed into stable state Bi4Si3O12 gradually. Therefore, calcination temperature played a crucial role in the formation of Bi2SiO5 powder. The field-emission scanning electron microscopy images disclosed that the Bi2SiO5 samples showed nest like morphology, which was soft aggregation of Bi2SiO5 nanosheets. Moreover, it also indicated that the mechanism of the process of molten salt synthesis was “dissolution–precipitation mechanism”.

Grafting cucumber plants enhance tolerance to sodium chloride and sulfate salinization

The aim of the current work was to determine whether grafting could improve salinity tolerance of cucumber using two different salt stressors such as NaCl and Na2SO4 with equimolar concentrations, and to study the changes induced by the rootstock in the shoot growth at agronomical and physiological levels. A greenhouse experiment was carried out to determine yield, growth, fruit quality, leaf gas exchange, electrolyte leakage, SPAD, and mineral composition and assimilate partitioning of cucumber plants (Cucumis sativus L. cv. ‘Akito’), either ungrafted or grafted onto the commercial rootstock ‘PS1313’ (Cucurbita maxima Duch.×Cucurbita moschata Duch.) and cultured in quartziferous sand. Plants were supplied with three nutrient solutions: non-salt control, 27mM Na2SO4, or 40mM NaCl. Significant depression of yield, shoot and root biomass production in response to an increase of salinity concentration in the nutrient solution was observed with more detrimental effects with NaCl treatment. The two salt treatments, especially NaCl, inhibited photosynthesis, pigment synthesis, and membrane integrity. Salinity with NaCl and Na2SO4 improved fruit quality in both grafting combinations by increasing fruit dry matter and total soluble solids content. Moreover, at the two salt treatments the percentage of yield and biomass reduction in comparison to control was significantly lower in the plants grafted onto ‘PS1313’ than ungrafted plants, with the highest yield, shoot and root reduction recorded with NaCl in comparison to those recorded with Na2SO4 treatment. Grafted cucumber plants exposed to Na2SO4 were capable of maintaining higher net assimilation rates, higher chlorophyll content (SPAD index), a better nutritional status (higher K, Ca and Mg and lower Na) in the shoot tissues and higher membrane selectivity in comparison with ungrafted ones. The higher crop performance of grafted cucumber recorded with Na2SO4 than with NaCl, was attributed to the inability of the rootstock to restrict Cl− shoot uptake, thus Cl−, which continues passing to the leaves, becomes the more significant toxic component of the saline solution.

Effect of a magnetron sputtered (Al2O3–Y2O3)/(Pt–Au) laminated coating on hot corrosion resistance of 8Nb–TiAl alloy

Novel (Al2O3–Y2O3)/(Pt–Au) laminated coatings were prepared on 8Nb–TiAl alloy by magnetron sputtering methods. (Na2SO4–NaCl)-induced hot corrosion and cyclic oxidation tests were adopted to investigate the high-temperature corrosion behaviours and the mechanical properties of the as-prepared laminated coatings. The results revealed that the multi-sealed (Al2O3–Y2O3) and (Pt–Au) layers can effectively suppress the inward diffusion of oxygen and corrosive fused salt to an extremely low level at 1000°C and 900°C respectively. Consequently, the high-temperature corrosion resistance of the 8Nb–TiAl alloy can be significantly improved. In addition, cyclic tests revealed the (Al2O3–Y2O3)/(Pt–Au) laminated coating can exhibit enhanced spallation and fracture resistance, which are attributable to the brittle/ductile laminated composite structure by means of energy release mechanisms and the increased thermal expansion coefficient of the coating by the addition of Pt–Au alloy.

Swelling behaviors of GMZ bentonite–sand mixtures inundated in NaCl–Na2SO4 solutions

a b s t r a c t In this study, the swelling behaviors of compacted GMZ bentonite–sand mixtures inundated in NaCl–Na2SO4 solutions are investigated and the influence of chemical solutions on the swelling behaviors of GMZ bentonite–sand mixtures as backfill/buffer material in China for high level radioactive waste (HLW) is investigated. The sand addition ratios of the bentonite–sand mixtures are 0%, 20%, 30% and 50%, and the total dissolved solids (TDS) of the NaCl–Na2SO4 (NaCl:Na2SO4 = 2:1 by mass) solution are 0.5, 1.0, 3.0, 6.0 and 12.0 g/L (pH 7.1). The specimens of bentonite–sand mixtures for swelling tests are prepared by static-compaction to various dry densities, ranging from 1.50 to 1.90 g/cm3. Test results indicate that liquid limit (LL) and plasticity limit (PL), swell time, maximum swelling pressure and maximum swelling strain decrease with the increase of TDS for GMZ bentonite–sand mixtures. All of the LL, PI and maximum swelling strain are decreased exponentially with TDS increase: very quickly as TDS 6.0 g/L. The maximum swelling pressure shows a linear reduction with the TDS increasing, but the pure bentonite indicates a high sensitivity than the bentonite–sand mixtures with 30% sand addition ratio. As NaCl–Na2SO4 (TDS = 0.5 g/L) solution was used according to the ground water, with initial dry density of 1.70 g/cm3, the maximum swelling pressure of specimens decrease exponentially while the maximum strain decrease linearly with the increase of sand addition. With 30% sand addition in 0.5 g/L NaCl–Na2SO4 solution, the maximum swelling pressure increase exponentially while the maximum strain increase linearly with the increase of initial dry density. Compared with the pure bentonite, bentonite–sand mixtures show a better tolerance withstanding the chemical attack to ground water chemistry because of the replacement of some quantity of expansive clay by quartz sand in the mixtures.

Activity Coefficients of Electrolytes in the NaCl + Na2SO4 + H2O Ternary System from Potential Difference Measurements at (298.15, 303.15, and 308.15) K

Potential difference measurements have been used to obtain the mean ionic activity and osmotic coefficients of NaCl and Na2SO4 in their aqueous solutions. Also, the mean ionic activity coefficients of NaCl in NaCl–Na2SO4–H2O ternary system with sodium as a common ion have been determined from cell potential measurements using: Na-ISE/NaCl (mNaCl); Na2SO4 (mNa2SO4)/Ag/AgCl combined with the reference cell: Na-ISE/NaCl (I = mNaCl + 3mNa2SO4), AgCl(s)/Ag. The measurements were made at ionic strength ratios for Na2SO4, yNa2SO4, of (0.0, 0.2, 0.4, 0.6, 0.8, and 1.0), at constant total ionic strengths, I, of (0.1, 0.5, 1.0, 2.0, 3.0, and 4.0) mol·kg–1 and at temperatures of (298.15, 303.15, and 308.15) K. The experimental mean ionic activity coefficients of NaCl were correlated and analyzed with the Harned rule and Scatchard and Pitzer models. The excess free Gibbs energies of mixing were calculated from the trace activity coefficient data of NaCl and analyzed versus system composition at different temperatures...

Preparation of Sn-Ir Binary Oxide Electrode and its Application in Degradation of Simulated Wastewater of <i>P</i>-Chlorophenol

Ti/Sn1–xIrxO2 electrodes were prepared on titanium substrates by thermal decomposition method. The structure and the surface morphologies of the electrodes were characterized by XRD, SEM, and the electrochemical properties were investigated by linear scan voltammetry. The results showed that in NaCl solution and Na2SO4 solution, with increasing the Ir content, the potential gap of electrochemical oxidation（△E）between chlorine evolution and oxygen evolution decreased. The electrode containing 30% Ir (by mol%) had the highest chlorine evolution efficiency. Using Ti/Sn0.7Ir0.3O2 electrode as anode, a simulated wastewater with p-chlorophenol as pollutant was degraded by constant current electrolysis. The degradation rate of p-chlorophenol in presence of NaCl was faster than in presence of Na2SO4.

Hot corrosion behavior of powder metallurgy Rene95 nickel-based superalloy in molten NaCl–Na2SO4 salts

Hot corrosion behavior of powder metallurgy (PM) Rene95 Ni-based superalloy in molten 25%NaCl+75%Na2SO4 salts at 650°C, 700°C and 750°C are investigated by weight loss measurements, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). Experimental results show that hot corrosion kinetics follow a square power law at 650°C and linear power laws at 700°C and 750°C. The corrosion layers on the surface of PM Rene95 superalloy are detected to be mainly composed of Cr2O3, NiO, and Ni3S2 at each temperature. Besides, small amounts of NiCr2O4 at 700°C and NaCl at 750°C are observed respectively. Cross-sectional morphologies and corresponding elemental maps indicate that corrosion layers near scale/alloy interface are composed of oxides at 650°C while duplex oxides and sulfides at 700°C and 750°C. According to these results, a cooperating mechanism of oxidation and sulfuration for hot corrosion of PM Rene95 Ni-based superalloy is confirmed.

Salt Effect on Substrate Specificity of a Subtilisin-Like Halophilic Protease

Enzyme-substrate interaction under the presence of high concentration of salts is of great interest for biotechnology applications and basic enzymology. In our previous work, the salt effect on halophilic subtilase SR5-3 was evaluated with Suc-AAPF-MCA and with the FRET peptide Abz-AAPFSSKQ-EDDnp. It was demonstrated that the magnitude of catalytic activity enhancement was affected by the presence of the prime site residues (Okamoto et al., 2009). In this work, a detailed analysis of the salt effect on SR5-3 protease substrate specificity was performed using chromogenic and coumarin substrates as well as FRET peptides derived from Abz-KLRSSKQ-EDDnp. The followings were demonstrated: 1) Preference of amino acid of SR5-3 protease at the P(3), P(2), P(1), P(1)' or P(2)' position of FRET substrates was almost similar with that of subtilisin. 2) Under the presence of the salts (3M NaCl or 1M Na(2)SO(4)), SR5-3 protease showed higher kcat values, lower Km values and totally 2-6 times higher kcat/Km values compared with those of control for FRET substrates, and salts did not significantly affect the preference of amino acid residues at the primary positions (P1 and P1'), but it affected the preference at the P(2) and P(2)' position. In contrast, for smaller substrates with only non-prime sites, SR5-3 protease showed 20-75 times higher kcat/Km values compared with those of control. These findings are in agreement with the notion that increases in enzyme-substrate interactions in subtilases alter the rate-determining step in peptide hydrolysis.

Influence of Pre-oxidation on the Hot Corrosion of DZ68 Superalloy in the Mixture of Na 2SO 4-NaCl

DZ68 alloy is a new Ni-base directionally solidified superalloy for the blade of advanced turbine engine with high ratio of thrust-mass In order to investigate the influence of pre-oxidation on the hot corrosion resistance of DZ68 alloy pre-oxidation treatment was conducted at 950 degrees C in air for 20 h A mixture of 75% Na(2)SO(4)+25% NaCl (in mass fraction) was used for hot corrosion study at 900 degrees C The microstructure of specimens was investigated by using a scanning electron microscope (SEM) equipped with an energy dispersive spectroscopy (EDS) The compositions of the corroded specimens were determined by X-ray diffraction (XRD) After pre-oxidation at 950 degrees C in air for 20 h a protective scale consisting of Cr(2)O(3) Al(2)O(3) NiO NiCr(2)O(4) and Ni(2)Ti(4)O formed on the DZ68 superalloy surface The pre-oxidation treatment improved the initial incubation stage of the alloy in the mixture of 75% Na(2)SO(4)+25% NaCl melts at 900 degrees C The oxide layer degraded gradually with increasing the time of hot corrosion Once the oxide layer was damaged the corrosion rate would increase rapidly accompanied by obvious spoliation of the corrosion products At 900 degrees C the pre-oxidation treatment could not inhibit the accelerated hot corrosion of DZ68 in the mixture of 75% Na(2)SO(4)+25% NaCl melts with a high corrosion rate

Production of LaPO4 coatings using a novel ultrasonically-assisted plating technique

Abstract Dense LaPO4 and LaPO4–Al2O3 coating films were produced on the surface of stainless steel substrates at room temperature and ambient pressure with the aid of a novel ultrasonic-based mechanical coating method, which we call UMCA. The main emphasis was on examining the conditions necessary for the successful coating operation and characterizing the as-deposited coatings for the thickness, uniformity and surface morphology. The experimental results suggested that hardness and thermal conductivity of balls and substrate are key parameters influencing the coating efficiency. The coated samples showed an improved hot corrosion resistant in Na2SO4–NaCl molten salts at 950 °C.

A new equation for predicting the density of multicomponent aqueous solutions conforming to the linear isopiestic relation

The linear isopiestic relation has been used together with well-known thermodynamic equations to establish a new simple predictive equation for density. This equation can provide the density for multicomponent solutions conforming to the linear isopiestic relation using only information on the corresponding binary sub-systems of equal water activity. No additional empirical parameters are involved. The predictive capability of the equation has been tested by comparison with the density measurements for the ternary systems NaCl–KCl–H2O, NaCl–CaCl2–H2O, KCl–CaCl2–H2O, NaCl–MgCl2–H2O, NaCl–Na2SO4–H2O, NaCl–MgSO4–H2O and NaBr–KCl–H2O and their corresponding binary subsystems over the whole experimental composition ranges at 298.15 K. The agreement between the predicted and measured densities is excellent over the entire experimental composition ranges.

The speciation of (CH3)2Sn2+ in electrolyte solution containing the major components of natural waters

Hydrolysis constants of dimethyltin(IV) cation, in different salt solutions (CaCl2: 0.15 ≤ I ≤ 0.90; MgCl2: 0.30 ≤ I ≤ 0.60; NaCl-–NaClO4, NaCl-–NaNO3 mixtures: I = 3; NaCl-–Na2SO4 mixtures: I = 1 mol dm-3) were determined by potentiometric ([H+]-glass electrode) measurements. These data, together with previous data (De Stefano et al., 1996b) were interpreted in terms of DHT (Debye–Huckel type) and Pitzer equations. The mixed electrolyte solution results also allowed us to obtain Θ and Ψ parameters for the Pitzer equation. Calorimetric measurements were made at different ionic strengths in order to find the temperature dependence of hydrolysis constants and of the relative interaction parameters. The body of results allows us to determine the speciation of natural waters in a wide range of ionic strengths and temperatures.

Sulfate solubility algorithms for CaSO4–NaCl–H2O and Na2SO4–NaCl–H2O in chlor alkali brine at 25, 65, 75 and 85 ∘C

Sulfate solubility algorithms for CaSO4–NaCl–H2O and Na2SO4–NaCl–H2O in chlor alkali brine at 25, 65, 75 and 85 ∘C

Thermodynamic properties of electrolyte solutions: emf study of the system NaCl–Na2SO4–H2O at 25, 35 and 45 °C

Electromotive force measurements have been carried out on the system NaCl–Na2SO4–H2O at l= 0.5, 1.0, 2.0, and 3.0 mol kg–1 and 25, 35 and 45 °C using a cell consisting of a sodium ion-selective electrode and an Ag/AgCl electrode. The binary and ternary interaction parameters of the Pitzer formalism and their temperature derivatives have been evaluated. The osmotic coefficients, excess free energies and heats of mixing of the system have been predicted at all the temperatures and ionic strengths studied. The activity coefficients of the second salt, Na2SO4, have been calculated.

Effect of zinc additions to NaCl-Na2SO4molten salt mixture on hot corrosion of Nimocast 713

Hot corrosion studies were conducted at 900°C in a simulated combustion gas atmosphere containing sulphur trioxide at a partial pressure of 750 Pa on a nickel-base super alloy (Nimocast 713) partially immersed in various ZnSO4–10wt-%NaCl–Na2SO4 molten salt mixtures. Weight changes were measured thermogravimetrically with time and it was found that the overall effect of the zinc sulphate addition was to reduce the degree of hot corrosion. Quantitative scanning electron microscopy investigations revealed no evidence of zinc in the attacked zone. It is postulated that the zinc reduces the chlorine activity in the system by forming a volatile chloride, thereby reducing the corrosive effect of the gas phase/molten salt mixtures. MST/507

Ineffectual role of proline metabolism in salt-stressed sugarcane leaves

Sugarcane var. CO 740 is known to be salt-sensitive. Effect of increasing concentrations of NaCl and Na2SO4 as prolonged salt stress, and of −10 bar NaCl and PEG as well as 10 EC NaCl Na2SO4, MgCl2 and MgSO4 as abrupt stress in base-nutrient solution has been investigated on proline metabolism. Neither of these stress conditions could effectively stimulate proline accumulation in the leaves of treated sugarcane plants, in spite of the abrupt drop in leaf osmotic potential. It can be concluded that the sugarcane var. CO 740 lacks this adaptive mechanism and hence seems to be salt-sensitive.

Response of Basin Wildrye and Tall Wheatgrass Seedlings to Salination1

AbstractTall wheatgrass [Agropyron elongatum (Host) Beau. ‘Jose’] and basin wildrye (Elymus cinereus Scribn. & Merr. ‘Magnar’) may have high potential for increasing forage production on degraded, saline/alkaline rangelands in the arid west. To compare their tolerance to salinity and decreasing soil osmotic potentials seedlings of each species were grown in salinized sand cultures in the greenhouse with isosmotic solutions of CaCI2, NaCI, Na2SO4, and equimolar CaCI2 plus NaCl and Na2SO4 plus NaCI. Calcium inhibited growth of both cultivars more than the other salts and was especially toxic to basin wildrye seedlings at osmotic pontentials below − 15 bars. Since Na2SO4, and NaCl are the predominant salts on Great Basin saline rangelands, Ca toxicity should not be a problem in field plantings, but high tolerance to Na should have adaptive value for both cultivars. Absolute yield of Jose shoots and roots exceeded that of Magnar at all soil osmotic potentials, but salination reduced root growth of Jose more than Magnar and reduced shoot growth of Magnar more than Jose. Even though both cultivars maintained relatively high turgor at low leaf water potentials small initial losses in turgor were associated with greatly reduced growth. Either the threshold turgor necessary for growth of these cultivars was very high under these experimental conditions or ionic imbalances or energy expenditures associated with osmotic adjustment limited growth despite high turgor pressure. Gradually salinized plants maintained positive turgor at average leaf water potentials of 12 bars lower than did control plants in which water stress developed rapidly due to decreasing soil matric potentials when water was withheld. Both species survived soil osmotic potentials down to ‐35 bars but grew very little below − 10 bars.

Gipslöslichkeiten in wässerigen Systemen mit NaCl, MgCl2, Na2SO4 und MgSO4

Gypsum solubilities in aqueous systems containing NaCl, MgCl2, Na2SO4, and MgSO4Solubilities of Gypsum (CaSO4·2H2O) have been determined within the systems MgSO4–MgCl2–NaCl–H2O and MgSO4–Na2SO4–NaCl–H2O at 21 different compositions of solutions per concentration range (0.01, 0.05, 0.1, 0.15, 0.5, and 1.0mol/l) of total easily soluble salt. Lines of equal solubilities of gypsum can be constructed form these data. They make possible to estimate gypsum solubility in solutions of similar composition. Small quantities of KCl or KNO3 may be taken as NaCl. Solubilities measured under percolation conditions deviate sometimes to lower, those measured at supersaturation to higher values. The tendency to supersaturation lowers with increasing content of crystal‐solution interfaces within the system. At concentrations of easily soluble salts from 0,01 to 0,15mol/l the solubility of gypsum is governed by the CL−:SO= 4‐ratio. Concentration of solution or Na+:Mg++ ‐ratio are of lower efficiency.

凝結核及び昇華核の化學的研究(第2報)

The investigation was carried out for the purpose of measuring the condensation nuclei essential for the formation of fog.The Chemical Compositions of fog water at Hitoyosi, Kumamoto Prefecture are as follows:The writer demonstrated that coal produced nuclei if this fuel were burnt. In my previous paper. it was shown that sea salt particles driven up from sea-surface are entirely sufficient to serve as condensation nuclei.From the analytical data mentioned above, the writer has proved that condensation nucle are mainly comp_??_sed of combustion products from coal (sulphuric acid. ammonia, soot, coal ashes etc.) or of sea salt particles dispersed in the atmosphere (CaSO4. Na2SO4 NaCl etc.).