Strontium Hydroxide Research Articles

Microwave-assisted dehydration of strontium hydroxide octahydrate: Experimental study and kinetic modeling analysis

In this context, the present study proposes the use of microwave irradiation to improve the dehydration rate and efficiency of strontium hydroxide octahydrate (Sr(OH)2·8H2O) without introducing contaminants. This study revealed that the use of microwave irradiation to dehydrate Sr(OH)2·8H2O is feasible and surprisingly efficient. The effects of this approach on important parameters were investigated using response surface methodology (RSM). The results revealed that the microwave dehydration process follows a linear polynomial model. In addition, compared with the heating time and material thickness, the microwave-assisted dehydration of Sr(OH)2·8H2O is sensitive to the microwave power and not to the material mass. The relative dehydration percentage reached 99.99% when heated in a microwave oven at 950 W for just 3 min. In contrast, a relative dehydration percentage of 94.6% was reached when heated in an electric furnace at 180 °C for 120 min. The XRD spectra also revealed that most of the Sr(OH)2·8H2O transformed into Sr(OH)2 after dehydration via microwave irradiation, whereas a significant portion of the Sr(OH)2·H2O remained after conventional electric dehydration. The experimental data were fitted and analyzed via the thin-layer drying dynamics model, and the results indicated that the dehydrating behavior of Sr(OH)2·8H2O could be well described by the Page model.

Crystallization thermodynamic properties and nucleation kinetics of Sr(OH)2·8H2O in an Sr(OH)2·8H2O-H2O system

There have been few reports in literature on the crystallization thermodynamic properties and nucleation kinetics of strontium hydroxide octahydrate despite their great importance to the reactor design and the regulation of crystal properties. In this work, the crystallization thermodynamic properties of Sr(OH)2·8H2O in pure water were investigated using a dynamic temperature-controlled process and an equilibrium process. The metastable zone width (MSZW) was examined under different crystallization process conditions including stirrer speed, solution concentration, cooling rate, and different strategies in adding seed crystals. In addition, models for the nucleation kinetics and MSZW were successfully constructed based on the classical nucleation model. Based on the data provided, it can be concluded that the dissolution of Sr(OH)2·8H2O in pure water is an entropy-driven endothermic process and its MSZW was gradually narrowed with an increase in stirring speed and concentration and with a decrease in cooling rate. Additionally, adding seeds was an effective strategy to narrow the metastable zone. Therefore, this endeavor provided a rational principle for subsequential investigations of Sr(OH)2·8H2O and other compounds.

Detection of strontium species and Sr(OH)2 NPs formation via double oxidation effect on coal oxide: Preparation and characterization of new coal oxide and its mixture

We introduce an approach double oxidizing process for obtaining water-soluble coal oxide (CObt) and its new mixture for low-cost Sr detection performance. CObt demonstrated a good carbon-based Sr detector with a tunable optical property under various pH conditions. The interaction of CObt with Sr metal cation (0.12 mol/L) indicated a turn-ON photoluminescence (PL) response signal in acidic and basic conditions. The CObt may combine with maghemite (γ-Fe2O3) to create a new mixture, and by forming a mixture we can recover adsorbed Sr by using magnet. The Sr adsorption behavior was also captured using Transmission Electron Microscope (TEM) image, and strontium hydroxide (Sr(OH)2) formation was observed. We observed Sr2+ adsorption performance on the CObt and its mixture up to 40 % of the initial concentration of SrCl2. The presence of maghemite (γ-Fe2O3) in the mixture makes the Sr separation more easily for practical separation. In addition, the formation of Sr(OH)2 (larger size) was identified in basic conditions, and the result also demonstrated a different phenomenon from acidic conditions. The energy dispersive X-ray spectroscopy (EDS) analysis revealed that Sr and Cl are strongly detected in acidic conditions. Additionally, the interaction time (>24 h) must be considered as an essential factor in the mechanism of Sr(OH)2 formation.

Characterization of plate-shaped strontium ferrite particles synthesized via co-precipitate and heat treatment in molten potassium bromide flux

Plate-shaped hexagonal strontium ferrite particles were synthesized using potassium bromide as the molten salt flux. The co-precipitate of strontium and iron hydroxides was heated in the temperature range of 670–870 °C in the flux. Clear peaks based on hexagonal ferrite and weak peaks based on α-Fe2O3 were observed after the heat treatment at 670 °C. The peaks based on α-Fe2O3 almost disappeared after the heat treatment at 730 °C, and the peaks observed in the particles heated at temperatures higher than 730 °C were consistent with the standard data for SrFe12O19. The particle shape tended to change from a hexagonal plate shape to a rounded plate shape with increasing temperature while maintaining a particle diameter of approximately 100–200 nm. The coercive force was approximately 420–440 kA/m, while the magnetization at the applied field of 1353 kA/m was approximately 62 Am2/kg at heating temperatures higher than 750 °C.

Mesoporous Strontium Hydroxide Hydrate as a Nanostructure-Dependent Electrocatalyst for Hydrogen Evolution Reaction

Mesoporous Strontium Hydroxide Hydrate as a Nanostructure-Dependent Electrocatalyst for Hydrogen Evolution Reaction

Synthesis of Bi/Sr doped zinc sulphide by spray pyrolysis technique : Effects of doping concentration on optoelectronic properties

Spray coated of Bi/Sr doped ZnS were prepared on glass substrate from a precursor solution of 0.045M zinc acetate dihydrate, 0.1M thioacetamide, 0.02M Bismuth nitrate and 0.07M Strontium hydroxide at deposition temperature of 200°C. The thin films were characterized using UV-Visible Spectrophotometry, scanning electron microscope (SEM), X-ray diffraction (XRD), flouromax-4 spectrofluorometer(PL) and Fourier transform infrared (FTIR) spectroscopy. The PL study revealed that 5ml Bi/Sr doped ZnS has the highest peak when compared with the pristine and it is closer to the visible region of the solar spectra. UV-visible analysis revealed a decrease in the bandgap energy from 3.25eV- 3.1eV at 5ml Bi/Sr doped ZnS. The structural analysis showed an increase in the intensity of the diffraction peak at 5ml Bi/Sr) doped ZnS thin film. It was concluded that 5ml Bi/Sr concentration is the best quantity of the dopant that can improve the properties of ZnS for optoelectronics application.

Synthesis of Bi/Sr doped zinc sulphide by spray pyrolysis technique: Effects of doping tempertures on solar cell application

With the aim of determining the best synthesizing substrate temperature that will improve the optical properties of Bi/Sr doped ZnS thin film, spray coated Bi/Sr doped ZnS thin films were deposited at a varying glass substrate temperature of 200 °C–350 °C using an interval of 50 °C. A constant volume of 40 ml of precursor solution was created by adding 10 ml of each of the following solutions: 0.045 M solution of zinc acetate dihydrate C4H6O4Zn.2H2, 0.1 M solution of thioacetamide CH3CSNH2, 0.02 M solution of bismuth nitrate Bi(NO3)3.5H2O, and 0.07 M solution of Strontium hydroxide Sr(OH).2. UV–Visible Spectrophotometry, scanning electron microscope (SEM), EDX, X-ray diffraction (XRD), photoluminescence, and Fourier transform infrared (FTIR) were all used to investigate the samples. 53.84 and 193.26% increment in carrier concentration and mobility, a 36.36% and 17.77% reduction in resistivity, and a band gap were obtained at a doping temperature of 300 °C. An open-circuit voltage (Voc) of 0.30 V and a power conversion efficiency of 0.58% were achieved. It was established that a doping temperature of 300 °C on Bi/Sr doped ZnS thin films can be used to lower the band gap of ZnS for solar cell applications.

Synthesis of highly active solid base catalysts of SrO-ZrO2 and SrO-SiO2 by solid–liquid interface reactions of hydrated strontium hydroxide with metal alkoxides

Highly dispersed SrO in amorphous ZrO2 or SiO2, SrO–ZrO2, and SrO–SiO2 mixed oxides were synthesized by applying the solid–liquid interface reaction of Sr(OH)2•8 H2O in the solid phase with an equal number of moles of Zr(OC3H7)4 or with twice the number of Si(OC2H5)4 moles dissolved in 2-propanol. After heat treating at 723 K, the SrO–ZrO2 catalyst exhibited a higher activity than the conventional solid base MgO catalyst for the base-catalyzed retroaldol reaction of diacetone alcohol. The catalytic activity of SrO–ZrO2 was higher by a factor of 1.5 than that of MgO prepared by the thermal decomposition of hydrated magnesium oxalate (MgC2O4•2H2O). By contrast, the highest activity of SrO–SiO2 obtained by thermal activation at 673 K was much lower than that of MgO. The active SrO–ZrO2 catalyst was composed of catalytically inactive species of SrZrO3, and small amounts of Sr(OH)2 and SrCO3. The expected active species of SrO was not detected in powder X-ray diffraction analysis in any sample. The formation of SrO in small crystal size dispersed in amorphous ZrO2 was strongly expected. Similar results were obtained in the SrO–SiO2 sample. An active site formed on SrO–ZrO2 surface is proposed.

Radioactive Waste Management Using Ag\CNTs Composite Prepared by Laser Ablation in Liquid

Over the last one to two decades radioactive waste management was a high priority with development of nuclear research, nuclear industrial and medical applications. Radioactive isotopes introduced drastic quantities of radioactive toxic pollutants to the environment. So, recently the evolution of radioactive waste management has focused on the development technological solutions to this problem. Therefore, in this study Strontium hydroxide (nuclear waste) was installed by Carbon nano-tubes sliver nanoparticles Ag\CNTs composite. The Nd-YAG laser with wavelength 1064 nm, energy 750 mJ operate in 100 pulses was used to prepare Ag\CNTs composite. Sr(HO)2 powder was added to the composite with a calculated ratio. The Sr(HO)2 change to strontium carbonate because of absorbing carbon dioxide from the air, the resulting solution becomes CNTs- AgNPs-SrCo3. To dry the solution samples, three drops of the solution were added one by one on glass slides. To check the amount of damage that may cause by radiation on the host material structure (Ag\CNTs), the sample was irradiated by beta source (90Sr/90Y) for different time periods. X-ray diffraction (XRD) was used to measure the structure properties, while the surface structure such as shape and size property was measured by scanning electron microscope (SEM). From XRD spectra its shows that for all samples before and after Beta irradiation showed appetences of higher peaks at 2θ = 25 degree, and the SEM micrograph showed a homogenous distribution of nanoparticles with average particle size about 24nm and the nuclear waste SrCo3 was well decorated the surface of Ag\CNTs and there was not any indications that there are difference in the composite morphology due to beta radiation exposure.

Distrontium Cerate as a Radiopaque Component of Hydraulic Endodontic Cement.

This study aimed to synthesize distrontium cerate (2SrO·CeO2: S2Ce) and evaluate its properties as an alternative component of the endodontic cement. S2Ce cement was prepared through calcination of strontium hydroxide and cerium carbonate. Subsequently, the crystal phase was confirmed using X-ray diffraction. S2Ce cement exhibited a rapid setting time (121 min) and achieved a high compressive strength (72.1 MPa) at 1 d after mixing, comparable to the compressive strength of a commercial mineral trioxide aggregate (MTA) cement (ProRoot MTA) after 28 d post mixing. However, the compressive strength decreased after 28 d of storage when the W/P ratio was 0.30–0.40 (p < 0.05). Ion dissolution test of the S2Ce cement showed that strontium ions were released after immersion in water (5.27 mg/mL after 1 d), whereas cerium dissolution was not detected. S2Ce exhibited approximately three times higher radiopacity (9.0 mm aluminum thickness equivalent) compared to the commercial MTA (p < 0.05). These findings suggest that S2Ce is a possible component for hydraulic endodontic cement that demonstrates a rapid setting and high radiopacity.

Effect of hydrogen, and vapors of water and organic compounds on the structure of Sr2CuO3

Abstract The effect of hydrogen, and vapors of water and the simplest organic compounds of various classes on the structure of strontium orthocuprate (Sr2CuO3) in the temperature range of 150–300 °C has been investigated. At temperatures up to 200 °C, hydrogen and water are embedded in the structure of Sr2CuO3 from the annealing atmosphere. Under these conditions, organic compounds are oxidized to form water followed by hydration of Sr2CuO3. It has been revealed that Sr2CuO3 is a catalyst for oxidation reactions. Water absorption &gt; 2 wt.% provokes hydrolytic decomposition of Sr2CuO3 with the formation of strontium hydroxide and copper-richer cuprates (SrCuO2 and SrCu2O3). At a temperature of 300 °C, organic compounds partially reduce copper, which is also the cause of the decomposition of Sr2CuO3.

Strontium hydroxide-modified nanoclay montmorillonite for CO2 capture: response surface methodology and adsorption mechanism

ABSTRACT In this work, the effects of surface activation and modification of nanoclay adsorbent on CO2 adsorption capacity were investigated. SEM analysis showed that after activation, the nanoclay layer structure has been retained and did not lose crystallinity as a layer structure. FTIR analysis concludes that structural changes occur even in the early stages of surface treatment with HCl. BET analysis showed that during surface activation, the MMT-4 sample had the highest specific surface area of 144.35 m2.g−1 and pore volume of 0.18 cm3·g−1. Besides, for the modified sample, mesoporous-microporous gradually decrease during surface modification with SH. In the optimisation, the effect of operating conditions including temperature, pressure, acid concentration for adsorbent surface activation, and the weight percent (wt. %) of strontium hydroxide were investigated using RSM. Optimal adsorption capacity of 102.21 mg/gwas obtained at temperature of 25°C, pressure of 9 bar, the acid concentration of 4.03 Mol/L, and SH of 16.25 wt.%. Investigation of adsorption isotherm models indicates a well-fitting correlation between the Sips isotherm model and experimental data. The best fit of the CO2 adsorption experimental data with Elovich model indicates the connection of CO2 to the modified sample by forming the chemical bonds due to the high surface energy. Thermodynamic parameters showed that the adsorption process is spontaneous and exothermic.

Immobilization of Nuclear Waste Using Carbon Nanotubes Prepared by Laser Ablation in Liquid Method

In an attempt to disposal from nuclear waste which threats our health and environments. Therefore we have to find appropriate method to immobilize nuclear waste. So, in this research the nuclear waste (Strontium hydroxide) was immobilized by Carbon nanotubes (CNTs). The Nd-YAG laser with wave length 1064 nm, energy 750 mJ and 100 pulses used to prepare CNTs. After that adding Sr(HO)2 powder to the CNTs colloidal in calculated rate to get homogenous mixing of CNTs-Sr(OH)2. The Sr(HO)2 absorbs carbon dioxide from the air to form strontium carbonate so, the new solution is CNTs-SrCO3. To dry solution putting three drops from the new solution on the glass slides. To investigate the radiation damage on CNTs structure, the sample was irradiation by Beta source (90Sr/90Y) for different period of time. The structure properties were measured using X-ray diffraction XRD while the shape and size property was measured by scanning electron microscope SEM.&#x0D; The result shows homogenous distribution of nanoparticles with average particle size about 20nm. The XRD spectra for all sample before and after irradiation shows the higher peaks that it’s almost appearance at 2 = 25 degree and when compared the XRD phase with Standard card the resultant nanomaterial is Strontium carbonite (SrCo3). From SEM micrograph, CNTs-SrCO3 were well decorated on the surface of CNTs and there was not any remarkable difference in the corresponding due to Beta radiation exposure.

Synthesis of SrO–Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; Solid Base Catalysts from Strontium Hydroxide and Aluminum Alkoxide by a Solid-liquid Interface Reaction

Synthesis of SrO–Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; Solid Base Catalysts from Strontium Hydroxide and Aluminum Alkoxide by a Solid-liquid Interface Reaction

Antimicrobial Potential of Strontium Hydroxide on Bacteria Associated with Peri-Implantitis

Background: Peri-implantitis due to infection of dental implants is a common complication that may cause significant patient morbidity. In this study, we investigated the antimicrobial potential of Sr(OH)2 against different bacteria associated with peri-implantitis. Methods: The antimicrobial potential of five concentrations of Sr(OH)2 (100, 10, 1, 0.1, and 0.01 mM) was assessed with agar diffusion test, minimal inhibitory concentration (MIC), and biofilm viability assays against six bacteria commonly associated with biomaterial infections: Streptococcus mitis, Staphylococcus epidermidis, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Escherichia coli, and Fusobacterium nucleatum. Results: Zones of inhibition were only observed for, 0.01, 0.1, and 1 mM of Sr(OH)2 tested against P. gingivalis, in the agar diffusion test. Growth inhibition in planktonic cultures was achieved at 10 mM for all species tested (p < 0.001). In biofilm viability assay, 10 and 100 mM Sr(OH)2 showed potent bactericidal affect against S. mitis, S. epidermidis, A. actinomycetemcomitans, E. coli, and P. gingivalis. Conclusions: The findings of this study indicate that Sr(OH)2 has antimicrobial properties against bacteria associated with peri-implantitis.

Effect of Alkali Metals and Alkaline Earth Metals Hydroxides on the Structure of Wool Fibers

ABSTRACT Wool is sensitive toward the effect of alkaline solutions which are usually used in the dissolution of wool fibers to regenerate keratin. In this investigation, the effect of different alkalis on the chemical composition and the secondary structure of wool was studied. Wool was treated with equivalent amounts of alkali metal hydroxides (lithium, sodium, and potassium hydroxides) as well as alkaline earth metal hydroxides (strontium and barium hydroxides). The effect of these alkalis on wool was monitored using amino acid analysis, elemental analysis, carboxylic content, acid, and base combining capacity, urea-bisulfite and alkali solubility, and FTIR spectroscopy. Further structure elucidation was conducted by thermo-gravimetric analysis, differential scanning calorimetry, and X-ray diffraction pattern. Scanning electron microscopy was used to assign the alteration of the fiber morphology of the alkali-treated wool. The results of this investigation indicate that the effect of the used alkalis on wool is not similar. Cystine, glycine, and the basic amino acids are the most affected species in the treated wool. Some elimination reactions were involved during alkaline treatment of wool; namely decarboxylation, desulphydration, and deamination. The secondary structure of wool treated with Sr(OH)2 and Ba(OH)2 was changed from the α-helical structure into the β-sheet form.

Reaction mechanism on the formation of (Sr, Ba)TiO3 and Ba(Zr, Ti)O3 at near room temperature by using A(OH)2•8H2O (A = Sr, Ba) and BO2•nH2O gel (B = Zr, Ti, Zr0.45Ti0.55)

ABSTRACT Recently, our group synthesized perovskite-type oxide ABO3 (A = Sr, Ba; B = Ti, Zr) with high crystallinity simply by leaving a powder mixture of A(OH)2•nH2O and BO2 hydrous gel at room temperature to 323 K for 3–10 days. In this study, perovskite solid solution (Ba, Sr)TiO3 and Ba(Zr, Ti)O3 were synthesized to investigate the reaction mechanism in this synthesis method in detail. The perovskite solid solution (Ba, Sr)TiO3 was obtained by using barium hydroxide, strontium hydroxide and TiO2 hydrous gel as the staring materials. On the other hand, in the case of using barium hydroxide and the mixture of TiO2 hydrous gel and ZrO2 hydrous gel as the starting materials, a mixed phase of BaTiO3 and BaZrO3 was obtained. B-site-substituted perovskite solid solution Ba(Zr0.45Ti0.55)O3 was obtained by using barium hydroxide and (Zr0.45Ti0.55)O2 hydrous gel as the starting materials. From the above, it was clarified that in this synthetic method, the Sr and Ba ions diffuse into the water part of hydrous gel and then slowly react with Ti(OH)4 to form a perovskite lattice.

Effects of Nanostructure Additives on Supercooling and Freezing of Distilled Water

The phenomenon of supercooling, which prevents freezing of water below the freezing point, is an obstacle to the production of inexpensive ice. In the case of ice heat storage systems using bio-preservation, low-temperature refrigeration of food and ice capsules in the HVAC industry, the supercooled water in capsules that indirectly come into contact with the outside is one of the problems that must be solved to maintain energy costs and the quality of food or organs. To improve this, experimental evaluation of additives that serve as crude nuclear agents is needed. However, research on this area needs to be supported because the types of additives are limited and their physical properties are unstable. In this paper, the effect of distilled water containing an additive of average diameter nanometer size on solution (frozen) supercooled below the freezing point was investigated. The supercooling time and supercooling level of each specimen were analyzed after addition of kaolin, strontium hydroxide, oxidizing mineral and nano-sized single-wall carbon nanotubes (SWCNT) as mineral fine particles in the distilled water. As a result, it has been confirmed that kaolin and SWCNT can be used as nuclear materials to release supercooling of water. In addition, when kaolin, a mineral fine particle, is used as a nuclear material, its size affects the performance of nuclearization. This confirmed the impact of nuclear material particle size and structure on overcooled emissions.

Visible Light Responsive Strontium Carbonate Catalyst Derived from Solvothermal Synthesis

A single crystalline phase of strontium carbonate (SrCO3) was successfully obtained from solvothermal treatments of hydrated strontium hydroxide in ethanol (EtOH) at 100 °C for 2 h, using specific Sr:EtOH mole ratios of 1:18 or 1:23. Other solvothermal treatment times (0.5, 1.0 and 3 h), temperatures (80 and 150 °C) and different Sr:EtOH mole ratios (1:13 and 1:27) led to formation of mixed phases of Sr-containing products, SrCO3 and Sr(OH)2 xH2O. The obtained products (denoted as 1:18 SrCO3 and 1:23 SrCO3), containing a single phase of SrCO3, were further characterized in comparison with commercial SrCO3, and each SrCO3 material was employed as a photocatalyst for the degradation of methylene blue (MB) in water under visible light irradiation. Only the 1:23 SrCO3 sample is visible light responsive (Eg = 2.62 eV), possibly due to the presence of ethanol in the structure, as detected by thermogravimetric analysis. On the other hand, the band gap of 1:18 SrCO3 and commercial SrCO3 are 4.63 and 3.25 eV, respectively, and both samples are UV responsive. The highest decolourisation efficiency of MB solutions was achieved using the 1:23 SrCO3 catalyst, likely due to its narrow bandgap. The variation in colour removal results in the dark and under visible light irradiation, with radical scavenging tests, suggests that the high decolourisation efficiency was mainly due to a generated hydroxyl-radical-related reaction pathway. Possible degradation products from MB oxidation under visible light illumination in the presence of SrCO3 are aromatic sulfonic acids, dimethylamine and phenol, as implied by MS direct injection measurements. Key findings from this work could give more insight into alternative synthesis routes to tailor the bandgap of SrCO3 materials and possible further development of cocatalysts and composites for environmental applications.

Simple and highly active strontium-based catalyst for detoxification of an organophosphorus chemical warfare agent simulant

A mixture of strontium carbonate, hydroxide and oxide was prepared by thermal decomposition of SrCO3 and employed as catalyst in the decomposition of the chemical warfare agent simulant methyl paraoxon, by means of its transesterification with 1-propanol. The catalyst, which was characterized by N2 physisorption (BET method), temperature programmed desorption (CO2-TPD), Fourier Transform Infrared spectroscopy (FTIR), X-Ray diffraction (XRD) and Raman spectroscopy, promoted rate enhancements of the order of 107-fold in comparison to the spontaneous propanolysis reaction, the greatest catalytic effect promoted by metal oxide-based catalysts ever reported for this reaction. Compared to the fresh catalyst, the catalyst directly stored in the reaction solvent showed similar catalytic performance. Analysis of the reaction products by liquid chromatography with electrospray ionization mass spectrometry detection confirmed the transesterification of the substrate leading to dimethyl n-propyl phosphate, a product structurally related to a family of trialkyl phosphate flame retardants.