Strontium Nitrate Research Articles

Bio-Template Synthesis of Strontium Titanate and Application for Heavy Metal Adsorption in Wastewater

Heavy metal ions, such as chromium, cadmium, mercury, nickel, copper, and zinc, cause severe pollution to water bodies as well as enormous harm to people and the biosphere. Adsorption and removal of heavy metal pollution in water is a low-cost and straightforward method. Researchers are currently looking for materials that are cheap and readily available, and have high adsorption and enrichment properties for heavy metal ions. Strontium titanate is a new type of ceramic material, and there have been few related research reports. The work reported a new method for the synthesis of strontium titanate adsorbent by the sol-gel biotemplate method. A sol-gel method, using different types of straws as biological templates, was selected to prepare nano-strontium titanate adsorption materials. In this experiment, chelate formed using tetra-n-butyl titanate and strontium nitrate as raw materials, and acetic acid as a chelating agent, thereby forming a sol. Then, corn straw and sunflower straw immersed in the sol and aged for a period. After drying and calcination, a strontium titanate adsorbent with a biofilm microstructure was obtained. Besides, the structure of strontium titanate synthesized was characterized by SEM and XRD. In this experiment, zinc ions were used as adsorbed ions to investigate the adsorption capacity of the synthesized strontium titanate adsorbents for heavy metal ions in water. Studies have shown that strontium titanate synthesized by the biological template method was a porous material retaining some of the natural tissue structure characteristics of the biological template. Compared with the strontium titanate obtained without using the biological template, the adsorption capacity of the strontium titanate powder synthesized by the biological template method to zinc ion was significantly improved. We studied the influence of the selection and adsorption of biological templates and pH conditions on the ability of strontium titanate to adsorb zinc ions.

Preparation of strontium doped mesoporous ZnO nanoparticles to investigate their dye degradation efficiency

Mesoporous strontium doped ZnO nanoparticles are synthesized as photocatalyst by using zinc nitrate hexahydrate, surfactant P123, strontium nitrate hexahydrate via the hydrothermal process. X-ray diffraction (XRD), UV-visible spectroscopy (UV), Fourier transform infrared (FTIR), Photoluminescence (PL), Energy-dispersive x-ray (EDX), Scanning electron microscopy (SEM), Transmission Electron Microscopy (TEM), and Brunauer–Emmett–Teller (BET) characterizations are used for the analysis of all the samples. XRD spectra disclose the disparity in the crystal size 14.98 to 22.74 nm. The study of UV spectroscopy revealed the energy bandgap difference between 3.3–2.92 eV. PL spectroscopy shows the effect of doping on the electron-hole recombination rate of the sample. FTIR analysis has utilized to determine the functional groups such as –OH, C=O=C, and –C–O present in the sample. EDX spectra show the elemental compositions of the sample. SEM images show the agglomerated morphology and TEM images show the different shape morphology of the sample. BET analysis shows the occurrence of 39.9 m2 g−1 surface area with mesoporous morphology. The effect of the increasing percentage of strontium on the photocatalytic capability of ZnO is checked against methylene blue and congo red dyes with 75% and 80% degradation.

Effect of Sr@ZnO nanoparticles and Ricinus communis biodiesel-diesel fuel blends on modified CRDI diesel engine characteristics

The current study aims to evaluate the performance and emission characteristics of a modified common rail direct injection (CRDI) diesel engine fueled by Ricinus communis biodiesel (RCME20), diesel (80%), and their blends with strontium-zinc oxide (Sr@ZnO) nanoparticle additives. The Sr@ZnO nanoparticles were synthesized using aqueous precipitation of zinc acetate dehydrate and strontium nitrate. Several characterization tests were performed to study the morphology and content of synthesized Sr@ZnO nanoparticles. The Sr@ZnO nanoparticles were steadily blended with RCME20-diesel fuel blend in mass fractions of 30, 60 and 90 ppm using a magnetic stirrer and ultrasonication process. For a long term stability of nanoparticles, Cetyl trimethylammonium bromide (CTAB) surfactant was added. The physicochemical properties of the fuel blends were measured using ASTM standards. The CRDI engine was operated at two compression ratios 17.5 and 19.5, 1000 bar injection pressure, 23.5°BTDC injection timing and constant speed. For enhanced swirl and turbulence, and improved spray quality lateral swirl combustion chamber and 6-hole fuel injector were used. The compression ratio of 19.5 and 60 ppm of Sr@ZnO nano-additives showed overall enhancement in engine characteristics compared to RCME20 fuel. The engine characteristics such as BTE, HRR and cylinder pressure increased by 20.83%, 24.35% and 9.55%, and BSFC, ID, CD, smoke, CO, HC and CO2 reduced by 20.07%, 20.64%, 14.5%, 27.90%, 47.63%, 26.81%, and 34.9%, while slight increase in NOx for all nanofuel blends was observed.

Stable nitrogen and oxygen isotope fractionation during precipitation of nitrate salt from saturated solutions.

Nitrate is an oxyanion similar to CO3 - and thus should undergo stable N and O isotope fractionation during dissolution or precipitation. This process should dominate abiotic soil nitrate processes in hyperarid regions of Earth and possibly Mars. The N and O isotope fractionations during the precipitation of nitrate salt from saturated solutions at ~20°C were determined by two methods: rapid precipitation by antisolvent crystallization and slow uninhibited precipitation in a desiccator. In the antisolvent crystallization procedure, increasing volumes of acetone were added to samples of saturated sodium and strontium nitrate solutions to instantaneously precipitate nitrate salt. In the slow procedure (requiring weeks), slow evaporative water loss drove the process. There was little difference between the two procedures. Using a Rayleigh model, the calculated N fractionation (15 εproduct-residual ) ranged from 1.69‰ to 2.77‰, whereas for O, the 18 εproduct-residual values were between 1.27‰ and 4.61‰. The N isotope fractionation between NO3 - and the metal solid is similar to that between C in dissolved CO3 -2 and carbonates. We found that O versus N isotope plots of soil nitrate in a cold/dry Antarctic chronosequence had slopes similar to those from the experiments, revealing abiotic transport. In the Atacama Desert, where the soil nitrates are a mix of biological and tropospheric nitrate, there is an inverse relationship between soil N and O isotopes. These two relationships were compared with the isotope composition of nitrate from Martian meteorite EETA79001. While the N and O isotope composition of the Martian nitrate is remarkably similar to that of the present Atacama Desert, the interpretation of the slope of the O versus N isotopes remains ambiguous due to the limited number of samples. Additional NO3 samples from Martian meteorites are needed to address the question of abiotic versus biotic alteration of NO3 - on Mars.

A Comparative Study for Application of Pitzer and ePC-SAFT Equations to Predict Volumetric and Saturation Properties in “Formation” Water

Predictions of salt solubility, brine vapor pressure and density are necessary to plan subsurface and surface operations. In this work, a comparative study was conducted to investigate prediction capabilities for salt solubility, equilibrium and volumetric properties of several minerals in “Formation” water by the Pitzer model (a commonly used industrial model) and by the ePC-SAFT equation of state (EOS). To achieve this, several validation and comparison steps were considered for reliable implementation of both models. Firstly, solubility, brine densities and vapor pressures for single-salt solutions were predicted. Afterward, the models’ applications were extended to several mixtures of two salts to predict solubility compared to experimental data from available literature. ePC-SAFT shows promising accuracy. The average relative deviation for prediction of liquid density (which cannot be estimated with the Pitzer model) for single-salt solutions of NaBr, KCl, NaCl and Na2SO4 are 1.13%, 0.70%, 1.02% and 0.36%, respectively. The average relative deviation from experimental data of vapor pressure for mixtures of NaCl and KBr is 0.75% and for mixtures of NaBr and KCl is 0.74% for systems with different concentrations. Moreover, a stochastic regression procedure is presented to evaluate the ePC-SAFT parameters. This technique is used for strontium in different salt solutions. The average relative deviation for mean ionic activity coefficients calculated by ePC-SAFT from experimental data using the ePC-SAFT parameters of strontium from the work of Held et al. [1] for single-salt solutions of strontium chloride, strontium bromide, strontium iodide, strontium nitrate and strontium perchlorate are 19.73%, 19.96%, 15.15%, 14.95% and 25.70%, respectively. These values using the ePC-SAFT parameters of strontium regressed in this work are 6.98%, 10.13%, 8.33%, 9.59% and 10.08%, respectively. Finally, the solubility of different salts was studied for mixing of formation water (FW) and injection water (SW).

Structural, optical, thermal, and magnetic properties of strontium nitrate doped l-Alanine crystal

L-Alanine (LA) and strontium nitrate added l-Alanine (SNLA) single crystals were grown using low-temperature solution growth technique. The lattice parameters are a = 6.02 Ả, b = 12.35 Ả, c = 5.77 Ả, V = 428.98 Ả3 and α = β = γ = 90˚, it confirms that both LA and SNLA have orthorhombic crystal structure with space group P212121. From the Tauc’s plot, the obtained band gap of LA and SNLA are 5.16 eV and 5.26 eV respectively. The observed thermal stability of LA and SNLA are 193.5 ̊C and 236.8 ̊C respectively. By using the Z- Scan technique, optical nonlinearity and the optical parameters like a nonlinear index of refraction (n2), nonlinear susceptibility and nonlinear absorption coefficient (β) were determined. From magnetic studies, there is an increase in magnetization and there is huge domain changes happened of the dopant, a decrease in retentivity.

Osteoclast and osteoblast response to strontium-doped struvite coatings on titanium for improved bone integration.

To develop implants with improved bone ingrowth, titanium substrates were coated with homogeneous and dense struvite (MgNH4PO4·6H2O) layers by means of electrochemically assisted deposition. Strontium nitrate was added to the coating electrolyte in various concentrations, in order to fabricate Sr-doped struvite coatings with Sr loading ranging from 10.6 to 115μg/cm2. It was expected and observed that osteoclast activity surrounding the implant was inhibited. The cytocompatibility of the coatings and the effect of Sr-ions in different concentrations on osteoclast formation were analyzed in vitro. Osteoclast differentiation was elucidated on morphological, biochemical as well as on gene expression level. It could be shown that moderate concentrations of Sr2+ had an inhibitory effect on osteoclast formation, while the growth of osteoblastic cells was not negatively influenced compared to pure struvite surfaces. In summary, the electrochemically deposited Sr-doped struvite coatings are a promising approach to improve bone implant ingrowth.

The Performance of Red Flare Pyrotechnic Compositions Modified with Gas Generating Additives

AbstractIn this work, an effective, but still not well‐explored area of red flare pyrotechnic formulations was investigated. High magnesium content (40–60 % w.t.) and the presence of conventional gas generating materials were the specific features of formulations explored herein. Such illuminant compositions possessed a low burning rate and high specific luminous intensity. The investigated system was based on strontium nitrate, rounded magnesium powder, chlorinated rubber, binder and gas generating additives. Emission spectra, light intensity and burning time have been measured during the experiment and recalculated to the specific luminous intensity and color purity. Additives in the form of 2‐cyanoguanidine, Melamine, Azodicarbonamide, Calcium resinate, Shellac, Strontium oxalate, Lactose, Dextrin, Phenolic resin, Lignin sulfonate, 5‐aminotetrazole, Urea, Guanidinium nitrate (GN), Hexamine and Sulfur were evaluated in Mg‐rich flare compositions. The use of GN was studied more carefully as an exceptionally efficient additive that increased the flares light intensity by 60 %, in comparison to the standard GN‐free composition, while maintaining high color purity of 90–97 %.

Effect of the Sintering Process on the Structure, Colorimetric, Optical and Photoluminescence Properties of SrWO4 Phosphor Powders

Scheelite-type strontium tungstate (SrWO4) phosphor powders were successfully synthesized using strontium nitrate and tungstic acid as starting materials by a gamma-ray irradiation-assisted polyacrylamide gel route. The phase purity, structure, functional groups, surface morphology, chemical composition, colorimetric, optical and photoluminescence properties of SrWO4 phosphor powders were systematically studied by various testing instruments. The crystallite size of SrWO4 phosphor powders increases with the increasing of sintering temperature. The color, optical and photoluminescence properties of SrWO4 phosphor powders are strongly dependent on the sintering temperature, carbon chain and the distortion of tetrahedral [WO4] clusters. The fluorescence emission at (310Â nm, 338Â nm, 360Â nm and 400Â nm) and 465Â nm can be ascribed to the new energy level formed by a carbon chain, amorphous SrWO4 or oxygen vacancy, and the distortion of tetrahedral [WO4] clusters, respectively.

The carbonate location in mixed calcium and strontium carbonated apatites

Mixed calcium/strontium carbonated apatites were obtained by aqueous addition of mixtures of calcium and strontium nitrate to NH4H2PO4 and Na2CO3 in the presence of both low and high sodium concentrations. The calcium: strontium ratios in the products were obtained by xrf and carbonate percentages by combustion analysis. Peak-fitting of the asymmetric carbonate region of the IR spectra, using the procedures developed previously, showed that an increase in the percentage of strontium in the apatite led to an enhancement in the percentage of A-type carbonate. Because of the larger size of Sr2+ relative to Ca2+, this result can be attributed to an expansion of the channel, which leads to an increased stability of carbonate in the channel. The cogwheel- like control of channel carbonate can be utilized to prepare apatites appropriate for various applications.

Fireworks: Requisite for Forensics Evolution from Conventional to Green Crackers in India - A Perspective

Social life in India is enriched with festivals, traditions and cultural events, often, associated with bursting crackers during celebration. Firework exhibition and bursting crackers are a symbol of jubilation. The hazardous effects of fireworks are often obscured by the cloud of smoke and amusement ultimately breeding root cause to severe accidental injuries. Fire accidents occur due to surpassing supervisory measures while handling fireworks [1-3]. The illicit production, sale, illegal trade of crackers is another major direct challenge for criminal judiciary system and regulatory authorities [4-6]. Television, print and social media are crammed with evidences apart from actual incident data where crackers played a major role in crime. The chemistry of conventional fireworks has not much transmuted since archaic times. Common constituents in fireworks are carbon centered fuel, a reducing agent and an amalgamation of metal salts functioning as oxidant and colourants. The lightening of fireworks commences with an exothermic process engendering smoke as a by-product holding gases like carbon monoxide, carbon dioxide, sulphur dioxide and nitrogen dioxide, as well as suspended particulate matter between PM2.5-PM10. Conventional fireworks also integrate hazardous chemicals like nitrates of strontium, sodium and barium, carbonates of strontium, calcium, barium and copper, sulphates of strontium and calcium, chlorides of calcium and barium, aluminium and magnesium salts, sodium oxalate, copper oxide, iron dust powder and potassium perchlorate, which act as stabilizers, oxidizers and colorants [7]. Both metals and radicals determine the presence of explosive material. All these residues are hazardous in nature

Synthesis, physical and photoelectrochemical characterizations of Sr0.5Nb3O8·1.7H2O: application to the Rhodamine B oxidation under solar light

The layered niobate Sr0.5Nb3O8·1.7H2O is synthesized by soft chemistry in aqueous electrolyte via Sr2+ → H+ exchange between strontium nitrate and niobic acid HNb3O8·H2O. The material is identified by X-ray diffraction using Rietveld refinement, thermal analysis (TG/DSC) and optical measurements. The semiconducting and photoelectrochemical properties are investigated for the first time. The band gap of Sr0.5Nb3O8·1.7H2O is evaluated at 3.67 eV, and the transition is directly allowed due to the charge transfer O2−: 2p → Nb5+: 4d. The thermal variation of the electrical conductivity shows that 4d electrons are localized and the data are fitted by a small-polaron hopping model: σ = σo exp {− 0.13 eV/kT}. The capacitance measurement done in the ionic electrolyte (Na2SO4, 10−2 M) indicates n-type semiconductivity with a flat band potential of − 0.09 VSCE. The conduction band, made up of Nb5+: 4d orbital, is located at − 0.22 VSCE. As application, Rhodamine B (RhB) is oxidized by photocatalysis on Sr0.5Nb3O8·1.7H2O through O2· radicals; 56% of the initial concentration (10 mg L−1) is eliminated after 3 h under solar light (90 mW cm−2), and the Rh B oxidation follows a first-order kinetic with a rate constant of 0.246 h−1.

Synthesis and characterization of strontium fluor-hydroxyapatite nanoparticles for dental applications

Being biocompatible, bioactive, having low solubility in a wet environment and showing similarities to mineral part of hard tissue in human's body, hydroxyapatite has so many applications in dentistry and related hard tissue concerns. Fluoride ion being found in bone and enamel can be joined to hydroxyapatite and reduce solubility and also hold biocompatibility relatively like hydroxyapatite. Playing main role in bone regeneration, strontium can be used partially or totally to treat biomaterials and increase biocompatibility and bioactivity. In this study hydroxyapatite and strontium hydroxyapatite were synthesized by chemical precipitation of different percentages of strontium by which substitutes calcium. Additionally, Fluoride was incorporated into the apatite structure, using pH-cycling method and producing Strontium- Fluoride hydroxyapatite. Diammonium phosphate, calcium nitrate, strontium nitrate and sodium fluoride were starting materials and solution of sodium hydroxide and nitric acid were used to control pH. Accordingly, synthesized nano-powders characterized by XRD, FTIR, F-selective electrode, inductively coupled plasma spectroscopy and SEM. Subsequently, biological assessment of fluoride's and strontium's influence on the proliferation and differentiation of MG63 cell line was conducted by MTT and ALP tests. Results of XRD and FTIR showed that nano-crystals of HA, SrHA, FHA and F-SrHA were successfully achieved by this method. SEM images revealed that prepared crystalline powders morphology was nano-size and spherical. Biocompatibility also approved by MTT tests. Also, since the process of calcification of hard tissues (bones and teeth) is effected by alkaline phosphatase enzyme (ALP), the influence of both alone and combined fluoride and strontium on cell differentiation was investigated. Consequently, results represent the ability of these elements to enhance remineralization of tooth enamel.

Fabrication of Strontium Nitrate Nanoparticles through a Spraying‐in Non‐Solvent Process Optimized by Taguchi Approach

AbstractThe operation variables of the solution spraying‐in non‐solvent as a micronization process were effectively optimized through Taguchi robust design to obtain Sr(NO3)2 nanoparticles. The process conditions, which were evaluated at two levels, included the concentration of Sr(NO3)2, type of the non‐solvent, the approach of solution adding to the non‐solvent, temperature, type and ratio of the modifier. Analysis of variance (ANOVA) was used to quantitatively evaluate the role of these operating conditions on the size of resulting Sr(NO3)2 particles. It was found that spraying‐in non‐solvent technique can be adjusted to efficiently control the size of Sr(NO3)2 particles by optimizing the operating conditions. The results showed that at the concentration of 85% (w/v) Sr(NO3)2 in aqueous solution, using methanol as the non‐solvent, tuning 5 as the non‐solvent temperature, adding the solution by spraying, utilizing methyl ethyl ketone (MEK) as the modifier and 1:4 as the modifier/non‐solvent ratio lead to optimal results in terms of the properties of the Sr(NO3)2 nanoparticles. The experimental data confirmed that the formation of Sr(NO3)2 nanoparticles with an average size of about 38 nm under optimal process conditions.

Response of Arabidopsis halleri to cesium and strontium in hydroponics: Extraction potential and effects on morphology and physiology

Stable isotopes of cesium (Cs) and strontium (Sr) as well as their radioactive isotopes are of serious environmental concern. The pollution of the biosphere, particularly soil and water has received considerable attention for removal of these contaminants in recent years. Arabidopsis halleri (A. halleri) is a hyperaccumulator plant species able to take up large amounts of several metals into its above ground organs without showing significant signs of toxicity. Therefore, we investigated responses, metal accumulation and element distribution in roots and leaves of A. halleri after treatment with stable Cs and Sr. Plants were hydroponically grown in different concentrations of cesium sulfate (between 0.002 and 20 mM) and strontium nitrate (between 0.001 and 100 mM).Uptake of Cs and Sr into leaves was analyzed from extracts by inductively coupled plasma mass spectrometry (ICP-MS). Although internal concentration of Cs and Sr increased with rising external concentrations, the amount of accumulated metal in relation to available metal decreased. Therefore, the potential of the plant to effectively transfer metals from growth medium to leaves occurred at low and moderate concentrations, whereas after that when the concentration of metal increased further the transfer factors were decreased. A. halleri accumulated Sr more efficiently than Cs. The transfer factors were higher for Sr (up to 184) than for Cs (up to 16). The results indicate positive correlation of Cs and Sr accumulation to K and Ca transport to leaves.The toxicity of Cs and Sr was assessed by measuring photosynthetic efficiency and growth parameters. In leaves, Cs and Sr affected the chlorophyll fluorescence at their low and high concentrations. Significant reduction of plant growth (dry weight of roots and leaves) was observed at Sr concentrations >0.01 mM. Cs-treated plants exhibited only decreased length of leaves at concentrations>0.02 mM.The distribution of the elements within the different tissues of leaves and roots was investigated by using Energy Dispersive X-Ray microanalysis (EDX) with a scanning electron microscope (SEM). EDX revealed that Cs and Sr were accumulated differently in root and leaf tissues.The hydroponic experiment showed a potential for A. halleri to treat hotspots with radioactive Cs and Sr.

Response of Plantago major to cesium and strontium in hydroponics: Absorption and effects on morphology, physiology and photosynthesis

Human activities lead to increasing concentration of the stable elements cesium (Cs) and strontium (Sr) and their radioactive isotopes in the food chain, where plants play an important part. Here we investigated Plantago major under the influence of long-term exposure to stable Cs and Sr.The plants were cultivated hydroponically in different concentrations of cesium sulfate (between 0.002 and 20 mM) and strontium nitrate (between 0.001 and 100 mM).Uptake of Cs and Sr into leaves was analyzed from extracts by inductively coupled plasma mass spectrometry (ICP-MS). It was increased with increasing external Cs and Sr concentrations. However, the efficiency of Cs and Sr transfer from solution to plants was higher for low external concentrations. Highest transfer factors were 6.78 for Cs and 71.13 for Sr. Accumulation of Sr was accompanied by a slight decrease of potassium (K) and calcium (Ca) in leaves, whereas the presence of Cs in the medium affected only uptake of K.The toxic effects of Cs and Sr were estimated from photosynthetic reactions and plant growth.In leaves, Cs and Sr affected the chlorophyll fluorescence even at their low concentrations. Low and high concentrations of both ions reduced dry weight and length of roots and leaves.The distribution of the elements between the different tissues of leaves and roots was investigated using Energy Dispersive X-Ray microanalysis (EDX) with scanning electron microscope (SEM). Overall, observations suggested differential patterns in accumulating Cs and Sr within the roots and leaves.When present in higher concentrations the amount of Cs and Sr transferred from environment to plants was sufficient to affect some physiological processes. The experimental model showed a potential for P. major to study the influence of radioactive contaminants and their removal from hotspots.

超臨界水熱合成法によるSrフェライト粒子の合成

Sr ferrite nanoparticles were synthesized by supercritical hydrothermal synthesis. The precursor as a raw material was prepared by neutralizing a solution of iron nitrate (III) and strontium nitrate with KOH. First, a batch type reactor was used to explore the condition (temperature and reaction time) to synthesize Sr ferrite. As a result, formation of Sr ferrite was observed under supercritical water condition, 653 K and 10 min even though hematite was included in the product as impurities. However, all the hematite was changed to Sr ferrite when the reaction time was enlongated to 60 min. Particle size was around 1 μm. In the case of a flow system that can achieve rapid heating by mixing precursor with high temperature water, even at very shot reaction time Sr ferrite was synthesized in a single phase without any inpurity. It is because of the rapid heating system that could suppress the formation process of hematite at a lower temperature range. The particle size was as small as 200 nm, which is probably because of the extremely high supersaturation in supercritical state just after the rapid heating. Effect of synthetic parameters on microstructure for obtained Sr ferrite nano-materials was investigated. Magnetization characteristic of Sr ferrite nanoparticle synthesized by the flow-through supercritical water synthesizer was also evaluated.

Microencapsulation of Stearic Acid into Strontium Titanate Shell by Sol‐Gel Approach for Thermal Energy Storage

AbstractMicroencapsulation of phase change material (PCM), stearic acid (SA) into strontium titanate (SrTiO3) shell was generated by means of sol‐gel approach using strontium nitrate and titanium tetraisopropoxide as precursors. The influence of core‐to‐shell ratio (stearic acid‐to‐strontium nitrate) was investigated on encapsulation ratio, stability and encapsulation efficiency in detail. It turned out that a maximum encapsulation efficiency of 41% and encapsulation ratio of 39% were resulted for the (1:2) ratio microencapsulated PCM. The TGA data confirmed that the fabricated MEPCMs degraded in two steps with less weight loss (78%) compared to pristine SA (99.76%). The cycling stability test recorded after 500 melting/solidification cycles revealed that the developed microcapsules retained excellent thermal stability. Detailed preparation of MEPCM and its analytical as well as thermal characterizations are presented.

Combustion Derived SrTiO3: Synthesis, Characterization and Evaluation of Electrochemical Behavior Towards Quantification of Hg(II) Ions

<p>In this work, we are reporting the synthesis of porous SrTiO3 nanoparticles by using solution combustion route employing strontium nitrate and titanium-peroxo complex as oxidizer. The results of physico-analytical techniques revealed that SrTiO3 have a relatively small particle size, good dispersibility and diminished agglomeration. Powder X-ray diffraction pattern shows cubic perovskite structure (space group Pm3m) and the morphology was observed using a scanning electron microscope. The band gap of 3.24 eV was calculated using the diffuse reflectance spectrum. The surface area (~26.51 m2/g) of SrTiO3 was measured by BET method. SrTiO3 nanoparticles show violet-blue-green photoluminescence emission spectrum at room temperature. The photocatalytic degradation was carried out to investigate the photocatalytic activity of SrTiO3 under UV-light and evaluated for the electrochemical quantification of Hg(II) ions in aqueous solution using differential pulse anodic stripping voltammetry. The results reveal that SrTiO3 nanoparticles show better quantification result for Hg(II) ions. </p>

Controlling the Composition and Magnetic Properties of Nano-SrFe12O19 Powder Synthesized from Oily Cold Mill Sludge by the Citrate Precursor Method.

This paper proposes a new method for producing nano-SrFe12O19 powder by the citrate precursor route using solid waste as a source of iron. This solid iron-containing waste, which exists in the form of an oily sludge, is produced by a cold rolling mill. This sludge was first subjected to a process, including sulfuric acid leaching, oxidation, precipitation, and nitric acid leaching, to obtain an iron nitrate (Fe(NO3)3) solution. Next, the Fe(NO3)3 solution was mixed with a strontium nitrate (Sr(NO3)2) solution obtained by subjecting strontium carbonate to nitric acid leaching. Subsequently, citric acid, as chelating agent, and ammonia water, as precipitating agent, were added to the mixed solution to form a gel. The gel was dried and spontaneously combusted, then annealed at different temperatures for 2 h in flowing air. The effects of the Fe3+/Sr2+ molar ratio and annealing temperature on the formation, morphology, and magnetic properties of SrFe12O19 were investigated. The results showed that single-phase SrFe12O19 powder was obtained by decreasing the Fe3+/Sr2+ molar ratio from the stoichiometric value of 12 to 11.6 and increasing the annealing temperature to 1000 °C for 2 h. Adjustment of the Fe/Sr molar ratio to 12 and the annealing temperature to 900 °C enabled the magnetic properties to be optimized, including saturation magnetization (Ms) 80.2 emu/g, remanence magnetization (Mr) 39.8 emu/g, and coercive force (Hc) 6318 Oe.