Magnesium Nitrate Hexahydrate Research Articles

Investigating the Physical Properties of Sintered Alumina in the Presence of MgO Nanopowder

Magnesium oxide nanopowder is synthesized using magnesium nitrate hexahydrate and oxalic acid as precursors via the sol-gel method. In order to investigate the effect of magnesia nanopowders on the physical properties of sintered alumina, 0.1, 0.3, and 0.5 wt% of MgO are added to alumina. The prepared specimens were sintered at 1570°C for 4 hours under an inert atmosphere. The morphology and size of nanopowders were characterized by transmission electron microscope (TEM) and scanning electron microscope (SEM). Structural analysis was investigated by means of Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). Outcomes show that by increasing the percentage of MgO, spinel phase (MgAl2O4) has been formed in the structure of alumina. During the sintering process, spinel phase diffused through the grain boundaries and pinned the grain boundaries which led to decrease in grain sizes. So, by decreasing the grain size, the physical properties of sintered alumina have improved.

Homoepitaxy of ZnO and MgZnO Films at 90 °C

The aqueous synthesis of uniform single crystalline homoepitaxial zinc oxide, ZnO, and magnesium zinc oxide, MgxZn1−xO, films under very low temperature conditions at T=90°C and ambient pressure has been explored. A maximum Mg content of 1mol% was recorded by energy dispersive spectroscopy. The growth on the polar (0001) and (0001¯) faces resulted in films that are strongly different in their structural and optical quality as evidenced by high-resolution X-ray diffraction, secondary electron microscopy, and photoluminescence. This is a result of the chemistry and temperature of the solution dictating the stability range of growth-governing metastable species. The use of trisodium citrate, Na3C6H5O7, yielded coalesced, mirror-like homoepitaxial films whereas adding magnesium nitrate hexahydrate, Mg(NO3)2·6H2O, favors the growth of films with pronounced faceting.

Characterization of Magnesium‐Doped Hydroxyapatite Prepared by Sol‐Gel Process

Pure and doped hydroxyapatite (HA) nanocrystalline powders (Ca10‐xMgx(PO4)6OH2) were synthesized using sol‐gel process. For this, calcium nitrate tetrahydrate, magnesium nitrate hexahydrate, and phosphorous pentoxide were used as precursors for Ca, Mg, and P, respectively. Calculated amounts of magnesium ions (Mg+2) especially from 0 to 10% (molar ratio) were incorporated as dopant into the calcium sol solution. The structure and morphology of the gels obtained after mixing the phosphorous and (calcium + magnesium) sol solution were different, and their condensations in time depend on the quantities of magnesium added. The several powders resulting from the gels dried and sintered at 500°C for 1 h were characterized by thermogravimetry (TG), Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), and inductively coupled plasma (ICP). Additionally, their agglomeration, morphology, and particle size were investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The specific surface area of each sample was measured by the Brunauer–Emmett–Teller (BET) gas adsorption technique. The results of XRD, FTIR, and ICP values ranged between 0.45 and 2.11 mg/L indicated that the magnesium added in the calcium solution was incorporated in the lattice structure of HA so prepared, while those obtained by SEM and TEM confirmed the influence of Mg on their morphology (needle and irregular shape) and crystallite size, which is about 30–60 nm. The as‐prepared powders had a specific surface area ranged between 6.37 and 27.60 m2/g.

Flame synthesis of MgO nanoparticles in a FASP Reactor

ABSTRACTThe purpose of this work is the development and control of a high temperature reactor for the production of engineered nanoparticles, taking advantage from our previous studies on combustion-generated fine carbonaceous particles. The reactor consists of a laminar premixed flame, homogenously doped with monodisperse droplets of metal precursors dissolved or dispersed in volatile solvents. The droplets are generated by a vibrating orifice aerosol generator, and injected directly into the burner. Fuel-lean and stoichiometric flames allow producing pure metal oxide particles of nanometric sizes.Particles are collected by thermophoresis inserting a cold substrate in the flame by means of a pneumatic actuator. Morphological and dimensional analysis are performed on the collected particles by Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). SEM and AFM allow inferring both qualitative and quantitative information on many physical properties including size, morphology, surface texture and roughness.Experimental results have been obtained from a premixed stoichiometric flame of ethylene and air, doped with 75 microns droplets of magnesium nitrate hexahydrate dissolved in ethanol. Roughly monodisperse magnesium oxide particles, having a desired size ranging from 50 nm down to 7 nm, have been produced by altering the precursor concentration in the solution and the residence time of the synthesis process.

Preparation and Properties of Starch/Poly(vinyl alcohol) Film Plasticized by Magnesium Nitrate Hexahydrate

The plasticized starch/poly(vinyl alcohol)(PVA) film was prepared by casting method using magnesium nitrate hexahydrate [Mg(NO3)2·6H2O] as the plasticizer.The micro morphologies of pure starch/PVA and Mg(NO3)2·6H2O plasticized starch/PVA film were observed by scanning electron microscope(SEM).The interaction between Mg(NO3)2·6H2O and starch/PVA molecule was investigated by Fourier transform infrared(FTIR).The crystallinity and thermal properties were measured by X-ray diffraction measurement(XRD) and thermogravimetric analysis(TGA).The mechanical properties were measured by tensile testing and dynamic mechanical analysis(DMA).It was found that Mg(NO3)2·6H2O could form some interaction with starch and PVA molecules.The addition of Mg(NO3)2·6H2O could improve the miscibility of starch and PVA.The XRD results showed that Mg(NO3)2·6H2O could destroy the crystals of starch and PVA.The TGA results showed that the thermal stability of starch/PVA decreased with the addition of Mg(NO3)2·6H2O.Tensile testing showed that Mg(NO3)2·6H2O was highly effective in modifying the mechanical properties of starch/PVA film,making the elongation at break of starch/PVA film largely increased from 8% of pure starch/PVA film to 514% with 60%Mg(NO3)2·6H2O.

The importance of London dispersion forces in crystalline magnesium nitrate hexahydrate

The role of London dispersion forces in crystalline magnesium nitrate hexahydrate [Mg(NO3)2·6H2O] has been investigated using terahertz spectroscopy and solid-state density functional theory modeling. The solid-state simulations were augmented with semi-empirical London dispersion corrections and revealed that such corrections are of negligible importance in this ionic solid. The comparison of the simulated and experimental crystal structures indicated a London force correction magnitude of less than 10% of that required in organic molecular solids of similar size and complexity. While London forces are certainly present in magnesium nitrate hexahydrate, electrostatic forces clearly dominate the intermolecular interactions governing its crystalline structure and dynamics.

CRYSTAL ANALYSIS OF MULTI PHASE CALCIUM PHOSPHATE NANOPARTICLES CONTAINING DIFFERENT AMOUNT OF MAGNESIUM

In this study, Mg doped hydroxyapatite [( Ca , Mg )10( PO 4)6( OH )2] and β-tricalcium phosphate nanoparticles were synthesized via sol gel method. Triethyl phosphite, calcium nitrate tetrahydrate and magnesium nitrate hexahydrate were used as P , Ca and Mg precursors. The ratio of ( Ca + Mg )/ P and the amount of magnesium ( x ) were kept constant at 1.67 and ranging x = 0 up to 3 in molecular formula of Ca 10- x Mg x ( PO 4)6( OH )2, respectively. Phase composition and chemical structure were performed using X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR). Phase percentages, crystallite size, degree of crystallinity and lattice parameters were investigated. The presence of magnesium led to form the Mg doped tricalcium phosphate (β-TCMP) and Mg doped hydroxyapatite ( Mg - HA ). Based on the results of this study, lattice parameters, degree of crystallinity and crystallite size decreased with magnesium content. In addition, with increasing magnesium content, the amount of CaO phase decreased whereas the amount of MgO phase increased significantly. Obtained results can be used for new biomaterials design.

Effect of magnesium oxide on adsorption of Cd2+ from aqueous solution

Mesoporous MCM-41 was functionalized using magnesium nitrate hexahydrate (denoted as MM). The adsorption behavior of Cd2+ on functionalized MCM-41 was investigated systematically. The adsorption isotherms of MM for Cd(II) could be described by the Langmuir isotherm model. The adsorption rates were very high and agreed well with pseudo second-order kinetics. The modified MCM-41 adsorbent displayed excellent Cd2+ adsorption efficiency (210.96 mg g−1) and the residual concentration of Cd2+ achieved was in line with drinking water quality standards. The regeneration capacity maintained 99% performance when the initial solution concentration was 5 mg L−1 (5000 ppb) at the eighth cycle, meeting the safe regulatory discharge standard for the first time. Furthermore, regeneration by an ultrasonic cleaning method to remove residual surface Cd2+ can reduce both the cost of traditional desorption agents and damage to the structure of the adsorbent. Therefore, the adsorbent MM has potential as a promising application in the field of water pollution control.

Hydrothermal Synthesis of MgBO<sub>2</sub>(OH) Nanomaterials

Magnesium borate hydroxide (MgBO2(OH) ) were synthesized using magnesium nitrate hexahydrate(MgNO3.6H2O) and borax decahydrate(Na2B4O7.10H2O) by hydrothermal route. Effect of reaction temperature , reaction time and water's volume on the composition , structure , and crystal morphology of the products were investigated, and the products were characterized by XRD and SEM. The results indicated that all of the products were szaibelyite with the reaction condition investigated, and crystal morphology could be tailored via varying the reaction condition.

Sol–gel synthesis of forsterite nanopowders with narrow particle size distribution

Forsterite (FS) nanopowders (∼27 nm) were synthesized using a sol–gel route with magnesium nitrate hexahydrate and tetra ethyl ortho-silicate as magnesium and silicon precursors, respectively. Nitric acid was used as a catalyst. After aging, the FS gel was calcined at 800 °C for 30 min. The calcined powders were characterized for phase composition using X-ray diffractrometry and fourier transform-infrared spectroscopy. The particle size and morphology was studied using transmission electron microscopy. The particle size distribution analysis of FS powders showed skewed distribution plot with particle size ranging from 5–90 nm. This study showed that high phase purity and narrowly distributed FS nanoparticles could be obtained using this simple sol–gel technique.

ChemInform Abstract: Al2O3/MeSO3H (AMA) as a Novel Heterogeneous System for the Nitration of Aromatic Compounds by Magnesium Nitrate Hexahydrate.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Templated epitaxial coatings on magnesium aluminate spinel using the sol-gel method

Polycrystalline magnesium aluminate (MgAl2O4) spinel has attractive properties for a range of applications including radomes, windows, and ballistic protection. A wet chemical approach using solutions of magnesium nitrate hexahydrate Mg(NO3)2 · 6H2O in 2-methoxy-ethanol (2-MOE) and aluminum nitrate nonahydrate (Al(NO3)3 · 9H2O) in ethylene glycol, was developed for spin coating on coarse-grain, polycrystalline spinel substrates. The coated substrates were subjected to isothermal heat treatments in the temperature range 1000–1400 °C, and subsequently examined using low voltage scanning electron microscopy, EBSD (electron back scattered diffraction), and transmission electron microscopy. The results showed that for annealing at 1200–1400 °C, the coatings were converted to crystalline MgAl2O4 which was epitaxial with the substrate grains. Heat treatment at lower temperatures, however, resulted in porous, fine-grained polycrystalline coatings. Thermal faceting of the grain surfaces was observed to occur. The observations suggest that faceting occurs preferentially on {100} and {110} planes. The morphology of the faceting was discussed in terms of the reported relative surface energy values for the low index planes in MgAl2O4 spinel. Finally, the influence of the coating process on spinel substrates which had been lightly abraded prior to spin coating was investigated.

Influence of titanium doping on the structure and morphology of MgO prepared by coprecipitation method

Ti-doped magnesium oxide powders were prepared by a chemical coprecipitation technique using magnesium nitrate hexahydrate and titanium tetrabutoxide as starting materials and ammonia hydroxide as precipitator. The influence of titanium doping on the structure and morphology of MgO powders was investigated by X-ray diffraction, X-ray fluorescence, X-ray photoelectron spectroscopy and transmission electron microscopy. The results show that titanium ion (Ti 4+) was successfully incorporated into the MgO crystal lattice, and consequently, caused the changing of MgO crystal lattice parameter. However, titanium doping resulted in varied particle sizes, and enhanced slightly the particle aggregation. It is attributed to the difference between the solubility product (K sp) of the two precursors, Mg(OH) 2 and TiO(OH) 2, which is one of important factors in the chemical coprecipitation process.

Improvement of poly(vinyl alcohol) properties by the addition of magnesium nitrate

AbstractAiming at the improvement of mechanical and dielectric properties of poly(vinyl alcohol) (PVA), we prepared composites of PVA and magnesium nitrate hexahydrate. It was found that the composites were very soft and rubber‐like, and the glass transition temperature decreased with increasing the salt concentration. Wide‐angle X‐ray diffraction and small‐angle X‐ray scattering revealed that the crystallites of PVA were destroyed by the additive and it was the cause of the softening. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

AI2O3/MeSO3H (AMA) as a Novel Heterogeneous System for the Nitration of Aromatic Compounds by Magnesium Nitrate Hexahydrate

Mg(NO3)2.6H2O was an efficient nitrating agent in the presence of a mixture of AI2O3/MeSO3H (AMA) as a novel heterogeneous system for the nitration of aromatic compounds without use of any organic solvents and with high selectivity. The reaction proceeds at room temperature for the nitration of highly reactive aromatic compounds such as phenols and anilines.

On the synthesis and optical absorption studies of nano-size magnesium oxide powder

Magnesium oxide (MgO) nano-size powder is synthesized using magnesium nitrate hexahydrate and oxalic acid as precursors with ethanol as a solvent. The process involves gel formation, drying at 100 °C for 24 h to form magnesium oxalate dihydrate [ α-MgC 2O 4·2H 2O] and its decomposition at 500, 600, 800, and 1000 °C for 2 h to yield MgO powder (average crystallite size ∼6.5–73.5 nm). The sol–gel products at various stages of synthesis are characterized for their thermal behaviour, phase, microstructure, optical absorption, and presence of hydroxyl and other groups like O C O, C O, C–C, etc. MgO powder is shown to possess an f.c.c. (NaCl-type) structure with lattice parameter increasing with decrease in crystallite size ( t av); typical value being ∼4.222(2) Å for t av∼6.5 nm as against the bulk value of 4.211 Å. Infrared absorption has shown MgO to be highly reactive with water. Also, a variety of F- and M-defect centres found in MgO produce energy levels within the band gap (7.8 eV), which make it attractive for application in plasma displays for increasing secondary electron emission and reducing flickering effects. The possible application of the intermediate sol–gel products, viz., α-MgC 2O 4·2H 2O and anhydrous magnesium oxalate (MgC 2O 4) in understanding the plants and ESR dosimetry, respectively, has also been suggested.

Experimental investigation of novel indirect solar cooker with indoor PCM thermal storage and cooking unit

In the present study, a novel indirect solar cooker with outdoor elliptical cross section, wickless heat pipes, flat-plate solar collector and integrated indoor PCM thermal storage and cooking unit is designed, constructed and tested under actual meteorological conditions of Giza, Egypt. Two plane reflectors are used to enhance the insolation falling on the cooker’s collector, while magnesium nitrate hexahydrate ( T m = 89 °C, latent heat of fusion 134 kJ/kg) is used as the PCM inside the indoor cooking unit of the cooker. It is found that the average daily enhancement in the solar radiation incident on the collector surface by the south and north facing reflectors is about 24%. Different experiments have been performed on the solar cooker without load and with different loads at different loading times to study the possibility of benefit from the virtues of the elliptical cross section wickless heat pipes and PCMs in indirect solar cookers to cook food at noon and evening and to keep food warm at night and in early morning. The results indicate that the present solar cooker can be used successfully for cooking different kinds of meals at noon, afternoon and evening times, while it can be used for heating or keeping meals hot at night and early morning.

Numerical heat transfer studies of PCMs used in a box-type solar cooker

Theoretical investigations on the phase change materials (PCMs) used as the heat storage media for box-type solar cookers have been conducted in this study. The selected PCMs are magnesium nitrate hexahydrate, stearic acid, acetamide, acetanilide and erythritol. For a two-dimensional simulation model based on the enthalpy approach, calculations have been made for the melt fraction with conduction only. Different materials such as glass, stainless steel, tin, aluminum mixed, aluminum and copper are used as the heat exchanger container materials in the numerical calculations. The large value of thermal conductivity of heat exchanger container material did not make a significant contribution on the melt fraction except for at very low thermal conductivities. Based on the theoretical results, stearic acid and acetamide are found to be good compatibility with latent heat storage system. It is also found that the initial temperature of PCM does not have very important effects on the melting time, while the boundary wall temperature plays an important role during the melting and has a strong effect on the melt fraction. The results also show that the effect of thickness of container material on the melt fraction is insignificant. The results obtained in this paper show that in a box-type solar cooker, acetamide and stearic acid should be used as a latent heat storage materials.

Ferroelectric poly(vinylidene fluoride-hexafluoropropylene) thin films on silicon substrates

Ferroelectric poly(vinylidene fluoride-hexafluoropropylene) (PVDF/HFP) thin films were prepared through a solution coating approach on aluminum-coated silicon substrates. The crystalline phase and morphology of the obtained PVDF/HFP thin films strongly depended on the drying temperature for the spin-coated films and chemical additives. When magnesium nitrate hexahydrate (Mg(NO 3) 2·6H 2O) was introduced into the solution precursor, dominant β phase, the desired ferroelectric phase, was formed in the thin films. Their ferroelectric and piezoelectric properties were investigated. The results indicate that our methods have overcome a critical barrier for integrating ferroelectric PVDF/HFP thin films for device applications.

Evolved gas analyses (TG/DTA–MS and TG–FTIR) on dehydration and pyrolysis of magnesium nitrate hexahydrate in air and nitrogen

Thermally evolved gases from [Mg(H 2O) 6](NO 3) 2 released in flowing air and nitrogen atmosphere have been analyzed and monitored by simultaneous thermogravimetry and differential thermal analysis coupled online with mass spectrometer (TG/DTA–MS) and with FTIR spectroscopic gas cell (TG–FTIR) up to 700 °C. Both in air and nitrogen the mass spectrometry (TG/DTA–MS) definitely proved parallel evolution of O 2 ( m/ z = 32, 16) and NO 2 ( m/ z = 30, 46, 47, 48) between 300 and 500 °C. The m/ z = 30 ion fragment with highest intensity among the fragments of nitrogen oxides might suggest parallel evolution of NO, anyhow, according to NIST reference spectra, m/ z = 30 is also the most intense fragment of NO 2 itself. The intense generation of oxygen resulted in parallel occurrence of m/ z = 44 and 45 fragments indicating N 2O or rather CO 2 originated from reaction of nascent oxygen with the surrounding furnace. Whilst, the TG–FTIR spectroscopy showed evolution of NO 2 indicated by two PR bands positioned at 1616 and 2911 cm −1, but no vibration bands of NO and N 2O gases could be detected, at all. At greater initial loads, IR absorption bands of HNO 3 vapour centred at 885, 1314, 1708, and 3566 cm −1 have been observed.