Preparation Of Mg Research Articles

Effect of the toluene content on the preparation of Mg(Al,Y)2O4:Cr3＋ nanopowders by Pechini-type hydrothermal process

Cr3＋ doped magnesia aluminum spinel has potential applications in the fields of sensing, scintillator and laser. The structure, morphology, photoluminescence and diffuse reflection spectra of Mg(Al,Y)2O4:Cr3＋ were examined as a function of toluene content during the Pechini-type hydrothermal process. Toluene solvent changed the microstructure of Mg(Al,Y)2O4:Cr3＋ nanopowders, especially for the ratio of Al:Mg in the sample. Toluene also improved the agglomeration of nanopowders, and the luminescent intensity of the sample prepared with 60% and 75% toluene was enhanced by 16%.

Preparation of Mg(OH)2/Calcined Fly Ash Nanocomposite for Removal of Heavy Metals from Aqueous Acidic Solutions.

A magnesium hydroxide (MH)-modified calcined fly ash (CFA) nanocomposite (CFAMH) with core-shell structure was obtained with a heterogeneous nucleation method, and its application for removal of copper, zinc and nickel ions from aqueous acidic solution was studied. The microstructure and surface properties of CFA, CFAMH and MH powders were characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller specific surface area (BET), X-ray diffraction (XRD) and Fourier translation infrared spectroscopy (FTIR), respectively. The preparation mechanism of CFAMH was discussed based on zeta potential and FTIR data. The results showed that nano-flake MH with thickness 13.4 nm was well coated on the surface of CFA. The specific surface area was increased from 2.5 to 31.0 m2/g. Si-O-Mg-OH bonds formed from the condensation of Si-OH and Mg-OH. The removal efficiency of heavy metals on CFAMH nanocomposite is higher than that of CFA and MH and follows an order of Cu2+ > Zn2+ > Ni2+. Solubility product constant (Ksp) is an important constant for the removal order of heavy metals on FA, CFAMH and MH. CFAMH nanocomposite can be a cheap material for removing heavy metal ions from acidic wastewater.

Facile method for treating Zn, Cd, and Pb in mining wastewater by the formation of Mg–Al layered double hydroxide

Heavy metal pollution threatens aquatic systems worldwide, and mining activities are an important pollution source. Currently, the treatment of polluted water using a cost-effective technology that can purify multiple pollutants and is sustainable, environmentally friendly, and simple is a major challenge. The in situ preparation of Mg–Al layered double hydroxides (LDHs) and the concurrent treatment of Zn, Cd, and Pb from mining wastewater are important for preventing multiple steps and increasing adsorption sites. This study focused on mining wastewater containing high concentrations of Mg2+ and Al3+, with anion chemistry controlled by SO42−, which facilitates the formation of LDHs. The required amounts of Mg2+ and Al3+ ions were added to the wastewater, and the conditions for the creation of Mg–Al LDHs were controlled. The heavy metals in the experimental wastewater were effectively removed after the treatment via Mg–Al LDH formation. The X-ray diffraction of the post-treatment products suggested the formation of Mg–Al LDHs. The Mg/Al molar ratio (2.3:1) in the product approached the initial ratio (2:1), which meets the general limits of Mg–Al LDH formation. Scanning electron microscopy revealed that the products had a sheetlike stacked morphology, providing evidence for the formation of Mg–Al LDHs. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy indicated that SO42− might be the intercalated anion in the Mg–Al LDH layers. Consequently, SO42− was removed from the mining wastewater, as it was captured between the LDH layers during the formation reaction of Mg–Al LDHs.

Mechanical, corrosion and biological properties of advanced biodegradable Mg–MgF2 and WE43-MgF2 composite materials prepared by spark plasma sintering

Newly developed magnesium composite materials with a continuous network of MgF2 prepared by powder metallurgy exerted enhanced corrosion resistance and seems to be suitable for application in medicine as biodegradable implants. In this work, the influence of conditions of preparation of Mg and WE43 composite materials on final mechanical and corrosion properties of spark plasma sintered samples is revealed. Immersion in HF leads to the significant improvement of corrosion properties of Mg and WE43, while mechanical properties of WE43 alloy are reduced due to the specific interface. Moreover, cytocompatibility tests revealed the nontoxic behavior of magnesium fluoride coating on both Mg and WE43 alloy. The better proliferation of cells was observed on the WE43 composite material.

Preparation of Mg(OH)2 nanoparticles modified PVDF membranes for efficient dye adsorption and rejection

Preparation of Mg(OH)2 nanoparticles modified PVDF membranes for efficient dye adsorption and rejection

Synthesis and orientational assemblies of MgO nanosheets with exposed (111) facets

MgO nanosheets with exposed (111) facets were obtained through the preparation of Mg(OH)2 precursor by a hydrothermal method in the presence of oleylamine and subsequent calcination in air. The different preferred orientational assemblies of MgO nanosheets, achieved by adjusting the polarity of dispersing solvents (ethanol and cyclohexane) during the sample preparation, show different structural and spectral features.

Facile synthesis of Mg(OH)2/graphene oxide composite by high-gravity technology for removal of dyes

A facile high-gravity strategy is proposed for preparation of Mg(OH)2/graphene oxide (MGO) composite using a rotating packed bed reactor at room temperature for 1 min. Lamellar Mg(OH)2 nanocrystals of about 60 nm in diameter with a narrow size distribution are distributed homogeneously on the graphene oxide sheets without aggregation. The specific surface area of MGO with mesoporous structure reaches 590 m2 g−1, which is the highest among those reported in the literatures. The as-prepared MGO nanocomposite exhibits excellent adsorption capacity for methylene blue (MB). The removal rate of MB reaches 98% in 1 min. The preparation process of MGO nanocomposite is rapid, simple, and suitable for a large-scale production, and the product has great potential in the field of environmental protection as a promising absorbent.

Ultralight MgO and its Efficient Adsorption to Pb2+ and Mn2+

Background and Objective: In this work, the precipitation combined with vacuum drying and supercritical CO2 drying was applied in the preparation of Mg(OH)2 which was thermally decomposed to MgO. Results: Results showed that the constant dropping rate of Mg(NO3)2 solution into NaOH aqueous solution under 90°C with a relatively high pH of 10.1 led to the MgO powder with high specific surface area and large pore volume with both vacuum drying and supercritical drying. Among the produced MgO, the pore volume1.45 cm3/g from the vacuum drying was the highest, and the bulk density 0.0247 g/ml from the supercritical drying was the lowest in the reported literature. Conclusion: Particularly, the MgO produced from the supercritical drying showed high adsorption of Pb2+ (as high as 3635 mg/g at pH=6 and 25°C) and Mn2+ (as high as 861 mg/g at pH=6 and 25°C). The adsorption isotherms and kinetics of Pb2+ and Mn2+ on the produced MgO were fitted well to the Langmuir model and pseudo-second order model. Keywords: Adsorption, lead, manganese, magnesium oxide, supercritical drying, silica.

Preparation of Mg–Al Layered Double Hydroxide Adsorbent: Characterization and Adsorptive Removal of Co (II) Ions from Aqueous Solutions

Preparation of Mg–Al Layered Double Hydroxide Adsorbent: Characterization and Adsorptive Removal of Co (II) Ions from Aqueous Solutions

Strategies for the enhancement of heat storage materials performances for MgO/H2O/Mg(OH)2 thermochemical storage system

MgO/H2O/Mg(OH)2 thermochemical storage system is still at an early stage of development and several research efforts are accomplished to bring this technology at an applicative stage. The material development is the key point for the system implementation. Among the investigated strategies, the synthesis route for the preparation of Mg(OH)2 over a carbonaceous support, i.e. exfoliated graphite (EG), significantly affect the stability of the hybrid material and its thermochemical performances. In this study the influence of the preparation method, namely Deposition-Precipitation and Reverse Deposition-Precipitation, on the morphology and thermochemical performances of EG/Mg(OH)2 hybrid materials have been investigated. Among the overall investigated samples, EG/Mg(OH)2 obtained by Deposition-Precipitation and Reverse Deposition-Precipitation realized through one shot addition of the precipitating agent and at 0°C allow to achieve the best thermochemical performance. As main result a storage heat value of 1166, 1163 and 1080kJ/kgMg(OH)2, respectively, has been obtained.

Mechanistic aspects of formation of MgO nanoparticles under microwave irradiation and its catalytic application

This work reports a preparation of Mg(OH)2 and MgO nanoparticles (NPs) using magnesium acetate in benzylamine and mechanistic study of its formation. The benzylamine acts as a solvent, base, promoter and capping agent in this reaction. The structure and morphology of particles were analyzed by X-ray diffraction pattern (XRD), transmission electron microscopy (TEM), high resolution TEM (HRTEM), selected area energy dispersion (SAED), energy-dispersive X-ray spectroscopy (EDAX), thermogravimetric analysis (TGA), FT-IR, CO2–temperature programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller (BET) surface area analysis techniques. The application of as prepared MgO NPs was used in catalysis as a catalyst for the formylation of amines with recyclability studies of nanocatalyst.

Superior Properties of Mg–4Y–3RE–Zr Alloy Prepared by Powder Metallurgy

Magnesium alloys are important materials for application in the automotive and aviation industries. During the last few years, the number of possible applications as biodegradable implants in medicine has grown. Mg–RE (rare earth) alloys belong to the most advanced group of products, offering the best combination of mechanical properties and corrosion resistance. Among these materials, WE43 (Mg–Y–Nd) is a very well-known commercial alloy that has been extensively studied for applications at increased temperatures and also in organisms. Although this material has been described, there are still possibilities to improve its properties and subsequently expand its applicability. Powder metallurgy has already been used for the preparation of magnesium alloys with superior mechanical properties and occasionally superior corrosion properties. Therefore, the present paper is oriented toward the preparation of Mg–4Y–3RE–Zr (WE43) alloy by the powder metallurgy technique (WE43-PM) and comparison of the final properties with the product of extrusion of as-cast ingot (WE43-IM). Our processing leads to a partial improvement in the mechanical properties and superior corrosion resistance of WE43-PM. The texture strength of WE43-PM was low, and therefore, anisotropy of mechanical properties was suppressed.

Preparation of Mg–Zn bimetallic doped Na-containing bioceramic from sodium metasilicate

Glass–ceramic materials in the composition (mol%) 23.5 Na2O–23.5CaO–xMgO–xZnO–47SiO2–(6-2x) P2O5 (x = 0 and 1.5) were prepared by the sol–gel technique using sodium metasilicate (Na2SiO3) as source of Na2O and SiO2. Bioactivity was investigated in vitro by examining apatite formation on the surface of the samples after treatment in acellular simulated body fluid (SBF). Formation of bioactive apatite layer on the samples was confirmed by using scanning electron microscope, X-ray diffraction and Fourier transform infrared spectroscopy. Reactivity of the materials in SBF was based on changes in pH and ionic concentration of the solution as a function of immersion duration. Results obtained indicated that the sample doped with Mg and Zn exhibited greater crystallinity containing phases such as CaMgSi2O6, Ca2MgSi2O7, CaSiO3, Na2CaSi3O9, Na2CaSi3O8, CaZnSi2O7 and a new secondary phase, clinohedrite (CaZnSiO4·H2O), while the undoped sample contained a single crystalline phase composed of Na2Ca2Si3O9. After 7 days in SBF, phase transformation occurred at different rates on the materials leading to formation of apatite layer. The result shows that controlled amounts of MgO and ZnO may be useful in tuning up the mechanical properties of bioactive glasses while maintaining bioactivity.

Preparation of Mg–Nd–Zn–(Zr) alloys semisolid slurry by electromagnetic stirring

The effects of electromagnetic stirring (EMS) including stirring time, applied voltage and rotational frequency on the microstructure of semisolid slurries of the Mg–Nd–Zn–(Zr) alloys were investigated. The results indicate that all of the parameters have large effects on the microstructure of the slurries. After being treated by EMS, the morphology of primary α-Mg phases in the Mg–3Nd–0.2Zn (NZ30) alloy slurries evolves from dendrite to three types: rosette, dendrite, and spheroid, while a semisolid microstructure with small and spheroidal particles is obtained in the Mg–3Nd–0.2Zn–0.4Zr (NZ30K) alloy slurries. The data for solid fraction with stirring time can be fitted to linear equations. The increase of applied voltage and rotational frequency makes the primary α-Mg phases initially refined and then coarsened. The optimal processing parameters are stirring time 120–180s, applied voltage 300–350V, rotational frequency ~20Hz for NZ30 alloy, and stirring time 30–180s, applied voltage ~350V, rotational frequency ~20Hz for NZ30K alloy. The average particle size of NZ30 alloy can be refined from ~879 to ~457μm. Furthermore, the effects of applied voltage and rotational frequency on undercooling and melt temperature were also discussed on the basis of thermodynamic theory.

Preparation of Mg(OH)2 hybrid pigment by direct precipitation and graft onto cellulose fiber via surface-initiated atom transfer radical polymerization

Mg(OH)2 flame retardant hybrid pigment is synthesized through simultaneous solution precipitation and adsorption of anionic dyes (C.I. Acid Red 6). The Mg(OH)2 hybrid pigment bearing vinyl groups after surface silane modification is immobilized onto the surface of bromo end-functional cellulose fiber by atom transfer radical polymerization (ATRP). The morphology and structure of Mg(OH)2 pigments and cellulose fibers grafted with modified pigments are characterized. The thermal properties, flammability and color fastness of cellulose fibers grafted with modified pigments are measured. The results reveal that anionic dye molecules are adsorbed onto Mg(OH)2 crystals and affect the formation of lamella-like Mg(OH)2 crystals. The cellulose fiber grafted with modified Mg(OH)2 hybrid pigment absorbs about four times heat more than original cellulose fiber with about 4% immobilization ratio of pigment, which shortens nearly half of afterflame time and afterglow time.

Cyclopentadienyl-bis(oxazoline) Magnesium and Zirconium Complexes in Aminoalkene Hydroaminations

A new class of cyclopentadiene-bis(oxazoline) compounds and their piano-stool-type organometallic complexes have been prepared as catalysts for hydroamination of aminoalkenes. The two compounds MeC(OxMe2)2C5H5 (BoMCpH; OxMe2 = 4,4-dimethyl-2-oxazoline) and MeC(OxMe2)2C5Me4H (BoMCptetH) are synthesized from C5R4HI (R = H, Me) and MeC(OxMe2)2Li. These cyclopentadiene-bis(oxazolines) are converted into ligands that support a variety of metal centers in piano-stool-type geometries, and here we report the preparation of Mg, Tl, Ti, and Zr compounds. BoMCpH and BoMCptetH react with MgMe2(O2C4H8)2 to give the magnesium methyl complexes {BoMCp}MgMe and {BoMCptet}MgMe. BoMCpH and BoMCptetH are converted to BoMCpTl and BoMCptetTl by reaction with TlOEt. The thallium derivatives react with TiCl3(THF)3 to provide [{BoMCp}TiCl(μ-Cl)]2 and [{BoMCptet}TiCl(μ-Cl)]2, the former of which is crystallographically characterized as a dimeric species. BoMCpH and Zr(NMe2)4 react to eliminate dimethylamine and afford {BoMCp}Zr(NMe2)3, which is crystallographically characterized as a monomeric four-legged piano-stool compound. {BoMCp}Zr(NMe2)3, {BoMCp}MgMe, and {BoMCptet}MgMe are efficient catalysts for the hydroamination/cyclization of aminoalkenes under mild conditions.

Properties of Mg Doped ZnO Films Prepared by Ultrasonic Spray Pyrolysis

This work is focused on the preparation of Mg doped ZnO films by ultrasonic spray pyrolysis and investigated the physical, optical and electrical properties of the films. These films were prepared from 0.02 M of Zn (CH3OO)2.2H2O and MgCl2 was used for doping. The atomic percentage ratio of Mg/Zn was varied from 0 to 9 at.%. The crystalline phase of all films was identified as ZnO polycrystalline structure with preferred orientation along the (002) plane. While, the grain shape of ZnO film was irregular shape, this shape changed to spherical shape with doped Mg concentration and changed again to rod shape with doped Mg concentration to 9 at.%. Although, the Mg dopant affects the shape of ZnO films but don’t affect resistivity of the films. Moreover, the Mg dopant shifts the absorption edge in transmittance spectra of films to lower wavelength and increases band gap of the films.

Characterizations and preparation of Mg(OH)2 nanocrystals through ultrasonic–hydrothermal route

Magnesium hydroxide [Mg(OH)2] nanocrystals with excellent dispersity and good crystallinity were efficiently synthesized through the ultrasonic and hydrothermal synergetic effect. The morphology, structure, and thermochemistry of Mg(OH)2 nanocrystals were researched by TEM, XRD, FT-IR, and DTA, respectively. The mechanism of ultrasonic–hydrothermal synergistic effect was discussed. In addition, Mg(OH)2 nanocrystals were added into polypropylene (PP) to form composite materials, and the mechanical properties of Mg(OH)2–PP composites were investigated. Compared with the other two Mg(OH)2 PP composites, the Mg(OH)2–PP composite had the best mechanical property when the Mg(OH)2 was synthesized by ultrasonic–hydrothermal route.

The preparation of Mg–Al spinels through the method of using templates

A series of MgO-rich MgAl2O4 samples were prepared by co-precipitation in the presence of CTAB, Triton X-100, and glucose or a combination of CTAB and glucose, which act as templates. The effects of different types and amounts of single template, as well as adding order of the mixed templates, on the specific surface area and particle size were investigated by BET and XRD analyses. The addition of the single template can lead to the increase of the specific surface area, wherein the samples using glucose as templates own the maximum specific surface area of 198 m2/g; as for the use of mixed templates, results revealed that adding CTAB first, followed by the addition of glucose, is better, giving a surface area of 223 m2/g.

Preparation of Mg–Al layered double hydroxide/polyamide 6 nanocomposites using Mg–Al–taurate LDH as nanofiller

A novel method using Mg–Al layered double hydroxide (LDH) intercalated with taurate (2-aminoethanesulfonate acid) was applied for preparation of LDH/polyamide 6 nanocomposites via in situ intercalative polymerization. Two polymerization mechanisms were used — hydrolytic and anionic polymerization of ε-caprolactam, in which the Mg–Al LDH intercalated with taurate was dispersed. The obtained LDH/polyamide 6 nanocomposites were characterized by a combination of wide- and small-angle X-ray scattering, transmission electron microscopy, differential scanning calorimetry and thermogravimetric analysis. It was found that LDH filler was exfoliated in the polymer matrix and the LDH/polyamide 6 nanocomposites were successfully prepared by anionic polymerization of ε-caprolactam in the presence of dispersed LDH.