In this study, Al/NANO-MGO composites were produced via vortex method (direct incorporation). MGO NANOparticles with 60-80 nm diameter (as reinforcement) and Al-356 (as metal matrix) were used for production of these composites. The molten composites were stirred, and then cast into a metallic mold. The effects of MGO volume percent with 1.5, 2.5 and 5%, and casting temperature (various temperatures, viz. 800, 850 and 950oC) on mechanical properties of composites were investigated. Results show that mechanical properties of samples have increased significantly compare to matrix metal. In this regard, the best compressive strength and hardness results were obtained in the specimens containing 1.5 and 5 vol% NANO-MGO produced at 850oC (which are 896 MPa and 73 HB), respectively.

Removal of antibiotics from water resources is essential for their harmful effects on living organisms. In this work, a polymeric membrane based on polyvinylidene fluoride deposited by cellulose loaded with Magnesium oxide NANOparticles (PVDF /Cellulose/MGO) has been prepared. The prepared membrane was characterized using FESEM, XRD, AFM, and contact angle measurement. The efficiency of the prepared membranes as an adsorbent for removing amoxicillin as a model pollutant was investigated. The effect of pH, amoxicillin concentration, and the time on the removal of amoxicillin was studied. The results showed that with a decrease in pH, a reduction in the initial concentration of amoxicillin, and an increase in time, the percentage of amoxicillin removal increases, and the maximum percentage of amoxicillin removal was obtained at about 85% at 200 mg/liter of amoxicillin, pH = 3, and 100 min. The kinetic of amoxicillin removal using PVDF/Cellulose/MGO membrane was also investigated. These results confirmed that PVDF/Cellulose/MGO membrane would be a potential adsorbent for removing amoxicillin from contaminated water.

Background and Objectives: PHenol is one of most common organic pollutants in aqueous environments. PHenol presenCe in the environment can make some health problems such as carcinogenesis, abnormality of heartbeat, etc for humans and poisonous problems for other organisms. Therefore, this pollutant must be removed from polluted effluents to prevent water pollution. Using NANOparticles in adsorption proCesses is considered as an effective method for contaminants removal. The aim of this study was to investigate the efficiency of magnesium oxide NANOparticles in pHenol removal from aqueous solutions.Materials and Methods: In this research, NANOparticles of magnesium oxide were used with size of 43 nm. After the prEPAration of pHenol stock solution, effects of pH, (3- 5- 7- 9- 11), contact time (10, 30, 60, 90, and 120 min), MGO dosage ( 20, 40, 60, 80 and 100 mg/L) and initial conCentration of pHenol (25, 50, 75 and 100 mg/L) Were investigated.Results: Results indicated that the removal efficiency increased with increasing pH, contacttime, MGO dosage to a Certain range and decreasing initial conCentration. Such that the maximum efficiency was equal to 81% in the pH of about 11, initial conCentration of 50 mg/L, MGO dosage of 80 mg/L and contact time of 60 min. It was found that adsorption kinetics and equilibrium data follow a pseudo-second-order kinetics model and a Langmuir isotherm model respectively.Conclusion: This study showed that the magnesium oxide NANOparticles have the ability to remove the pHenol and can be used effectively in removing pHenol from aqueous solution Document Type: Research article

Magnesia–Doloma refractories are considered as a mixed product of alkali products i.e. sintered (fused) magnesia and doloma in which 50-80wt% magnesia is contained. These refractories enjoy some advantages such as high slag resistance corrosion, high-temperature performance, potential for production of pure molten iron and low cost due to abundance of magnesia and doloma resources in access. However, poor resistance of hydration can be cited that may constrain the amount of this refractory in various industrial applications. in this work the effect of NANO-sized Fe2O3 on microstructure and hydration resistance of MGO-CaO refractories with 35wt.% CaO were investigated. MGO-CaO refractories with 35wt.% CaO content were prepared by using dolomite and magnesite calcined as starting material and NANO-sized Fe2O3 as additive. Samples were uniaxially pressed in to briquettes at a pressure of 90 MPa. Briquettes after drying at 110 for 24 hr were sintered at 1650 for 3 hr. Hydration resistance was measured at 25oC in 95% relative humidity through the weight gain after 72 hr. according to the results, with the addition of NANO-sized Fe2O3, bulk density and hydration resistance of the samples increase while apparent porosity decreased. Densification of MGO-CaO refractories was promoted with increase of NANO-sized Fe2O3 content. NANO- sized Fe2O3 addition lead to formation low melting phases such as C2F(2CaO.Fe2O3), CF(CaO.Fe2O3) and C3A(3CaO.Al2O3). Formation of this low melting point surrounding the CaO and MGO grain and grain boundaries and promoted densification of MGO-CaO refractories. The nature of NANO-sized Fe2O3 promoting densification is promoting the liquid phase sintering.

The mixed metal NANOcomposite MGO∙Al2O3∙ZnO has been prepared by coprecipitation method. The product was characterized by XRD. The average particle size was found to be 34.89 nm from XRD data. SEM and SEM-EDS were studied for evaluating surface morphology and elemental composition. The FTIR spectrum of prepared mixed metal NANOcomposites MGO∙Al2O3∙ZnO and MGO∙2∙ZnO-curcumin were studied. The optical properties of the NANOcomposites were studied by PL (Photoluminescence). The quantum efficiency (F) of MGO∙Al2O3∙ZnO and MGO∙Al2O3∙ZnO-curcumin was found to be 0.86 and 0.31, respectively in acetone. The photocatalytic activity of the NANO composite, MGO∙Al2O3∙ZnO was investigated over methyl violet 6b (MV) dye under UV-Visible light irradiation. The photocatalytic activity was assessed with various parameters including variation of pH, effect of H2O22 and reusability. The dye degradation efficiency of NANOcomposite was observed to be 48.7% and 93.42% for catalyst and catalyst with H2O2 at pH 9. The efficiency was 86.96% for catalyst with H2O2 at pH 7.

Magnesia-doloma refractories are alkali products from sintered (or fusion) doloma and magnesia fusion), which have 50-80 wt. % MGO. These refractory have many advantages such as high corrosion resistance against slag, high temperature performance, ability to produce clean meet, and cost-effective (due to the abundance of dolomite and magnesite ores in Iran). However, the use of this type of refractories has been faced with restrictions due to poor hydration resistance in various industries. In this study, the effect of adding zirconium oxide NANOparticles on microstructure and hydration resistance of magnesia – doloma refractories containing 35 wt. % CaO is evaluated. Cylindrical samples were pressed under pressure 90MPa, and after it were dried and fired at 110oC for 24 h and, heated t0 1650oC with 5min /oC the for 3 h. Results show that the positive effect of adding zirconium oxide NANOparticles on the sintering temperature samples, due to the larger atomic radius of Mg than Ca thus lower the bond strength of Mg-O tend replacement Ca2+ with Zr+4 cations network with CaO greater than Mg2+ in MGO networks and the formation of calcium zirconate phase (CaZrO3). According to the result it can be found thet in doloma free CaO reduced by creating (CaZrO3) phase, as well as cavities formed by replacing the cationic in the network, increased the diffusion and sintering process which it led to creates a more dense structure and hydration resistant improvement.

Nowadays, SiC is one of the refractory materials which is used widespread because of its unique properties like structural stability in high temperatures. SiC NANO whiskers are important in reinforcement of different kinds of composites like ceramic base materials, thanks to their outstanding mechanical, thermal, and chemical properties like low expansion coefficient, high thermal resistant, high elastic coefficient, low density, and high resistant to oxidation. The most important problem of MGO-C refractories is carbon oxidation in high temperatures, resulting in the porosity and loss of strength. Using SiC as an antioxidant in such refractories also improves thebehavior of MGO-C refractories. In this study ferrosilicon has been used to prepare insitu NANO SiC whiskers and the effects of insitu SiC NANO-whiskers on mechanical, physical and corrosion properties of MGO-C refractories during heat treatment have been investigated. The strength was measured by Cold crushing strength (CCS) according to ASTM C133-97 and Brazilian test. Also, bulk density (BD) and apparent porosity (AP) were studied according to ASTM C-20-92. XRD and SEM have been used to study phase composition and observing the structure, respectively. The results showed that by the formation of these NANO-whiskers at high temperatures the strength was increased and corrosion and physical properties have been improved.

Cubic crystalline oxides such as Y2O3 and MGO is used to stabalized zirconia phases at high temperature. In this paper the Y2O3 powder was added to stabilized zirconia and preparing a mixture of MgAl2O4 Spinel by mixing 1mol of NANO-MGO with 1 mol of NANO-Al2O3 powders. The spinel was added to the Y2O3-ZrO2 by various weight percentage (5, 10, 15, 20 and 25 wt%), and after that the specimens was prepared by axial pressing and sintered at 1550 o C for 4 hours as soaking time. The grain size was tested by using Atomic Force Microscopy (AFM) and calculated for surface of specimens and it was found to be decreasing (> 0. 6 µ m) to (~ 108 nm). The thermal properties were clearly influenced by the structural characteristics of the MAS. The thermal conductivity and thermal diffusion was decreased slightly from 5. 7 to 5. 5 W/m. K and from 2. 5 to 1. 5 mm 2 /s, respectively. The thermal capacity was increased from 483 to 615 J/kg. K, and thermal expansion coefficient was increased from 10 to 7. 5×10-6 o C-1 due to the compatibility of thermal expansion coefficients of (Y-PSZ)-MAS oxides. Thermal properties values are compatible with thermal insulation requirements in energy storage applications.