Due to the limited uranium reserves and advantages of thorium fuels over uranium fuels, the development of the thorium fuel cycle in various countries including Iran, has been considered significantly. One type of thorium fuels used in nuclear reactors is a mixture of uranium dioxide and thorium. The type of powder synthesis method is a key point in improving the efficiency of this fuel in the reactor. The main objective of the present study was to achieve mixed nanoparticles of 30-70% (Th-U)O2. The effect of four parameters including concentration, time, initial percentage of uranium-thorium nitrate in solution, and temperature was studied using Taguchi's experimental design. The synthesized nanoparticles were characterized by XRD, BET, EDS, and SEM analyses. The results showed that at the best conditions, the nanoparticles were synthesized with a weight percentage of 32. 28 and 67. 72%, a particle size of 13. 25 nm, high purity, and high surface area. Also, the results showed that the supercritical hydrothermal method has performed well for mixed nanoparticles of 30-70% (Th-U)O2 production.

In this research, nanopowder alumina was produced by sol-gel method. Boehmite sol was prepared from aqueous solution of aluminum nitrate in pH = 8 and 80°C. In the first section of the research, some amount of this sol was transformed to gel after heating at 100°C. Post heat treatment on the dried gel was in 1100°C for 2 hours. Alpha alumina was synthesized with specific surface area of 12 m2/g, particle size average of 450 nm and crystal size 35 nm. In the second section of the research, microwave was used for transformation of the starting sol into gel. alpha alumina was synthesized by heating the dried gel in microwave for 20 minutes. Specific surface area of 35 m2/g and of crystal size of 25 nm was attained by this method.

Introduction: Yttria stabilized zirconia (YSZ) has been under consideration due to its desired properties for preparing dental restorations. The aim of this research was to produce the YSZ nano powder via sol-gel rout.Materials and methods: The present research was an experimental study and in vitro evaluation. Appropriate amount of zirconium oxide chloride, ZrOC12.8H2O, and yttrium nitrate, Y (NO3)3.6H2O, to reach 3mol% yttrium oxide in final product, were mixed in anhydrous ethanol ona magnetic stirrer. After drying the obtained gel at 50oC, it was calcined at 600oC for 1, 2 and 3hours. Phase identification, particle size and distribution determination, functional group identification and micro structural investigation were performed using XRD, SEM, TEM and FTIR techniques.Results: Results revealed that the tetragonal zirconia phase nano powder has been obtained. Crystallite size of the powder was about 20 nm and the size of particles was about 80 nm. The optimum temperature and time for calcimine process was 600ºC and 3 hours, respectively.Conclusion: The obtained Yttria stabilized zirconia with special characteristics duo to nano scale structure, could be a desired biomaterials for preparing dental restorations such as inlay, on lay, post and core, crown, and bridges in dentistry.

Alumina is an important material in industrial applications. In the present article, an Al2O3 nanopowder was synthesized by a wet chemical method using AlCl3· 6H2O and aluminum powder. The effect of pH on the structural evolutions and morphological characteristics of the nanopowder were investigated by X-ray diffractometry, scanning electron microscopy, thermal analysis and Brunauer-Emmett-Teller surface area measurement. The results showed that an amorphous powder and AlOOH were formed at pH values of 2 and 9 respectively. The surface area of synthesized powders at pH value of 2 and calcined at 800oC was 55 m2/g. The surface area of the powder increases to 170 m2/g, by increasing the pH value up to 9. Nanopowders in alkaline solution were finer than acidic solution.

Nanocrystalline powders of hydroxyapatite (HA) were prepared from Ca (NO3)2·4H2 O and P2O5 using a simple sol–gel approach. The resultant gel precursors obtained based on the concentration of the starting solutions were either transparent or translucent. Fourier transform-infrared spectroscopy (FT-IR) results combined with the X-ray diffraction (XRD) indicated the presence of amorphous HA in the as-dried gel precursor. X-ray patterns collected on the powder after heat-treatment at 900°C for 12 h in air exhibited single phase of HA. Scanning electron microscopy (SEM) showed that nanocrystalline (50 nm) HA particles have obtained in the powder after heat treatment at 900oC.

In this study, synthesis of silicon nitride by mechanical alloying and the effects of important parameters of milling time and heat treatment temperature, time and rate are presented. Silicon micro powder and nitrogen gas were used as precursor materials. Synthesized phases, morphology and particle size were investigated by X-ray diffraction pattern (XRD) and Fieldemission scanning electron microscopy (FE-SEM), respectively. X-ray fluorescence analysis (XRF) was used for silicon nitride purity investigation.The optimum sample was produced at 30 h milling time, heat treatment at 1300oC and 22 oC /min heating rate conditions. X-ray fluorescence analysis showed more than 98% purity.

The use of plant extract in the phytosynthesis of nanoparticles can be an eco-friendly approach and have been suggested as possible alternative to conventional method namely physical and chemical procedure. In the present research, all the chemical reagents were of analytical grade and used without further purification in these experiments.A conventional heating phytosynthesis route by using Fumaria Officinalis was used to produce the Ag nanoparticles. The radical scavenging activity test was used to check their anti-oxidant activities using 2, 2-diphenyl-1-picrylhydrazyl (DPPH). The morphological properties and particle size of synthesized Ag nanoparticles have been confirmed by Scanning Electron Microscope (SEM-EDX), Fourier transform Infrared (FT-IR) and Dynamic Light Scattering (DLS). The synthesized nanoparticles were characterized by XRD for the crystallinity, phase purity and average particle crystallites size. Based on FT IR results the OH groups are responsible for reducing and capping of Ag cations. The increase in the intensity of carbonyl group confirms this issue. Moreover, the synthesized nanoparticles possess a range of diameter between 30-40 nm according to the results of SEM. Antibacterial activity against L.monocylogenes, L.monocytogens and E.coil were investigated. Eventually, a cream containing as-synthesized Ag nanoparticles was produced using Rosa cannina extract through a green method. The data from the present research show that stable and spherical Ag nanoparticles were produced using different concentration of Rosa cannina extract which used as precursor. The findings proved that biosynthesis could produce natural cosmetic products like cream as a bio-friendly and cheap method.

The main objective of the present study was to investigate Cd(II) adsorption by immobilized silica nanopowder within calcium alginate and to determine the isotherm, kinetics, and thermodynamics of the adsorption process. Batch flow mode reactors were used to investigate the effects of initial pH, contact time and metal ion concentration on Cd (II) adsorption. The optimal contact time and initial pH for Cd (II) adsorption were found to be 120 min and 4.0, respectively. Increasing Cd (II) ion concentration from 10 to 1000 mg/L led to increasing adsorbed Cd (II) ions from 5.71 to 100.65 mg/g. The results showed that the Langmuir isotherm model was the best model to describe the experimental data (R2=0.997). The maximum adsorption capacity (qm) for Cd(II) adsorption onto the adsorbent was estimated to be 72.99 mg/g. Based on the mean free energy of adsorption (E) obtained from Dubinin-Radushkevich (D–R) isotherm model, Cd(II) adsorption onto immobilized silica nanopowder follows a chemical mechanism (E=8.451 kJ/mol). The kinetic study indicated that the pseudo-second order model was a more suitable model than the pseudo-first order one for describing Cd (II) adsorption (R2=0.999). Additionally, the negative DHo and DGo values demonstrated an exothermic and spontaneous Cd (II) adsorption onto immobilized silica nanopowder.