In this study, magnetic Fe3O4 nanoparticles were synthesized by co-precipitation method and then Au shell was extended over these nanoparticles via chemical reduction of chloroauric acid with sodiumborohydride under ultrasound irradiation. The obtained Au/Fe3O4 nanoparticles were characterized by using X-ray diffraction technique and Fourier transform infrared spectroscopy and their physical properties was studied by scanning electron microscopy and transmission electron microscopy. The characterized nanoparticles were used as efficient catalyst in the degradation of Rhodamine 6G dye in aqueous solution. UV-Vis spectroscopy was used to determine the dye concentration during optimization of the reaction conditions, and effect of various parameters such as pH, catalyst loading, temperature, and amount of the oxidant was investigated. It was found that Au/Fe3O4 catalyst at 80 oC in the pH of 12 can effectively degrade Rhodamine 6G dye molecules in the presence of hydrogen peroxide as an inexpensive and available oxidant. The catalyst after recycling was also, able to perform its role in successive runs.

In this work, core (SiO2) – shell (CuS) nanostructures have beendeveloped using a simple wet chemical route. X-ray diffraction analysis (XRD), diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), EDS and fourier transform infrared (FT-IR) were used to characterize the products. The morphological studies revealed theuniformity in size distribution with core size of 250 nm andshell thickness of 7. 5-17 nm. The structural studies indicate hexagonal structure of covellite (CuS) shell with no other trace for impurities in the crystalstructure. This CuS layer exhibit the band gap energy of3. 1 eV, due to quantum confinement and numerousdefects presence. Photocatalytic activity of nanocomposites was studied for degradation of Methylene Blue (MB) under visible light. Several parameters were examined, catalyst amount (0. 1– 1 g L-1 ), pH (1– 13) and initial concentration of MB (0. 96– 10 ppm). The extent of degradation was estimated from the residual concentration by spectrophotometrically.

In this paper, Fe3O4@SiO2 core/shell magnetic nanostructure has been synthesized and modified by N- (2-aminoethyl) -3-aminopropyltrimethoxysilane (AEAPTMS). Fe3O4@SiO2 was used as a novel adsorbent for separation of hexachloroplatinic acid. X-ray diffraction (XRD), scanning electron microscopy (SEM), and FT-IR technique were used to characterize morphologies and surface texturing of these adsorbents. The effective factors on adsorption, such as pH, contact time; salt effect and temperature were studied systematically. The optimal conditions of Platinum adsorption were obtained at temperature of about 25oC, pH about 2.5 and the equilibrium time of 30-40 minutes. The maximum adsorption capacity (qmax) in the optimal conditions was equal to 74 mg/g. The magnetic separation of the absorbent was achieved by a magnet and finally the absorbent was compared with other absorbents. Inductive coupled plasma optical emission spectrometer (ICP-OES) was used for determination of metal ion concentrations in the aqueous solution.

More than 22% of the world's agricultural land is saline, and this trend continues to increase with climate changes. Salinity stress causes leaf color change, osmotic stress, ionic toxicity, prevents growth, photosynthesis and plant performance. Due to their size less than micron, metal nanoparticles have a great absorption and transmission power in plants. Salinity stress is a major problem in hot and dry areas under tomato cultivation. For this purpose, investigating the mutual effects of the size and type of zinc oxide and iron oxide nanoparticles on the improvement and change of growth and increasing the resistance to salt stress in tomato plants of the early urbana variety were carried out in the form of a completely randomized and factorial design with 4 replications, at a significant level of 5%. In this research, zinc oxide nanoparticles in 25 and 50 nm sizes, iron oxide in 25 nm sizes and sodium chloride in 0 and 75 mM levels were used. nanoparticles and salinity treatments were both applied to the plants. The results showed that salt stress led to a decrease in plant growth parameters such as shoot and root length, leaf area, RWC, ion leakage. Also, NaCl led to an increase in the accumulation of prolin and other aldehydes, sodium, iron and zinc. The application of nanoparticles had a slight effect in stress-free conditions, but in stressed conditions, these two nanoparticles alone and especially in combination neutralized the effect of salinity and reduced the damage caused by salinity stress.