Sonochemical synthesis of Pr6MoO12 nanostructures as an effective photocatalyst for waste-water treatment.

Synthesis of pure Pr6MoO12 nanoparticles was the aim of the present work, which was prepared by sonochemical method which is a controllable rout on size, purity, and morphology of products. The experiments were carried out under a probe as sonication source, and its power was adjusted in 30 W (9 kHz), 50 W (15 kHz), and 80 W (24 kHz) for different samples. The optimum product with the smallest size and highest purity was synthesized by changing time, power of sonication, solvent and capping agent. Besides, the formation of various phases of praseodymium molybdate was investigated in different experimental conditions that proved the presence of ammonia, sonication and calcination are necessary factors for the preparation of pure Pr6MoO12 nanoparticles. Products were characterized by various analyses such as SEM, XRD, TEM, FT-IR, DRS, and EDS. Furthermore, the photocatalytic activity of Pr6MoO12 nanoparticles under UV irradiation was studied by photodegradation of methylene blue and acid red 92 as organic pollutants. The most active photocatalytic agent was determined superoxide anion radicals and kinetics model of photocatalytic reaction was considered as pseudo-first order.

Sonochemical-assisted synthesis of pure Dy2ZnMnO6 nanoparticles as a novel double perovskite and study of photocatalytic performance for wastewater treatment.

Herein, successful synthesis of pure Dy2ZnMnO6 nanoparticles as a new double perovskite was reported. The samples were prepared using various base and surfactants under ultrasound waves (30 W and 20 kHz). The effects of base type and surfactant type as effective parameters on morphology and size of products and the roles of calcination temperature and sonication as operative procedures on purity of products were investigated. According to the results tepa was chosen as favorite base to produce the smallest particles with the most homogeneity and T ≥ 900 °C was considered as desirable calcination temperature for synthesis of pure product. It seemed that high temperature of ultrasound waves can decrease the required calcination temperature, so facilitates the achievement of pure product. Moreover, photocatalytic performance of the prepared product was examined by decolorization of three dyes including Eriochrome Black T, Methyl orange and Methyl violet under UV irradiation. The most and the least percent of degradation were assigned to Methyl violet (90.44%) and Methyl orange (48.39%), respectively. Paramagnetic property of this product was considered as the other advantage for its photocatalytic performance because of it can be easily separated by magnetic field and recycles again.

Investigation of experimental and instrumental parameters on properties of PbFe12O19 nanostructures prepared by sonochemical method.

It is the first time that PbFe12O19 nanostructures were successfully synthesized by sonochemical method. The instrumental and experimental parameters were optimized to achieve the appropriate product. The results showed that Pb+2 to Fe+3 molar ratio and the type of capping agent as experimental parameters and time and power of sonication as instrumental variables can influence on the purity and particle size of products, respectively. According to the results, the synthesis process could improve to sol-gel assisted sonochemical method in presence of PEG as capping agent. In this method, pure product obtained by using the high temperature and pressure in sonication treatment and hydrolysis and condensation processes in sol-gel method, simultaneously. Concurrent presence of sonication treatment and PEG were necessary for preparation of pure hexaferrite nanostructures. Because of metal oxides nanostructures as major product and hexaferrite as minor product were produced in the absence of them. So, sol-gel assisted sonochemical method can be introduced as an effective method for preparation of hexaferrite nanostructures. Furthermore, it was found that the instrumental parameters should be optimized, because of increasing the time and power of sonication is not always favorable for preparation of ultrafine particles and small structures.

SrCrxFe12-xO19 nanoceramics as an effective catalyst for desulfurization of liquid fuels: Green sol-gel synthesis, characterization, magnetic and optical properties.

In this work, SrCrxFe12-xO19 (x = 0.0, 0.5, 1.0, 1.5) nanostructures were successfully synthesized by sol-gel auto-combustion method, and different aminoacids were used as green reductants. Various analysis results show that SrCrxFe12-xO19 nanoparticles synthesized successfully.The present study shows that SrCrxFe12-xO19 nanoparticle could be used as adsorbent for the desulfurization of liquid fuels. Increasing of nanoparticles concentration was caused to increase the adsorption rate of sulfur contents of fuel. The adsorption rate of sulfur contents of fuel in various concentrations 4.5, 9.5, and 18.5 g. L -1 of SrCrxFe12-xO19 nanoparticles in solution was estimated about 39, 50, and 62% for 30 min, respectively. The results of catalytic tests reveals that SrCrxFe12-xO19 nanoparticles have the potential to be used as a new kind of semiconductor catalysts for the desulfurization of liquid fuels. Magnetic property of the final sample was measured at room temperature by a vibration sample magnetometer (VSM) and shown that the intrinsic coercivity of product is about 6000 Oe and it exhibits characteristics of single magnetic domains (Mr/ Ms = 0.53).

ZnCr2O4 Nanoparticles: Facile Synthesis, Characterization, and Photocatalytic Properties.

In this work, zinc chromite (ZnCr2O4) nanostructures have been synthesized through co-precipitation method. The effect of various parameters such as alkaline agent, pH value, and capping agent type was investigated on purity, particle size and morphology of samples. It was found that particle size and morphology of the products could be greatly influenced via these parameters. The synthesized products were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), fourier transform infrared (FT-IR) spectra, X-ray energy dispersive spectroscopy (EDS), photoluminescence (PL) spectroscopy, diffuse reflectance spectroscopy (DRS) and vibrating sample magnetometry (VSM). The superhydrophilicity of the calcined oxides was investigated by wetting experiments and a sessile drop technique which carried out at room temperature in air to determine the surface and interfacial interactions. Furthermore, the photocatalytic activity of ZnCr2O4 nanoparticles was confirmed by degradation of anionic dyes such as Eosin-Y and phenol red under UV light irradiation. The obtained ZnCr2O4 nanoparticles exhibit a paramagnetic behavior although bulk ZnCr2O4 is antiferromagnetic, this change in magnetic property can be ascribed to finite size effects.