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.

Tb2MoO6 nanostructure: Ultrasonic controlling the size and morphology, characterization and investigation of its photo-catalytic activity for dyes as the water pollutants under UV light illumination.

For the first time, pure Tb2MoO6 nanostructures were successfully fabricated using Tb(NO3)3.6H2O and (NH4)6Mo7O24.4H2O as a precursor by ultrasonic method and characterized by via X-ray powder diffraction (XRD), Fourier-transformed infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), and Energy-dispersive X-ray spectroscopy (EDS). The various parameters such as the type of capping agent, ultrasonic time and power were optimized to achieve the appropriate sample. The results showed that the type of capping agent, ultrasonic time and power can influence on the morphology, size, and purity of the products, respectively. In this work, pure Tb2MoO6 nanostructures observed by PVP as capping agent in ultrasonic time and power of 30 min and 80 W, respectively. Optical property of optimized product was investigated via diffuse reflectance spectroscopy (DRS). The photo-catalytic activity of proposed nanostructure was studied in the presence of various dyes such as Methylene blue, methyl orange, and acid blue 92 as the water pollutants under UV light illumination. At 0.05 g of nanostructure, Methyl orange pollutant destruction was higher than the two other dyes.