Studies on Synthesis and Characterization of Fe3O4@SiO2@Ru Hybrid Magnetic Composites for Reusable Photocatalytic Application

Degradation of dye pollutants by the photocatalytic process has been regarded as the most efficient green method for removal organic dyes from contaminated water. The current research work describes the synthesis of Fe3O4@SiO2@Ru hybrid magnetic composites (HMCs) and their photocatalytic degradation of two azo dye pollutants, methyl orange (MO) and methyl red (MR), under irradiation of visible light. The synthesis of Fe3O4@SiO2@Ru HMCs involves three stages, including synthesis of Fe3O4 magnetic microspheres (MMSs), followed by silica (SiO2) coating to get Fe3O4@SiO2 MMSs, and then incorporation of presynthesized Ru nanoparticles (~3 nm) onto the surface of Fe3O4@SiO2 HMCs. The synthesized HMCs were characterized by XRD, FTIR, TEM, EDS, XPS, BET analysis, UV-DRS, PL spectroscopy, and VSM to study the physical and chemical properties. Furthermore, the narrow band gap energy of the HMC photocatalyst is a significant parameter that provides high photocatalytic properties due to the high light adsorption. The photocatalytic activity of synthesized Fe3O4@SiO2@Ru HMCs was assessed by researching their ability to degrade the aqueous solution of MO and MR dyes under visible radiation, and the influence of various functional parameters on photocatalytic degradation has also been studied. The results indicate that the photocatalytic degradation of MO and MR dyes is more than 90%, and acid media favors better degradation. The probable mechanism of photodegradation of azo dyes by Fe3O4@SiO2@Ru HMC catalysts has been proposed. Furthermore, due to the strong ferromagnetic Fe3O4 core, HMCs were easily separated from the solution after the photocatalytic degradation process for reuse. Also, the photocatalytic activity after six cycles of use is greater than 90%, suggesting the stability of the synthesized Fe3O4@SiO2@Ru HMCs.

Amphipathic Engineering of Magnetic Composites Reinforced with Ion-Copolymers-Activated Protein-Bioconjugate Functionalized Surface

Structurally stable, multifunctional ion-copolymer composites with enhanced ionic, hydrophilic and hydrophobic properties are developed utilizing multimodal materials. These hyperbranched polymeric composites function as strong supports in multifunctional applications. The integration...

Synthesis and characterization of a new magnetic composite MnFe2O4/clay based on a natural clay obtained from Turkestan deposit

The work is devoted to the development of a new method for the synthesis of magnetic composites based on manganese ferrite on a natural clay, coupling with their physico-chemical characterization. In the study, a natural clay of Kazakhstan obtained from the Turkestan deposit was used for the preparation of magnetic composites. The formation of materials with magnetic properties is an urgent task of our time, due to the needs of various applications of magnetically controlled materials for biomedical systems, electronic devices, catalytic and adsorption processes. The advantage of such materials is the ability to control them using a magnetic field for shaking, recovery, induction heating, among others. In this work, samples were prepared by co-precipitation of manganese and iron salts with 5 mol L-1 NaOH over the Turkestan clay (TC). Materials were characterized by various analyses, such as Fourier-Transform infrared spectroscopy (FTIR), X-ray diffractometric analysis (XRD), and elemental analysis. According to the results of physical and chemical studies of the XRD and thermal analysis, kaolinite is the main mineral in the composition of TC. Magnetic adsorbents MnFe2O4/clay with perfect magnetic separation characteristics were successfully obtained by chemical co-precipitation

Reduction of Core-loss in the High Frequency Band of the Fe-Si-Cr Crystalline Alloy According to Particle Size

In order for soft magnetic composites (SMCs) to achieve the high-performance requirements expected of them even at high frequencies, high permeability and low core-loss are required. In this study, we used different sizes of gas atomized Fe-Si-Cr alloy powder to produce SMCs, this alloy has higher resistivity than existing materials used in SMCs such as Fe-Si alloy or pure Fe. These powders were prepared by sieving raw materials which had an average size from less than 25 µm to over 63 µm. Our experiments show that as particle size decreases, the magnetic saturation tends to increase, the sample made from the powder with particles 25-38 µm in size recorded the highest magnetic saturation of 169.38 emu/g. Additionally, as particle size decreased, permeability increased. The sample made from powder with particles under 25 µm had a permeability of 20.7 H/m at 1 MHz. Also, the relationship between particle size and quality factor was found to be inversely proportional. Finally, the minimum core-loss was 187.26 kW/m3 at 1 MHz for the sample made from powder whose constituent particles are under 25 µm. We also observed that the core-loss is proportional to particle size.