Synthesis, microstructure, and magnetic properties of monosized MnxZnyFe3 - x - yO4 ferrite nanocrystals

Highly efficient visible light photocatalysis of Nix Zn1-x Fe2O4 (x= 0, 0.3, 0.7) nanoparticles: Diclofenac degradation mechanism and eco-toxicity

Pharmaceuticals and personal care products occupy a predominant position with respect to both utility and release into the ecosystem, thereby contributing to environmental pollution at alarming rates. Of the several methods identified to minimize the concentration of PPCPs, nanomaterial based photocatalysis seems to be a potential alternative for it being highly economical and eco-friendly. In this study, we synthesized Nickel zinc ferrite (Ni-ZF) [Ni_x Zn_1-x Fe₂O₄ (x = 0, 0.3, 0.7)] nanoparticles with an average diameter of ∼400 nm by a co-precipitation method towards diclofenac degradation. The composite showed greater degrees of crystallinity devoid of any impurities. Nearly complete DCF degradation (∼99%) was achieved after 50 min reaction time with the nanoparticles at pH 7 for an initial DCF concentration of 50 mg/L. The degradation process followed a pseudo first-order rate law with the rate constant of 0.1657 min^{- 1}. Microbial toxicity and phytotoxicity studies demonstrated negligible toxicity imposed by the contaminated water treated with the prepared composite, suggesting it as a promising photocatalyst benefitting in all aspects.

Synthesis, characterization and in vitro cytotoxicity study of Co and Ni ferrite nanoparticles prepared by sol-gel method

In this study, we report the synthesis and characterization of NiFe2O4 and CoFe2O4 nanoparticles (NPs) which are widely used in the biomedical area. There is still limited knowledge how the properties of these materials are influenced by different chemical routes. In this work, we investigated the effect of heat treatment over cytotoxicity of cobalt and niquel ferrites NPs synthesized by sol-gel method. Then the samples were studied using transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM), Fourier Transform Infrared Spectroscopy Analysis (FTIR), and X-ray fluorescence (XRF). The average crystallite sizes of the particles were found to be in the range of 20–35 nm. The hemocompatibility (erythrocytes and leukocytes) was checked. Cytotoxicity results were similar to those of the control test sample, therefore suggesting hemocompatibility of the tested materials.

Effect of pH on Structural, Magnetic and FMR Properties of Hydrothermally Prepared Nano Ni Ferrite

Nano nickel ferrite particles were prepared at pH values 1.5, 4, 7, 10, 13 by a hydrothermal method using metal chlorides and NaOH as an oxidant and solution basicity controller. There is a phase transition from hematite to spinel ferrite that begins when the pH reaches 4. The lowest crystallite size (4 nm) was associated with a highest lattice constant (8.345 Å), at pH=4. Whereas maximum crystallite size 64.5 nm corresponds lattice constant of 8.298 Å at pH=10. The highest magnetization (48 emu/g) value was achieved for the sample prepared at pH=7, which at the same time has a lower coercivity. The samples synthesized at pH ≥4 show superparamagnetic behavior owing to its low particle size and to zero field cooling and field cooling measurements. The ferromagnetic resonance (FMR) cavity tests analysis show that the broadened linewidth (770 Oe) and high imaginary permeability or high microwave absorption which is linked to high magnetization and low coercivity of superparamagnetic particles and their aggregation. There was a shift in the resonance field due to internal fields and cation distribution.

The effects of surface spin on magnetic properties of weak magnetic ZnLa0.02Fe1.98O4 nanoparticles

In order to prominently investigate the effects of the surface spin on the magnetic properties, the weak magnetic ZnLa0.02Fe1.98O4 nanoparticles were chosen as studying objects which benefit to reduce as possibly the effects of interparticle dipolar interaction and crystalline anisotropy energies. By annealing the undiluted and diluted ZnLa0.02Fe1.98O4 nanoparticles at different temperatures, we observed the rich variations of magnetic ordering states (superparamagnetism, weak ferromagnetism, and paramagnetism). The magnetic properties can be well understood by considering the effects of the surface spin of the magnetic nanoparticles. Our results indicate that in the nano-sized magnets with weak magnetism, the surface spin plays a crucial rule in the magnetic properties.