Structural and magnetic studies of NiFe2O4 and NiFe2O4@SiO2-Silane agent samples useful for the removal of Cu2+ ions

Statistically Analyzed Heavy Metal Removal Efficiency of Silica-Coated Cu0.50Mg0.50Fe2O4 Magnetic Adsorbent for Wastewater Treatment

“…The crystallite size of silica-coated CuMgFe 2 O 4 was measured to be 23 nm, slightly lower than the crystallite size of pristine ferrite. Silica coating generates a barrier to crystal growth and prevents aggregation by reducing surface energy, consequently reducing crystallite size. , Such reduction in crystallite size results in an increased surface area to volume ratio of ferrites, which consequently offers excessive active sites and upsurges the absorption capacity of composite ferrite adsorbents for heavy metals . Leal et al performed surface treatment MFe 2 O 4 (M = Cu, Ni, Co, Mn, and Fe) spinal ferrites through silanization and chitosan functionalization.…”

Superparamagnetic and Light-Emitting Bifunctional Nanocomposites of Iron Oxide and Erbium or Thulium Doped Yttrium Orthovanadate

“…3groups, respectively [9,30,36]. The strong band at 436 cm −1 can also be assigned to the asymmetric stretching vibration of the Y/Er 3+ -O and Y/Tm 3+ -O bonds, but coupled with both, the in-plane antisymmetric bending vibration of the Si-O bonds and the asymmetric stretching vibrations of the Fe-O bonds located in the octahedral sites [24]. Finally, the band at 561 cm −1 is assigned to the asymmetric stretching vibrations of Fe-O bonds located in the tetrahedral sites of the inverse spinel [1,3,16].…”

“…This value will vary slightly because the magnetic properties are directly related to the shape and size of the particles [16]. This decrease is observed in nanometric-sized magnetic materials due to surface effects produced by the particle size reduction, where the magnetic moments are tilted on the surface and lose directionality [24]. The spin canted layer of magnetic nanoparticles is higher with smaller particle size, where M s varies according to Eq.…”

“…For a long time, research has also been carried out to obtain magnetic nanoparticles of magnetite (Fe 3 O 4 ) that are currently of great interest due to their large potential for use in many technological applications. Nanoparticles of this composition, smaller than 15 nm, offer unique advantages over other materials, such as that they can be synthesized by low-cost methods, they are physically and chemically stable, biocompatible, and non-toxic [9,24]. They also have strong magnetic saturation and superparamagnetism at room temperature, which means that these nanoparticles can be temporarily magnetized in presence of an external magnetic field and this magnetization disappears when the field is removed [9,16,25].…”

“…Their toxicity and efficacy will depend on the particle size, as well as the fluorescence emission intensity of lanthanide-doped materials, which varies with crystallinity and particle size [26,27]. Likewise, the magnetic properties will be affected, being able to find superparamagnetic behaviors below 20 nm [9,24]. These particle sizes can be controlled using different synthesis routes and methods, as well as by varying reaction parameters such as temperature, time, concentration, or pH.…”