Effect of a Low-Frequency Magnetic Field on the Release of Heat by Magnetic Nanoparticles of Different Shapes

Catalysts Based on Nanoscale Iron and Cobalt Immobilized on Polymers for Catalytic Oxidation of Aromatic Hydrocarbons: Synthesis, Physico-Chemical Studies, and Tests of Catalytic Activity

“…The formation of magnetite occurs through an intermediate stage of formation of ferrihydrite. The advantages of this method are high product yield, narrow distribution of nanoparticles in size, and resistance to aggregation and sedimentation [13,23,32,[39][40][41][42][43][44][45][46][47][48]. Co-precipitation occurs in two stages: first, the nucleation of crystals (when critical supersaturation is reached) occurs; the second stage is the slow growth of embryos through the process of diffusion of dissolved substances to the crystal surface.…”

“…To stabilize magnetic nanoparticles, their surface is coated with materials of both organic and inorganic nature. Such coatings solve a dual problem: firstly, they prevent the aggregation of nanoparticles and the oxidation of magnetite (both problems are, for example, fundamental in the transport of nanomaterials); secondly, they allow for modification of the surface of nanoparticles with various specific ligands for the intended use [11][12][13][14][15][16][17][18][19][20][21][22][23][24]. Currently, a promising direction is the synthesis and application of magnetic nanoparticles stabilized by modifiers: polymers of natural and artificial origin.…”

Catalysts Based on Iron Oxides for Wastewater Purification from Phenolic Compounds: Synthesis, Physicochemical Analysis, Determination of Catalytic Activity

“…In recent years, oxidative degradation in the presence of solid catalysts has been used to clean wastewater contaminated with organic compounds, among which materials containing iron ions fixed on various carriers (zeolite, coals, aluminosilicates, and clays) are promising. Heterogeneous catalytic oxidation of organic compounds in aqueous solutions makes it possible to avoid secondary contamination of wastewater with iron ions and to carry out destruction with the formation of non-toxic products [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44]. Despite the large number of developments for the purification of industrial waste from phenols, this problem cannot be considered solved.…”

“…Therefore, it is quite difficult to ensure highly effective purification from phenol compounds in most enterprises. The search for catalysts for the oxidation of organic substances in aqueous solutions is an urgent task [40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55].…”

“…This increased interest is due to the fact that the synthesized nanoparticles have unique physicochemical properties (optical, electrical, magnetic) and mechanical properties. The reason lies in the effect of the transition from micro-dimensions to nano-dimensions, wherein the ratio of surface to volume, that is, the proportion of surface atoms in relation to volumetric units, increases [32,33,[38][39][40][41][42][43]56]. The most noticeable in such cases are changes in the magnetic properties of nanoparticles compared to micro-sized materials.…”