Structure and Properties of Nanosized Composites Based on Fe3O4 and Humic Acids

Modified Fe3O4 Magnetite Core@Shell Type Nanomaterials for Highly-Responsive LPG Sensing: A Comparative Analysis

“…The lattice parameters for modified magnetite nanoparticles are smaller than the same for bare magnetite [JCPDS-ICDD 19-629] but larger than for maghemite [JCPDS-ICDD 39--1346]. This phenomenon is explained by the partial oxidation of iron ions (II) during functionalization due to an additional oxidative effect on Fe 3 O 4 by oxidizing Fe 2+ to Fe 3+ by quinoid groups 42 and phenolic moieties 43 of humic acids, for example, during the synthesis in situ ("the one pot"), which correlates with the results of electron-paramagnetic resonance spectroscopy, 43 showed a direct relationship between the concentration of free radicals in HS and the amount of Fe (III) reduced by them. 44 for Fe 2 O 3 to ½ for Fe 3 O 4 due to partial oxidation of Fe 2+ during drying, functionalization, and oxidation.…”

Humic acids-modified mesoporous silica encapsulating magnetite: crystal and surface characteristics

“…15 Humic acids (HA) emerge as promising candidates for controlling the size and morphology of iron oxide nanoparticles (NPs). 16 These supramolecular systems, comprised of natural macromolecules, possess numerous carboxyl and hydroxyl groups. 17 This grants them properties of anionic polyelectrolytes, exhibiting a distinct affinity for surface complexation with iron oxide NPs.…”

Phase Composition and Magnetic Properties of Nanoparticles with Magnetite–Maghemite Structure

“…Magnetic iron oxides (magnetite Fe 3 O 4 and maghemite γ-Fe 2 O 3 ) possess a wide range of useful properties. Their nanoparticles can be used as magnetic agents in medicine and biology for marking biomaterials, for penetrating cells of living organisms, or for local heating [3][4][5][6][7][8][9]. They also can be photocatalytically active [10], and can be used in agriculture as bioactive fertilizers [11][12][13].…”