Magnetic adsorbents based on micro- and nano-structured materials

Abstract

Micro-and nano-sized magnetic adsorbents on the basis of elemental metals, iron oxides, and ferrites, supported by inorganic (carbon, graphene, silica, zeolites) or organic (macromolecules, polysaccharides, polymers, biomolecules) compounds, are reviewed. Main attention is paid to magnetic hydrogels, xerogels, and aerogels due to their high number of environmental and biomedical applications. Role of carbohydrates and polysaccharides (starch, alginic acid, chitosan, etc.) for stabilization of magnetic nanoparticles and use the formed composites for adsorbtion purposes is described. Magnetic adsorbents are mainly used for heavy metals removal, separation, destruction and adsorption of oil, dyes, toxic organic compounds, several biomolecules and drugs, as well as widely in the catalytic processes. These last applications of magnetic adsorbents, in particular ferrites, are emphasized. Their main advantage for these or other possible applications is that the adsorbent or catalyst can be easily removed from reaction media after adsorption or completion of reactions via a simple magnet. Magnetic behavior studies of magnetic adsorbents are also discussed.

Magnetic carbon composites with a hierarchical structure for adsorption of tetracycline, prepared from sugarcane bagasse via hydrothermal carbonization coupled with simple heat treatment process

“…Magnetic adsorbents have evolved to attractive materials for environmental decontamination of aqueous systems, allowing for simple separation using an external magnet after completed adsorption (Kharissova et al, 2015). The rapid and effective separation of a magnetic adsorbent from aqueous solution shortens the duration of the whole decontamination process, thereby reducing the costs, which is a critical advantage especially in industrial scale applications.…”

Facile synthesis of γ-Fe2O3 nanoparticles integrated H2Ti3O7 nanotubes structure as a magnetically recyclable dye-removal catalyst

“…So far four different methods have been employed to load the magnetic nanoparticles on the titanate nanostructures. Although reusable magnetic adsorbent systems have been reported for the removal of metal-cations and organics, [14][15][16][17][18][19][20] to the best of our knowledge, there is no report available in the literature yet on the effect of addition of magnetic property on the dye-adsorption capacity of the titanate-based magnetic nanocomposites synthesized via the novel ion-exchange mechanism. 11 However, in this method, the magnetic nanoparticles may get dissolved during the subsequent acid-washing step.…”

Synthesis of Ce(III)-doped Fe3O4 magnetic particles for efficient removal of antimony from aqueous solution

“…As an alternative mode, magnetic adsorbents (e.g., ␥-Fe 2 O 3 , Fe 3 O 4 , nZVI, etc.) exhibited combine adsorption properties with the magnetic properties, which make the adsorbents separated from liquid phase using an external magnetic field easily, and could be re-applied several times after desorbing the adsorbed contaminants [18][19][20]. Magnetic separation of magnetic adsorbents is a more efficient approach to solid-water separation than conventional methods (e.g., centrifugation, sedimentation, filtration) [21].…”