Síntese, caracterização e uso de nanodispositivo magnético para remoção de poluentes químicos e microbiológicos de ambientes aquáticos

Abstract

Magnetite (Fe3O4) is a spinel-type iron oxide of the general formula MFe2O4, where M may be a divalent or trivalent cations. Such compounds may be combined with polymers to give rise composite materials. An interesting polymer that can be combined with magnetite is the water-soluble carbomer, carboxylic groups rich called carbopol. In the present study, we produce in a pilot scale, a nanodevice resulting from the association of the magnetite with different carbopol polymer concentrations, obtaining pure Fe3O4 (C0), Fe3O4/Carbopol-0.1% (C1), Fe3O4/Carbopol-0.25% (C2) and Fe3O4/Carbopol-0.5% (C3), for directed magnetically decontamination of chemical and microbiological pollutants in aquatic environments. FTIR and DRX data confirmed the structure of magnetite (C0). In addition, the chemical bonding of carbopol with magnetite was confirmed, since after exhaustive washing of the compounds, the spectra showed bands of both magnetite and carbopol. The magneto-rheology assays showed that samples C1 and C2 were dragged by the applied magnetic field. Methylene Blue (AM) adsorption studies showed adsorption capacity in the following order: C3>C2>C1>C0. Also, experiments to evaluate the ability to remove microorganisms from water using Escherichia coli strain ATCC 25922 showed that the removal capacity was the inverse of the adsorption capacity: C0>C1>C2≈C3. These data suggest that pure magnetite has a greater ability to eliminate microorganisms from water, probably due to its catalytic effect on the bacterial cell wall, which is minimized by polymer coating. The cell viability assay with the culture of murine macrophages J774A.1showed tolerable levels of cytotoxicity at low concentrations, for all compounds (except C0, which showed cell viability below 70% at all concentrations) and cell viability levels below 70% for all compounds in concentrations greater than 400 µg/mL. A significant ability of C1 to remove microorganisms in water was observed, suggesting that this material can be used simultaneously to eliminate chemical and microbiological pollutants in an aqueous environment.