Use of γ-Fe₂O₃/Chi/Pani nanocomposite for the multipurpose removal of water contaminants

Full text: There is a growing concern about the environmental impacts associated to the contamination of water resources caused by the textile, electronics and pharmaceutical industries. As a consequence, a strong drive exists today for methods of minimizing the presence of dyes, heavy metal ions and hormones in wastewater. In this work, we present preliminary results of the application of a magnetic nanocomposite of iron oxide/chitosan/polyaniline (γ-Fe₂O₃/Chi/Pani MNC) as a multifunctional adsorbent for the removal of contaminants such Cr (VI) ions, dyes and the 17α-estradiol hormone. For this, we initially synthesized magnetic nanoparticles of maghemite/chitosan (γ-Fe₂O₃/Chi MNPs) through a chemical co-precipitation method. Subsequently, these MNPs were coated with polyaniline by means of a emulsion polymerization process using the aniline monomer, resulting in the γ-Fe₂O₃/Chi/Pani MNC. We used UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscopy (SEM), and magnetic measurements to characterize the nanocomposites prepared. From the initial studies, it was possible to observe that with the use of only 4 mg of the γ-Fe₂O₃/Chi/Pani MNC we were able to achieve a high removal efficiency for Cr (VI) (44,9%), Metil Orange (64.4%), Rhodamine (57.6%), Safranin (28.0%), Methylene blue (18.6%), Black eriochrome (18.1%) and the hormone 17α-estradiol (40%). These preliminary results indicate that our hybrid γ-Fe₂O₃/Chi/Pani nanocomposite exhibits unique properties that could allow its more widespread use as a highly efficient multipurpose adsorbent for the simultaneous removal of different types of contaminants dissolved in aqueous media. (author)