Synthesis of magnetic nanocomposite Fe_3O_4 coated polypyrrole (PPy) for Chromium(VI) removal

摘要

In recent years there is a continuously increasing worldwide concern for the growth of wastewater treatment technologies. The utilization of iron-oxide nano-materials has attracted much interest due to their unique properties, such as extremely small size, high surface-area-to-volume ratio, surface modifiability, excellent magnetic properties and great biocompatibility. hi this study, Fe_3O_4 coated polypyrrole (PPy) magnetic nanocomposite was prepared via in situ polymerization of pyrrole monomer for the removal of highly toxic Cr(VI).The PPy/Fe_3O_4 nanocomposite was characterized by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction pattern (XRD) and Fourier-transformed infrared spectroscopy (FTIR). The adsorption properties of the PPy/ Fe_3O_4 nanocomposite for the removal of Cr(VI) were thoroughly studied. Up to 99% adsorption was found with 220 mg/L Cr(VI) aqueous solution at pH 2. Adsorption results showed that Cr(VI) removal efficiency by the nanocomposite decreased with an increase in pH. Adsorption kinetic was best described by the Pseudo-second-order rate model. Desorption experiment showed that in spite of the very poor recovery of the adsorbed Cr(VI); the regenerated adsorbent can be reused efficiently at least for two successive adsorption-desorption-cycles without significant loss of its initial capacity.