Synthesis and Application of Fe3O4@SiO2@Carboxyl-Terminated PAMAM Dendrimer Nanocomposite for Heavy Metal Removal

In present study Fe3O4 magnetic nanoparticles (MNPs) were prepared using co-precipitation method. Prepared MNPs were coated by SiO2 layer via sol-gel process. Subsequent Michel-addition reaction and amidation were used to synthesize G(3) polyamidoamine dendrimer on prepared Fe3O4@SiO2. Fe3O4@SiO2@ PAMAM dendrimer was reacted with monochloroacetic acid for preparation of final Fe3O4@SiO2@Carboxyl-terminated PAMAM dendrimer nanocomposite. Successful synthesis of Fe3O4@SiO2@Carboxyl-terminated PAMAM dendrimer nanocomposite was confirmed by FTIR spectroscopy and CHN analysis. The nanostructure of prepared composite MNPs was investigated using TEM. X-ray diffraction pattern and thermal stability of pure MNPs and composite MNPs were studied using XRD and TGA analysis respectively. Unmodified and modified MNPs were used as adsorbent for the removal of Cu(II), Cd(II) and Pb(II) form aqueous solutions. It was observed that the modification of MPNs enhances the ability of MPNs for removal of these heavy metals significantly. Also it was shown that this modification enhances the accessibility of MNPs to heavy metal ions at low concentrations.