Magnetic halloysite nanotubes/iron oxide composites for the adsorption of dyes

Iron oxide nanoparticles were synthesized on the halloysite nanotube (HNT) to prepare the magnetic sorbent HNT-Fe3O4, which was explored the adsorption for three dyes, namely methylene blue (MB), neutral red (NR) and methyl orange (MO). HNT-Fe3O4 was characterized by transmission electron microscopy, Fourier transform infrared spectroscopy. X-ray diffraction and thermogravimetric analysis. HNT was attached with clusters of Fe3O4 nanoparticles, and the HNT component was about 50.5 wt% in HNT-Fe3O4. Magnetic properties illustrated that HNT-Fe3O4 was superparamagnetic with a saturation magnetization (27.91 emu g(-1)). The magnetic HNT-Fe3O4 exhibited better adsorption on MB than NR, while the adsorption of MO was very little. And as the adsorbent, HNT-Fe3O4 could be easily separated from the aqueous solution in a magnetic field. (C) 2011 Elsevier BM. All rights reserved.