Preparation and properties of magnetic Fe3O4–chitosan nanoparticles

Magnetic Fe3O4–chitosan nanoparticles were prepared by the covalent binding of chitosan (CTS) onto the surface of magnetic Fe3O4 nanoparticles which were prepared by hydrothermal method using H2O2 as an oxidizer. Transmission electron microscopy (TEM) showed that Fe3O4 particles and Fe3O4–chitosan nanocomposites were regular sphere with a mean diameter of 23 nm and 25 nm, respectively. X-ray diffraction patterns (XRD) indicated that the magnetic Fe3O4 nanoparticles were pure Fe3O4 with a spinel structure and the coating of chitosan did not result in a phase change. The coating of CTS onto the Fe3O4 nanoparticles was also demonstrated by the measurement of thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectra. Magnetic measurement revealed that the saturated magnetization of the Fe3O4–chitosan nanoparticles reached 21.5 emu g−1 and the nanoparticles showed the characteristics of superparamagnetism.