Synthesis and Characterizatation of Magnetite Nanoparticle Coated Humic Acid (Fe3O4/HA)

Magnetite nanoparticles (Fe3O4) coated humic acids (HA) by a co-precipitation method using ammonium hydroxide. The HA was extracted from peat soil of Sambutan, East Kalimantan, Indonesia and then have been succesfully coated onto the surface of Fe3O4. Characterization of FT-IR spectra indicate that the coating Fe3O4/HA have been bound by Fe-COOR chemical bond. The XRD measurements does not affect the crystals structure. Scanning electron microscopy revealed the magnetic particle size is almost homogenous of 10-18 nm. Both of Fe3O4 and the coating Fe3O4/HA were of the cubic spinel structure and spherical-shaped morphology. The modification of HA on Fe3O4 can decrease the saturation magnetization from 71.3 emu/g to 69.5 emu/g.