Ferritization of industrial waste water and microbial synthesis of iron-based magnetic nanomaterials from sediments

The precipitation of iron and associated heavy metals in industrial waste water and in model solution using ferritization and aerobic bacterial culture was investigated. Magnetic sediments extractable by magnetic separation (specific saturation magnetization of 16–36.8 G cm3/g) were produced by precipitation of iron by ferritization method at рН (8–10) and 60–80°С for 15–30 min. Nanoparticles of ferrihydrite or ferric hydroxide doped with associated metals (Co, Ni) were produced under precipitation of ferric iron in model solution with bacteria at the temperature 26–34°С. The radii of synthesized particles are 1–5 nm and nanoparticles of ferrihydrite are superparamagnetic in both un‐doped and doped (Co, Ni, Zn) sets. Dispersed structure of biogenic nanoparticle sols, their magnetic and other properties were studied by atomic force microscopy, X‐ray small‐angle scattering, X‐ray diffraction, electron magnetic resonance, Mössbauer and X‐ray photoelectron spectroscopy. © 2016 American Institute of Chemical Engineers Environ Prog, 35: 1407–1414, 2016