Ion reduction in iron oxide and oxyhydroxide nanoparticles during ultrasonic treatment

The effect of ultrasonic treatment of iron oxide and iron oxyhydroxide nanoparticles (ferrihydrite nanoparticles synthesized by Klebsiella oxytoca microorganisms, ferrihydrite nanoparticles synthesized by a chemical method and hematite nanoparticles) is studied. Samples of nanoparticles were investigated using transmission electron microscopy, Mössbauer spectroscopy and X-ray diffraction methods. The formation of the α-Fe metal phase from nanoparticles of iron oxides and iron oxyhydroxides was detected. The metal phase is formed as a result of the reduction of iron ions during cavitation treatment. According to the experimental results, the presence of a protein or a polysaccharide component is necessary for the course of this reaction.