Amorphous Titania-Coated Magnetite Spherical Nanoparticles: Sonochemical Synthesis and Catalytic Degradation of Nonylphenol Ethoxylate

Well-defined magnetically separable, amorphous titania-coated magnetite spherical nanoparticles were successfully synthesized by a sonochemical method using 20 kHz ultrasound. Amorphous magnetite particles were generated by the pyrolysis of Fe(CO) 5 within the cavitation bubbles. The simultaneous formation of titania particles from titanium isopropoxide in the bulk liquid led to the incorporation of the magnetite nanoparticles into the titania particles. Transmission electron microscopy images of the titania-coated magnetite nanoparticles showed that they were relatively uniform in size with an average size of ∼150 nm. The M – H hysteresis loop for titania-coated magnetite particles indicated that the composite spherical nanospheres exhibit superparamagnetic characteristics at room temperature. The titania-coated magnetite nanoparticles were found to be useful for the removal of a wastewater pollutant (nonylphenol ethoxylate) by a combined process of heterogeneous catalysis and ozonation.