Formation of iron oxide particles with aerosol-OT (AOT)/isooctane/water emulsion was carried out employing a coprecipitation reaction for Fe 3O4 particles. Emulsions containing Fe2+/ Fe3+ were mixed with those containing OH-. Iron oxide particles were formed by changing the concentration ratio of AOT to iron ions and maintaining the volume fraction of water in the emulsion at 0.25. Particle formation was also carried out using nonemulsified aqueous solutions as a reference. The morphology, crystal structure, magnetic property and hydration degree of the particles formed under various conditions were compared. The α-FeOOH or amorphous particles are formed instead of Fe3O 4 when the AOT concentration is comparable to, or higher than, the iron ion concentration. These particles contain an OH group and water, and are oxidized to become α-Fe2O3 by heating in N 2. The Fe-AOT complex as the origin of OH-rich particle formation was the focus of this investigation. The IR measurement was carried out for the Fe-AOT complex, separately prepared with the aqueous solution. It was found that the Fe-AOT complex was hydrated, indicating that hydration of the complex affects the properties of particles formed by the emulsion. A possible mechanism for formation of α-FeOOH or amorphous particles with emulsion is proposed.
- Iron oxide
ASJC Scopus subject areas
- Chemical Engineering(all)
- Renewable Energy, Sustainability and the Environment
- Waste Management and Disposal