Low temperature synthesis of monolithic mesoporous magnetite nanoparticles

Magnetite nanoparticles are commonly used for drug delivery, as MRI contrast agents, and as adsorbents for the removal of heavy metal cations from waste water. The smaller the particle sizes the higher the efficiency of these particles in these applications. Different methods have been explored for the preparation of magnetic nanoparticles with this size limitation. Co-precipitation is one of the most versatile methods in this regard, and is characterized by the ability of preparation of a high yield of nanoparticles. Control of the particle size distribution, phase purity and type of porosity of the formed magnetite nanoparticles has been always considered a challenge. In the current study, magnetite mesoporous nanoparticles with an average particle size of 55 nm were prepared in pre-adjusted highly alkaline aqueous media at relatively low temperatures. Phase purity of the deposited magnetite was confirmed by X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Scanning (SEM) and transmission electron microscopy (TEM) graphs showed homogenously dispersion of spherical magnetite nanoparticles. Agglomeration of the mesoporous nanoparticles took place forming clusters with unified pore size distribution due to the homogenous particle size distribution. Magnetic susceptibility measurements at room temperature confirmed the magnetization characteristics of the nanoparticles.