Stability of Fe3O4 nanoparticles in various model solutions

In this study, magnetite nanoparticles were tested to check their stability in various model solutions such as: distilled water, 0.9% NaCl, white wine, citric acid, acetic acid, and ethanol. The experiment was carried out at room temperature holding nanoparticle powders distributed in the solutions for one, two and three weeks period. The analyzed nanoparticles before and after solubility/durability experiment were studied by transmission electron microscopy, X-ray diffraction and infrared spectroscopy to observe occurring modifications of the crystalline structure of the tested nanoparticles cores and changes of the surface chemistry, respectively. Mossbauer spectroscopy allowed to follow qualitative changes of the magnetic properties of nanoparticles exposed to different media in time scale. The solutions were analyzed by Atomic Absorption Spectroscopy method to measure variation of the iron atoms content. It was observed that: (i) rather neutral environments for magnetite nanoparticles are: distilled water, the solution of 0.9% NaCl and ethanol; (ii) acids caused significant dissolution of particles core; (iii) wine modifies mostly only particle surface.