Characterization of iron oxides embedded in silica gel obtained by two different methods

A new way of obtaining iron oxides embedded in amorphous silica gel matrices using Fe2+, oxygen and tetraethoxysilane (TEOS) as precursors is described. The product of this new method was compared to the compound produced when hydrochemically synthesized iron ferrite (magnetite) was directly embedded in silicon oxide (SiO2). The two xerogels were characterized and found to differ substantially. The compound obtained using the first procedure is amorphous iron oxide-hydroxide embedded in silica gel and lacks magnetic properties. In contrast, the silicon oxide particles in the second compound become partly coated by the magnetite, such that its magnetic properties are similar to those of magnetite proper.