Chemical and physical characterization of iron-intercalated vermiculite compounds

摘要

Herein we report on synthetic iron-intercalated vermiculites prepared from a Mg-vermiculite mineral from Santa Olalla, Huelva, Spain, by means of an ion exchange process from aqueous solutions of FeCl₂ and FeCl₃. Thermogravimetric, X-ray diffraction, magnetic susceptibility and Mössbauer spectral studies have been used to characterize the synthetic iron-intercalated vermiculites. The results suggest that the intercalation process employed induces modifications in both the interlayer spacing and in the octahedral sheet; the disordered structure of the Mg-vermiculite mineral is not altered. The presence of solvated Fe(H₂O) _n 2+ ions has been shown by the Mössbauer spectroscopy. No magnetic order has been observed between 2 and 300 K neither in the Mg-vermiculite mineral nor in the two synthetic iron-intercalated vermiculites.