Mössbauer and XRD investigations of layered double hydroxides (LDHs) with varying Mg/Fe ratios

Mössbauer, XRD and TEM Study on the Intercalation and the Release of Drugs in/from Layered Double Hydroxides

“…The XRD pattern of the pristine CaFe-LDH and its derived structural parameters (Table 1) are in agreement with those we used earlier [19] showing that the initial LDH was prepared indeed by the applied co-precipitation method. Significant differences have been observed between the Xray diffractograms of heat-treated, intercalated and drugreleased CaFe-LDHs.…”

“…The change in the isomer shift values recorded at 293 K and 78 K reflects only the corresponding regular temperature shift, [15] in agreement with the characteristics of CaFe-LDH materials. [19] However, the Mössbauer spectra of intercalated compounds registered either at 78 K (Table 2) or at 293 K showed significant differences in the quadrupole splitting compared to those of the pristine substance. …”

“…All spectra were satisfactorily decomposed into a doublet in accordance with the evaluation of Mössbauer spectra of other LDHs. [18][19][20] The Mössbauer parameters are depicted in Table 2.…”

“…[19,20] This spectrum corresponds to high spin Fe 3+ ions occupying the centres of shared octahedra, whose vertices contain hydroxide ions, which connect to form the layers of LDHs.…”

“…[14] 57 Fe Mössbauer spectroscopy [15,16] is a useful technique to characterise LDHs, in which Fe 3+ ions are constituents of the layers. In our previous works on LDHs, [17][18][19][20] Mössbauer spectroscopy revealed whether the iron was in the LDH structure formed or not [17] when the Ca : Fe [18] or Mg : Fe [19] ratios were altered. It could also provide with structural information when different organic anions were intercalated into a CaFe LDH.…”