FTIR and Raman Spectroscopic Characterization of Anionic Clays Obtained from Bauxite Tailings (Amazon, Brazil)

Anionic clay-type materials with layered double hydroxide (LDH) structures in the MgAlFe and ZnAlFe ternary systems were successfully synthesized via co-precipitation, utilizing bauxite tailings from the Amazon region as the starting material. X-ray diffraction (XRD) confirmed the formation of well-defined LDH phases, with basal reflections indicative of the effective incorporation of divalent and trivalent cations into the lamellar structure. Scanning electron microscopy (SEM) revealed distinct morphological differences: MgAlFe LDHs exhibited rough, disordered surfaces, while ZnAlFe variants formed larger, plate-like aggregates. Raman and FTIR (ATR) spectroscopy identified characteristic vibrational bands, reflecting the influence of metallic composition on the structural organization of the materials. This study demonstrates a sustainable and efficient route for the synthesis of anionic clays from industrial waste, emphasizing their potential for technological and environmental applications.