Iron oxyhydroxide nanostructured in montmorillonite clays: Preparation and characterization

Abstract

Akaganéite is a very rare iron oxyhydroxide in nature. It can be obtained by many synthetic routes, but thermohydrolysis is the most common method reported in the literature. In this work, akaganéite-like materials were prepared through the thermohydrolysis of FeCl 3·6H 2O in water and suspensions containing clay minerals. X-ray diffractometry (XRD), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM) data show that the clays determine the crystal phase and size of the iron oxyhydroxide crystals. According to XRD and FTIR data, β-FeO(OH) (akaganéite) is the main metal oxyhydroxide phase. Considering the small basal spacing ( d 0 0 1 ) displacement observed when comparing the XRD patterns of pristine clays with the composites containing β-FeO(OH), the iron oxyhydroxide should be mostly located on the basal and edge surfaces of the clay minerals. UV–Vis electronic absorption spectra indicate that the preferred phase of the iron oxyhydroxide is determined by the nature of the clay minerals.