Characterization of lalithe, a new bentonite-type Algerian clay, for intercalation and catalysts preparation

Iron-intercalated clay has been obtained starting from a natural bentonite-type clay sample from Maghnia (Algeria). The natural compound contained, besides the clay material, impurities such as quartz, β-cristobalite and calcite. The quartz phase was removed by applying a purification protocol based on sedimentation. The two other phases remained in the solid but did not apparently affect the intercalation process. The intercalation process has been optimized to lead a microporous solid with a reticular distance of 16 Å and a specific surface area of 260 m2 g−1. High-resolution electron microscopy with EDX analyses showed that the sample had a relatively inhomogeneous composition with a typical delaminated structure. It confirmed the pillaring but also showed some goethite particles. These particles certainly formed because of the delamination are few and small and do not affect the Mössbauer spectra showing only one ferric iron species and confirming that most of the iron was in the pillars. The thermal stability of the iron-pillared clay has been studied. It was shown that the structure started to collapse before 773 K which is rather low for polyoxocations-intercalated clay but comparable for other iron-intercalated clays.