2D→3D transformation of layered aluminosilicate upon base treatment

The present study describes a novel preparative route to sodalite from layered aluminosilicates such as kaolinite, montmorillonite, and Al2O3-pillared montmorillonite (Al-PILC), those which are subjected to react directly with sodium hydroxide as low as 100 °C under an ambient atmosphere. Powder X-ray diffraction (XRD) analysis, infrared absorption (IR) spectra and 27Al and 29Si magic-angle-spinning nuclear magnetic resonance (MAS NMR) spectra reveal that the resulting solid products are crystalline sodalites with cubic symmetry (a=8.92±0.05 Å) consisted of zeolitic Al–O–Si networks with an alternating ordering of Al and Si tetrahedra. Scanning electron microscopy (SEM) indicates that the sodalites derived from the two-dimensional aluminosilicates consist of nano-sized sodalite particles (30–50 nm) with preserved lamellar characters of the pristine layer silicates. Among the starting aluminosilicates, Al2O3-pillared montmorillonite is found to be an active precursor to zeolitic sodalite because of the high microporosity and the compositional and structural similarities.