Ion-Selective Properties of Armbrusterite Mineral and the Prospects for Its Laboratory Synthesis

In this paper, results of studying the properties of armbrusterite, a natural heterophyllosilicate, are presented. Due to its crystal structure consisting of parallel HOH-type sheets separated by a network of large-diameter (4-6 Å) channels, this mineral is of interest as a prototype for producing novel compounds to be used as sorbents. The studies were conducted by X-ray powder diffraction and X-ray single crystal diffraction analyses, electron microscopy, and IR spectroscopy. The natural sample is shown to be able to selectively extract monovalent cations from the solution of complex composition consisting of mono- and divalent salts. Furthermore, the preliminary results of hydrothermal synthesis of an analog of this mineral are reported. It is demonstrated that the mineral can be produced under milder conditions than the known methods for synthesizing heterophyllosilicates using platinum capsules (Tuttle bombs) at 380-450 °C.