Nanoporous inorganic materials from mineral templates

The crystal architecture of layer-lattice minerals has been used to prepare inorganic materials containing pores of closely controlled size and shape. The template minerals are activated, either by thermal or mechanical treatment, and selectively leached with acid to remove the octahedrally-coordinated component, or with alkali to remove the tetrahedral (silica) component. Some acid-leached products contain hydrophilic slit-shaped pores with narrow size distributions typically in the nanopore range, whereas the alkali-leached products contain unimodal pore distributions of larger size (2–3 nm). The leaching by-products have also been used to prepare combined anion and cation exchange material potentially useful for simultaneous removal of PO4− and NH4+ from waste waters.