NANOSCALE ENCAPSULATION - THE STRUCTURE OF CATIONS IN HYDROPHOBIC MICROPOROUS ALUMINOSILICATES

Hydrophobic microporous aluminosilicates created by the modification o f zeolites and clays are currently being investigated as storage media for hazardous cations. Addition of an organic monolayer to the surfac e of an aluminosilicate after introduction of an ion into the zeolite or clay reduces the interaction of water with the material. The result ant systems are approximately 20 times more resistant to leaching of t he stored ion than the unmodified ion-exchanged materials. XAS spectra demonstrate that byproducts from the organic modifier can complex wit h the encapsulated cation. This complexation can result in a decreased affinity of the cation for the aluminosilicate matrix. Changing the o rganic modifier eliminates this problem. XAS spectra also indicate tha t the reactivity and subsequent speciation of the encapsulated ion alt ers upon application of the hydrophobic layer.