EXAFS investigation on the incorporation mechanisms of Tl and Pb within the structures of pyrochlores and hollandites.

Hollandites and pyrochlores are minerals featuring tunnel-like cavities within which a wide variety of mono- and divalent cations can be hosted. The aim of our project is to evaluate the ability of such structures to incorporate and remove heavy metals from contaminated waters. Preliminary experiments revealed that both pyrochlores and hollandites can incorporate Tl and Pb via ionic exchange.
We want to perform XAS measurements at the L3 edge of Tl and Pb on exchanged samples of pyrochlores and hollandites to obtain information on the coordination environment of Tl and Pb within the tunnels of the crystal lattice of hollandites and pyrochlores. Specifically, we want to determine the incorporation mechanisms and the effect of the ionic exchanges on the local structure by means of EXAFS quantitative analysis of Tl and Pb.