Adsorption Mechanisms of Cadmium onto Pillared Clays and Chalcogenides

Interactions between Cd, pillared clays and chalcogenedies have been studied using nanomineralogical experiments. XRD, DSC and chemical analysis. The synchrotron-based X-ray absorption spectroscopy (XAS) was applied to characterize the reaction phases. The mean bond lengths between, Cd-S, Fe-S, Sb-S, Cd-Cd (in chalcogenedies), Al-Cd, Cd-Ti, and Fe-Cd, (in pillared clays) were determined by XAS method. The ligands information around cadmium atoms was obtained directly from EXAFS and indirect from XANES experiments. Cadmium bearing phases and diffusion of Cd in phases were distinguished by HRXRD, SEM and EPMA. The XAS analysis showed that cadmium sorbed onto pillared clays through a distinct mechanism. These data indicated that the major adsorbent of Cd is a complex of Al, Ti and Fe pillared clays.