Concentration-Dependent Adsorption of CsI at the Muscovite-Electrolyte Interface.

The interfacial structure of muscovite in contact with aqueous CsI solutions was measured using surface X-ray diffraction for several CsI concentrations (2-1000 mM). At CsI concentrations up to 200 mM, Cs adsorption is likely hindered by HO, as both cations compete for the adsorption site above the muscovite hexagonal cavity. Above this concentration, more Cs adsorbs than is required to compensate the negatively charged muscovite surface, which means that coadsorption of an anion takes place. The I anion does not coadsorb in an ordered manner. Moreover, the hydration ring and water layers do not change significantly as a function of the CsI concentration.