In situ space- and time-resolved sorption kinetics of anionic dyes on individual LDH crystals.

Fluorescence spectroscopy is employed to follow the ion exchange of an emissive dye--a carboxylated perylene imide--on a layered double hydroxide. The exchange of the carboxylate ions starts at the edges of the layered double hydroxide crystals and is followed by diffusion to the basal plane. Such space-resolved observations provide a solid basis for modelling and studying the mechanisms of exchange.