Preparation of Mg-Al layered double hydroxide intercalated with Coomassie Brilliant Blue R anion and its uptake of aromatic compounds from aqueous solutions.

The objective of this study is to evaluate the capacity of Mg-Al layered double hydroxide (Mg-Al LDH) intercalated with organic dye to adsorb aromatic compounds in aqueous solutions. Mg-Al LDH intercalated with Coomassie Brilliant Blue R anion (BB(-)) was prepared by coprecipitation. The BB(-)-intercalated Mg-Al LDH was able to adsorb aromatic compounds from an aqueous solution, despite the electron density in the benzene ring of the aromatics. This uptake is caused by π-π stacking interactions, either between the electron-rich benzene rings of intercalated BB(-) and the benzene rings of aromatics with a low electron density or between the electron-poor benzene rings of intercalated BB(-) and the benzene rings of the aromatics with a high electron density.