Anion exchange in layered double hydroxides by surfactant salt formation

Abstract

In this paper a method of anion exchange in layered double hydroxides (LDHs) based on the formation of a salt between an anionic and a cationic surfactant, which is extracted from aqueous solution into an organic unmixed phase, is discussed. Two Zn(II)–Cr(III) LDHs, synthesised by direct coprecipitation under constant pH intercalated with dodecylsulfate (DS) and dodecylbenzenesulfonate (DBS), were used as starting materials (precursors). By this method various inorganic and organic anions can be intercalated by exchange with the surfactant anion in the interlamellar domain, resulting in new intercalated materials. The kinetics of such exchange and the possibility of controlled partial exchange are also discussed.