SYNTHESIS OF LI/AL LAYERED DOUBLE HYDROXIDE-GUEST COMPOSITES UNDER MILD ACID CONDITIONS

Abstract

Layered double hydroxides (LDHs) are known as ‘anionic clays’. They comprise a class of material with positively charged octahedral double hydroxyl layers and exchangeable anions. The Li/Al LDH term includes a group of LDHs with Li/Al octahedral double hydroxyl layers. We have demoastrated a modifed method, using Li/Al LDH-OH (OH- as interlayer anions) as the starting material, for preparing Li/Al LDH-A (X represents interlayer anions, including dioctyl sulphosuccinate (DOSS), dodecyl sulphate (DDS), mercaptoacetate (MA), EDTA, Tiron and dichromate) under mild acid conditions (pH in the range 4 to 5). However, in the case of acid- sensitive anions, Fe(CN)6-4, Li/Al LDH-Fe(CN)6-4 can be prepared by a two-step procedure using Li/Al LDH-DOSS or similar compounds as intermediates to react with acid-sensitive anions under mild alkaline conditions (pH ≈ 9).