Synthesis of layered zinc hydroxide chlorides in the presence of Al(III)

Zinc hydroxide chloride particles were synthesized by hydrolysis of ZnCl2 solutions dissolving AlCl3 at different atomic Al/Zn ratios from 0 to 1.0 and characterized by various techniques. Increasing Al/Zn ratio changed the crystal phases of the products as ZnO -> ZnO + ZHC (Zn-5(OH)(8)Cl-2 (.) H2O) -> ZHC -> LDH (layered double hydroxides, Zn-Al-Cl) and the particle morphology as agglomerates (ZnO) -> fine particles (ZnO) plates (ZHC)+ rods (ZnO)-> plates (ZHC)-> plates (LDH). The atomic Cl/Zn ratios of LDH particles of formed at Al/Zn >= 0.3 were ca. 0.3 despite the increase of Al/Zn ratio, being due to the intercalation of CO32- into the LDH crystal. The OH- content of LDH estimated by TG was reduced by the deprotonation of OH- to Counteract the excess positive charge produced by replacing Zn(II) with Al(III). ZHC exhibited a high adsorption selectivity of H2O. (c) 2006 Elsevier Inc. All rights reserved.