Study of the properties of intercalation and grafting of phosphonate ions in layered double hydroxides

Layered double hydroxides (ldhs) have been investigated for many years as host materials for a range of anion exchange and intercalation reactions. the ion exchange of phosphonate ion in zn-al-chloride layered double hydroxides was investigated. the chloride precursors prepared by coprecipitation at ph 9 preserved their lamellar structure following ion exchange. it was found that the aging time is important in controlling the crystallization of the phosphonate-exchanged compounds. the best phase,in terms of crystallinity,was obtained for an aging time of 3 h at 25°c in 0.01 m phosphonate solution. the grafting of the anion onto the hydroxylated sheets by moderate thermal treatment was confirmed by a combination of several techniques,including powder x-ray diffraction (xrd) and infrared (ir) spectroscopy.