Syntheses of nanocrystalline Mg-Al-LDHs and PO4 3-, P2O7 4- anion-pillared layered double hydroxides under the conditions of microwave

Nanocrystalline [Mg-Al-CO3] layered double hydroxides were prepared by using microwave irradiation and varied rate of dripping alkali. Then [Mg-Al-PO4] and [Mg-Al-P2O7] layered double hydroxides were successfully synthesized by the direct reaction of free PO4 3- and P2O7 4- with [Mg-Al-CO3] layered double hydroxides precursor using microwave technique and the anion-intercalation method. By using this method [Mg-Al-CO3] layered double hydroxides with a particle size of about 10 nm to 40 nm were produced. The effect of microwave and the rate of dripping alkali on [Mg-Al-CO3] layered double hydroxides was discussed. And the samples thus obtained were characterized by FT-IR, TEM and XRD. The results show that the initial interlayer carbonate ions can be completely replaced by PO4 3-and P2O7 4- under the controlled microwave conditions employed in a short time.