title: Synthesis of a novel layered double hydroxides [MgAl(4)(OH)(12)](Cl)(2)·2.4H(2)O and its anion-exchange properties.
abstract: A novel layered double hydroxide of Mg and Al with composition [Mg(0.96)Al(4.00)(OH)(12)]Cl(1.86)(CO(3))(0.03)·2.4H(2)O, designated as MgAl(4)-Cl, was synthesized by mixing crystalline gibbsite (γ-Al(OH)(3)) and solid MgCl(2)·6H(2)O with subsequent hydrothermal treatment at 160 °C for 72h. The MgAl(4)-Cl exhibited a crystalline material of a layered structure, as evidenced from X-ray diffraction. Anion uptake experiments with the MgAl(4)-Cl showed that Cl(-) in the interlayer space can be exchanged with anions such as Br(-), H(2)PO(4)(-), CO(3)(2-) or dodecyl sulfate (DS(-)) from aqueous solutions with preservation of the layered structure. Uptake of NO(3)(-), BrO(3)(-) or SO(4)(2-) on the MgAl(4)-Cl showed different behavior; these anions can be exchanged within 1h maintaining the layered structure, but a release of Mg(2+) cations from the sample was observed with increased reaction time, resulting in collapse of the layered structure and formation of the gibbsite phase, as determined from chemical analyses and X-ray diffraction.
authors.affiliation: Health Research Institute, National Institute of Advanced Industrial Science and Technology, 2217-14 Hayashi-cho, Takamatsu 761-0395, Japan. chitrakar-ramesh@aist.go.jp
authors.forename: Ramesh
authors.initials: R
authors.lastname: Chitrakar
authors.forename: Yoji
authors.initials: Y
authors.lastname: Makita
authors.forename: Akinari
authors.initials: A
authors.lastname: Sonoda
authors.forename: Takahiro
authors.initials: T
authors.lastname: Hirotsu
mesh_terms: D000837:Anion Exchange Resins; D018360:Crystallography, X-Ray; D006878:Hydroxides / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning
chemical_list: D000837:Anion Exchange Resins; D006878:Hydroxides