Incorporation with Possible Regular Arrangement of Silver Ion in Interlayer Region of Mg/Al Layered Double Hydroxide with Interlayer Thiosulfate Ion
Eiji KANEZAKI* and Kazuki MAEDA
Department of Chemical Sciences and Technology, Faculty of Engineering, The University of Tokushima; 2-1 Minamijosanjima, Tokushima-shi 770-8506 Japan
We have incorporated Ag+ ions in the interlayer region of Mg/Al layered double hydroxide (Mg/Al-LDH) by means of a two-step procedure; thiosulfate was intercalated between layers of Mg/Al-LDH by coprecipitation thus producing a precursor LDH at first, then Ag+ ions were reacted with the precursor in an aqueous solution. FT-IR spectra of the Ag+-incorporated Mg/Al-LDH (Ag+-LDH) indicated that the interlayer metal cation was coordinated by two sulfur atoms of the interlayer thiosulfate thus forming a linear complex. In the DTA curve of the Ag+-LDH, several endo/exothermal peaks, which were observed in the curve of the precursor LDH, were also observed whereas some of these peaks were shifted from the locations in the latter DTA curve. The profile of the TG curves of the Ag+-LDH corresponded to the chemical formulae of the solids. In the powder X-Ray diffraction (PXRD) patterns of the precursor LDH and the Ag+-LDH, well developed (00l) lines are commonly observed, which indicates the stacking regularity of layers along the c-axis. The intensity of (002) relative to that of (001) increased apparently with the increase of the silver content in the LDH. Increment of the diffraction intensity could result from a new crystal lattice including Ag+ ions with the basal spacing as much as a half of the original one.