Synthesis and Characterization of Zn/Al Layered Double-Hydroxides with Interlayer Naphthalene Derivatives.

Abstract

Naphthalene-2, 6-, -1, 5- and -2, 7-disulfonates (abbreviated as N26DS, N15DS and N27DS, respectively, and collectively abbreviated as NijDS) are intercalated individually in the interlayer region of Zn and Al layered double-hydroxides (Zn/Al-LDH). The intercalated products are prepared by means of mixing one of the organic isomers and 500°C-calcined carbonateintercalated Zn/Al-LDH under weak alkaline conditions. When N26DS or N15DS is used as an intercalated guest, two solid phases with basal spacings, 15 Å and 17 Å, abbreviated as 15 Å and 17 Å phases, respectively, are observed in powder X-ray diffraction (XRD) patterns. In contrast, only the 17 Å phase appears when N27DS is intercalated. The different basal spacings result from alternative orientations of NijDS (ij = 26 and 15) in the interlayer. The 15 Å phase appears exclusively in XRD patterns although the 17 Å phase is produced together with a by-product. NijDS (if =15 and 26) is more closely packed in the interlayer of the latter phase. The solid state chemistry has been investigated by using UV-visible diffuse reflection (DR) spectroscopy, differential thermal analysis/thermogravimetry (DTA/TG) and X-ray photoelectron spectroscopy (XPS).