Anion-Exchange Properties of Hydrotalcite-Like Compounds

Shigeo Miyata
Kyowa Chemical Industry Co., Ltd., 305 Yashimanishi-machi Takamatsu, Kagawa, 761-01, Japan

Abstract: Ion-exchange isotherms between hydrotalcite-like compounds (HT) of the NO3-, Cl-, and SO4- forms and F, Cl Br, I, OH, SO42−, CO32−, and Naphthol Yellow S (NYS2−) ions were determined, and the spacing and the width of the 003 reflection were measured as a function of HT composition. The ion-exchange equilibrium constant for HTs of monovalent anions are in the sequence OH > F > Cl > Br > NO3 > I, those for divalent anions are in the sequence CO32− > NYS2− > SO42−. The ion-exchange equilibrium constants tend to increase as the diameters of the anions decrease, and the crystallite size in the 001 direction tends to increase with anions having higher selectivity. The OH-form of HT has the smallest basal spacing and the largest crystallite size in the 001 direction.

Key Words: Anion exchange • Anion selectivity • Crystallite size • Hydrotalcite • Naphthol Yellow S • X-ray powder diffraction

Clays and Clay Minerals; August 1983 v. 31; no. 4; p. 305-311; DOI: 10.1346/CCMN.1983.0310409
© 1983, The Clay Minerals Society
Clay Minerals Society (www.clays.org)