Mary Frances Traynor1, M. M. Mortland1, T. J. Pinnavaia1
1Departments of Crop and Soil Science and Chemistry, Michigan State University, East Lansing, Michigan, 48823, USA
Tóm tắt
AbstractThe binding of tris-bipyridyl metal complexes of the type M(bp)32+ (M = Fe2+, Cu2+, Ru2+) to hectorite surfaces is shown to occur by two mechanisms. (1) replacement of Na+ ions in the native mineral by cation exchange up to its cation exchange capacity and (2) intersalation of excess salt beyond the exchange capacity. In the cation exchange mechanism, the binding of metal complex is strongly favored over Na+. The intersalation reactions are dependent on the nature of the counter-anion: SO42-, Br- > CIO4−, Cl−. The homoionic M(bp)32+-hectorites, which exhibit rational 18 Å X-ray reflections, have been characterized with regard to their BET surface areas, water adsorption isotherms, types of water present, selected reactions in the intercalated state, and orientation of the complex ions in the interlayer regions. Mixed Fe(bp)32+, Na+-hectorites have also been examined and the results suggest segregation of the two ions between interlayers or within interlayers. Solid state intersalated phases have been isolated with 18 Å and 29.5 Å spacings. In general, surface areas of the intersalated phases are low, but the 18 Å phase derived from [Fe(bp)3]SO4 adsorption shows a high surface area, which even exceeds the surface area of homoionic Fe(bp)32+-hectorite.
