Effect of Pressure on the Sorption of Yb by Montmorillonite

Steven E. Miller1, G. Ross Heath2 and Richard D. Gonzalez1
1 Department of Chemistry, University of Rhode Island, Kingston, Rhode Island 02881
2 School of Oceanography, Oregon State University, Corvallis, Oregon 97331

Abstract: X-ray diffraction, infrared, and cation-exchange capacity measurements of the reaction products of montmorillonites with YbCl3·6H2O show that at 1 atm irreversible sorption of Yb3+ increases with increasing temperature in the range 20° to 280°C, whereas at 110atm it decreases with increasing temperature. Above 100°C, less irreversible sorption occurs at 110 atm than at 1 atm. The decreased sorption at high pressure is attributed to reduced cation hydrolytic fixation and to rapid expulsion of interlayer Yb3+ by interlayer water at higher temperatures, with a concomitant decrease in Yb3+ migration to octahedral sites. At 110 atm, 160° and 200°C treatments cause changes in infrared absorption bands (884 cm−1, 848 cm−1) suggesting that sorbed Yb3+ is charge compensated by the deprotonation of Fe3+- and Mg2+-hydroxyl groups. At 290°C deprotonation is restricted to Fe3+-hydroxyl groups.

Key Words: Cation fixation • Deprotonation • Infrared spectroscopy • Lanthanides • Ytterbium

Clays and Clay Minerals; February 1983 v. 31; no. 1; p. 17-21; DOI: 10.1346/CCMN.1983.0310103
© 1983, The Clay Minerals Society
Clay Minerals Society (www.clays.org)