A New Method of Dehydration for Pure Clay Materials using Peldri II

Jacek Wierzchoś, Carmen Ascaso, Maria Teresa Garcia-Gonzalez and Edmund Kozak
Centro de Ciencias Medioambientales, c/ Serrano 115 Dpdo., 28006 Madrid, Spain
Institute of Agrophysics, Polish Academy of Sciences, ul. Doświadczalna 4, 20236 Lublin, Poland

Abstract: A new chemical, Peldri II, is evaluated as a compound for drying soft clay materials. Peldri II, a fluorocarbon (1,1-difluorotetrachloroethane), is a solid at room temperature and is a liquid above 25°C. Clay gels are embedded in Peldri II by immersing them in the liquid and allowing it to solidify. Once solidified, Peldri II will sublime, with or without vacuum, to a dry specimen, probably without introducing surface tension. Wyoming montmorillonite saturated in 10$#x02212;3 M NaCl and 1 M CaCl2 solutions has been examined to compare preservation of its initial structure after Peldri II, critical point, and freeze drying techniques. Transmission electron microscopy of ultrathin sections, scanning electron microscopy, and mercury intrusion porosimetry techniques were used. No differences were detected between Peldri II and critical point drying methods. Peldri II appears to be a significant improvement as an alternative drying agent for clay materials in studies of their structural properties. It is also very convenient for drying large numbers of samples.

Key Words: Critical point drying • Freeze drying • Mercury porosimetry • Montmorillonite • Peldri II • SEM • TEM

Clays and Clay Minerals; April 1992 v. 40; no. 2; p. 230-236; DOI: 10.1346/CCMN.1992.0400212
© 1992, The Clay Minerals Society
Clay Minerals Society (www.clays.org)