WATER-STRUCTURE FOR SUSPENSIONS OF SAPONITE IN BINARY AQUEOUS MIXTURES AS PROBED BY NMR

The structure at the liquid/solid interface of a lithiated saponite is monitored by NMR methods, For clay suspensions in water/methanol mixtures, the two components at the clay interface are correlated: the liquid structure is enhanced until alcohol molar ratios of ca. 0.1. With acetone as a cosolvent, water and acetone molecules behave independently, As the ketone content increases, acetone molecules penetrate more extensively into the interfacial region, solvating exchangeable lithium ions; water molecules at the clay surface are not significantly affected, A similar behavior is observed with acetonitrile as a cosolvent. (C) 1995 Academic Press, Inc.