Supported clay membrane: A new way to characterize water and ion transport in clays

Abstract

The ability to characterize the diffusion of water and ions through soils and clays is a fundamental component in understanding the environmental processes and fate of pollutants. This note demonstrates that important physico-chemical aspects of these processes could be investigated using a very simple experimental system, based on a clay layer immobilized between two porous nitrocellulose filters. The properties of this three-layer membrane, separating two aqueous solutions, were characterized by membrane electrical conductivity and trans-membrane potential. Results revealed that the transport of aqueous salt solutions is characterized by at least two kinetic phases, fast and slow, both of which follow reversible first-order kinetics and in this aspect are similar to the results of batch or column experiments. © 2001 Elsevier Science Ltd.