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

摘要

The ability to characterize the diffusion of water and ions through soils and clays is a fundamental components in understanding the environmental processes and fate of pollutants. This note demonstrates that important physicochemical 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 tow 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.