CHARACTERIZING
CLA Y MINERAL SUSPENSIONS USING ACOUSTIC AND ELECTROACOUSTIC SPECTROSCOPY
- A REVIEW
MARIANNE
GUERIN AND JOHN C. SEAMAN
The University of Georgia, Savannah River Ecology Laboratory, Savannah
River Site, Aiken, South Carolina 29802, USA
Abstract-
Recently, significant advances have been made in the theory and application
of acoustic and electroacoustic spectroscopies for measuring the particle-size
distribution (PSD) and zeta potential (~ potential) of colloidal suspensions,
respectively. These techniques extend or replace other techniques, such
as light-scattering methods, particularly in concentrated suspensions.
In this review, we summarize acoustic and electroacoustic theory and published
results on clay mineral suspensions, detail theoretical constraints, and
indicate potential applications for the study of environmentally significant
clay mineral suspensions. Using commercially available instrumentation
and suspensiol1 concentrations up to 45 vol. %, acoustic spectroscopy
can characterize particle sizes from 10 nm to 10 I.1m, or greater. Electroacoustic
spectroscopy can determine the ~ potential of a suspension with a precision
and accuracy in the m V range. Despite the clear potential for their use
in environmental settings, to date, acoustic methods have been used mainly
on clay mineral colloids with industrial application, typically combined
with similar measurements such as isoelectric point (IEP) determined from
shear yield stress or ~ potential from electrophoretic mobility measurements.
Potential applications in environmentally relevant suspension concentrations
are significant, as PSD and ~ potential are important factors influencing
the transport of mineral colloids and associated contaminants through
porous media. Applications include determining the effects of suspension
concentration, surfactants, electrolyte strength, pH and solution composition
on soil clay properties and colloidal interactions, and determining changes
in PSD, aggregation and ~ potential due to adsorption or variations in
the clay mineralogy.
Key Words-Acoustics, Aggregation, Electroacoustics, Electrokinetics,
Particle-size Distribution, PSD, Zeta Potential.
SREL Reprint #2734
Guerin, M. and J. C. Seaman. 2004. Characterizing clay mineral suspensions using acoustic and electroacoustic spectroscopy - A review. Clays and Clay Minerals 52:145-157.
