SREL Reprint #2220

Goethite morphologies investigated via X-ray diffraction of oriented samples

Robert G. Ford, Paul M. Bertsch, and John C. Seaman

University of Georgia, Advanced Analytical Center for Environmental Sciences,
Savannah River Ecology Laboratory, Aiken, South Carolina 29802

Introduction: Synthetic and natural goethites display a variety of particle morphologies that are dependent on solution conditions during formation (Schwertmann 1990). Factors influencing goethite morphology include pH and the presence or absence of specifically adsorbing ions in solution. Particle morphology can affect goethite dissolution behavior and will govern the distribution of coordination sites available on the particle surface (Comell et al. 1974; Colombo et al. 1994). Morphological information can be obtained via electron microscopic imaging (Schulze and Schwertmann 1984) or profile analysis of X-ray diffraction (XRD) patterns (Koch et al. 1986). These methods are essential for determination of absolute particle dimensions, but they may require a significant time commitment or advanced level of analysis. In order to facilitate rapid preliminary comparison of synthetic goethite samples, we have investigated the use of powder XRD to derive similar qualitative information via the influence of preferred orientation during sample preparation.

Keywords: Goethite, Oriented Film, Particle Morphology, Powder X-ray Diffraction, XRD

SREL Reprint #2220

Ford, R. G., P. M. Bertsch, and J. C. Seaman. 1997. Goethite morphologies investigated via X-ray diffraction of oriented samples. Clays and Clay Minerals 45:769-772.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).