Comparison of Techniques for Determining the Fractal Dimensions of Clay Minerals

Malekani, Kalumbu; Rice, James A.; Lin, J. S.

doi:10.1346/ccmn.1996.0440511

Cited by 41 publications

(35 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The smooth nature of the Georgia kaolinite surface is further supported by the work of Malekani et al (1996) who determined that the fractal dimension of highly crystallized Georgia kaolinite was --2.0, indicating a flat or smooth surface. Sokolowska et al (1989) have also reported a fractal dimension of 2.12 for particles of Georgia kaolinite.…”

Section: R E S U L T S a N D Discussionmentioning

confidence: 73%

Nanomorphology of Kaolinites: Comparative SEM and AFM Studies

Zbik

1998

Clays and clay miner.

111

View full text Add to dashboard Cite

Abstraet--Nanomorphological structure of well-crystallized Georgia and poorly crystallized North Queensland kaolinite particles have been compared using field emission scanning electron microscopy (SEM) and atomic force microscopy (AFM). In general, there is good agreement in information from the 2 very different imaging techniques. AFM gives more detailed information on step and ledge dimensions, microvalleys and crystallographic orientation of irregularities on basal planes and edges of the crystallites. There are major differences in nanomorphology and surface structure between the 2 kaolin samples with the Georgia kaolin showing 200-500-nm, relatively flat basal planes with some cascade-like step growth 50-100 nm wide. The edges, apparently fiat and right-angled in SEM images, appear beveled in AFM images due to artifacts from the aspect ratio of the AFM tip. The North Queensland kaolinite has much more complex surface structure with anhedrai crystallites attached to larger particles, high density of steps and nm-scale irregularities (often crystallographically directed). The additional step edge site contribution from the attached crystallites is estimated as a minimum of 6%, giving a total edge contribution above 30% of the kaolinite total surface area. These structures will generate a substantial pH-dependent charge across the surfaces of the North Queensland kaolinite platelets. An idealized, uniform, pH-independent, negatively charged basal plane cannot be assumed from these structures. There is also some evidence, from both SEM and AFM images, of curvature in the thinner, poorly ordered structures of the North Queensland kaolinite particles.

show abstract

Section: R E S U L T S a N D Discussionmentioning

confidence: 73%

Nanomorphology of Kaolinites: Comparative SEM and AFM Studies

Zbik

1998

Clays and clay miner.

111

View full text Add to dashboard Cite

show abstract

“…Important questions connected with clay dispersions have been those of size/shape of individual particles and their aggregates [5], influence of salt and temperature [6] or concentration [7] on the ability of clay suspensions to form gel-like structures and granules, and the dynamics of layered silicate crystallization [8]. For the solid-like clay structures, studies have been made on the intercalation of metal ions within the interlayers of clay platelets [9], on the heterogeneity of stacks of platelets in the dehydrated state [10], and on the variation in surface fractal dimension between different natural clays [11]. Compared to X-rays, neutrons have the advantage that SANS data may reflect more accurately the dimensionality of matrix-pore interfaces [12].…”

Section: Introductionmentioning

confidence: 99%

Small-angle neutron scattering from a nano-layered synthetic silicate

Knudsen

Fossum

Helgesen

et al. 2004

Physica B: Condensed Matter

View full text Add to dashboard Cite

“…In particular, scanning electron microscopy (SEM) has been largely used to observe natural soil aggregates (Remley and Bradford, 1989;Sullivan, 1990;Robertson and Eggleton, 1991;Watanabe et al, 1992;Boer and Crosby, 1995;Jeong, 1998;Harris and Hollien, 2000;Laird, 2001) and also applied to inorganic soil components and their associations. Malekani et al (1996) used this technique in a study of the fractal dimension of clay minerals. Associations of aluminium -iron species with silica particles (Taylor et al, 1990) and with clay minerals (Sakurai et al, 1990) and complexes of copper ions and iron-oxidecoated sand (Lai et al, 2000) have also been described by SEM.…”

Section: Introductionmentioning

confidence: 99%

Characterization of model soil colloids by cryo-scanning electron microscopy

et al. 2004

View full text Add to dashboard Cite

The cryo-scanning electron microscopy (cryo-SEM) consists of the SEM examination of samples whose microstructure has been fixed by plunge-freezing into a liquid with a high thermal conductivity, such as nitrogen slush. The advantage of this cryopreparation method is that it can transform the interstitial water of the samples into ice whose crystalline domain dimensions (a few nm to a few tens of nanometers) do not exceed those of the finest details that can be observed, and thus do not modify sample morphology at the observation scale. Cryo-SEM was applied to the study of wet-state model soil colloids: a soil humic acid, a commercial smectite, a synthetic ferrihydrite and their binary and ternary associations. The cryo-SEM images have given the following information: The smectite suspension behaved as a non-oriented network, the ferrihydrite suspension was formed from particles of various shapes and dimensions, and the humic acid exhibited a sponge-like structure. The micromorphology of the ferrihydrite -humic acid association was close to that of pure ferrihydrite, while the smectite-containing associations recalled the basic network of the smectite. The comparison of the images obtained by cryo-SEM, and by conventional SEM performed on the same samples after they had been freeze-dried, points out the morphologic modifications deriving from the conventional drying process. Besides SEM investigation, the soil colloids have been characterized by X-ray diffractometry, FTIR spectroscopy, elementary analysis and surface area determination. D

show abstract

Comparison of Techniques for Determining the Fractal Dimensions of Clay Minerals

Cited by 41 publications

References 27 publications

Nanomorphology of Kaolinites: Comparative SEM and AFM Studies

Nanomorphology of Kaolinites: Comparative SEM and AFM Studies

Small-angle neutron scattering from a nano-layered synthetic silicate

Characterization of model soil colloids by cryo-scanning electron microscopy

Contact Info

Product

Resources

About