Surface area of vermiculite with nitrogen and carbon dioxide as adsorbates

Clays and Clay Minerals
By:  and 



Surface-area studies were made on several homoionic vermiculites with both nitrogen and carbon dioxide as adsorbates. These studies show that only very slight penetration occurs between individual vermiculite platelets. This is in contrast to an earlier investigation of montmorillonite where it was found that the degree of penetration between layers is quite high, particularly for carbon dioxide, and is governed by the size and charge of the interlayer cation. The inability of these adsorbates to penetrate substantially between vermiculite platelets is due primarily to this mineral's high surface-charge density.

The extent of penetration of nitrogen and carbon dioxide at the edges of vermiculite platelets, though slight, is influenced by the coordinated water retained within the sample at a given degassing temperature. Forces between layers are weakened with increasing water content, which permits slightly greater penetration by adsorbate gases. Thus, the surface area of vermiculite, as determined by gas adsorption, is larger than the calculated external surface area based upon particle size and shape considerations. In addition, "extra" surface is provided by the lifting and scrolling of terminal platelets. These morphological features are shown in scanning electron micrographs of a naturally occuring vermiculite.

Publication type Article
Publication Subtype Journal Article
Title Surface area of vermiculite with nitrogen and carbon dioxide as adsorbates
Series title Clays and Clay Minerals
DOI 10.1346/CCMN.1969.0170403
Volume 17
Issue 4
Year Published 1969
Language English
Publisher The Clay Minerals Society
Description 5 p.
First page 205
Last page 209
Google Analytic Metrics Metrics page
Additional publication details