Methylene Blue Absorption by Clay Minerals. Determination of Surface Areas and Cation Exchange Capacities (Clay-Organic Studies XVIII)

Pham Thi Hang and G. W. Brindley
Department of Geochemistry and Mineralogy, The Pennsylvania State University, University Park, Pa. 16802
Materials Research Laboratory, The Pennsylvania State University, University Park, Pa. 16802

Abstract: Under appropriate conditions, both surface areas and cation exchange capacities of clay minerals can be measured by absorption of methylene blue from aqueous solutions. The method has been applied to two kaolinites, one illite, and one montmorillonite, all initially saturated with Na+ ions. For Na-montmorillonite, the total area, internal plus external, is measured. For Ca-montmorillonite, entry of methylene blue molecules appears to be restricted by the much smaller expansion of the Ca- clay in water. X-ray diffraction data clarify the absorption behavior in Na- and Ca-montmorillonite, and in particular it is shown that two orientations of the methylene blue molecules are involved.

Clays and Clay Minerals; November 1970 v. 18; no. 4; p. 203-212; DOI: 10.1346/CCMN.1970.0180404
© 1970, The Clay Minerals Society
Clay Minerals Society (www.clays.org)